What Hurts Worse?

The science of pain presented as a very interesting question. Which hurts worse: childbirth or getting kicked in the testicles?

Admit it, you've always wondered.

The Curious Case of the Earworm (Part 2)

In Part 1 of this topic, we explored the reasons why we like certain songs. But what transforms that likable melody into an earworm? Or is likability even a contributing factor? We took the biochemical/neurological route in Part 1, so now we’re gonna go all psychology for this one with a paper published in 2011 in Psychology of Music.

Let’s get some terminology out of the way first. We all have internally-directed thought (all that stuff you think to yourself), and we also experience spontaneous cognitions, which are those “common, everyday experiences that occur against a backdrop of deliberate goals-directed mental processes.” Musical imagery is associated with this. Involuntary musical imagery (INMI) is when a piece of music comes unbidden into your mind and repeats outside of your conscious control. It is the “earworm”, “brain worm,” “sticky music,” “cognitive itch,” and/or “stuck song syndrome.” This 2011 study looked to see if there were any patterns in everyday life that lead to an INMI episode, basically what prompts an earworm. The researchers first wanted to catalog known instances of earworms. So they used a radio feature where listeners could contact the presenter/DJ to describe their earworm experiences, and they used an online survey on the radio’s website to collect earworms. This survey allowed people to answer questionnaires and even write descriptions of the songs stuck in their heads. Their results showed eight dominant themes to describe INMI triggering. These themes were then grouped into four abstract categories (listed from most common cause to least):

Music exposure – this theme is divided into recent and repeated. Recent exposure is when you hear music and then later have an INMI experience. Repeated exposure is when you hear the music on multiple occasions before an earworm occurs.

Memory triggers – this theme relates to INMI episodes that are triggered not when you hear a song but when you remember a song. This can happen through Association in which you might sight a person, situation, word, sound, or rhythm that triggers the earworm. Or it may happen through Recollection, a personal memory that acts as the trigger. It may also be the result of Anticipation, an upcoming event that is connected to a tune.

Affective states – this theme is more situational. Your mood, stress level, and emotions can all cause earworms.

Law attention states – this theme is abstract in that it relates to circumstances where the demands on your brain are low. These times are usually when you are dreaming or when your mind wanders.

This is a psychology study and so delves into involuntary retrieval theory and states of mind. I won’t go in to all of that. I’ll simply say that this study is interesting because it categorizes the cues associated with earworms. A simple but effective exercise. If you are like me, then you probably read most or all of those and thought, “Yep, that’s how it happens with me,” or something similar.

A recent study published in Applied Cognitive Psychology, looked into this question of earworms a bit more. These researchers wanted to know what gets stuck and why. This study first uses a survey designed to collect earworm experiences, focusing on the cues that cause them, the nature of re-experiencing the song, and if commonly stuck songs are liked or disliked.

This survey found that a person’s connection to the song predicted which songs became earworms (you usually know your earworm well), and it is usually the result of recent exposure (supporting the "music exposure" results of the previous study). It also showed that the song itself was unique to the individual, and that people generally liked the song stuck in their heads but less so the more often it got stuck. That makes sense; the longer that song is in there the more you just go AHH! You know how you repeat only part of the song over and over, usually the chorus? This science says you aren’t alone, this is how it happens with a lot of people. However, if you are a musician or someone who listens to music constantly or for a large part of the day, you are more likely to develop an earworm. When the researchers had people keep an earworm diary, they found similar results.

Next, the scientists ran a few lab experiments. The first experiment tried to induce an earworm by having participants evaluate songs, then engage in an unrelated task (solving a maze), and then report any earworms. They found no effects of music type but that song order affected both earworm duration and the likelihood that the earworm would return. The last song you hear is probably the one that will get stuck in your head. The next lab experiment investigated the role of cognitive load (how strained your brain is). They used the method of the first experiment with the exception that they made the tasks harder (Sudoku puzzles of various difficulty levels), making the brain work more (hard puzzle = large cognitive load). They found that the last song became an earworm more often regardless of cognitive load, but it played for a longer time in people with more challenging puzzles. Also, if a person reported the last song as an earworm playing during the puzzle then they were more likely to have the song return later (during a lower cognitive low) as compared to those people who didn’t have the song playing during their puzzle. The last experiment was an extension of the cognitive load experiment, this time using a verbal task (solving anagrams of various difficulties) instead of a puzzle. Here, the researchers found similar results to the second experiment in that song order was important, especially for more difficult tasks. However, the last song was experienced less when completing verbal tasks than nonverbal tasks.

