Laura’s Psychology Blog

You may think I have far too much time on my hands (definitely not true as we enter the “midterm” phase of the quarter), but I took some time out to enjoy a feature on the BBC, one of my favorite news sources. The feature includes six different tests that are supposed to tell you if you think more like a man than a woman. Not too surprisingly, my overall results show that I think like a woman, but a fairly systems oriented one.

My results were quite mixed. My finger length is quite female, but I did very well on some of the spatial tests. I find masculine looking men more attractive (anyone who knows my husband would say “duh” to this). I’m not too good at matching eyes to emotions, and I am definitely more interested in systems than most women. That probably explains the football/videogame thing, not to mention my interest in science and engineering.

In a less scientific mode, Blogthings offers another male/female “brain test.” On this one, I scored 47% female and 53% male–not too sure what to make of that. Maybe I’ll try their “How Redneck Are You?” test next…..

Some people are still rather upset at the idea that men and women might think differently. I’ve noticed that this is a much more comfortable concept in Great Britain than in the United States. For an outstanding review of sex differences, check out Doreen Kimura’s article for Scientific American.Then go ahead and take the tests with a grain of salt, but enjoy!

I love computers. My students are blissfully unaware of the challenges of typing a dissertation on a Smith-Corona portable electric typewriter or using a slide rule in a graduate statistics course. Still, I’d like to continue to think that the human brain can outperform computers, at least in some tasks.

One of our traditional advantages has been our ability to quickly categorize visual information. If usually takes us about 20 ms to decide whether an object is an animal or not. Now Thomas Poggio and his colleagues at MIT have designed a computer model that does a pretty good job on these rapid recognition tasks. [1]

The computer model also lends support to a hierarchical model of visual perception in rapid recognition tasks, in which simpler processing is built upon by more complex layers of processing. Eventually, one reaches a hypothetical ”grandmother” cell that responds to the image of your grandma at the front door for a visit. Because the computer model does not use feedback loops, in which higher level processes revisit lower levels, while producing responses that were similar to human responses, Poggio and colleagues suspect that rapid recognition does not require feedback loops in people either.

The full-text of this article along with the stimuli used and other resources may be found on the PNAS website.

1.  Serre, T., Oliva, A., & Poggio, T. (2007). A feedforward architecture accounts for rapid categorization. Proceedings of the National Academy of Sciences, USA, 104(15), 6424-6429.

Whenever I’ve felt blue, I know that one sure cure is to tackle my garden. Of course, living in California makes this a year-round option. No matter what type of problem had been bothering me, I always felt better after spending some time outdoors, even if that meant yanking weeds.

Researchers at the University of Bristol and the University College London might have shed some light on my favorite mood-boosting exercise. Mice exposed to a type of bacteria commonly found in soil, Mycobacterium vaccae, acted as though they had received treatment with antidepressant medication. Apparently, exposure to M. vaccae boosted the activity of serotonergic neurons. Serotonin activity, of course, appears to be correlated with mood.

These experiments originated from observations that cancer patients being treated with M. vaccae reported improvements in well-being. Why would we use bacteria to treat cancer? Apparently, M. vaccae treatment has a beneficial effect on a person’s immune system [2].

Oddly enough, when I looked around for pictures of kids playing in dirt for this post, I found more warnings about NOT doing this due to the potential for lead poisoning. One government site features this picture with the admonition to “Cover bare dirt where children play with plants, paving stones, concrete, or bark.”

Perhaps a little common sense is useful. In our quest to meet modern standards of cleanliness, we are also reminded that a little bit of playing in the mud may not be such a bad thing. After all, our ancestors were no Martha Stewarts.

1. Lowry CA, et al., Identification of an immune-responsive mesolimbocortical serotonergic system: Potential role in regulation of emotional behavior, Neuroscience (2007), doi: 10.1016/j.neuroscience.2007.01.067
2. Rook GA et al. (2004). Mycobacteria and other environmental organisms as immunomodulators for immunoregulatory disorders. Springer Seminars in Immunopathology 25: 237-255.

Kevin Corcoran and Gregory Quirk have demonstrated an interesting difference in the way learned and innate fears are managed by the brains of rats [1].

Learned fear is typically demonstrated using classically conditioned emotional responses. While a rat barpresses for food, a neutral stimulus such as a tone is presented followed by an electric shock. After several pairings, rats will reduce their barpressing rate during the tone (fear in rats often results in freezing, which of course is incompatible with barpressing for food).

Corcoran and Quirk deactivated the prelimbic cortex of the rats prior to testing using tetrodotoxin (TTX), which blocks sodium channels on the axon membrane, bringing signaling to a halt. TTX is found in some species of pufferfish, and is responsible for the illness or death of some people enjoying fugu, or sushi made from puffers. The rats treated with TTX showed little or no signs of fear during testing with the tone, demonstrating that the prelimbic areas were necessary for the normal expression of fear.

In contrast, when the rats were treated with TTX, they responded with normal freezing in situations that are believed to represent innate fear. If cats were placed in an adjacent enclosure, the rats would freeze. When placed in an open space, which is normally quite frightening to rodents, the treated rats ran for the walls just like untreated rats.

The basic conclusion, therefore, is that the prelimbic areas are not necessary for responding to innately fearful situations, but are quite necessary for the expression of learned fear. These anatomical differences between learned and innate fears might ultimately lead to more effective treatments for learned fears such as phobias and post-traumatic stress disorder.

1.  Corcoran, K.A., & Quirk, G.J. (2007). Activity in prelimbic cortex is necessary for the expression of learned, but not innate, fears. Journal of Neuroscience, 27(4), 840-844.

Once again, Antonio Damasio and his colleagues have found a creative way to illustrate the effects of specific brain damage, in this case the ventromedial prefrontal cortex or VMPC. Participants with damage to the VMPC due to aneurysm or tumor growth, healthy participants, and participants with brain damage in areas outside the VMPC were asked to respond to a number of moral dilemmas reminiscent of Kohlberg’s research on moral development.

Here is one of the scenarios. What would you do?

“You are the captain of a military submarine travelling underneath a large iceberg. An onboard explosion has caused you to lose most of your oxygen supply and has injured one of your crew who is quickly losing blood. The injured crew member is going to die from his wounds no matter what happens.

The remaining oxygen is not sufficient for the entire crew to make it to the surface. The only way to save the other crew members is to shoot dead the injured crew member so that there will be just enough oxygen for the rest of the crew to survive.

Would you kill the fatally injured crew member in order to save the lives of the remaining crew members?”

The participants with VMPC damage were more likely to say that they would kill the injured crew member than the healthy controls or people with damage to other brain areas. In contrast, people with VMPC damage were equally likely as other participants to agree that a vaccine that saves a lot of people should be used even if it produces adverse effects in a few individuals. Damasio and his colleagues argue that the latter scenario is relatively unemotional and impersonal, whereas the submarine scenario requires personal action.

Given the role of the VMPC in producing normal social emotions, these results indicate that typical moral judgments are not a matter of pure logic. Instead, emotions play an important role in our sense of right and wrong.