Sensorimotor interaction and time perception: An empirical study and a philosophical discussion

Duygu Özbağcı

Time perception is a crucial aspect of experiencing and acting upon the world. This thesis is composed of an empirical part, where the potential interactions between action and visual time perception are studied using psychophysical methodologies and a discussion part, where the results are discussed within a philosophical framework. The general procedure of the experiments includes a comparison between the visuomotor and passive visual observation conditions. The findings show that the perceived durations in the visuomotor conditions are underestimated. It is also demonstrated that the action induces a reduction in the perceived speed. It is claimed that the effects reported here might be modulated in the dorsal route. In fact, it is demonstrated that action-induced duration compression disappears using isoluminant stimuli. This provides further evidence that the locus of these effects should be somewhere, where the neurons are sensitive to luminance-modulation and temporal change. In a final control experiment, it is shown that color discrimination performance is not influenced by the execution of a concurrent motor act, which together implies that attentional factors cannot explain our main results. Broader indication of empirical studies is that the dorsal route has a principle role in the timing of visuomotor sequences. These results support the current philosophical stand that temporal consciousness is both (i) embodied; the body’s actions and states have an influence on the perceived time, and (ii) extended; the external information has direct contributions to the perceived time.