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Eckart Zimmermann, Gereon Fink, Patrick Cavanagh; Perifoveal spatial compression. Journal of Vision 2013;13(9):630. doi: https://doi.org/10.1167/13.9.630.
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© ARVO (1962-2015); The Authors (2016-present)
Perception of location is vulnerable to large errors around the time of a sudden event like abrupt stimulus motion or an eye movement. We found a strong compression of space in the absence of eye or image motion where brief probes were attracted toward a visual reference that was followed by a mask. The visual reference presented in the near-periphery was followed after 100-180 ms ms by a brief whole-field mask. At various times around the mask onset, a probe dot was flashed. Subjects had to estimate the position of the probe in relation to a comparison bar. The probe location was perceived nearly veridically when presented long before or after mask onset. However, when the probe was presented within 50 ms of the mask, it appeared shifted toward the reference by as much as 50 percent of their separation. The reference had to appear briefly before mask onset to attract the probe dot. No compression occurred when the reference was presented long before or after the mask. When we presented the probe and reference with similar brief durations, the more peripheral stimulus always shifted toward the more foveal stimulus independently of their temporal order. We suggest that the attraction can be explained by the summation of the neural activity distributions of probe and reference. Underlying the observed effect might be a mechanism that tries to establish spatial continuity of changing objects. The perception of two flashed objects, reference and probe, offset in space an time would normally trigger the perception of apparent motion. However, if the transient of such a motion is masked, then the two objects will appear closer to each other to match the reduced transient strength.
Meeting abstract presented at VSS 2013
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