JUDGMENT: DRAWING CONCLUSIONS FROM EXPERIENCE
So far we’ve been discussing the content of thought, with an emphasis on how thoughts are represented in the mind. Just as important, though, are the processes of thought—what psychologists call directed thinking—the ways people draw conclu-sions or make decisions. What’s more, these two broad topics—the contents of thought and the processes—are linked in important ways. As we’ve discussed, representing ideas with images will highlight visual appearance in our thoughts and thus may call to mind objects with similar appearance. Likewise, representing ideas as propositions will cause activation to spread to other, associated, nodes; and this too can guide our thoughts in one direction rather than another.
But, of course, the flow of our thoughts also depends on what we’re trying to accom-plish in our thinking. So it will be useful to divide our discussion of thought processes into four sections, each corresponding to a type of goal in our thinking: We will, therefore, con-sider judgment, reasoning, decision making, and problem solving. Let’s begin with judgment.
The term judgment refers to the various steps we use when trying to reach beyond the evidence we’ve encountered so far, and to draw conclusions from that evidence. Judgment, by its nature, involves some degree of extrapolation because we’re going beyond the evi-dence; and as such, this always involves some risk that the extrapolation will be mistaken. If, for example, we know that Jane has enjoyed many trips to the beach, we might draw the conclusion that she will always enjoy such trips. But there’s no guarantee here, and it’s surely possible that her view of the beach might change. Likewise, if you have, in the past, preferred spending time with quiet people, you might draw a conclusion about how much you’d enjoy an evening with Sid, who’s quite loud. But here, too, there’s no guarantee—and perhaps you’ll have a great time with Sid.
Even with these risks, we routinely rely on judgment to reach beyond the evidence we’ve gathered so far—and so we do make fore-casts about the next beach trip, whether the evening with Sid would be fun, and more. But how do we proceed in making these judgments? Research suggests that we often rely on a small set of shortcuts called judgment heuristics. The wordheuristics,borrowed from computer sci-ence, refers to a strategy that’s relatively efficient but occasionally leads to error. Heuristics, in other words, offer a trade-off between efficiency and accuracy, helping us to make judgments more quickly—but at the price of occasional mistakes.
Let’s start our discussion with two of these shortcuts—the avail-ability and representativeness heuristics, first described by Amos Tverskyand Daniel Kahneman (Figure 9.7); their research in this domain is
part of the scholarship that led to Kahneman’s winning the Nobel Prize in 2002.* As we’ll see, these heuristics are effective but often do lead to errors, and so we’ll turn next to the question of whether—and in what circumstances—people can rise above the shortcuts, and use more accurate judgment strategies.