  Most decisions require information gathering from a stimulus presented with
different gaps. Indeed, the brain process of this integration is rarely
ambiguous. Recently, it has been claimed that humans can optimally integrate
the information of two discrete pulses independent of the temporal gap between
them. Interestingly, subjects' performance on such a task, with two discrete
pulses, is superior to what a perfect accumulator can predict. Although
numerous neuronal and descriptive models have been proposed to explain the
mechanism of perceptual decision-making, none can explain human behavior in
this two-pulse task. In order to investigate the mechanism of decision-making
on the noted tasks, a set of modified drift-diffusion models based on different
hypotheses were used. Model comparisons clarified that, in a sequence of
information arriving at different times, the accumulated information of earlier
evidence affects the process of information accumulation of later evidence. It
was shown that the rate of information extraction depends on whether the pulse
is the first or the second one. The proposed model can also explain the
stronger effect of the second pulse as shown by Kiani et al. 2013.
