Category: Cognitive anthropology

Smell, fear and sensory learning

Blogging on Peer-Reviewed ResearchWen Li, James D. Howard, Todd B. Parrish, and Jay A. Gottfried have a fascinating article in the most recent edition of Science, ‘Aversive Learning Enhances Perceptual and Cortical Discrimination of Indiscriminable Odor Cues.’ The researchers trained subjects to discern between the aroma of chemicals that initially were indistinguishable using electric shocks (!) coupled with one of the two aromas. The research is a great example of perceptual learning, a form of neural enculturation that I think is absolutely essential to understanding cultural difference but little appreciated in anthropology.

Subjects in the experiment were given a test of their ability to discern between very closely related chemicals: ‘On each trial, subjects smelled sets of three bottles (two containing one odorant, the third containing its chiral opposite) and selected the odd stimulus.’ Before the training, subjects selected the odd odor out 33% of the time — no better than random. After the repeated association of one chemical with shocks, subjects’ ability to discriminate the smells improved markedly, showing that negative reinforcement training could ‘enhance perceptual discriminability between initially indistinguishable odors.’ Moreover, the neural representation of the smells changed, as found with fMRI.

From their abstract:

We combined multivariate functional magnetic resonance imaging with olfactory psychophysics to show that initially indistinguishable odor enantiomers (mirror-image molecules) become discriminable after aversive conditioning, paralleling the spatial divergence of ensemble activity patterns in primary olfactory (piriform) cortex. Our findings indicate that aversive learning induces piriform plasticity with corresponding gains in odor enantiomer discrimination, underscoring the capacity of fear conditioning to update perceptual representation of predictive cues, over and above its well-recognized role in the acquisition of conditioned responses. That completely indiscriminable sensations can be transformed into discriminable percepts further accentuates the potency of associative learning to enhance sensory cue perception and support adaptive behavior.

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How your brain is not like a computer

At the end of my last post, or the one before that, I had a late-night ‘inspiration’ that must have sounded a bit like an outburst about how our brains are not like computers. There’s lots of good reasons for making that assertion, whether or not it’s an outburst. But one of the key issues is concern about ’embodiment’ in cognitive science and the discussion of embodied cognition. Daniel, in his comments, put a link to the posting by Chris Chatham, 10 Important Differences Between Brains and Computers, which is excellent. There’s also an interesting discussion of this going on at Dr. Ginger Campbell’s blog on her Brain Science Podcasts, both of which (discussion and podcasts) I strongly recommend. See the first two topics on the list you can find here on ‘Artificial Intelligence.’

For the anthropologists in our audience, however, the term ’embodied cognition’ is a bit unfortunate, not because it’s not a great term, but because an earlier intellectual movement in anthropology already snagged the adjective ’embodied’ and then didn’t push the issue far enough to actually deal with physiological and biological dimensions of being embodied. That is, in anthropology, the term ’embodiment’ has not been allowed to really stretch its wings, and has instead been more narrowly constrained to dealing with phenomenological, interactional, and theoretical issues deriving primarily from feminism, Foucauldian post-structuralism, and Bourdieu-ian sociology. All of these streams are important, but they do not yet engage with the sort of material that cognitive scientists mean when they use the term ’embodied.’ The danger is that anthropologists will see the term, ’embodied cognition,’ and it will not seem quite as disruptive to anthropology-as-usual as it should be.

Chatham’s posting makes this key issue clearer in his tenth reason that brains are not like computers: brains have bodies:

This is not as trivial as it might seem: it turns out that the brain takes surprising advantage of the fact that it has a body at its disposal. For example, despite your intuitive feeling that you could close your eyes and know the locations of objects around you, a series of experiments in the field of change blindness has shown that our visual memories are actually quite sparse. In this case, the brain is “offloading” its memory requirements to the environment in which it exists: why bother remembering the location of objects when a quick glance will suffice? A surprising set of experiments by Jeremy Wolfe has shown that even after being asked hundreds of times which simple geometrical shapes are displayed on a computer screen, human subjects continue to answer those questions by gaze rather than rote memory. A wide variety of evidence from other domains suggests that we are only beginning to understand the importance of embodiment in information processing.

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Time Globalized

Blogging on Peer-Reviewed ResearchStefan Klein has an editorial, Time Out of Mind, in today’s New York Times, where he writes “the quest to spend time the way we do money is doomed to failure, because the time we experience bears little relation to time as read on a clock. The brain creates its own time, and it is this inner time, not clock time, that guides our actions.”

 He elaborates on this argument as follows:

Inner time is linked to activity. When we do nothing, and nothing happens around us, we’re unable to track time… To measure time, the brain uses circuits that are designed to monitor physical movement. Neuroscientists have observed this phenomenon using computer-assisted functional magnetic resonance imaging tomography. When subjects are asked to indicate the time it takes to view a series of pictures, heightened activity is measured in the centers that control muscular movement, primarily the cerebellum, the basal ganglia and the supplementary motor area. That explains why inner time can run faster or slower depending upon how we move our bodies — as any Tai Chi master knows.Time seems to expand when our senses are aroused. Peter Tse, a neuropsychologist at Dartmouth, demonstrated this in an experiment in which subjects were shown a sequence of flashing dots on a computer screen. The dots were timed to occur once a second, with five black dots in a row followed by one moving, colored one. Because the colored dot appeared so infrequently, it grabbed subjects’ attention and they perceived it as lasting twice as long as the others did. 

