Gimme Your Lunch Money!: Feeding Behaviors in Hummingbirds

Ubatuba, São Paulo, Brazil; 9 October 2014 © Almir Cândido de Almeida

I just put out my hummingbird feeder this season. It didn’t take those little guys long to find it either. Now I’ve got their cute little bodies whizzing about all over the place. They need Yackety Sax to play as their soundtrack. But it got me to thinking about hummingbirds and to looking through recent papers for a good study. I came across one in Zoologia about the feeding behavior of hummingbirds in artificial food patches. Perfect.

First, a little background on hummingbirds. They belong to the family Trochilidae and are closely related to swifts. Males are typically more colorful that females, having highly reflective feathers on their chest and heads. Perhaps these birds are best known for their unique flying. They are able to produce power with both the down- and up-beat of their wing flap, getting 75 percent of their lift from their wings’ downstroke and the remaining 25 percent from the upstroke. This allows for both increased agility and sustained hovering ability. They are the only birds that truly hover and fly backwards. They also move those wings really fast: 60 times per second! So it is little wonder that they have among the highest metabolic rate among vertebrate animals.

Hummingbirds are specialized and consume predominately nectar. To collect enough nectar to maintain that high metabolism, they forage many flowers each day. But not all flowers are created equally. Their sugar concentration can vary between 20-25 percent. In order to get the most sugar-bang for their hover-buck, hummingbirds must select and protect the richest food patches in their area. Three behavioral strategies have been observed for foraging:

1) Dominance/territoriality – a bird will defend its flowers
2) Intruder/subordinance – a bird sneaks into other patches until it is kicked out
3) Trapline foraging – repeatedly visiting a set of plants in different patches without being territorial.

Often, a bird will perch near a good food source and let others know that it is theirs. But defending a territory can be up to three times more energetically expensive, so those flowers need to be really good.

The researchers conducted their study in Itacolomi State Park in the city of Ouro Preto, Minas Gerais, southwestern Brazil, in the Atlantic forest remnant. They created four artificial food patches, each patch containing a single sugar-water solution concentration of 5, 15, 25, or 35 percent. They observed the birds (using binoculars) for 3 hour stretches in the early mornings and late afternoon, recording all behaviors during that time. They looked at the time spent in each food patch and the behaviors of the birds (feeding, alert, vocalizing, expelling, fighting, frightening, expel attempt) in each patch. In this way, they could identify the birds’ strategies.

They found that the most-visited feeders were those containing the highest concentration of sugar. Five of the seven species observed fed more on the 25-35 percent sucrose feeders. But there was a difference in the frequency of visitations for different species. The Brazilian ruby (Clytolaema rubricauda, pictured above), Scale-throated hermit (Phaethornis eurynome), and Phaethornis spp. visited the 35 percent feeder more often. And the Brazilian ruby won most of the aggressive encounters with other hummingbirds, both total and in individual patches. This species often stood alert and fought more often, and even “stood impassive” when faced down by the Violet-capped woodnymph (Thalurania glaucopis). I wonder if they looked down their long little beaks at the other birds with a f*ck off attitude? What a badass...hmm, or a bully. The Violet-capped woodnymph visited the 25 percent patch more often, the White-throated hummingbird (Leucochloris albicollis) and Versicoloured emerald (Amazilia versicolor) visited the 15 percent patch more often, and the Glittering-bellied emerald (Chlorostilbon lucidus) was the one that less frequently visited the food patches. Interestingly, the Phaetornithinae applied a hide-and-wait strategy, where they would be chased away by the territorial bird only to hide in the shrubs, remain quiet, and return to the feeder after the dominant bird left the area. Sneaky sneaky. The time spent feeding was found to be correlated with aggressive behaviors and also with body size. Big birds, big appetites, big aggression. The subordinate species chose resources depending on the presence or absence of the dominant species, preferring patches that were not guarded. This may be why they were seen in lower concentration sugar patches more often.

Those itty bitty birds can pack some serious aggression. I guess it isn’t really surprising after seeing all of the chasing that goes on around my feeder. Yackety Sax remains appropriate.

Lanna, L., de Azevedo, C., Claudino, R., Oliveira, R., & Antonini, Y. (2017). Feeding behavior by hummingbirds (Aves: Trochilidae) in artificial food patches in an Atlantic Forest remnant in southeastern Brazil Zoologia, 34, 1-9 DOI: 10.3897/zoologia.34.e13228


If you would like to put out your own hummingbird feeder, I recommend this kind because it is simple, inexpensive and does a great job.

The important part is the big red flowers with yellow centers. Hummingbirds really hone in on those color ques. Do NOT use honey in your feeder! And forget the red dye, if your feeder has red color on it then that is plenty to attract the hummingbirds.

Here is a nice and simple recipe to make your own hummingbird food:

¼ cup granulated sugar
2 cups water

Mix the ingredients in a small saucepan. Bring to a boil. Boil for a few minutes or until all of the sugar is dissolved. Let cool to room temperature. Whatever doesn’t fit in the feeder can be stored in the refrigerator.

Increase the recipe as needed, it's a 1:4 ratio of sugar:water

Change the solution in the feeder every 3 days, sooner if it is really hot outside. Make sure to rinse the feeder each time it is refilled. Scrub away any growths (fungi, etc.) as needed.


Brazilian Ruby picture via The Cornell Lab of Ornithology
Feeder image via World of Hummingbirds

Flyfocals: Vision and Vectors Help Hunting Robber Flies

Image credit: Thomas Shahan

Robber flies (Asilidae family) are not your typical house flies. They are small, predatory insects that feed on a vast array of other arthropods. While they are small in size (10 times smaller than a dragonfly), these guys are serious hunters. For example, Mallophora omboides is known as the “Florida bee killer” for its taste for honey bees. Other robber flies hunt down wasps, dragonflies, spiders, or grasshoppers, just to name a few. Perhaps almost as impressive as the types of prey is how they are subdued. Typically, robber flies will perch out in an open sunny place and wait, seizing their prey in flight and injecting it with neurotoxic or proteolytic enzymes that both immobilizes it and liquefies its insides.

A recent study in Current Biology took a closer look at the robber fly’s “aerial attack strategy.” The authors focused on the genus Holcocephala, a group native to the Americas. Let’s start by going over something you know about but probably never realized had an actual term: constant bearing angle (CBA) strategy. Initially, I tried to describe this just using text, but it is really best visualized with the help of a supplemental graphic from the paper.

Figure S1 from Wardill et al. (2017). Diagram showing how the constant bearing angle strategy (CBA) and proportional navigation can be used to intercept targets. It looks like an eye, but you are actually looking down on the "Human" and seeing the top of the head (black) and shoulders (white). 

Visualize this: You are walking along and ahead of you a ball is rolling along the ground from your left. But you decide that you want to get to the ball before it would intercept your path. If you want to catch the ball you can’t run straight for where you see it or it will have rolled past that spot before you get there. If you want to intercept that ball while it is still on your left, you will technically have to turn to backward, changing your “bearing angle.” You must anticipate where it will be and run in a straight line to that spot. This line is a “parallel range vector.” There are several of these vectors, depending on when you choose to change course.

The study considered whether the flies were using this CBA strategy to catch their prey. To do this, the researchers went out to a field and hung up a big white sheet as a backdrop for their high-speed video cameras. Next, they set up their “fly teaser,” a custom made plastic frame that housed a stepper motor and several pulleys to move taut fishing line. This allowed for precise, computer controlled movements of the beads they attached to the fishing line. When a robber fly perched on a blade of grass in their study area, they “teased” it with a bead (a.k.a. dummy prey item for the fly). They included several variations including bead size and direction. They recorded the fly with two synchronized cameras running at 1000 fps to get a 3D view of the attack. For each attack video, they analyzed the frame at which the flies started to take off and until it began a terminal deceleration on final approach of the target. Then: measure, measure, measure, math, math, math.

