Effects of auditory stimulus intensity on response force in simple, go/no-go, and choice RT tasks

Influence of sleep deprivation and auditory intensity on reaction time and response force

Arousal and activation are two variables supposed to underlie change in response force. This study was undertaken to explain these roles, specifically, for strong auditory stimuli and sleep deficit. Loud auditory stimuli can evoke phasic overarousal whereas sleep deficit leads to general underarousal. Moreover, Van der Molen and Keuss (1979, 1981) showed that paradoxically long reaction times occurred with extremely strong auditory stimuli when the task was difficult, e.g., choice reaction or Simon paradigm. It was argued that this paradoxical behavior related to reaction time is due to active disconnecting of the coupling between arousal and activation to prevent false responses. If so, we predicted that for extremely loud stimuli and for difficult tasks, the lengthening of reaction time should be associated with reduction of response force. The effects of loudness and sleep deficit on response time and force were investigated in three different tasks: simple response, choice response, and Simon paradigm. According to our expectation, we found a detrimental effect of sleep deficit on reaction time and on response force. In contrast to Van der Molen and Keuss, we found no increase in reaction time for loud stimuli (up to 110 dB) even on the Simon task.

Influence of Time Pressure in a Simple Response Task, a Choice-by-Location Task, and the Simon Task

Abstract The influence of strategy was examined for a simple response task, a choice-by-location task, and the Simon task by varying time pressure. Besides reaction time (RT) and accuracy, we measured response force and derived two measures from the event-related EEG potential to form an index for attentional orienting (posterior contralateral negativity: PCN) and the start of motor activation (the lateralized readiness potential: LRP). For the choice-by-location task and the Simon task, effects of time pressure were found on the response-locked LRP, but not on the onset of the PCN and the stimulus-locked LRP. Thus, strategy influences processing after the start of motor activation in choice tasks. A small effect of time pressure was found on the peak latency of the PCN in the Simon task, which suggests that time pressure may affect attentional orienting. In the simple response task, time pressure reduced the amplitude of the PCN. This finding suggests that strategy affects attentional orienting to stimuli when these stimuli are not highly relevant. Finally, the effect of time pressure on RT was much larger in the simple response task than in the other tasks, which may be ascribed to the possibility of preparing the required response in the simple response task.

The influence of time pressure and cue validity on response force in an S1-S2 paradigm

Hypotheses about variations of response force have emphasised the influences of arousal and of motor preparation. To study both types of influences in one experiment, the effects of time pressure and of validity of S1 were investigated in tasks wherein a first stimulus (S1) indicated the most probable response (80% valid) required after a second stimulus (S2). Under time pressure, responses were executed more forcefully while, as could be expected, response times were shorter and errors were more frequent. This pattern of results was not only obtained when time pressure was varied between blocks, but also when varied from trial to trial, by information given by S2. Also invalidly cued responses were executed more forcefully but, as could be expected, in contrast to time pressure, response times were longer and errors were more frequent. The results demonstrate that latency and force of responses may vary in different directions. Ways are outlined on how current hypotheses must be extended in order to account for these results.