Whew. That was a lot of info in a small amount of space. If we sum up Part 1 and 2, what did we learn? Well, when you hear something you like your brain releases dopamine, the feel good, reward stuff. Your brain stores information about the kinds of songs you like and later uses that information to decide if it likes a song if you’ve never heard before. If it decides that you like it then it gives you your reward, making you want to hear that song again. Songs you enjoy are more likely to develop into earworms, particularly if they are the last song you hear, but there are other situational and emotional experiences that can trigger and earworm too (that whole science-is-never-simple thing again).

“I’m gonna pop some tags – Only got twenty dollars in my pocket….” ....*sigh*


Williamson, V., Jilka, S., Fry, J., Finkel, S., Mullensiefen, D., & Stewart, L. (2011). How do "earworms" start? Classifying the everyday circumstances of Involuntary Musical Imagery Psychology of Music, 40 (3), 259-284 DOI: 10.1177/0305735611418553

Hyman, I., Burland, N., Duskin, H., Cook, M., Roy, C., McGrath, J., & Roundhill, R. (2013). Going Gaga: Investigating, Creating, and Manipulating the Song Stuck in My Head Applied Cognitive Psychology, 27 (2), 204-215 DOI: 10.1002/acp.2897


Did you know you can still participate in the earworm study? Just go over to The Earwormery

The above image and a good little article on this topic can be found at 100.3 the Q's article "You Say Earworm, I Say Musicosis"

Music, Earth to Space

The first ever space-to-Earth musical collaboration occurred on February 13, 2013. This endeavor was commissioned by CBCMusic.ca and The Coalition for Music Education with the Canadian Space Agency to celebrate music education in schools across Canada. Col. Chris Hadfield, a Canadian astronaut who is currently living aboard the International Space Station (I.S.S.), Barenaked Ladies, and the Wexford Gleeks from Toronto’s Wexford Collegiate School for the Arts recorded a fantastic single called “I.S.S. (Is Somebody Singing)." The song was co-written by Hadfield and Ed Robertson and explores what it's like to look down on the Earth from outer space. It will also be the official song for this year's edition of Music Monday, which takes place on May 6, 2013.




Here's the sheet music and lyrics courtesy of Music Monday:

Chris Hadfield has become a social media success and is one of the geeks you should be following on Twitter:

Also check out:

Debut of "I.S.S. (Is Somebody Singing)" on CBC Music
CBC Music article: "Ed Robertson takes us behind the writing of 'I.S.S. (Is Somebody Singing)'"

Story via:

Laughing Squid: "Barenaked Ladies Record a Song with Astronaut Chris Hadfield, First Ever Space-to-Earth Musical Collaboration"
Wired: "Astronaut Chris Hadfield Records Single (From the ISS), With Earthbound Barenaked Ladies"

Happy Earth Day!

Happy Earth Day from your friendly, tree hugging, dirt worshiping science blogger!

Here's some Earth Day humor for you.

(images via EarthDayApril, someecards, and videobash)

The Curious Case of the Earworm (Part 1)

I have had “Thrift Shop” stuck in my head for what seems like days.Yes, it is always on the radio, and yes, I usually listen to it when it is playing. Don't judge me. But why (*Stella scream* wwhhhhyyyyy!) has it established a permanent residence in my brain? I’m going to use a few studies to make the case that it isn’t my fault; I’m led around by my biochemistry. Basically, I’m blaming it on my neurons.

Hmmm…where to start. Let’s try to figure out why we like a song (or music in general) in the first place. A study by Valorie Salimpoor et al. in 2011 suggests that it comes down to the biochemistry of pleasure. We, as humans, as animals, find many things in our lives to be pleasurable. Why is this? Well, our brain tells us so. Pleasure is, in essence, a reward for a good stimulus. In the brain, it is largely mediated by dopamine, which also works to reinforce and motivate these behaviors. Now, most people will agree that music is a pleasurable stimulus, but as an abstract stimulus (one not directly related to survival) is it regulated by the same dopamine pathways? In this 2011 study, subjects were asked to select their own “highly pleasurable music” to play for these tests (since musical preferences are so individualized). Then the researchers used PET scanning to estimate dopamine release. Since there are physiological changes that occur during moments of extreme pleasure, they also used the “chills” or “musical frission” response, an objective phychophysiological measurement of clear and discrete patterns of autonomic nervous system arousal. To tease out the response to the music versus the anticipation of the music, they combined the temporal specificity of functional MRI (through the temporal profile of blood oxygenation level - BOLD) with the neurochemical specificity of the PET scan.

