Capacity limits of transsaccadic event perception: The line motion illusion

There is extensive psychophysical and neurophysiological evidence that the visual system integrates motion information over time. However, it has
recently been suggested that the summation of two motion signals is not
specific in space, time or direction, and can instead be completely explained by a decision mechanism such as probability summation [Morris et al, 2010
Journal of Neuroscience 30(29) 9821–9830]. Here, we employed random dot pattern stimuli measuring motion coherence and motion detection
thresholds. With the former measure we found that motion integration is temporally specific and that motion signals can be integrated over large areas,
as previously reported [Burr et al, 2009 Vision Research 49(10) 1065–1072].
On the other hand, motion detection integration was spatially specific, as
well as showing a shorter integration time window than motion coherence. These results are inconsistent with a purely decisional account of motion integration
and suggest that duration thresholds for random dot pattern tap into lower level of motion processing than coherence threshold measurements.