Stimulus size scaling and foveal load as determinants of peripheral target detection

This paper reports two experiments on the effect of scaling the size of stimuli (using factors derived from consideration of cortical magnification) on the detection of peripheral visual targets. In the first experiment two levels of magnification, fully M-scaled and half M-scaled, were used to scale stimuli that were presented briefly. The performance decrement normally associated with increasing retinal eccentricity did not occur with both levels of magnification. There was an unexpected decline in performance at low eccentricities and possible explanations are discussed. The second experiment investigated the effects of half M-scaling on a peripheral detection task with the addition of foveal cognitive loading as would be found in many practical tasks. Half M-scaling improved performance with and without the presence of foveal loading, and the improvement was greater for the foveal load condition when the target was at the larger eccentricities. These results provide a useful indication of the possibility of reducing the effect of tunnel vision for visual inspection tasks on visual displays or, possibly, control panels through the development of variable resolution projection displays matching the psychophysical properties of the human visual system.