Saturday, November 29, 2008

The Value of Believing in Free Will

Vohs, K.D. & Schooler, J.W. (2008). The Value of Believing in Free Will. Psychological Science, 19, 1, 49-54.

This study found that weakening people's belief in free-will increased ignoble behaviors, specifically cheating. In the first experiment, a passive cheating paradigm was explored in which a computer "glitch" allowed the correct answer to a question to be flashed onto the screen unless the participant explicitly suppressed it. The experimental group was read a statement encouraging a belief in determinism, while the control condition was read an unrelated statement. Those in the experimental group showed weaker free will beliefs and more frequent cheating.

In the second experiment, an active cheating paradigm was explored. After reading either a pro-free-will statement or an anti-free-will statement, participants were left in the room on the "honor system" and told to reward themselves for their number of correct responses. In this experiment, as in the previous one, participants were under the impression that their anonymity was preserved. Results were similar with the determinism condition showing weaker free will beliefs and higher than average cheating. Thus, people's beliefs regarding their sense of control and self-agency may have social implications.

Saturday, November 22, 2008

Different lateral amygdala outputs mediate reactions and actions elicited by a fear-arousing stimulus

Amorapanth, P., LeDoux, J.E., & Nader, K. (2000). Different lateral amygdala outputs mediate reactions and actions elicited by a fear-arousing stimulus. Nature Neuroscience, 3, 1, 74-79.

One common reaction to threat is elicitation of unlearned species-typical defense reactions. Another is the ability to take novel actions in threatening situations, which may also prove advantageous. In escape-from-fear (EFF) tasks, animals come to learn that an arbitrary response (e.g. stepping into the adjoining chamber) terminates a CS which predicts shock. Authors placed lesions throughout the fear circuit to see try to elucidate function. Lateral amygdala (LA) is believed to be the sensory interface where CS information enters the amygdala; lesions here block acquisition of both conditioned freezing responses, as expected, but also block acquisition of the CS's reinforcement of a new response in the EFF task. Central nucleus (CE) lesions block expression of hard-wired motoric output (i.e. freezing itself), but not the EFF. Basal nucleus (B) lesions had no effect on conditioned freezing, but did block the EFF. By way of interactions between the B and striatal circuits, reinforcement in the amygdala may come to reinforce novel motor responses. Thus, it may be that activation of LA by a CS triggers a reactive response output system via the CE and an active output system via the B.