Susceptibility to the Ebbinghaus illusion: sequential presentation of target and context
LE3 .A278 2018
Bachelor of Science
The current study newly examined the effect of asynchronous presentation of a target and flankers on participants’ susceptibility to the Ebbinghaus illusion (EI). Twenty-eight participants were presented with a target circle surrounded by four circular flankers (modified version of the EI) and were asked to indicate the apparent size of the target circle relative to a comparison circle. Flanker circle size, comparison circle size, and the SOA of the target and flanker circles were also manipulated. Participants perceived the target circle to be smaller (or larger) when surrounded by large (or small) flankers, illustrating the classic EI. However, two-way interactions between flanker size and comparison circle, flanker size and timing, and comparison size and timing revealed that the illusion was strongest when the target circle was presented first and weakest when the flanker circles were presented first. While the pattern of results with respect to the target-flanker timing were not entirely as hypothesized, it did illustrate that the EI is affected to some extent by timing parameters.
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