Information processing: response complexity and the speed- accuracy tradeoff
Creators: name: Rollo, Diana Lynn
Publisher: name: University of British Columbia
Year: 2010

description: The purpose of this investigation was to determine whether stress for speed and/or accuracy would differentially affect information processing of tasks of low, versus greater complexity in a choice reaction time situation- It was postulated that a stress for speed would result in the adoption of a response strategy favouring the complex response whereas an accuracy stress would result in the employment of no such strategy. The complex response involved the depression of five keys in a predetermined sequence. In comparison, the simple response consisted of the depression of only two keys. One control (simple reaction time) and four experimental (choice reaction time) conditions were used in the testing of four separate hypotheses. The experimental conditions included: accuracy stressed on both, speed stressed on both, accuracy stressed on the simple response and speed stressed on the simple response. Response latencies for 500 trials were obtained from each of the 24 male subjects during five one-half hour testing sessions. Each subject was tested in all five conditions. Subsequent to an analysis of variance, Dunnett's test was administered to test each hypothesis. The empirical results did not support the predictions from the proposed model. Subjects did not adopt a defensive response strategy by preparing for the more difficult response when stressed for speed on both tasks. The difference in response latency between the two responses when either speed or accuracy was stressed on them both, was equivalent to the difference found in the simple reaction time condition. Thus, no favouritism in the form of decreased stimulus processing nor selective attention for either response was involved. However, favouritism did appear to be involved when the simple response was stressed for speed or accuracy. This was evidenced by the reduced response latency for the simple response as shown by the difference between the tasks being larger in these conditions than in the simple reaction time condition, as well as the greater number of errors for the complex response. In both the simple and choice reaction time conditions the response latency for the complex response was slower than that for the simple response. This supports the contention that complex responses require longer read out time of their motor programs due to the greater number of subroutines involved, in comparison with simple responses. This result is in partial contrast to previous investigations which found complex responses to have faster response latencies than simple responses in choice reaction time conditions with both stimuli being equally probable. The discrepancy in findings may be explained by the direction of the response strategy employed. In the present study, the simple response was favoured when a speed or an accuracy stress was imposed on it. It is suggested that in the previous studies, with the absence of an external reward system that relegated importance to the particular responses, subjects favoured the complex response. They favoured it by putting either a speed or an accuracy stress on it, thereby reducing its response latency.