They found that the flies were fairly consistent with the CBA model. If they decelerated or reversed the bead during the attack, the robber flies compensated, actively keeping the range vectors parallel. One unexpected finding occurred in cases where the bead moved in front of the fly and it took off with a head-on collision course. They found that the fly still intercepted the bead while flying at a backward angle, meaning that the latter part of its trajectory was distinctly curved. When they took a closer look, the found the results to reflect a “lock-on” process “during which the fly has a new heading and the speed is fixed to a value slightly higher than that of the prey.” This lock-on strategy has not been described in any other flying animal. The flies were able to compensate for unexpected changes in the target’s velocity and uncertainties in the location, size, and speed of the target.

Adapted from paper's graphical abstract

This type of hunting relies very heavily on vision. So each robber fly was captured for later, high detailed analysis of the head and eyes. It is important to remember that insects have compound eyes. Repeating units (the ommatidia, which have hexagonal faces called facets) that make up the eyes function as separate receptors that, when put together, assemble view of the environment. The researchers measured several parts and angles within the eyes, and once again math, math, math. This revealed the ommatidia in the front, center portion of each eye (colored red in the picture) to be nearly double the size of those in other areas, have extended focal lengths and smaller receptors. This means that the flies can reduce diffraction, focus incident light, and optimize resolution in this area. This results in a frontal fovea, or area within the eye that provides greater visual acuity than the rest of the eye. Sort of like the embedded lens of bifocal glasses; while that is an incredibly simplified way to look at it, it tells you a lot about how the flies might strategize prey capture. Also, they could be judging distance using stereopsis. This is when they use both eyes in combination to depth and 3D structure. The authors sum things up nicely, so I'll leave it in their words: "[It is kind of amazing the] accurate performance that a miniature brain can achieve in highly demanding sensorimotor tasks."

Interested in more details? Here’s a video summary put together by the researchers:

Wardill, T., Fabian, S., Pettigrew, A., Stavenga, D., Nordström, K., & Gonzalez-Bellido, P. (2017). A Novel Interception Strategy in a Miniature Robber Fly with Extreme Visual Acuity Current Biology, 27 (6), 854-859 DOI: 10.1016/j.cub.2017.01.050


Read more about robber flies at University of Florida's Featured Creatures page.

Where Are My Chocolates?: The Role of Gift Giving on Valentine's Day

I think that the day after Valentine’s Day is actually the best. After all, chocolate is 50 percent off. However, using the holiday as an excuse to delve into the myriad of studies that attempt to explain the complexity of human attraction and relationships is pretty fun. Last year I examined moves, specifically some fly dance moves and rather cheesy pick-up lines. Today, I think I’ll explore gift giving.

In the field of animal behavior, gift giving (or nuptial gifts) is practically its own subdiscipline, particularly in insects. These gifts are typically food items (but sometimes are inedible tokens) presented from the male to the female during courtship. They may be to show the female that he is worth her time, show how healthy the he is, how good a provider he can be, or simply to keep her distracted from eating him during the actual mating (except in those cases of specialized body parts or “suicidal food transfers”…now that is the ultimate sacrifice for your bae!). The gift giving behavior, especially if it involves an extreme sacrifice on the part of the male, can only arise if the giver has some net fitness benefit. He must be able to increase his paternity share (particularly in polyandrous mating systems) and/or boost the female’s fecundity, thereby increasing the number of offspring.

Humans are not insects. Obviously. But gift giving, and many of its underlying behavioral mechanisms, is still very important to our mating system. I’ve already mentioned chocolate that, while offering little nutritive value, sure does make us ladies happy. As you know, these are not the only gifts given on Valentine’s Day. An interesting paper by Rugimbana et al., published in the Journal of Consumer Behavior in 2003, examines the role of gift giving on Valentine’s Day. The authors point out right up front that if you think about this “holiday,” you might notice that it is rather small in scale compared to the high rollers (i.e., Christmas). However, it is unique in that it has become almost ritualistic in its symbolic gift giving. So much so that it has become over-commercialized and now causes increased anxiety and pressure to those who involve themselves in it. The study looks at the role of social power exchanges as the basis for gift giving on Valentine’s Day, specifically in young men. To assess this, they interviewed male participants aged 18-25, asking about their attitudes towards Valentine’s Day, perceptions of female expectations and various types of gifts, and the appropriateness of various types of gifts to the length of a relationship.

This study found that for young men “the overwhelming motive for [giving] gifts on Valentine’s Day was obligation.” The men thought that gift giving was necessary when in a relationship simply because their significant other was expecting it. How romantic. This obligatory gift giving was thought essential early on in a relationship, especially if they wanted to avoid a conflict. The phrases “all hell would break loose” and “I hope…I’d still have a girlfriend” were used. However, only 25 percent of men replied that they expected something in return for the Valentine’s Day present. That sounds a bit harsh. But not so fast. When the researchers broke things down by their altruistic value, or lack of, some interesting patterns emerged. For example, when men were asked “if you were to buy lingerie for your partner, would it be for you, or for her?,” 90 percent said that it would be for themselves. Shocker on that one, I know. That isn’t to say that altruistic answers weren’t given (e.g., “you don’t need a day to say I love you”), just that it is difficult to separate from self-interest (e.g., “if you do it right, you’ll be glad”).

The authors were able to boil Valentine’s Day gift giving down to three motives: 1) obligation, 2) self-interest, and 3) altruism. Importantly, these motives existed in combination and a “social power exchange” was present. In other words, giving rewards the giver. All of this sounds rather callous and almost Machiavellian. Ladies, we sound rather demanding…I mean, “all hell will break loose” over one day and one gift? Wow. And guys, while turning an obligation into a reward is rather cunning and evolutionarily arguable, it is also sort of cliché at this point. Perhaps both sexes should consider the gift giving rules of other holidays like Christmas. Just a thought.


Rugimbana, R., Donahay, B., Neal, C., & Polonsky, M. (2003). The role of social power relations in gift giving on Valentine's Day Journal of Consumer Behaviour, 3 (1), 63-73 DOI: 10.1002/cb.122



(image via Valentines Day Pictures)

Mutualism a.k.a Caterpillars Drugging Ants To Do Their Bidding

From the study - Figure 1. Attendant Workers of
Pristomyrmex punctatus standing on or around
Narathura japonica caterpillars

The manuscript is done! Submitted! Summer interns are finished. Boot up Normal Life Mode, please. Recommence blogging. So many good papers have come out during my hiatus. Where to start…where to start…

If you have read this blog for any amount of time then you will come across my fascination with ant manipulation, particularly zombification. This is why my cursor stopped over a new paper in Current Biology about caterpillars manipulating ants to do their bidding.

Let’s start with mutualism. This is a topic that I have visited in the past, and in ants for that matter. It’s a nice little relationship between species that involves an exchange of goods and/or services. In the natural world, this often means food and protection.

In this study, the researchers chose the Japanese oakblue butterfly (Narathura japonica), a lycaenid belonging to the Theclinae subfamily of butterflies. Many in this group are myrmecophilic, meaning they associate (often mutualistically) with ants in some way. The Japanese oakblue caterpillar has a specialized exocrine gland, the “dorsal nectary organ (DNO),” that is located on the seventh abdominal segment and is flanked by tentacle organs (TO). The DNO secretes sugar- and amino acid-rich honeydew while the TO secretes scents to “talk” to the ants. A “Come on down!” or “Danger, Will Robinson!” type thing. The ants tend to the caterpillars and keep them safe for a nice, sugary food reward. But is that all to the story? Obviously not or this post would end here.

