We’ve now seen that people can remember without realizing they’re remembering—and so the processes of memory can to a large extent go forward without consciousness. Likewise, people can perceive without realizing they’re perceiving—and so perception, too, can function without consciousness. Other evidence, drawn from people who are neurologically intact, also reveals unconscious mental processing and, intriguingly, documents the sheer complexity of what the unconscious processes can achieve.
In an early experiment by Nisbett and Schachter (1966), participants were asked to endure a series of electric shocks, with each shock slightly more severe than the one before. The question of interest was how far into the series the participants would go. What was the maximum shock they would voluntarily accept?
Before beginning the series of shocks, some of the participants were given a pill and told that it would have several side effects: shaky hands, butterflies in the stomach, irregular breathing, and the like. Of course, none of this was true. The pill was a placebo—a substance that had no medical effects. Even so, this inert pill was remark-ably effective: Participants given the pill and told about its side effects were willing to accept a level of shock that was four times the strength of the control participants’ maximum.
Why was the placebo so effective? Nisbett and Schachter proposed that their control participants—those who didn’t receive the pill—noticed that their hands were shaking, their stomachs were upset, and so on. (These are standard reactions to electric shock.) The participants then used these self-observations as evidence in judging that they were quite uncomfortable in the experiment. It’s as if participants said to themselves, “Oh, look, I’m trembling! I guess I must be scared. Man, these shocks must really be bother-ing me.” This thinking led them to terminate the shock series relatively early. Placebo participants, in contrast, attributed these same physical symptoms to the pill. “Oh, look, I’m trembling! That’s just what the experimenter said the pill would do. So I guess I can stop worrying about the trembling. Let me look for some other sign that the shock is bothering me.” Consequently, these participants were less influenced by their own phys-ical symptoms. They detected those symptoms but discounted them, attributing them to the pill rather than the shock. Essentially, they overruled the evidence of their own anx-iety and so misread their own internal state (for related studies, see Bargh, 2005; Nisbett Wilson, 1977; T. Wilson, 2002; T. Wilson & Dunn, 2004).
In this study, there’s no question that the participants who received the pill (and the instructions about its side effects) behaved differently from other participants. It seems clear, therefore, that these participants were thinking about the pill. But they were entirely unaware of this thinking. When specifically asked why they had accepted so much shock, they rarely mentioned the pill. When asked directly, “While you were taking the shock, did you think about the pill at all?” they responded with answers like, “No, I was too worried about the shock to think of anything else.”
It seems, therefore, that the participants’ thinking about the pill was unconscious; and let’s note the complexity of this thinking. The participants are observing “symptoms” (such as their own trembling hands), generating hypotheses about those symptoms, drawing conclusions, and then making decisions (about accepting more shock) based on these conclusions. As it turns out, in this case the participants reached erroneous conclusions because they were misled about the pill by the experimenter. But that takes nothing away from what they’re doing intellectually—and unconsciously.