About Rationally Speaking

Rationally Speaking is a blog maintained by Prof. Massimo Pigliucci, a philosopher at the City University of New York. The blog reflects the Enlightenment figure Marquis de Condorcet's idea of what a public intellectual (yes, we know, that's such a bad word) ought to be: someone who devotes himself to "the tracking down of prejudices in the hiding places where priests, the schools, the government, and all long-established institutions had gathered and protected them." You're welcome. Please notice that the contents of this blog can be reprinted under the standard Creative Commons license.

Thursday, August 10, 2006

Neurological evidence for contrast between emotional and rational decision-making

Ever since Plato philosophers and then scientists have talked about the contrasting roles of emotions and reason in our decision making. Usually, emotions get the short shrift, epitomized by the Star Trek characters of Spock and Data, who are so efficient and cool precisely because they are all rationality and no emotion. Then again, David Hume recognized the fundamental motivational role of emotions, and famously said that “Reason is, and ought only to be the slave of the passions” (Dr. McCoy couldn't have said it better himself!).

A recent paper in Science magazine (4 August 2006, pp. 684-687) by Benedetto De Martino and collaborators has made a major contribution to the scientific investigation of how exactly emotions and reason interplay in our daily lives. First of all, they demonstrated that subjects were making different decisions according to how a particular choice was presented, what is known as the “framing effect.” It turns out that given exactly the same choices, people tend to take more risks if the problem is framed in a negative sense (“you are going to lose $30 out of $50”) than in a positive one (“you are going to win $20 out of $50”). Using a functional MRI scan of the brain, the investigators found that the framing effect was correlated with the activity of the amygdalas, structures well-known to be associated with emotional reactions.

De Martino et al. then investigated what was happening in the brain when subjects were making decisions that were contrary to their general tendency, i.e., when they were using their rational analysis to override their emotional inclinations. In this case, the anterior cingulate cortex was activated, indicating a role of this structure in countering the influence of the amygdalas. The scientists then noticed that there was variation among subjects for their sensitivity to the framing effect, and traced these differences to the degree of activity of a third area of the brain, the orbital and medial prefrontal cortex: the higher the activation of the cortex, the more the subjects behaved rationally and the least they were susceptible to the emotionally-driven framing effect. Previous research had shown that lesions in the orbital and medial prefrontal cortex lead to impairments in decision-making ability, and in particular to impulsive decisions with little regard for long-term consequences.

I'm not sure what this says about the murky concept of “free will,” but it certainly suggests that our brains have a complex and interacting circuitry that allows us to make decisions based on a balanced combination of emotions, rational thinking, and external information. This circuitry can be put off balance by a variety of factors, including presumably emotional stress, or low-quality information available to the brain. Lest you scoff at this as being only of academic interest, think of how crucial the question of “framing” is in political debate, and how the current Republican administration both plays on highly emotional issues (fear-mongering for the “war on terror,” homophobia for gay marriages) and provides the public with distorted information (weapons of mass destruction, the alleged inability of gay couples to raise children). Science is only beginning to catch up with political demagoguery.


  1. I have often thought that free will is just the ability to respond rather than react, which is entirely consistent with the study.

    What seems to complicate the free will problem is the quest to establish grounds for judgement, going back to the idea of heaven and hell. How to extract that kind of free will from a naturalistic scheme is indeed a problem.

    Our legal system also needs the assumption of free will, but this is less of a problem. Responsibilty would be the uncarved block from which little bits are subtracted (e.g., temporary insanity) as needed.

  2. Susan Balckmore, in "The Meme Machine", argued that choices such as "I'll have fish instead of meat" are in fact emotional responses (i.e., "I like fish more than meat"), so if all our emotions were purged (pace Data and Spock, or the Cybermen), we would be paralyzed into inactivity. Of course, whether the decision to eat fish instead of meat is driven for health reasons (wishing to avoid a heart attack) or emotional ones (prefering the taste of fish to the taste of meat) leads to another set of questions, which De Martino amongst others is clearly trying to answer.
    Political demagoguery, however, comes under the rubric of "insoluble problems"...

  3. As one you tends to over analyze everything, I can say from practical experience that I experience "analysis paralysis" more often than those who make a more emotional decision.

    Whether or not my decisions are better in the long run, I cannot say. I'm almost sure I would have eliminated the framing difference in my analysis -- heck, I probably would have whipped out a spreadsheet. One downside is that I have also noted that I'm not good/comfortable making quick decisions on my feet.

    Although I will note that many times part of the rational analysis is how much weight I give to an emotional or aesthetic component of a decision. So my emotions do get factored in to the process.

    Desmond Morris in "The Human Zoo" noted that leaders are perceived as great for making authoritative and decisive decisions even if they are wrong. A rational leader with thousands of data points to consider would come across as unable to make a decision or wishy-washy as the murky data may not lead to a strong conclusion.

    Finally, to me this topic has nothing to do with the idea/conundrum of "free will". The whole process of neurons thrashing about trying to make a decision while various parts of the brain do battle may very will be predetermined in a deterministic universe. Every neuron firing is a physical event which according to the laws of physics had to happen given the set of initial conditions.

    As for our judicial system: Even if we had no free will, it doesn't mean that we would want (even if we had a "real" choice) criminals roaming the street. Those criminals may not have had any "real" choice in being criminals, but they would still pose a danger that others would want to isolate/remove. If we are nothing but machines anyway, then the moral dilemma of punishment lessens to the extent that we are removing defective machines. Again - in a universe without free will, we were doomed to become what we are as a society anyway.

  4. "Hmmm; interesting"!

    Is there a body of study that imposes cultural conditioning on the responses of these brain functions? Experience tells me that some seemingly logical conclusions in one society are considered heretical in others...

  5. Look, it's a purely instinctive comment so excuse me if it sounds too speculative: if most of the decisions are predictible because of a chain of deterministic reactions interacting with the frame but we change our environement to make the frame as we want it to be--an added level of integration--making for us possible to enable only the decision-making-processes we want, in other words have a choice...
    Didn't 'Dumbledore' said that it's our choices which make us what we are, LOL!! Sorry (he he), I'm too young for Star Trek..


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