To do this experiment, butterfly eggs and their associated ants (Pristomyrmex punctatus) were collected and reared separately. Then three test situations were set up with 50 ants per treatment:

1. “Experienced” ants – had free access to the caterpillars and their DNO secretions
2. “Inexperienced” ants – no caterpillar access, just some sugar soaked cotton balls
3. “Unrewarded” ants – had access only to caterpillars that had their DNO’s blocked (a little bit of clear nail polish goes a long way)

After 3 days in their test situation, 10 ants from each treatment were moved to Petri dishes that were set on pieces of white paper with a line on it to divide the dishes into 2 halves. After the ants acclimated to their new little plastic arenas, they were observed to see how many times they crossed the center line (“locomotory activity”). Also at the 3 day time point, ants and caterpillars were frozen in liquid nitrogen until their brains could be dissected out, specifically removing the optic lobes. Now, I’ve done some pretty small dissections, but those come nowhere close to ant brain removal! Wow, just wow. Once those itty bitty brains were out, they were processed for liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) for serotonin, dopamine, octopamine, and tyramine. Very simply, that means making an ant-brain-aerosol that is then separated and identified by component.

They found that experienced ants had significantly less locomotory activity than the other two groups. So what does an ant walking, or in this case not walking, across a line even mean? Well, the fact that the ants are staying put signals that they are “standing guard” for the caterpillars. Okay, let’s say that standing means guarding, how do we know that this is really caterpillar-related and not just standing there? Well, first of all, it was only the experienced ants that did this. Second, the researchers observed that the caterpillars often “everted their TOs,” meaning that they turned them outward. This is typically a response the caterpillar makes when it is attacked by a predator – “Raise shields!” Experienced ants responded differently than the other two when they saw this caterpillar behavior in that they responded aggressively. This aggression is a response to the caterpillars’ alarm, one that has the ants defending against the predator. The fact that only experienced ants had these responses suggests that something in the DNO secretions is eliciting these defense behaviors.

So what is it about these secretions? That’s where the LC-MS/MS comes in. Biogenic amines are known function as neurotransmitters, neuromodulators, and/or neurohormones. This means that they can modify behavior in insects. DNO secretions contain biogenic amines. This analysis showed that experienced ant brains had low dopamine levels. Now, that’s important because dopamine has been shown to be involved in both locomotory activity and aggression in well studied organisms like fruit flies. Starting to see some links here, yes? To confirm the linkage, ants from each treatment were given reserpine, a small-molecule inhibitor that depletes dopamine but not serotonin in the brain. This test resulted the same behaviors, but the LC-MS/MS showed increased dopamine and serotonin in the ant brains. So same but different.

There is another aspect to consider: Who loses if the mutualism goes away? The honeydew is not the sole source of nourishment for the ants. They can leave and be still be fine. The caterpillar has much more to lose than the ant (its life via predation). So the caterpillars must be doing something besides sugar-loading their ants.  This is where the caterpillar gets sneaky - finding a way to make their ants to both stick around and defend against predators. As the authors put it, they they insert “manipulative drugs [into the honeydew] that could function to enforce cooperative behavior…from attendant ants.” Put that way, I’m okay calling it “ant mind control.”


Hojo, M., Pierce, N., & Tsuji, K. (2015). Lycaenid Caterpillar Secretions Manipulate Attendant Ant Behavior Current Biology DOI: 10.1016/j.cub.2015.07.016

p.s. The supplementary materials have a nice little video of ants in lined Petri dishes.

(image is Figure 1 from the above paper)

Not So Simple: Social Evolution in Silk-Weaving Ants

Silk weaving ants. That in and of itself is really neat. Then you see this picture of Polyrhachis shattuck...I mean, look at her! How many cool points can one animal rack up? A new study in Behavioral Ecology and Sociobiology takes a look at these arboreal nesting and silk-weaving ants.

Let's begin with sociality. It is one of those subjects in biology that is considered its own discipline. When you think of social animals you probably think of herds of mammals or maybe schools of fish. Sociality reaches its peak in eusociality, a surprisingly complex and truly social organization. These animals live in groups, cooperatively care for juveniles, divide labor, and overlap in generations. Studies of these social systems has shed light onto broader concepts of collective decision making, even leading to advances in our own technology (traffic flow, communications networks, internet searches, etc.). However, as much as we know about the social mechanics, we know very little about the evolution of such systems.

Most eusocial animals are found in the phylum Arthropoda, with the order Hymenoptera being the largest and most well-known, and all ants classified as eusocial species. And ants are the focus of today's chosen study. Ant larvae spin individual protective cocoons of silk and, depending on the species, that silk is either allocated to the colony or sequestered for the larvae’s individual needs. Donated silk is used by the worker caste to weave together leaves into nests. The “lowest grade” of arboreal (a.k.a. tree-dwelling) ants, Dendromyrmex, have larvae that produce silk without any interaction or provocation from the worker ants. In “intermediate grade” ants, Camponotus senex and Polyrhachis ?doddi (re-described as Polyrhachis robsoni (Kohout 2006)), the workers hold larvae at the work site and, with simple ritualized behaviors, the workers collect the silk. In the “highest grade” genus, Oecophylla, the larvae donate their silk supply to the colony. A worker ant will use highly ritualized behaviors - bring the larvae to the work site, straddle a leaf seam, use antennae to tap the head of the larva (telling it to extrudes silk from its salivary glands), use silk to glue together the seam, repeat.

A comparison of ant genera in this way, simple to complex, is thought to represent possible evolutionary steps in nest-weaving behavior. However, molecular sequence data suggests that nest-weaving has evolved independently in each of the four genera in which it occurs. This new study focuses on Polyrhachis ants. This genus offers good within-taxa comparison of multiple life strategies as different species vary in their nesting locations, from intertidal to subterranean to arboreal, the presence of nest construction, and even silk sources.

A total of 37 specimens of ants from all 13 currently recognized (*grr*, an often frustrating term in insect taxonomy) subspecies and five outgroup taxa were used for this study. The researchers isolated total genomic DNA and amplified and sequenced DNA from six fragments using specific primers for each gene region. After they collected the sequences, they analyzed and aligned them using computer programs. In their complicated analysis (they used Bayesian…that always makes my eyes cross) they input the gene level data along with variables of nesting preference (ground = soil, logs, stones vs. arboreal = twigs or leaves in trees) and nest construction (silk weaving vs. no silk vs. other silk). All of this allowed them to construct phylogenies (like an evolutionary family tree) and infer relationships among the species and ancestral states for behavior.

Their results showed robust phylogeny with strong support for the monophyly of the genus Polyrhachis, further supported by the inclusions of nesting preference and nest construction.This is good because it provides a nice, solid ancestral reconstruction for the evolution of the different species and their relationships to each other. It also allows for the comparison of the different nesting strategies within the framework of evolution. The investigation turned up some very interesting results. Simply, their results do not support the stepwise evolution of simple to complex. They found that the production of arboreal silk nests is the ancestral state with at least two transitions to subterranean nesting and the loss of silk weaving as species become more derived. There is also some flexibility and reversal in the behavior. Basically, the ants evolve, abandon and then re-evolve the nest weaving practices. The loss of silk nest weaving seems to occur with the transition from arboreal to terrestrial nesting followed by the re-evolution of silk nest weaving. This suggests a strong but flexible link between nesting preference and nest construction.

