The human visual system contains a large number of narrowly-tuned spatial-frequency-specific channels. Does it contain an analogous set of channels tuned to a narrow range of temporal frequency? On the basis of data gathered with the use of a threshold elevation technique it is argued that human sensitivity to flicker can be accounted for by assuming the existence of just two filters, one a low-pass filter peaking gently at around 6 Hz and one a band-pass filter peaking at around 9 Hz. Similar data gathered from studies of interocular transfer suggest that at least some of the mechanisms involved are binocular, rather than being purely monocular as has previously been suggested.