Salimpoor's group found that the pleasure experienced when listening to music is associated with dopamine activity, that there was a positive correlation between the intensity of “chills” and dopamine release, and an increased BOLD response. In fact, dopamine levels surge during key passages of favorite music and just in anticipation of it. This release is pivotal for establishing and maintaining the behavior, making listening to music a valued experience.

Ok, biochemistry…check. Let’s go bigger: What parts of your brain light up when you hear music you like? Salimpoor et al. has published a new study in the April 2013 edition of Science that looks at neural processes active when this pleasurable musical event is happening. Specifically, they look at the reward value the first time a song is heard. We now know that dopamine is involved in familiar music, so what about previously unheard music? To test this, the researchers recruited people, asked them to share their musical tastes (“indie” and “electronic” were the most popular), and used music excerpts selected from a music-recommendation software to pick a unheard song within that preference. To assess reward value, to see if participants liked a song enough that they wanted to hear it again, they were given the option purchase the music with their own money (I know if I have to use my own money then I make sure I love it). Then the participants underwent fMRI scans while listening to musical excerpts and were asked to provide bids of how much they were willing to spend for each song.

The researchers found that the reward value (amount of the bid) was directly related to the region of the brain associated with positive prediction error (the NAcc for you brain folks), or pleasant surprises. Increased functional connectivity with this region was made with the auditory cortices, the region known to play a role in the retrieval of previously stored sound information (STG), and the areas implicated in beat processing (caudate and premotor areas). Additionally, increased connectivity was found in regions associated with emotional processing and value-guided decision-making (VMPFC, OFC, and amygdala), but only when sounds gain reward values. When added to the dopamine findings, the activity in these brain regions suggests that when you hear new music your brain looks at its stored information about sound relationships and makes a decision on whether or not to like it based on previous listening experiences and the expectations of tonal events associated with that type of music. If you like it, then your brain gives you a pleasure reward and you end up using your money to buy the song (or otherwise find ways to hear it again). If you like it better than you expected, you get even more delight.

Now we know why we like the song and want to hear it again (and again and again…).In the next post we will go further and explore what turns this likeable song into an earworm. Or is it its likeablity at all? (insert cliffhanger music here…dun dun duuuunnnn…)


Salimpoor, V., Benovoy, M., Larcher, K., Dagher, A., & Zatorre, R. (2011). Anatomically distinct dopamine release during anticipation and experience of peak emotion to music Nature Neuroscience, 14 (2), 257-262 DOI: 10.1038/nn.2726


Salimpoor, V., van den Bosch, I., Kovacevic, N., McIntosh, A., Dagher, A., & Zatorre, R. (2013). Interactions Between the Nucleus Accumbens and Auditory Cortices Predict Music Reward Value Science, 340 (6129), 216-219 DOI: 10.1126/science.1231059


...and an article in ScienceNOW "Why Your Brain Loves That New Song"


(image via rockandtheology)

Scientifically Accurate Spider-Man

What if Spider-Man had the characteristics of a real spider? He probably wouldn't be as popular as he is now.



Note: This will be gross to some people, but pretty hilarious to everyone else. Oh, and it contains some "language," you've been warned and I've been disclaimed

(via NerdApproved via Laughing Squid)

What You Should Know About Dark Matter

This is a really nice infographic about dark matter. You can find more over at SPACE.com including some great links to more information.

Source SPACE.com: All about our solar system, outer space and exploration

Claim Your Place in Space!

KLM is running a particularly awesome contest. You can win a trip to space!

Besides having a ridiculously cool contest website, this is a completely legit contest to win a trip to space worth more than $95,000 (£60,000). You could be part of a revolutionary space project that will see the first commercial space trip take off from Curacao on January 1, 2014.

So how does this work?

On April 22, KLM will launch a special high altitude balloon from the Nevada desert in the US, carrying cameras and a GPS to monitor its exact progress. When you go on to their website you go through a few easy steps to predict how high this balloon will get before it pops. The closest predictor to the actual pop-site wins! KLM will will fly you and a friend to Curacao to stay at a luxury hotel before getting on board the SXC Lynx spaceship.

If you choose to register with a social media account, your friends can even help up your chances to win!

Speaking of which, I posted my entry on Science Storiented's Facebook page. Feel free to help me win!

You only have 6 more days to enter. So hurry!

Here's the contest website:

http://space-origin.klm.com/

Om Nom Nom: The Links Between Plant Diversity and Herbivory

I usually start a post with the reason why a particular article caught my eye. Today, I’m not sure why my eyeballs glommed on to this paper, but they did. As it turns out, they have a pretty good taste in articles. Who knew?

