Effect of stimulus intensity on LRP latency, RT in simple and choice tasks A Nowik1, J Moczko2, E Marzec3 |
|---|
1Department of Biophysics, Poznan University of Medical Sciences, Poland |
| Van der Molen and Keuss [1979, Quarterly Journal of Experimental Psychology, 31, 95-102; 1981, Quarterly Journal of Experimental Psychology, 33, 177-184] reported U-shaped relationship between reaction time (RT) and loudness in difficult tasks requiring choice responses. This effect was replicated by Jaskowski and Wlodarczyk [2006, International Journal of Psychophysiology, 61, 98-112] for ultrabright and large visual stimuli. In the current study, we used ERP to investigate the locus of this paradoxical elongation of RTs for extremely bright and large stimuli. The luminance of stimuli was manipulated. Same we also tested a different group of participants with two disparate auditory tons and a five different loudness conditions, task simple and choice reaction. The RT-luminance relationship was monotonic for simple responses and U-shaped for choice responses. Notably, LRP-R was independent of stimulus intensity for both tasks. S-LRP latency changed with brightness similarly to RTs. These results support Van der Molen and Keuss’ proposal that it is the response selection stage that is affected by very strong stimuli. Our study clearly indicates that response selection is influenced by intensity changes irrespective of whether visual or auditory stimuli are used, resulting in a U-shaped relationship between RT and intensity when the task is difficult. |
| Up Home |
|---|