It well known that we can voluntarily allocate attention to a specific point in time at which we expect a relevant event to occur. In this study we examined the time course of this endogenous allocation of temporal attention with the constant foreperiod paradigm. In the 'contingent condition' of this paradigm, the foreperiod duration (i.e., the interval between the onset of a warning signal and the onset of the target) is constant within a block, but varies between blocks. Thus, within each block of this condition there was full temporal certainty. The target was a letter presented for a brief duration (16 ms), and the task was to identify the letter. Letter identification was not speeded. Unlike previous studies we included a wide range of foreperiods (75-2400 ms). Critically, to avoid effects of exogenous temporal attention we employed a warning signal that did not include an intensity change. Finally, the warning signal in the 'non-contingent condition' did not bear any temporal contingencies with the target (i.e., the point in time at which the target appeared and the point in time at which the signal appeared were randomly picked from completely independent distributions). Hence, in this condition there was no temporal certainty. We found significantly higher identification accuracy with than without temporal certainty. This finding supports the claim that the allocation of temporal attention to a specific point in time improves perceptual processing. Importantly, such effects of temporal attention were found even with the shortest foreperiod - 75 ms. This finding suggests that the allocation of endogenous temporal attention is extremely fast, faster than the allocation of endogenous spatial attention. Currently we are testing the other prevalent paradigm of temporal attention a?? the temporal orienting paradigm, with a similar range of foreperiods and a similar control for exogenous effects.
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