To illustrate this evolve-abandon-re-evolve point, the researchers present the example of Hedomyrma, a subgenus within a larger clade of subterranean nesters. This larger clade has already lost both arborality and nest weaving. But there are 2 species of Hedomyrma (Polyrhachis argentosa and Polyrhachis fervens) that have reverted to arborality. The re-evolution of this nesting preference has come with the modification of building nests within the hollow internodes of bamboo sans silk. Another reversal pattern is seen in a third species of Hedomyrma (Polyrhachis turneri), which has larvae that retain all of their silk for their own cocoon-constructing needs. Rather, worker ants steal silk from spiders to build nests on the sides of rocks. So the nest construction characteristic is what has re-evolved, just with a different mechanism. Larval cocoons have been lost in 2 of the arboreal nest-weaving species studied, and the allocation of larval silk to colony rather than individual need is considered a more derived but decoupled characteristic of nest construction.

I think that both the flexibility and the rapid evolution (or re-evolution) of this system is what attracted me to this paper. We know that evolution is a complex concept that we often boil down to from-simple-to-complex, and in many cases it is exactly that. This study almost reads like a sequel, a what-happens-next sort of thing.


Robson, S., Kohout, R., Beckenbach, A., & Moreau, C. (2015). Evolutionary transitions of complex labile traits: Silk weaving and arboreal nesting in Polyrhachis ants Behavioral Ecology and Sociobiology DOI: 10.1007/s00265-014-1857-x


(image of Polyrhachis shattuck, Maliau Basin, Sabah via AntWiki via California Academy of Science Ant Course)

Trick-or-Treating: What Do You Hand Out On Halloween?

Halloween is almost here. And you know what that means: Candy! It’s one of those Halloween traditions that I just never seem to have grown out of. Those little chocolate bars are seriously dangerous to my waistline. Remember how much Halloween candy you ate when you were a kid? Were you one of those kids who gorged on all that sugary goodness, or were you the type to parse it out and make it last? I was a Trader, that kid that made deals to trade all her bad candy for the good stuff. Anyway, the topic of Halloween candy got me to searching through the scholarly journals in search of an article for today’s post. I came across a paper that asks if children really need all of that candy on Halloween. My first instinct was “Of course they do! It’s Halloween!” But, well, read on…

It seems that being a fat American isn't just limited to adults, childhood obesity has been on the rise over the last 3 to 4 decades. Access to unhealthy foods and the poor nutritional quality of their diets is much to blame for this. The promotion and glorification of high sugar, high fat foods on Halloween is simply a good example. It probably comes as no surprise that research has shown that when children are given free access to tasty food that they eat it, especially if it’s sweet, even when they are not hungry. But is there a good alternative that kids will like? A slightly older paper published in Journal of Nutrition Education and Behavior investigated the option and value of nonfood treats as substitutes for candy on Halloween.

To do this, the researchers gave 284 trick-or-treating children a choice of a toy or candy. The toys included stretch pumpkin men, large glow-in-the-dark insects, Halloween theme stickers, and Halloween theme pencils. The candy choices were recognizable name brand lollipops, fruit-flavored chewy candies, fruit-flavored crunchy wafers, and “sweet and tart” hard candies. All of these toy and candy options ranged between 5 and 10 cents per item. When a trick-or-treating child arrived at a door, they were asked for their age, gender and a description of their Halloween costume (pretty typical…except maybe the gender question). Then they were presented with 2 identical plates: 1 with 4 different types of toys and the other with 4 different types of candy, alternating by site/household which on side the plates were located. Only children between 3 and 14 were included. And, if the child asked for both toy and candy, they were allowed to take both but were excluded from the study, but only 1 little girl did that.

The results of the study showed that children chose toys as often as they chose candy. This suggests that children may forego candy more readily than adults expect. The authors cite Social Cognitive Theory as providing a way for candy alternatives to become more commonplace. According to this Theory, when parents see that children are accepting the candy alternatives they are more likely to continue the new toy giving behavior. Factor in the other fun Halloween activities – dressing up, walking around the neighborhood at night, etc. – and these toy treats become positively associated with the fun and the holiday.

Okay, so what about the Halloween-only-comes-once-a-year argument. I’ll admit it is a good one and it something that the authors spend time to address. They point out that Halloween isn’t the only holiday where food and candy are advertised. Well, isn’t that the truth. They even make a nice list of other food laden holidays and events: weddings, new babies, graduation, back-to-school, birthdays, Christmas, Hanukkah, Valentine’s Day, Easter, St. Patrick’s Day, Cinco de Mayo, Earth Day (wait…you get food on Earth Day?), Mother’s Day, Father’s Day, and Independence Day. What they don’t add in are all of the other food-filled events that come seasonally (picnics, cook-outs, etc.) and socially (happy hours, get-togethers, etc.). Put together, that’s a lot of bad food choices all year long.

Ultimately, what the authors are getting at is promoting healthy choices throughout the year. Part of this is giving children healthier options and traditions. It is almost more of a change for adults than it is for children. Breaking those food habits and associations isn’t easy, y’all. Food isn’t love, no matter how many Hershey’s Kisses you give someone. Wow did that ever sound shrinky!

But I’ll throw in a last little note that I think almost every child on the planet would agree with: Don’t be that house than hands out toothbrushes.


Schwartz, M., Chen, E., & Brownell, K. (2003). Trick, Treat, or Toy: Children Are Just as Likely to Choose Toys as Candy on Halloween Journal of Nutrition Education and Behavior, 35 (4), 207-209 DOI: 10.1016/S1499-4046(06)60335-7


(image and product via epicurious)

Spoiler Alert!: Are You Wasting Your Time Avoiding Spoilers?

Lately I have been cranking though a lot of media – TV, movies, books, podcasts, etc. To the point that I start to wonder how I have time for actual life. During this mass consumption of media, I've been thinking about, and discussing with friends, the topic of spoilers. Bring up this topic with just about anyone and you’ll find that it’s actually a pretty controversial one. As for me, I fall in the no spoilers category. Spoil one of my beloved TV shows and you will go from friend to “friend” just that fast. But I know that there are those out there that don’t mind being spoiled or actually prefer it. That got me to thinking back to a study from few years ago about this topic. The study got quite a bit of attention from the media, specifically applying the findings to film and TV. After doing some searches on Web of Science for similar studies, I can see why. There just aren’t any – to the point that even this older study has only been cited 3 times, and not by other media related studies. So, well, what the heck?

In 2011, a short little study published in Psychological Science by Leavitt and Christenfeld asked if spoiling a story decreased peoples’ pleasure in it. The universal element of all types of media is story. When you talk about spoilers you are inherently talking about changing someone’s enjoyment of the story. The study asked 176 males and 643 females (just a little sex biased and not broken down by any other demographics) to take part in three experiments in which they read three different sorts of short stories selected from anthologies: (1) Ironic-twist stories, (2) Mysteries, and (3) Evocative literary stories. For each of the stories, some of the participants’ stories included a spoiler paragraph that summarized the story and gave the outcome. Afterwards, the participants were asked to rate the story for enjoyment on a 10 point scale – a “hedonic rating.” They found that the participants significantly preferred spoiled over unspoiled stories in all categories and reported that the spoiler paragraph was not out of place or jarring.

Figure 1 from the study. These are hedonic ratings of the individual spoiled and unspoiled stories.

