Links for Splash Students

If you came to How Human Memory Works, and want more interesting psych/neuroscience to read, I recommend:

Blogs:

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Some myths about the brain, such as the idea we only use 10% of our grey matter, are notorious, especially among neuroscientists. These myths crop up every now and then (look at the premise of the Lucy movie this summer), but they are quickly shot down by those in the know.

In contrast to these enduring stories, other misconceptions are stealthier and slip beneath the radar unrecognised. One of these is the idea that the human brain is served by five senses. This belief is so ingrained that even the scientifically literate will treat it as taken-for-granted common knowledge.

From Christian Jarret at the BBC, “How many senses do we have?”

Perceptual psych folks often talk about how we have more than five senses; I think this is the first time I’ve seen someone put forth a hypothetical grouping in which we have fewer.

From the “Mind-Blowing Animal Behavior” files

I’m not going to even to try to summarize this; just go over to Ed Yong’s blog and read about how groupers and moray eels collaborate to hunt down prey. Using gestures to communicate. There are videos.

The giant moray eel can grow to three metres in length and bites its prey with two sets of jaws—the obvious ones and a second set in its throat that can be launched forward like Hollywood’s Alien. It’s not a creature to be trifled with. But the coral grouper not only seeks out giant morays, but actively rouses them by vigorously shaking its body. The move is a call to arms that tells the moray to join the grouper in a hunt.

The two fish cooperate to flush out their prey. The grouper’s bursts of speed make it deadly in open water, while the moray’s sinuous body can flush out prey in cracks and crevices. When they hunt at the same time, prey fish have nowhere to flee.

Sanity-checking

Last week, I ran some EEG data through an analysis that should find clusters of electrodes that recorded high activity at the same time. In other words, it looks for spatial and temporal adjacency. The cluster that it found looks like this:

wonky-cluster

That’s a map of all of the electrodes on our EEG nets, and the big blue circles overlay the electrodes that were part of my cluster. Hopefully it is apparent to you that this cluster has a topographically odd feature – the hole in the middle! Clusters don’t (generally) have holes like that – the correlation between adjacent electrodes is pretty high – and I knew from looking at the maps of overall activity that there wasn’t an activity dip in the center of that cluster. The particular electrode making up my hole was even more disconcerting because it is electrode Cz, the one that sits at the center of the top of the head, and when we record our EEG data that electrode is the reference. As data comes off the system, the trace at Cz is always zero, because measuring voltage requires a reference point. Although the data should have been re-referenced before the clustering algorithm, the worst-case “What when wrong here” answers involved the re-referencing having been lost, and that would be a major bug in an analysis that has been used already in several studies in the lab. Scary.

It turned out not to have been that bug, but another issue entirely. The first step in the clustering analysis is to take the spatial layout of electrodes, and define each electrode’s “neighborhood” – which other electrodes should be counted as “adjacent” to the electrode in question. The piece of code that does this takes in a list of names of electrodes you want to define neighborhoods for (in my case, all of them except the two eye-movement channels) and matches that list to a master list of electrode names and their positions. And in that master list, the electrode Cz was listed with its name as Cz’. Turns out, Cz and Cz’ don’t match, if you’re a computer, so Cz is never included in any neighborhoods, and so doesn’t turn up in the final cluster. Fixing the master layout list got me clusters including Cz, and all is well.

This kind of thing really illustrates the importance of having a human being look at your output, and think about whether the answer the computer is giving is plausible. I’m still working on how to best teach students to bring their critical eyes to this kind of output, and not just assume that the computer is right. Part of it is just developing enough experience to know what the results “should” look like, but in a lot of cases students already have a great deal of knowledge to bring to bear. It’s the same reason that I plot really raw data as often as I can – I’m not necessarily going to publish these graphs, but understanding what’s happening in my data set is essential, both for sanity-checking and to develop a theoretical understanding of what participants, or their brains, are doing.

Music is one of those topics my students always want to know about, and that I feel totally unqualified to teach. This colloquium at BU tomorrow looks really interesting, I wish I could make it over there!

The Science of Music: 150 Years Since Helmholtz’s On the Sensations of Tone

If you click through, the list of speakers and titles is pretty exciting. For example,

“Musical Illusions, Perfect Pitch, and Other Mysteries”
Diana Deutsch
Psychology, UC San Diego

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.