This study investigated whether perceptual fluency could affect duration judgments. Fluency refers to levels of subjective ease, in which stimuli can be processed (Lanska, Olds, & Westerman, 2014). The study was conducted with experimental within group factorial design. Visual stimuli were selected from Snodgrass and Vanderwarts (1980) standardized set of 260 pictures. Pairs were made with low and high levels of complexity. Duration was about 1000 milliseconds with .10 variations. 1/3 of pairs were without variation. Participants were asked to judge which image was presented for longest time. Total amount of participants was 37. Main hypothesis was that low levels of complexity would be judged, to a greater frequency, as having been presented for longer duration. Observed mean (M= 20.27, SD = 2.90) was slightly lower than level of chance (M = 21) and the difference was non significant, t(36) = -1.53, p > .13. The null hypothesis was not rejected.

It is known that concurrent secondary tasks or attentionally salient stimuli shorten reproduced temporal durations. The main aim of this thesis is to use three types of secondary tasks to see their effects on duration judgments. The Attentional Gate Model (Block &amp / Zakay, 2006) served as theoretical background for a series of 4 experiments. There were 2 baseline/control experiments for studying the effect of 2 different and novel secondary tasks which are temporal comparison and non-temporal executive tasks. Three duration lengths (short-moderate-long) were used (15, 30 and 45 sec) that subjects had to reproduce. In Exp-1 (control experiment for Exp-2) subjects had to reproduce almost empty time intervals. Exp-2, which investigated the role of a secondary temporal task, revealed significantly decreased reproduced durations as compared to Exp-1 which is in line with our hypothesis. In Exp-3 (control experiment for Exp-4) subjects carried out a non-temporal/non-executive secondary task. Exp-4, in which a Simon task was used as a non-temporal executive secondary task, resulted in significantly decreased reproduced durations as compared to Exp-3 as well. Moreover, duration length effects were found for all experiments that included an attention consuming secondary tasks (Exp-2-3-4), i.e., longer durations were more underestimated than shorter ones in the presence of attention demanding tasks. We conclude that secondary temporal tasks and even more so executive non-temporal tasks can lead to decreased temporal duration judgements, thus affecting subjects&rsquo / time perception, in line with the Attentional Gate Model.