Considering all of the attention this study got when it was published and the applications made to a variety of media, I’m going to throw in a little more personal critique than I do normally. Start out by asking: Are their data wrong? Well, no. But there are some methodologies and assumptions that I question. They assume that I have the same experience each time I read a story. The authors do focus on that first reading but also state that “people’s ability to reread stories with undiminished pleasure, and to read stories in which the genre strongly implies the ending, suggests that suspense regarding the outcome may not be critical to enjoyment and may even impair pleasure by distracting attention from a story’s relevant details and aesthetic qualities.” As someone who rereads her favorite books over and over again, I say “not so!” Their statement suggests that I did not enjoy the shock of a scene the first time around when in fact I did. You know what I mean: that “holy-crap-did-that-just-happen?!!!” moment. Am I saying that twist is all there is? Of course not, but one of the memorable parts of the first reading - the surprise - would not have been the same without it. Upon rereads, my undiminished pleasure comes from the writing and spending more time in a world with characters that I love (or love to hate).

The study’s authors conclude that “people are wasting their time avoiding spoilers,” but go on to say that that their data “do not suggest that authors err by keeping things hidden.” They point out that readers who read stories that open with the outcomes still anticipate additional revelations at the end. To me, this statement suggests that readers still expect twists in the story even though they've just read all of them, that they are waiting for the shock, the twist. A good example might be someone who is seeing a film adaptation of a book they've read; they are looking for the differences in the movie. Considering this, I think would have liked more detail in the methods about how their spoilers were presented. I wonder if a big “Spoiler Alert” warning on that summary paragraph would have made a difference – one that labeled and explained it as something that spoiled everything. Perhaps this would remove this erroneous anticipation? Or what about a before questionnaire that scored anticipation levels? Personally, I am way more upset if someone spoils something I've been looking forward to compared to something I could care less about. What about gauging viewpoints on spoilers by asking a simple question like: Do you read the last chapter of a book first to see what happens?

Did I come into this paper with some preconceived notions? Sure, but I seem to have more problems with this study than most. Upon reflection, I think that stems from problems I have with the study's methodology added to the attention it has gotten (it hasn't escaped me that I’m giving it even more with this post). It has been used to justify spoiling a story – a behavior that I typically find to be one of smug superiority. I think it is important to keep in mind that this is a single small study, and one that had I been a reviewer for would have gotten hacked to pieces. I'm a fan of a nice, simple study but I'm not a fan of lack-of-detail, particularly in the methods.

But I'm not a psychologist, what do I know? What do you think? Do you love or hate spoilers? How would you have done a study on this topic?


Leavitt, J., & Christenfeld, N. (2011). Story Spoilers Don't Spoil Stories Psychological Science, 22 (9), 1152-1154 DOI: 10.1177/0956797611417007


Here's some of the media attention this study received and a couple other articles on the topic. Spoiler Alert - some of these contain spoilers.

Film School Rejects: "How Bad Do Spoilers Spoil?: A Super Scientific Study
Smithsonian: "Are Spoilers Misnamed?"
UC San Diego News Release: "Spoiler Alert: Stores Are Not Spoiled by 'Spoilers'"
/Film: "Spoilers Are Good For You, Says Study"
The Atlantic: "Here's the Twist: Good Films Are Good Even If They've Been 'Spoiled'"
io9: "The Cultural Curse of Knowledge and Movie Spoilers"
io9: "Why I refuse to watch movies without spoilers"
Vulture: "Spoilers: In Defense of the American Watercooler"
Vulture: "Spoilers: The Official Vulture Statutes of Limitations" (I like this proposes a stature of limitations on spoilers based on the media type)
Techie.com: "Spoiler Alert: A Survival Guide to All Things" (also the source of the image)

What Type of Procrastinator Are You?

Joseph Ferrari is a master of procrastination. And by that I mean a Ph.D. in psychology who studies procrastination and task avoidance. Recently, the folks over at OfficeTime used Dr. Ferrari's findings to create a flow chart that helps you to identify what type of procrastinator you are.

Me? Well, I'm a Thrill Seeker.



You can find more over at Life Hacker and Science Dump.

The Charge of the Crazy Ant: Chemical Warfare Between Invading Species

LeBrun, Jones, and Gilbert (2014) Figure 1A

I’ll be the first to admit that I've been a little blog-negligent lately. Even when all of the ice and snow we've gotten here on the East Coast forced me to stay inside I just binge watched shows on Netflix instead. I’m not sure what brought me out of my procrastination funk and compelled me to do a little reading and writing. If you've been following the Facebook page then you've been getting a lot of yummy sciency tidbits, but it’s time for me to get back on the hard science wagon. I think I’ll start off with a great couple of papers about ant chemical warfare.

These papers focus on invasive ants, a big problem in many regions. To really grasp one of the underlying aspects of their warfare strategies, you must first understand the basics of an invasive species. Start by recognizing the difference between a native species and an exotic species. Put simply, a native species occurs naturally (or natively) to a habitat and an exotic species does not. Exotics can come in any biological form, but they are not necessarily a problem to their new habitat (think: earthworms). It’s when an exotic species becomes an invasive species that there is a problem because invasives cause environmental, economic, and/or human health harms. The reason for this is that they did not evolve together with the ecosystem in which they find themselves. There are no checks and balances in place to curb their population growth, things like predators, parasites, and competitors. Their unnaturally large population numbers then become harmful to the native species that suddenly have to deal with and compete against them, dramatically altering the community and habitat.

It is often the case that multiple species invade a region. Throughout the rest of this post I’ll be discussing new papers by Michael Kaspari and Michael Weiser and by LeBrun, Jones, and Gilbert (specifically at the latter) that take a look at just such a case in ants. The red imported fire ant (Solenopsis invicta) first came to the United States from South America around 1930. This species is far more aggressive than your typical American ant, not only in how they like the bite the hell out you (that’s a lot of personal experience talking) but also in their predatory abilities and landscape re-engineering. Now enter the tawny crazy ant (Nylanderia fulva). This new exotic invasive species was transported to the southeastern U.S. in the early 1980s and has begun to spread.. These two species have common source assemblages, their native ranges overlapping in northern Argentina, Paraguay, and southern Brazil. Until the introduction of crazy ants, the fire ant has enjoyed an uninterrupted domination of the native grassland ant assemblages. But now that the crazy ant has arrived on the scene they are displacing the fire ants. Why is this?

Since the fire and crazy ants have overlapping native habitats, they have evolved to compete directly for resources. The tawny crazy ant easily expels the fire ant from any food items it controls, up to 93 percent of the time. Also, tawny crazy ants have often been found living inside fire ant mounts, having usurped the mound and evicted the owners. Fire ants are strong and resilient and so the crazy ants must have a strong competitive advantage.

Now, finally, we get to the meat of the post: chemical warfare. If you've been stung by a fire ant (or ants, plural, as is usually the case) then you know that they pack a wallop! They have an alkaloid venom called Solenopsin that to humans causes a painful, fiery sting, and to other ants acts as a topical insecticide. The crazy ants do not have stingers but instead possess an acidopore (a specialized exocrine gland) on the end of the abdomen that sprays their venom into a mist of formic acid. They will charge into masses of fire ants misting as they go. But the fire ants don’t just stand by idly to be sprayed with venom and die, they fight back. The fire ants “gaster flag,” extruding venom from their stingers and dabbing it onto a nearby attacking ant. Normally this would result in the death of said ant. However, LeBrun and his colleagues have observed what they are calling a “detoxifying behavior” in the attacking tawny crazy ants. In this behavior, an afflicted ant stands on its hind legs, run its front legs through its mandibles, and grooms itself vigorously, periodically reapplying its acidopore to its mandibles (check out the video!).

