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A review of recent experimental and theoretical findings is presented which relates the results of neurophysiological and psychological research on attention and eye movement to cognitive theorizing. With respect to the relation between shifts of attention and saccadic eye movements, several experiments have demonstrated that it is possible to dissociate the line of attention from the gaze direction. On the other hand, there is some indirect (although not yet conclusive) evidence that saccadic eye movements always produce a concomitant shift of attention. Another question is whether there is a moment-to-moment control of each consecutive saccade and latency or whether indirect control models (i.e. planning several saccades in advance) are more appropriate. The function of attentional processes which have to coordinate stimulus driven (bottom-up) and concept driven (top-down) mechanisms are discussed and related to some studies investigating local and global scanpaths.

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A quantitative model of temporal integration and visible persistence is described and tested. The model treats visible persistence as resulting from processing activity within sustained visual channels whose temporal response is modelled using a second-order control system. Temporal integration of two successive stimuli is assumed to be enabled by the overlap between the two periods of activity and to be impaired by the non-overlapping activity. The model successfully predicts the effects of inter-stimulus interval and of stimulus duration on goodness of temporal integration.

Two experiments were conducted to examine the inXuence of the spatial frequency content of natural images on saccadic size and Wxation duration. In the Wrst experiment 10 pictures of natural textures were low-pass Wltered (0.04-0.76 cycles/deg) and high-pass Wltered (1.91-19.56 cycles/deg) and presented with the unWltered originals in random order, each for 10 s, to 18 participants, with the instruction to inspect them in order to Wnd a suitable name. The participants' eye movements were recorded. It was found that low-pass Wltered images resulted in larger saccadic amplitudes compared with high-pass Wltered images. A second experiment was conducted with natural stimuli selected for diVerent power spectra which supported the results outlined above. In general, low-spatial frequencies elicit larger saccades associated with shorter Wxation durations whereas high-spatial frequencies elicit smaller saccades with longer Wxation durations.