Karl H. Pribram

My interactions with B.F. Skinner at Harvard were especially memorable and led to a decade of primate operant conditioning experiments, which developed into subsequent research in cognitive neuropsychology. Shortly, I was able to automate and extend the operant equipment to record (including reaction time) the results of individual choices among a dozen possible panel presses. Later, over my three decades at Stanford (1959-1989), these responses were recorded in a large variety of problem-solving situations. The computer-controlled testing apparatus was dubbed Discrimination Apparatus for Discrete Trial Analysis (DADTA).

At one point in our interaction, Skinner and I came to an impasse over the possible mechanism involved in the chaining of responses. Chaining was disrupted by resections ofthe far frontal cortex. Skinner suggested that proprioceptive feedback might have been disrupted, but this hypothesis was not supported by my experiments. Furthermore, as I indicated to Skinner, he, as a Ph.D. in biology, could propose such an hypothesis, but I, as a loyal Skinnerian, had to search elsewhere than within the “black box” for an answer to our question. George Miller overheard some of our discussions and pointed out to me that he had available a procedure that made chaining of responses easy: a computer program. Miller explained to me the principles of list programming which he had just learned from Herbert Simon and Alan Newell. The culmination of the collaboration begun by these encounters in the halls of Harvard was Plans and the Structure of Behavior, a book influenced also by our interactions with Jerome Bruner, who had organized a conference on thinking at Cambridge University in 1956 to which we had been invited. The book was written in 1958-1959 at the Center for Advanced Studies in the Behavioral Sciences, adjacent to the campus of Stanford University.