부산대학교 도서관

The present study investigated the discrimination of brief empty time intervals and compared three different sensory modality conditions for marking time: when two successive signals are tactile (intramodal condition, TT), and when a first tactile signal is followed by a either a visual (V) or an auditory (A) signal (intermodal conditions: TV and TA). Twelve participants completed a bisection task over the course of eight experimental sessions. Three factors were manipulated: the marker modality (TT, TV, and TA), the duration range (300 and 900 ms), and the preparation (certainty, uncertainty). In the latter case, participants knew that the first marker was T, but were uncertain about the modality of the second marker. In general, TT intervals were better discriminated than intermodal intervals at 300 ms, but this effect fades at 900 ms. No difference in the discrimination level was observed between the intermodal conditions. For the perceived duration, there was no difference between TT and TA conditions, but the TV intervals were perceived as longer than the TT intervals. As well, the TV intervals were perceived as longer than the TA intervals. These results are interpreted in terms of attentional and sensory effects caused by the signals themselves (onset and alerting properties, prior entry). [ABSTRACT FROM AUTHOR]