A different sort of American Revolution took place in the ‘60s and ‘70s. The rift was again between the US and Britain, with those American upstarts once more insisting on going their own way. But this was a quiet revolution, so quiet that few people even noticed it. It was a revolution in how we think about thinking.
The study of thinking has long roots—insert the usual praise of the ancient Greeks and William James here—but it took a definite turn in England in the early 1960s due to the work of Peter Wason. If you are a cognitive psychologist, you are familiar with a couple of Wason’s great inventions, namely the rule discovery task and the 4-card selection task. Both of these are simple tasks that make profound points about how people think.
In the rule discovery task, participants are asked to discover the rule generating sequences of three numbers. They are given an example of a sequence that satisfies the rule (2, 4, 6). Then they generate their own sequences and receive feedback until they are able to figure out the rule that the experimenter has in mind. Most people have a lot of trouble finding the rule. It’s just too simple. People tend to think of rules like “increasing by two” or “even numbers” when in fact the rule is very permissive (it is “ascending numbers”). The problem, according to Wason, is that people fail to test sequences that violate their hypotheses, focusing only on sequences that are consistent with the rule that they believe is operative. On Wason’s view, we think “inside the box”; we have trouble generating hypotheses that aren’t strongly associated with the data in front of us because we don’t test the possibility that we’re wrong.
Wason’s other invention, the 4-card selection task, is even better known. You can find demonstrations of it all over the web, for example, in the video below.
In the 4-card selection task, participants are shown a conditional rule of the form “If antecedent, then consequent,” and a set of four cards. Each card has either the antecedent or its negation on one side and the consequent or its negation on the other, but only one side is shown (one with the antecedent true, another with the antecedent false, one with the consequent true and the last with the consequent false).
Participants must choose the smallest number of cards necessary to determine if the proposed conditional rule is true or false. Instead of choosing the cards that propositional logic dictates they should (the card with the true antecedent and the one with the false consequent), people tend to choose the cards that match the antecedent (as they should) and sometimes choose the card with the true consequent. Defying the prescription of propositional logic, people frequently fail to choose the card showing the false consequent.
One partial interpretation of what is happening is that we’re asymmetric when we reason conditionally: It’s easier for us to reason from antecedent to consequent than from consequent to antecedent.
These tasks didn’t just provide classic demonstrations for introductory cognition classes.
They set an agenda for a field.
Following Wason, and thanks in great part to the prolific work of his students Jonathan Evans and Phil Johnson-Laird, generations of cognitive psychologists have done work on reasoning. Much of the work was inspired by, if not a direct extension, of the efforts of Peter Wason. The field of reasoning was born with an emphasis on how people reason deductively, that is how we draw conclusions with certainty from premises. This massive research effort has revealed that the mind draws inferences in ways that deviate systematically from the methods taught by logicians.
The geography of the field of reasoning offers a lesson about the sociology of science.
Centered originally in England, reasoning research spread to other parts of Western Europe, but never really managed more than a toehold in the US or Canada. There are definite exceptions. Researchers like Russ Revlin and Denise Cummins in the US and Henry Markovitz and Valerie Thompson in Canada have been on the forefront of work on deduction. In fact, Johnson-Laird himself moved to Princeton in 1989. But the field as a whole never really took off on the American side of the pond. It’s center of mass remains a few miles east of Plymouth, a lovely seaside town in the southwest corner of England.
That doesn’t mean Americans didn’t think about thinking.
The study of thinking took a different direction in North America. Developments there had a couple of catalyzing influences. One was the set of ideas surrounding the origins of cognitive science. In the 1950s, Noam Chomsky developed formal grammars that he applied to develop models of the syntax of natural language but were, at the time, contenders as models of other aspects of language and of the language of thought too. At roughly the same time, Herb Simon and Allen Newell developed computer programs that could solve math and word problems that promised a future computational theory of mind: A theory of how the mind worked in the form of a computer program that embodied artificial intelligence. Much of early cognitive psychology in America followed their lead, focusing on work on problem solving and sentence comprehension and the development of computer programs as models of higher-level cognition.
Another important influence in America was the study of decision making, with its roots in subjective probability, brought to the attention of cognitive psychologists by Ward Edwards and others. This branch of the field exploded after the seminal work of Kahneman and Tversky.
Kahneman and Tversky were not originally American but they made homes in the US and Canada relatively early in their careers, did much of their most important work there, and shaped the study of thinking in the final quarter of the 20th century and onward onward. It brought the study of reasoning in close contact with both economics and social psychology.
This division of the science of reasoning and thinking between America and Europe is en route to becoming one more victim of globalization and the Internet. The two geographic traditions are no longer as distinct as they used to be. One sign of this is that the International Conference on Thinking will make its first appearance in the US in August of 2016. The conference takes place every four years and all previous meetings have been in Europe.