To test this behavior the researchers conducted a series of experiments to see if there is really a detoxifying component, to see where it is coming from, and to evaluate the species-level specificity of the behavior. For the first they staged antagonistic interactions between the two species, sealing a portion of the crazy ant acidopores, and then observing afflicted individuals for behavior and survivorship. They found that those tawny crazy ants that had had their acidopores sealed had a low survival rate (only 48 percent). However, those with working acidophores had a 98 percent survival rate, supporting the detoxifying hypothesis. The Dufour’s and venom glands (exocrine glands used for communication and defense) both duct to the acidopore in this species. To see where the detoxifying agent was coming from they applied solutions of fire ant venom and tawny crazy ant glandular products to Argentine ants (Linepithema humile), which are morphologically similar to crazy ants but do not have the detoxifying capability. These tests showed the venom gland of the crazy ant to contain the detoxifying agent. When the crazy ant’s formic acid was tested it was found to be the compound responsible for detoxifying fire ant venom.

The production and application of this antidote is a potentially costly endeavor for the crazy ants. Yes, it is the difference between life and death, but when to apply it must be considered. Why use a costly resource if you don’t have to? The authors conducted a series of ant interaction tests where they had crazy ants interact independently with eight Texas ant species including fire ants, observing when the crazy ants chose to apply their detoxifier. They found that after chemical conflict with fire ants, crazy ants detoxified themselves with almost 7 times more frequently than the average response to other ant species. This suggests that this detoxifying behavior is specifically adapted to competition with fire ants, and it is probably a key factor in the displacement of invasive fire ants now underway in the southern United States.


LeBrun, E., Jones, N., & Gilbert, L. (2014). Chemical Warfare Among Invaders: A Detoxification Interaction Facilitates an Ant Invasion Science, 343 (6174), 1014-1017 DOI: 10.1126/science.1245833


Kaspari, M., & Weiser, M. (2014). Meet the New Boss, Same as the Old Boss Science, 343 (6174), 974-975 DOI: 10.1126/science.1251272


U.S. Fish and Wildlife Service's page on Invasive Species
The University of Texas at Austin Fire Ant Project
Texas A&M AgriLife Research Extension page on Tawny Crazy Ants

Going to the Movies: The Seat Choice Dilemma (Part 3)

Welcome to Part 3, the final step in our science-tastic trip to the movie theater. I’d suggest checking out Part 1 and Part 2 as so far, you've purchased your expensive ticket, wondered at high concession prices, agonized over which size popcorn to buy, and learned how that choice will ultimately determine how much you will eat. Now you are ready to go find a seat for the show! You pick up your concessions from the counter, figure out how to carry them in such a way as to not spill anything and yet still be able to hand your ticket to be torn, walk down the hallway to find your theater number, go down the dark felt-covered tunnel, and then stand at the bottom of the stairs contemplating which row to sit in.

Let’s start by asking if where you sit will really affect what you see? There is an older, interesting piece written by James Cutting in 1986 that looks at the shape and psychophysics of cinematic spaces. Probably haven’t heard the term psychophysics, right? I know I hadn't. Well, it is a branch of psychology that’s concerned with how physical processes (the intensity of stimulants like vision and sound) affect your sensations, perceptions, and mental processes. Basically, a mind-body problem. Movies have the capacity to draw us in such that we get “lost” in them; we project ourselves into a new space and time, one that the filmmakers have created for us. The high picture quality and larger screens have been shown to help give us viewers the impression of “being there.” Dimming the lights dims out the real world, the large screen fills our optic array, the smoothness of the frame rate (flicker threshold) allows the images we see to become lifelike, and the pacing of scenes and cuts can enhance our emotions. However, a movie is ultimately an optical projection and it would be logical to think that where you sit may matter in how you see the movie (geometry, distortions, etc.). But in his paper, Cutting describes why this isn't so. He uses static art as an example, asking you to look at a picture from different angles. Then he explains that affine and perspective transformations affecting the look of rigidity of objects on the screen is actually very difficult for people to discern (what he terms La Gournerie’s paradox). In search of why this is so, he goes through a lot of history, and geometry, and equations, and well, I’m not even gonna touch those. But essentially, he comes down to two possibilities: (1) our brains compensate for and rectify any distortions we see by using information about screen slant, and (2) we preserve information about the transformations we see to ensure our perception remains unperturbed. So when you’re standing at the bottom of those stairs looking around for a seat, know that where you sit doesn't really matter in how you view the movie. Your brain’s got it covered.

Choosing a seat, however, is a conscious choice. Like any other choice it is influenced by the characteristics of the item, particularly (and especially in this case), the location. Let’s start simple and consider our lateralized tendencies, a.k.a. which side of the theater you like to sit on, right or left. A study published in Cortex in 2000 looked at handedness as a predictor of behavioral asymmetries. Previous studies of cerebral organization show that the brain’s right hemisphere shows a considerable advantage for face recognition, spatial stimuli, and emotions. With this knowledge, this study asked if these directional biases are reflected in the seat choices we make at the cinema. The researchers screened and interviewed participants for handedness (right, left, mixed). Then they gave them maps of five theaters, each differing in the location of the entries/exits and aisles, and dividing seats into equal parts with the middle seats marked as sold out. They found a preference for right positions when watching movies in the three handedness classes underlying a left-directed perceptual bias, which they found to be most evident in right handers and decreased progressively from them to the left handers. The author postulates that this is because the leftward orientation of attention fosters the activation of the right hemisphere cultivated through the learned reflexes of previous biases. A study published in Laterality in 2006 also looked at this seat-side preference, also by asking participants to look at various maps of theater seating, this time altering screen location. This study confirmed the overall right side seat preference, with a stronger preference if the screen were at the top or right of the map, and additional preference for seats at the back of the cinema. However, they found that the turn at the entrance to the theater to perfectly correlate with the chosen seat-side. A result that could reflect general turning habits (I really hope that someone has termed this the Zoolander Hypothesis).

I think we can all agree that handedness is a rather simple way to look at something. There is obviously more going on here. A paper, this time in Applied Cognitive Psychology in 2010, added the role of motivation to their study. They wanted to know if people highly motivated to see a movie would choose the right side of the theater, since these seats are better suited to processing information from the left visual field and therefore direct access to the visual and emotional side of the brain (right hemisphere). In their first experiment they told all of the participants that a movie was highly recommended and half of them were further advised that they would rather avoid watching the movie because the story was sad and depressing (thereby negating the positive motivation of the recommendation while also giving negative motivation). Then they asked the participants to choose a seat from a seating chart. Knowing that some dark or depressing stories often achieve immense commercial success (e.g. The Dark Knight), they also conducted an experiment where they reversed the status of the negative emotional content. They found that when right-handers were positively motivated they chose seats on the right side. This bias disappeared when they were negatively motivated. This held true even when a depressing movie was spun a positive. Non-right-handers did not exhibit such lateral biases regardless of experimental condition.

Personally, I’m a middle theater, middle seat kind of person. That particular bias hasn't really been addressed by the studies above, in fact they grey-out the middle seats to force people to choose a side. This is what Rodway et al. considered when they conducted their study in 2012. They decided to compare the right-side preference to the center-stage effect. The latter suggests that people’s choice decisions are guided by the perception that good, important people occupy the middle. They examined this closer in a first experiment where they presented people with five identical pictures (of random regular things like butterflies or waterfalls) arranged in a line and asked them to pick their most and least preferred items. The results showed a significant trend for people to select their most preferred item in the middle position, a result not seen when choosing the least preferred item. A second experiment looked at the array format to see if the center tendency extended to vertically arranged items, knowing that top positions are generally associated with positive attributes and vice versa. As with the first experiment, participants chose items in the center rather than the top or bottom, adding robustness to this center-stage theory. A final experiment wanted to see if these preferences are associated with real items rather than just pictures. As with the other two, this experiment showed a preference for center items, although there was also a significant reduction for the items at the lowest two locations. Did they actually go into a theater and ask people about seats? Well no. But I included this study because I have yet to come across a paper that has asked this, and being a center-seater, I thought it was a rather important aspect to the whole seat-choice dilemma.

