AbstractsBiology & Animal Science

Does expectancy in Lateral Masking explain a target prevalence effect in Visual Search?

by B.P. Geelen




Institution: Universiteit Utrecht
Department:
Year: 2015
Keywords: Lateral masking; crowding; visual search; prevalence effect; expectancy
Record ID: 1251178
Full text PDF: http://dspace.library.uu.nl:8080/handle/1874/311939


Abstract

The hypothesis tested in this paper was that manipulating target prevalence has an effect on lateral masking (measured as maximum gaze deviation from the target before it cannot anymore be perceived), which corresponds to what as has been reported in the literature on visual search, smaller maximum gaze deviations being associated with longer search times. The literature on visual search shows that low target prevalence causes longer search times in target present trials, but only at low levels of target prevalence. At higher target prevalence levels this is not the case. The present data suggest indeed a similar pattern of results in a lateral masking task: in target present arrays maximum gaze deviation appears to be reduced with lower target prevalence, but only at low target prevalence levels. In addition, in a control condition, in which subjects knew and perceived that a target was always present, larger maximum gaze deviations occurred. This supports the associated hypothesis that expectancy affects lateral masking. Taken together, these results are in line with the idea (Wertheim et al., 2006) that lateral masking could well be an important factor in visual search.