Design and development ofthe time discrimination threshold computerized task

The aim of the present study wasto design the Persian versionof the time discrimination task. Thirty-one volunteer elementary school students participated in this experiment. By means of a computerized test, selected pictures of the International Affective Pictures System (IAPS) were presented to all participants both in 1000 and 2000 milliseconds (ms). The discrimination threshold of subjects was then calculated using the Levitt’s proposed formula (1971). Participants required 261/5 msand 373/06 msto differentiate the comparative stimulus from target one in 1000 ms and 2000 ms, respectively. These values were considered as time discrimination threshold. In conjunction with classic findings in psychophysics, the results of the current investigation indicated that when the intensity of stimulus increases, the magnitude of discrimination threshold rises accordingly. Meanwhile, doubling the intensity does not necessarily double the perceived discrimination threshold. We suggest prospective paradigm time discrimination studies toconsider using the currently developed task as an investigational tool.