Useful Matlab Snippet of the Day

The filesep command for cross-platform compatibility.

F = filesep returns the file separator character for this platform.
The file separator is the character that separates
directory names in filenames.

We Aren’t the World

Economists and psychologists, for their part, did an end run around the issue with the convenient assumption that their job was to study the human mind stripped of culture. The human brain is genetically comparable around the globe, it was agreed, so human hardwiring for much behavior, perception, and cognition should be similarly universal. No need, in that case, to look beyond the convenient population of undergraduates for test subjects. A 2008 survey of the top six psychology journals dramatically shows how common that assumption was: more than 96 percent of the subjects tested in psychological studies from 2003 to 2007 were Westerners—with nearly 70 percent from the United States alone. Put another way: 96 percent of human subjects in these studies came from countries that represent only 12 percent of the world’s population.

Henrich’s work with the ultimatum game was an example of a small but growing countertrend in the social sciences, one in which researchers look straight at the question of how deeply culture shapes human cognition. His new colleagues in the psychology department, Heine and Norenzayan, were also part of this trend. Heine focused on the different ways people in Western and Eastern cultures perceived the world, reasoned, and understood themselves in relationship to others. Norenzayan’s research focused on the ways religious belief influenced bonding and behavior. The three began to compile examples of cross-cultural research that, like Henrich’s work with the Machiguenga, challenged long-held assumptions of human psychological universality.

from the Pacific Standard, via my cousin Peter on the Facebook.

Read the whole thing, it’s an excellent introduction to the research that led to the hypothesis that most psych studies are carried out on a WEIRD (Western, Educated, Industrialized, Rich, and Democratic) population, and that people growing up in WEIRD societies may have drastically different understandings of the world. The discovery that many things we thought were hardwired into humans are actually strongly affected by culture has shaped conversations across psychology in the last few years, and the article has many examples of both small and large cultural differences that shape human behavior.

Crossmodal processing of vision and olfaction

Crossmodel perceptual illusions and effects are long-established, but they usually involve the relationship between vision and audition (like in the McGurk effect).

I’ve seen more of these involving other modalities lately, though. Last year’s Best Illusion of the Year winner was a vision/proprioception illusion:

And a recent paper in J Neuroscience uses olfaction to affect binocular rivalry.

In their main experiment, Zhou and colleagues showed people rival pictures of a rose and a banana at the same time. While doing this, they gave their volunteers the smell of a rose, and people became more likely to see the image of the rose.

When they gave them the smell of the banana, they were more likely to see the banana.

From NeuroDojo.

“they concealed themselves under beds in students’ rooms”

The consistently-fascinating Mind Hacks has a story today about a really pretty sketchy study from 1938, in which researchers were trying to measure some aspects of student conversation without inducing any reactivity.

In order not to introduce artifacts into the conversations, the investigators took special precautions to keep the subjects ignorant of the fact that their remarks were being recorded. To this end they concealed themselves under beds in students’ rooms where tea parties were being held, eavesdropped in dormitory smoking-rooms and dormitory wash-rooms, and listened to telephone conversations.

The rest of his write-up is here.

Simulated grunts throw off non-tennis-players in a “where’s that ball” task

Do y'all remember, from earlier this summer, the outrage that was arising in the pro tennis world over grunting? Pro-grunting players argue that producing such a sound when hitting the ball is a completely reasonable technique to get as much power as possible, while anti-grunting players argue that "excessive" noises are cheating, by preventing the opponent from hearing the sound of the ball hitting the racket, and are distracting to boot.

A PLoS ONE paper that just came out looked at precisely this question. Well, sorta this question. A laboratory approximation of this question, in which undergraduate students (none with "more than recreational tennis experience," they reassure us) watched clips of a tennis ball being hit and had to say where it landed.

They had "a professional tennis player" (no discussion of the gender or skill level of this player) hit forehand or backhand shots down a court towards a video camera centered on the far baseline, and collected clips of shots that landed in a 2 x 2 meter square at the corner of the sideline and the baseline. They counterbalanced their collection so that they had equivalent numbers of forehand and backhand shots going to each side, and then they showed each clip four times: twice with a simulated grunt (500 ms of white noise) and twice without; of these, each was shown once with the clip ending immediately upon the ball's landing, and once with the clip playing for 100 ms longer. (The instant-cutoff made the judgment task harder; the longer time to process the visual was easier. Maybe grunts only matter for hard-to-perceive things.) They asked the students who watched these clips to determine if the ball landed to the left or the right of the camera.

And what did they find?

Tennis fig 1
Here we see reaction time (so, lower is faster/better); dark bars are when the video was shown with a grunt, white bars are clips shown in silence. The hard judgements (when the clip ended exactly as the ball landed) are clearly made more slowly than the easy judgements – that's not surprising. More impressive is that the simulated grunt clearly slows people down (their ANOVA found no interaction between decision difficulty and sound; that is, the grunt had the same effect on easy-decision trials and hard-decision trials). People are 20 – 30 ms slower when they hear the noise at the same time as the player hits the ball.

