Story of Psychology - Morton Hunt [355]
But with the advent of the cognitive revolution, research on reasoning became an active field. The IP (information processing) model enabled psychologists to formulate hypotheses that portrayed, in flow-chart fashion, what went on in various kinds of reasoning, and the computer was a piece of apparatus—the first ever—with which such hypotheses could be tested.
IP theory and the computer were synergistic. A hypothesis about any form of reasoning could be described, in IP terms, as a sequence of specific steps of information processing; the computer could then be programmed to perform an analogous sequence of steps. If the hypothesis was correct, the machine would reach the same conclusion as the reasoning human mind. By the same token, if a reasoning program written for the computer produced the same answer as a human being to a given problem, one could suppose that the program was operating in the same way as, or at least in a similar fashion to, that of the human mind.
How does a computer do such reasoning? Its program contains a routine, or set of instructions, plus a series of subroutines, each of which is used or not used, depending on the results of the previous operations and the information in the program’s memory. A common form of routine is a series of if-then steps: “If the input meets condition 1, then take action 1; if not, take action 2. Compare the result with condition 2 and if the result is [larger, smaller, or whatever], take action 3. Otherwise take action 4… Store resulting conditions 2, 3… and, depending on further results, use these stored items in such-and-such ways.”70
But when computers carry out such programs, whether in mathematical computing or problem solving, are they actually reasoning? Are they not acting as automata that unthinkingly execute prescribed actions? The question is one for the philosopher. If a computer can, like a knowledgeable human being, prove a theorem, navigate a spacecraft, or determine whether a poem was written by Shakespeare, who is to say that it is a mindless automaton—or that a human being is not one?
In 1950, when only a few primitive computers existed but the theory of computation was being much discussed by mathematicians, information theorists, and others, Alan Turing, a gifted English mathematician, proposed a test, more philosophic than scientific, to determine whether a computer could or could not think. In the test, a computer programmed to solve a certain kind of problem is stationed in one room, a person skilled in that kind of problem is in another room, and in a third room is a judge in telegraphic communication with each. If the judge cannot tell from the dialogue which is the computer and which the person, the computer will pass the test: it thinks.71 No computer program has yet won hands down, in publicly conducted contests, although some have fooled some of the judges. The validity of the Turing test has been debated, but at the very least it must mean that if a computer seems to think, what it does is as good as thinking.
By the 1960s, most cognitive psychologists, whether or not they agreed that computers really think, regarded computation theory as a conceptual breakthrough; it enabled them for the first time to describe any aspect of cognition, and of reasoning in particular, in detailed and precise IP terms. Moreover, having hypothesized the steps of any such program, they could translate them from words into computer language and try the result on a computer. If it ran successfully, it meant that the mind did indeed reason by means of something like that program. No wonder Herbert Simon said the computer was as important for psychology as the microscope had been for biology; no wonder other enthusiasts said the human mind and the computer were two species of the genus “information-processing system.”72
The ability to solve problems is one of the most important applications