An early view paper from the Journal of Ecology looks at how the large herbivores of the African savanna affect the diversity and community structure of plants. More and more studies these days are taking a phylogenetic approach to community ecology questions. That is, they are looking at the evolutionary development and history of a species or taxonomic group to explain the patterns that we currently see. This new study takes this approach in the subtropical woodland biome, or “bushveld,” of the Kruger National Park (KNP) in northeast South Africa. This area is home to 148 mammal species, of which 30 are large herbivores such as elephants, rhinos, and giraffes. The vegetation of this area consists of 1974 species, including 458 species of trees and shrubs. KNP varies from dense thicket, savanna woodlands to forests characterized by tall trees and a closed canopy. These plant communities are under occasional pressure from periodic fire and under constant pressure from large herbivores. This study looks at the impacts of these herbivores on the phylogenetic structure of woody plant assemblages and evaluates the impacts of their removal on plant community composition and structure.

The researchers used DNA sequencing to reconstruct the phylogeny of 448 species of trees and shrubs (using Amborella as an outgroup), representing 246 genera, 71 families and 31 orders. ... Let’s pause for a second to say “Wow!” ... Then they calculated divergence times and used speciation models on these data. Next was the community sampling along a north-south transect through KNP. This transect has enclosures situated along it where large herbivores are partly or fully excluded. These enclosures have been established in the park for between 8 and 43 years. Within 15 defined “ecozones,” the researchers surveyed 110 50x50 meter unrestricted herbivory plots and 15 50x50 meter plots in each of the five herbivore exclusion enclosures. Within these plots they recorded all species of trees and shrubs and the number of individuals per species (abundance). Then they evaluated various physical and mechanical plant defense traits (not including chemical defenses), using wood density of quantify plant resistance to physical damage and specific leaf area (SLA) as a proxy for leaf nutrient content.

All sorts of indices (MPD, MNTD, SR, Shannon, NRI, NTI) and statistics were used that I’m not going to go into because they will just confuse everyone. But when all the statistics were done, they found a latitudinal gradient in diversity with the highest diversity in the south and extreme north and low diversity in the center (which matches rainfall patterns). In parallel, they found shifts in community phylogenetic structure comparable to these changes in community diversity, indicating that the communities in the center are more highly phylogenetically clustered (composed of more closely related species). Plant diversity in the KNP is strongly spatially structured and this clustering is reflective of generalist browsing, the geomorphology of the area, and the patchy distribution of large herbivores. In plots where herbivory is unrestricted they found significant phylogenetic clustering of plant communities, likely the result of the heavy pressure from the herbivores. They also found that plant defense traits had a weak but significant phylogenetic signal, suggesting that they do not fit well into the simple model they used. When the researchers compared the enclosures to the unrestricted areas they found “that when megaherbivores are excluded, species diversity generally decreases, but changes in phylogenetic diversity [vary] by spatial location.” When large herbivores are excluded, plant community structure is contingent upon the initial community structure. If a community was initially overdispersed then the shift towards a more clustered community would occur by excluding large herbivores and vice versa. Ultimately, they conclude that the exclusion of large herbivores results in impoverished species communities.

I think that it is important to mention that these researchers were limited by the study design they had to work with. These enclosures had already been set up by other people. As such, the scientists encountered some issues that they would have been able to control for if they had set up the site themselves. Issues like enclosure age and location. For example, one enclosure was located on a river that periodically floods, altering local plant diversity. Such issues make it difficult for them to predict how specialist vs. generalist herbivores impact community structure and prevents them from drawing strong conclusions about the underlying causes for the patterns they saw.

On the upside, their results add valuable knowledge critical for predicting the impacts of overall herbivore decline on African ecosystems and local increases of these animals in protected reserves. This study “shows not only that large herbivores are key to maintaining woody plant diversity, but also that they may impose specific phylogenetic structure on plant communities.” Shifts in this structure have downstream consequences in that phylogenetic diversity can capture genetic and functional diversity, which has been linked to ecosystem productivity. And, ultimately, we want to keep our ecosystems happy and productive, right?


Kowiyou Yessoufou, T. Jonathan Davies, Olivier Maurin, Maria Kuzmina, Hanno Schaefer, Michelle van der Bank, & Vincent Savolainen (2013). Large herbivores favour species diversity but have mixed impacts on phylogenetic community structure in an African savanna ecosystem Journal of Ecology : 10.1111/1365-2745.12059


(image via Animals Time)

Epic Battle of Electricity

If you haven't watched Epic Rap Battles of History then you need to hop on that train. It is hysterical! Here's a recent rap battle featuring two epic minds of their time and their actual battle over electricity.

Unraveling Spider Silk

An interesting infographic about spider silk.

(via The Guardian)