These studies all look at a simple choice aspects, which, admittedly, is a good place to start. However, I think I would like to read about how group size matters. You know you ask your friends where they want to sit, right? Or what about how people don’t like to sit next to each other? What about choosing a seat in a theater where many of the seats are already taken? If your preferred seats are gone, where do you sit?

Well, that’s all for our trip to the cinema. Now that you've found your seat, enjoy the show!


James E. Cutting (1986). The shape and psychophysics of cinematic space Behavior Research Methods,, Instruments, & Computers, 18 (6), 551-558 DOI: 10.3758/BF03201428

George B. Karev (2000). Cinema Seating in Right, Mixed and Left Handers Cortex, 36, 747-752 DOI: 10.1016/S0010-9452(08)70550-1

Matia Okubo (2010). Right Movies on the Right Seat: Laterality and Seat Choice Applied Cognitive Psychology, 24, 90-99 DOI: 10.1002/acp.1556

Paul Rodway, Astrid Schepman, and Jordana Lambert (2012). Preferring the One in the Middle: Further Evidence for the Centre‐stage Effect Applied Cognitive Psychology, 26, 215-222 DOI: 10.1002/acp.1812

Peter Weyers, Annette Milnik, Clarissa Muller, & Paul Pauli (2006). How to choose a seat in theatres: Always sit on the right side? Laterality, 11 (2), 181-193 DOI: 10.1080/13576500500430711



(image via The Expert Institute)

Going to the Movies: The Story of a Popcorn Pit (Part 2)

Welcome to Part 2 of my journey to the movie theater. This will make sense if you haven’t read Part 1, but to enjoy the full impact of this visite du cinéma, I suggest you read both. If ya just don’t wanna then here’s a summary: (1) movie tickets are expensive, (2) as far as I can tell, nobody has really done a direct study of why, (3) economists try to explain why all movies cost the same through their “uniform pricing for differentiated goods” theory, (4) as it turns out, variable or differentiated pricing is probably better, (5) concessions are expensive too, (6) theaters get all of this “consumer surplus,” (7) channels of ticket distribution, group size, and theater characteristics affect concession sales, and (8) theaters get as much money as possible from people willing to pay it.

So far, we've made it past the door with our high priced tickets, and we stood in front of the concession stand wondering why those prices are also so high. Let’s say that you decide to take the monetary plunge and buy some concessions. You look over the candy, the nachos, the questionable looking hot dogs and you decide to go with popcorn. You look at the sizes of the containers, perhaps ask to see one a little closer, and go with the medium. But wait! The large is only 25 cents more! Okay, so you go with the large. I mean, if you are going to pay 5 dollars for popcorn then there might as well be a lot of it right?

What are the effects of ordering that 18 cup bucket of inflated food? It is slathered in a buttery goodness that makes it pretty frickin’ yummy, but are you really going to eat all of that? Most people tend to think that how much they eat is based on the taste of the food. Studies in the absence of environmental cues have largely shown this to be true. That makes sense if you think about it. When you have no distractions you can concentrate on the flavor of your food. However, the movie theater is the opposite of a distraction-free environment.

In 2001 Wansink and Park published a study where they gave 161 moviegoers free popcorn and soft drinks. The same popcorn was given in either a medium (120g) or large (240g) container, with before and after weights taken to see how much was eaten. Then they asked the participants to fill out a questionnaire after their movie about the taste of the popcorn. The results showed that people who rated their popcorn as tasty ate 49 percent more if it was in a large container than a medium one. Surprisingly, people who rated the taste of their popcorn as unfavorable still ate 61 percent more if it was put in a larger container. A related study from 2005, also headed by Wansink, looked at how container size can influence food intake, even when it is less palatable. Again they randomly gave 158 moviegoers either a medium or large container of popcorn, weighing the containers before and after the movie. But this time they purposefully changed the taste of the popcorn, giving participants either fresh or stale (14 days old…eww). Similar to the first study, the results showed that moviegoers ate 45.3 percent more popcorn from a large container than from a medium container when the popcorn was fresh. And while the moviegoers with stale popcorn negatively described their food as “stale,” “soggy,” or “terrible,” they still ate 33.6 percent more if they were given large containers than if they were given medium containers.

A more recent study published in the journal Appetite also looked to see if people consumed more food with larger containers, this time focusing on portion size vs. container size. They served M&M’s for free to 88 undergraduate students watching a 22 minute long TV show. Participants were served either a medium portion of M&M’s in a small container, a medium portion in a large container, or a large portion in a large container. Given the same amount of food, people with the large containers ate 129 percent (199 kcal) more than people with the medium containers, and when given a larger portion size they ate 97 percent more. Basically, that large bucket of food stimulates your food intake over and above the portion size. So perhaps that large popcorn you purchased wasn't the best idea.

But fear not! There is actually an up-side. You know how you eat most of your popcorn before the movie even starts, during the ads and previews? Well, an article published online this year in the Journal of Consumer Psychology looked at how “oral interference” (i.e. eating) affects the impact of those ads on people’s brand attitudes and choices. In their experiments, they gave free popcorn and chewing gum to participants and asked them to watch a movie preceded by a series of real but foreign commercials (so they hadn't seen them before), asking them to eat as soon as the commercials started. Then one week later they assessed the participants and a control group (no free popcorn or gum) for their purchasing choices. The researchers found that the control group spent more money and had a preference for the brands they saw in the commercials. The participants that ate during the commercials showed no such preferences. Yeah! Pop blocked!

I’ll see you next week for the last, and final, part of this series. Happy eating!


B. Wansink and S.B. Park (2001). At the movies: how external cues and perceived taste impact consumption volume Food Quality and Preference, 12, 69-74 DOI: 10.1016/S0950-3293(00)00031-8

B. Wansink and J. Kim (2005). Bad Popcorn in Big Buckets: Portion Size Can Influence Intake as Much as Taste Journal of Nutrition Education and Behavior, 37 (5), 242-245 DOI: 10.1016/S1499-4046(06)60278-9

D. Marchiori, O. Corneille, & O. Klein (2012). Container size influences snack food intake independently of portion size Appetite, 58, 814-817 DOI: 10.1016/j.appet.2012.01.015

S. Topolinski, S. Lindner, & A. Freudenberg (2013). Popcorn in the cinema: Oral interference sabotages advertising effects Journal of Consumer Psychology DOI: 10.1016/j.jcps.2013.09.008


Just for interest’s sake, an interesting article from the Smithsonian about the history of popcorn and the cinema: "Why Do We Eat Popcorn at the Movies?"



(image via birthdayexpress.com)

Going to the Movies: The Story of a Money Pit (Part 1)

I love movies. Love to sit and watch them at home. Love to have movie nights with my friends. Love going to see them at the theater. On that last one, I think we can all agree on one thing: movie theaters are money pits. Essentially you just walk up to their front door and start throwing all of your money at them. You bitch and moan but you accept it. You knew before you ever left your house that you were going to spend an exorbitant amount of cash for a load of calories and an unknown experience. With my frequent trips to the theater and the resulting cash outflow I got to wondering why. In an attempt to answer this I took a step-by-step approach, looking at a typical trip to the cinema.