Tennis fig 2
Same pattern for accuracy – people make fewer errors on easy trials than on hard ones, and fewer errors when the grunt is played than without. It's a difference of 3-4 %, but that's non-trivial in professional tennis!

This is a very pretty set of data – they've got a clean-cut effect, that's significant when measured in both error/accuracy and in reaction time – I'm jealous. My data should be this pretty.

My questions for these guys are about the validity of their task. In particular, they're showing people monocular stimuli -  a video on a computer screen isn't going to give you the three-dimensionality that you get when viewing stimuli with two eyes in the real world.

They also used a 500 ms burst of white noise for the simulated grunt – how does the length of that compare to the actual tennis grunts that are the source of such controversy?

Finally, how precise was the timing of that burst of noise? They only say "during the shot" – we know from work on the bouncing/streaming illusion that the timing of sounds played during visual perception can have huge effects on how we perceive objects to be moving.

Sinnett S., & Kingstone A. (2010). A preliminary investigation regarding the effect of tennis grunting: Does white noise during a tennis shot have a negative impact on shot perception? PLoS ONE 5(10): e13148. doi:10.1371/journal.pone.0013148

In which I continue to be a total Jonah Lehrer fangirl

The [emotional importance of authenticity also] applies to brands. Although we outgrow stuffed animals, we never get beyond the irrational logic of authenticity and essentialism. There are certain things whose value depends largely on their legitimacy. While I might listen to bootleg music on my iPhone, I want the phone to be genuine. I want that Apple logo to be real. Why? Because the brand has effectively woven itself into my emotional brain.* Because when I see that logo, I don’t see a functional object. Instead, I’ve learned to respond to everything that isn’t functional, all those subtle connotations conveyed in the glossy ads. There are many blankets in the world. But there is only one blankie. The best brands are blankies.

at The Frontal Cortex

Patience : The Frontal Cortex

This study, led by Bernd Figner at Columbia, used TMS to disrupt the lateral prefrontal cortex while people were debating whether or not to delay for a larger reward. The end result was that people became much more impulsive: when the massive beam of electromagnetism was aimed at our forehead, we found it harder to delay gratification, and became significantly more likely to choose $20 right now, instead of $25 next month.

The Frontal Cortex – Patience

Yet another round of fMRI lie detection attempts

An attorney in NY is pushing to use fMRI evidence to demonstrate that a witness is telling the truth. While there are some studies showing differences in activation between deception and truth-telling, there's broad doubt that these findings are replicable in real-life settings, where the stakes are higher and the task is less constrained. And then there's the problem of asking juries to assess this evidence.

Juries tend to be overly credulous about any evidence offered as forensic or scientific evidence. And other studies show that imaging studies generate an extra layer of overcredulousness. (On those, see Dave Munger and Jonah Lehrer.) So when an 'expert' shows a jury a bunch of brain images and says he's certain the images say a person is lying (or not), the jury will led this evidence far more weight than it deserves.

Neuron Culture: Who
you gonna believe, me — or my lyin' fMRI?

Scholars Turn Their Attention to Attention – The Chronicle Review – The Chronicle of Higher Education

In the Chronicle:

Foerde and her colleagues argue that when the subjects were
distracted, they learned the weather rules through a half-conscious
system of "habit memory," and that when they were undistracted, they
encoded the weather rules through what is known as the
declarative-memory system. (Indeed, brain imaging suggested that
different areas of the subjects' brains were activated during the two

That distinction is an important one for educators, Foerde says,
because information that is encoded in declarative memory is more
flexible—that is, people are more likely to be able to draw analogies
and extrapolate from it.

"If you just look at performance on the main task, you might not see
these differences," Foerde says. "But when you're teaching, you would
like to see more than simple retention of the information that you're
providing people. You'd like to see some evidence that they can use
their information in new ways."

via marbury

This is one of the sanest reviews I've seen of what we know about multitasking, attention, and learning. No flailing about how the Internet is destroying civilization, but some real concerns about the compatibility of multitasking and specific tasks.

The recent kerfuffle over Chronic Fatigue Syndrome has highlighted how strongly many people still believe in a distinction between the physical and the psychological

When the philosopher A.C Grayling (who seemed to be giving an impression of a philosopher rather than actually being one) came to speak, he peered out at the audience over his horn-rimmed glasses and said something like, "I don't expect there are any dualists here, and there certainly aren't on this panel". His point being that the old Cartesian idea that there are minds and bodies and never-shall-the-twain-meet has been decimated in recent decades, as a respectable intellectual position, by the amazing discoveries of scientists studying the brain.

And yet elsewhere this assumption lives on. In this otherwise very good piece in yesterday's Times on chronic fatigue syndrome, everyone, from the writer to the experts to the sufferers, frames the question of the condition's causes as if we were still living in a dualist world. To take one example:

Stephen Holgate, professor of immunopharmacology at the University of
Southampton, chairs the Medical Research Council’s expert group on CFS/ME.
“As a clinician who sees patients with this group of diseases I recognise
there’s a real thing here, it’s not all psychiatric or psychological,” he


The Mind Hacks article he links to is also excellent.