Heart rate, skin potential response, and latency of overt response, as indicators of problem recognition and solution

Heart rate, skin potential, and response latency were studied in relation to the recognition and solution ofproblems by 18 high-school students. A continuous series of rule-induction problems was presented without any pause between problems. The problems were sequentially related in that each new problem demanded a refinement of the rule just induced for the preceding problem. Increases in skin potential and response latency occu"ed when new problems were introduced, and decreases in the same measures were hund when they were solved. Heart rate was not indicative of recognition or solution of problems. When events during trials-stimulus, response, feedback-were looked at separately, the events of stimulus onset and response were associated with significant increases at recognition. Only the feedback event was associated with a significant decrease at solution. It was suggested that these changes indicate a labile state during which problem solving occurs. Decreases in skin-potential response and latency of overt response occurred at solution of problems in a previous study (Elias & White, 1969). This resuIt led to the speculation that these responses might subsequently increase when a new problem was recognized and diminish when it, in turn, was solved. The present study was designed to test response to recognition as weIl as solution of a problem. Changes in response in detail were also studied by separating events during trials and analyzing trial-by-trial changes. Problem recognition, as weIl as solution, was introduced by designing tasks that presented aseries of problems requiring increasing refinement of a rule for solution in an uninterrupted sequence of trials. Slides that required a choice among four items were presented. In order to choose correctly, the S had to induce a rule, such as "the even number." When a rule had been successfully learned, an anomalous slide was presented with two items correct by the rule. A refinement of the rule was now required in order to distinguish which of the two items was correct. The term "anomaly" is defined as a phenomenon that cannot be accounted for by the mIes currently operating. In the continuing stream of experience, recognition of anomaly would seem to be a necessary condition for the solution of a problem. One must recognize that one has a problem in order to solve it. In order to determine more precisely what accounted for the changes at recognition and solution of problems, the study separated response to events in each trial: slide presentation, button-press response with which the S indicated bis choice, and onset of a light telling him wbich choice was, in fact, correct. This procedure was suggested by Germana (1968) in arecent review of studies on physiological correlates of learning. In the same article, Germana postulated an activational peak at the time of acquisition of a conditioned response. A trial-by-trial analysis was made in the present study in order to test Germana's hypothesis on a more complex type oflearning task. The response systems being studied were heart rate, skin potential, and response latency. Skin-potential response and latency of overt response were used because they had been found to show reliable changes in the earlier study cited above. Heart rate was incIuded because of indications in the literature that suggested that it rnight vary with learning. Deceleration in anticipation of a signal has been demonstrated by Lacey (1965). Since such decelerations rnight vary in amplitude with recognition and solution of problems, it was decided to measure decelerations in anticipation of the S's button press and the feedback light. Blatt (1961) reported accelerations at key points' during the process of problem solving. Accordingly, we measured accelerations as responses after each event in a trial.