Klein then links this argument to stress: “Believing time is money to lose, we perceive our shortage of time as stressful. Thus, our fight-or-flight instinct is engaged, and the regions of the brain we use to calmly and sensibly plan our time get switched off. We become fidgety, erratic and rash… Tasks take longer. We make mistakes — which take still more time to iron out. Who among us has not been locked out of an apartment or lost a wallet when in a great hurry? The perceived lack of time becomes real: We are not stressed because we have no time, but rather, we have no time because we are stressed.”

 His conclusion? “The remedy is to liberate ourselves from Franklin’s equation. Time is not money but ‘the element in which we exist,’ as Joyce Carol Oates put it more than two decades ago (in a relatively leisurely era). ‘We are either borne along by it or drowned in it’.”

 By coincidence, Kevin Birth, professor of anthropology at Queens College-CUNY, wrote us about our blog recently, highlighting his own work on time, anthropology and biology.  Birth has a recent article, “Time and the Biological Consequences of Globalization (full pdf).”  Given that we live on a “rotating globe where each locale has its own cycles of day and night,” our present globalized economic system produces some severe contradictions that people struggle with in everyday life: “temporal conflicts between locations on the globe, desynchronization of biological cycles, and lack of correspondence between those cycles and social life.”

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Puzzles and Cultural Differences

Blogging on Peer-Reviewed ResearchHere’s some interesting research where neuroscientists are using brain scans to show that cultural differences reach down to the level of functional activation in the brain.  Americans had a harder time with visual puzzles that required manipulating objects in context than “East Asians.”  Here a quote from the news article:

 

Neuroscientists Trey Hedden and John Gabrieli of MIT’s McGovern Institute for Brain Research asked Americans and East Asians to solve basic shape puzzles while in a functional magnetic resonance imaging (fMRI) scanner. They found that both groups could successfully complete the tasks, but American brains had to work harder at relative judgments, while East Asian brains found absolute judgments more challenging. Previous psychology research has shown that American culture focuses on the individual and values independence, while East Asian culture is more community-focused and emphasizes seeing people and objects in context. This study provides the first neurological evidence that these cultural differences extend to brain activity patterns.

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Autism and Mirror Neurons

Autism has been my latest lens for learning about neuroanthropology. It started with reading claims that autism is linked to mirror neuron disfunction. Mirror neurons are currently used to explain how the brain understands the intentions and emotions of others. Researchers suggest that lack of brain activity in mirroring areas of the brain found in autistic children could explain deficits in social interaction and empathy. A related article on the site links the mirror system to the study of culture: Culture Influences Brain Cells: Brain’s Mirror Neurons Swayed By Ethnicity And Culture. A study compared reactions of subjects to both American and Nicaraguan hand gestures, measuring differences in mirror neuron activity in the brain depending on who was giving the information and whether they were a member of their own ethnic group or a different group.

“We believe these are some of the first data to show neurobiological responses to culture-specific stimuli,” said Molnar-Szakacs. “Our data show that both ethnicity and culture interact to influence activity in the brain, specifically within the mirror neuron network involved in social communication and interaction… An important conclusion from these results is that culture has a measurable influence on our brain and, as a result, our behavior. ” “We are the heirs of communal but local traditions,” said Iacoboni. “Mirror neurons are the brain cells that help us in shaping our own culture. However, the neural mechanisms of mirroring that shape our assimilation of local traditions could also reveal other cultures, as long as such cross-cultural encounters are truly possible. All in all, our research suggests that with mirror neurons our brain mirrors people, not simply actions.”

I’m still trying to wrap my mind around this article—it seems as if it would be a given that culture impacts behavior so am not sure if they discovered something new so much as found a more scientific way of measuring it. Could this possibly be a tool that would indicate whether someone would suffer from culture shock? And linking it back to the first article, would this imply that autistic people would have equal trouble picking up on social cues regardless of who they are with while for others it would depend on whether they share the same cultural background?

Neuroanthropology and Everyday Design

Today’s article by John Tierney, Why Nobody Likes a Smart Machine, from the Tierney Lab illustrates several points that neuroanthropologists should pay attention to.  It’s about the work of Donald Norman, best known for his book “The Design of Everyday Things,” and his analyses for why modern technology often frustrates people so much.  (By the way, I just bought my wife one of those picture frames mentioned in the article for Christmas—ah, a bundle of frustrating joy.)  So, in the course of the article, Tierney and Norman mention four different aspects of how we relate successfully or unsuccessfully to machines (and, from my point of view, much of the world).  They are: 

-Predictability (the pedestrian who keeps walking so the bicyclist easily avoids him)

-Being Understandable (human-sized signals like the whistle from a tea kettle; having an intuitive feel—read, culturally modeled, metaphorically presented, and visually and tactically available)

-Control (the clever solution to wrapping a wet paper towel around the electronic sensor on the bathroom faucet)

-Feeling Helpless (computerized shades that worked on their own without being able to be locally manipulated) 

These factors are tied up into three related phenomena—evolution, culture, and the brain—at the core of neuroanthropology.  In this case, they are (1) achieving behavioral success in often stochastic evolutionary environments, where acting on environmental information in goal-directed ways often led to good things (like food) (the evolutionary problem), (2) how culture built off human tendencies—our ability to apply learned, controllable, regular solutions in novel ways (but not badly designed ways—hence the problems with some technology) (the cultural side), and (3) the brain systems that handle stress, where unpredictable, uncontrollable stressors are the ones that make us react the most (the brain).  Hence, the predictable line of frustration, anger, and then simply giving up and making do the best you can with the present situation. 

Plus Norman did participant observation and interviewing as his methodological approach!  If you want to talk more, just email me at dlende@nd.edu.  Best, Daniel Lende