Post Hoc Rationalization

SPLITTING BRAINS

Ferreting out counterintuitive ideas is an exhilarating activity. For a few months, you experience the titillating sensation that you’ve just entered a new world. After that, the novelty fades, and your thinking returns to business as usual. The world is dull again until you find another subject to be excited about (or manage to put another hotshot in a state of total rage).

For me, one such antilogic came with the discovery—thanks to the literature on cognition—that, counter to what everyone believes, not theorizing is an act—that theorizing can correspond to the absence of willed activity, the “default” option. It takes considerable effort to see facts (and remember them) while withholding judgment and resisting explanations. And this theorizing disease is rarely under our control: it is largely anatomical, part of our biology, so fighting it requires fighting one’s own self. So the ancient skeptics’ precepts to withhold judgment go against our nature. Talk is cheap, a problem with advice-giving philosophy we will see in Chapter 13.

Try to be a true skeptic with respect to your interpretations and you will be worn out in no time. You will also be humiliated for resisting the urge to theorize. (There are tricks to achieving true skepticism; but you have to go through the back door rather than engage in a frontal attack on yourself.) Even from an anatomical perspective, it is impossible for our brain to see anything in raw form without some interpretation. We may not even always be conscious of it.

Post hoc rationalization. In an experiment, psychologists asked women to select from among twelve pairs of nylon stockings the ones they preferred. The researchers then asked the women their reasons for their choices. Texture, “feel,” and color featured among the selected reasons. All the pairs of stockings were, in fact, identical. The women supplied backfit, post hoc explanations. Does this suggest that we are better at explaining than at understanding? Let us see.

A series of famous experiments on split-brain patients gives us convincing physical—that is, biological—evidence of the automatic aspect of the act of interpretation. There appears to be a sense-making organ in us—though it may not be easy to zoom in on it with any precision. Let us see how it is detected.

In split-brain patients, surgery has severed major connections between the cerebral hemispheres, restricting how information passes between them. These patients are jewels, rare and invaluable for researchers. Under certain experimental conditions, it is as if you can communicate separately with the two sides; differences in their responses offer clues about hemispheric specialization. This splitting is usually the result of surgery to remedy more serious conditions like severe epilepsy; no, scientists in Western countries (and most Eastern ones) are no longer allowed to cut human brains in half, even if it is for the pursuit of knowledge and wisdom.

Now, say that you induced such a person to perform an act—raise his finger, laugh, or grab a shovel—in order to ascertain how he ascribes a reason to his act (when in fact you know that there is no reason for it other than your inducing it). If you ask the right hemisphere, here isolated from the left side, to perform the action, then ask the other hemisphere for an explanation, the patient will invariably offer some interpretation: “I was pointing at the ceiling in order to …,” “I saw something interesting on the wall,” or, if you ask this author, I will offer my usual “because I am originally from the Greek Orthodox village of Amioun, northern Lebanon,” et cetera.

Now, if you do the opposite, namely instruct the isolated left hemisphere of a right-handed person to perform an act and ask the right hemisphere for the reasons, you will be plainly told, “I don’t know.” Note that the left hemisphere is where language and deduction generally reside. I warn the reader hungry for “science” against attempts to build a neural map: all I’m trying to show is the biological basis of this tendency toward causality, not its precise location. There are reasons for us to be suspicious of these “right brain/left brain” distinctions and subsequent pop-science generalizations about personality. Indeed, the idea that the left brain controls language may not be so accurate: the left brain seems more precisely to be where pattern interpretation resides, and it may control language only insofar as language has a pattern-interpretation attribute. Another difference between the hemispheres is that the right brain deals with novelty. It tends to see the gestalt (the general, or the forest), in a parallel mode, while the left brain is concerned with the trees, in a serial mode.

The point is that a fluent explanation can conceal how little the speaker knows about the cause of an action.