According to the National Association of Theater Owners, the average cost of a movie ticket in the U.S. rose to from $7.96 in 2012 to $8.38 in 2013. Granted, this rise is due, in part, to rising surcharges for 3D, IMAX films, and “luxury cinemas;” it is also indicative of an overall rise in movie ticket prices. When I fired up a few of my favored scholarly search engines, I found literature mostly on the movie industry itself but a surprising lack of literature on movie ticket prices, regional differences, surcharges, etc. There are a few papers that address movie ticket prices in terms of economic theory, but that’s kinda it. These papers look at cost-based explanations for why there is one price for all movies, all the time. It is what economists call “uniform pricing for differentiated goods,” which is usually compared to a price differentiated or variable pricing system.  Sure, there are senior and student discounts as well as matinee rates (so called “third degree price discrimination”), but in general, each moviegoer pays the same price for all movies at any time. Theater quality, seat location, quality of the movie, etc. – same price.

A paper by Rosen and Rosenfield in 1997 argues for an optimal two-part pricing system where consumers with the greatest demand buy higher priced tickets to earlier performances, a strategy that was propositioned around the same time by Universal CEO Edgar Bronfman. A scheme that was obviously not adopted. Papers published in 2001 and 2007 by Orbach and Einav examine and support the argument that theaters could benefit from price differentiation across movies and show times. However, they point out that uniform pricing may persist because consumers may perceive variable pricing as unfair, that the short life cycles of movies make it difficult to adjust prices, and the difficulties continue between distributors and theater owners. The latter is examined in more detail in a publication in Marketing Science by Eliashberg, Elberse, and Leenders that reviews the process of movie making and distribution. In the Exhibition section of their paper, they describe the contractual arrangements between distributors and cinemas and pay special attention to the relative powers of these two parties. The distributors’ power lies in the expected success of a particular movie and the amount of promotional support they are willing to commit. The theaters’ power lies in its location and relative shortage (or surplus) of available screens. Overlying all of this is the uncertainty of demand and it filters down into ticket prices. These prices are a dance between the distributors and the theaters. Theaters often prefer lower ticket prices to compete more effectively with other theaters. This has the knock-on effects of increasing attendance and revenues from concessions. Naturally, distributors want high prices and have even actively sought, although largely unsuccessfully, to increase their revenues through variable price structuring. To sum up, how much you pay at the box office essentially comes down to how consumers value goods, the legal constraints on the relationships between distributors and theaters, and the negotiations that occur between these parties.

So now you’ve purchased a ticket which is considered low by both the distributers and the theaters. Okay, we’ll go with that. Next, you walk inside to hear the pop-pop-pop of the popcorn machine, the whoosh of the soda dispenser, the lights of the menus and candy displays, and the oh-so-mouthwateringly good smell of butter. Yep, you are faced with the concession stand and the high prices that go along with it. You know those “low” ticket prices the theater owner has negotiated for you? They are offset by the sale of these concessions, revenues that are not shared with the movie distributors. Also, most theaters bar you from bringing your own food and exploit your immobility by charging high prices for their products. So how likely are you to buy those tempting confections? A paper published in Economic Inquiry back in 1991 looks at these high prices, pointing out that “if all movie viewers ate popcorn at the movies and ate the same amount, the question of pricing at the concession stand would be of little interest. The only thing that would matter would be the combined price of the ticket and the [refreshment].” But in actuality only a fraction of customers purchase concessions and by charging a high price the theater is able to extract consumer surplus.

A study by Gil and Hartmann in 2007 took a look at the role and determinants of concession sales using data from 22 Spanish theaters in 19 cities (11 provinces) between January 2003 and April 2005. This data set contained information on weekly concession sales, box office revenue, and attendance including tickets sold through 5 different selling channels. They also collected information on different markets and local theater characteristics that may relate to concession revenues (population, unemployment, advertising, etc.). Their data shows a strong correlation between theater attendance and concession sales. I would say that is pretty logical. They also associated concession sales with three broad categories of factors:

1. Channels of Ticket Distribution - For this they divided ticket sales into two categories: tickets sold at the box office and tickets not sold at the box office (further divided into subcategories). They found that people that don’t buy their tickets at the box office spend more on concessions, specifically those people that buy their tickets at home on the Internet or at kiosks.
2. Audience Composition -  For this category the authors looked at the number of tickets per transaction. Basically, group size. According to their results, if you go to the theater as part of a large group you’ll probably buy more concessions than if you are in a small group. This relationship stands even considering that people in groups tend to share their concessions. 
3. Theater Characteristics - Large theaters, measured by number of screens and seats per screen, tend to sell more concessions than small theaters even after controlling for attendance. They also found that theaters located in highly populated cities collect less revenue from concessions. Theaters located in cities with higher unemployment rates have lower concession sales, and theaters located in cities with a larger number of commercial activities per person have higher concession sales. Put together, it may actually be local characteristics that are the more important determinant of concession revenues.

Gil and Hartmann also published a study in Marketing Science in 2009 looking at metering price discrimination, a second-degree price discrimination scheme. Basically, “aftermarket goods” (i.e., the concessions) are set well above cost and the customer’s intensity of demand for these goods provides a meter of how much they are willing to pay for primary goods (i.e., the ticket or admission price). The authors created a model (they call it simple, I call it a headache-inducing mathmare) and fed in some available data on concession sales, box office revenues, and theater attendance (again from Spanish theaters). Their results confirmed the presence of the demand conditions for metering with high priced concessions extracting more money from people willing to pay for the admission ticket. Although, they are not sure if theaters are consciously trying to discriminate across customers with their concession pricing strategies. I’m gonna call it getting as much money possible from people willing to pay it.

I've divided this journey to the movies into three parts. If you've made it this far you’ll know why. At this point I’ll leave you with the argument for a new, more current study. A study (likely multiple studies) that take into account the impacts of the most recent recession on prices, the rise of theaters such as the Alamo Drafthouse (which serve dinner and cater to cinephiles), the influence of independent theaters, the increasingly health conscious consumer, and the rise of digital technology (and the associated surcharges), among other things.

 See you soon so that we may choose what to purchase at the concession stand and then we'll make our way to our seats for the movie.

Sherwin Rosen and Andrew M. Rosenfield (1997). Ticket Pricing The Journal of Law and Economics, 40, 351-376

Barak Y. Orbach and Liran Einav (2001). Uniform prices for differentiated goods: The case of the movie-theater industry Harvard Law & Economics Center, Olin Discussion Paper 337 (Harvard University, Cambridge, MA) DOI: 10.2139/ssrn.290813

Barak Y. Orbach and Liran Einav (2007). Uniform prices for differentiated goods: The case of the movie-theater industry International Review of Law and Economics, 27, 129-153 DOI: 10.1016/j.irle.2007.06.002

Jehoshua Eliashberg, Anita Elberse, and Mark A.A.M. Leenders (2006). The Motion Picture Industry: Critical Issues in Practice, Current Research,and New Research Directions Marketing Science, 25 (6), 638-661 DOI: 10.1287/mksc.1050.0177

Pascal Courty (2011). Unpriced quality Economics Letters, 111 (1), 13-15 DOI: 10.1016/j.econlet.2010.12.009

John R. Lott and Russell D. Roberts (1991). A Guide to the Pitfalls of Identifying Price Discrimination Economic Inquiry, 24, 14-23 DOI: 10.1111/j.1465-7295.1991.tb01249.x

Ricard Gil and Wesley R. Hartmann (2007). The Role and Determinants of Concession Sales in Movie Theaters: Evidence from the Spanish Exhibition Industry Rev Ind Organ, 30, 325-347 DOI: 10.1007/s11151-007-9139-7

Ricard Gil andWesley R. Hartmann (2009). Empirical Analysis of Metering Price Discrimination: Evidence from Concession Sales at Movie Theaters Marketing Science, 28 (6), 1046-1062 DOI: 10.1287/mksc.1090.0494

Ticket pricing info via ScreenCrush


(image via GeekTyrant)