TALK: Talk by Kate Storrs "You look different, somehow"
What you see depends on what you have already seen. After seeing a squashed ellipse, a perfect circle tends to look elongated – a shape aftereffect. After seeing a female face, an androgynous face tends to look masculine – a face aftereffect. Aftereffects are ubiquitous in vision, but have several plausible explanations. I will discuss some of these, and present two novel tests to help diagnose the cause of an aftereffect.
First, does a given aftereffect depend only on the properties of retinal images, or does it depend on more abstract representations? Shape aftereffects provide a good test of this, as many different retinal images can create the impression of the same real-world shape (imagine looking at the top of a coffee mug from many different angles). I will show new evidence that shape aftereffects follow perceived, not retinal shape, demonstrating that even apparently simple shape aftereffects reflect the computations required to transform variable retinal images of a common object into a stable impression of form.
Second, do high-level aftereffects simply reflect a contrast between successive impressions, or do they indicate a process of normalisation (as in colour adaptation), where an internal ‘average’ is re-adjusted to better match recent experience? Using a novel paradigm, I compared the characteristics of aftereffects generated by adapting to colour, to expanded or contracted faces, and to male or female faces. Colour and facial distortion aftereffects were consistent with normalisation, but facial gender aftereffects were not. These data suggest that superficially similar aftereffects may have different underlying mechanisms; not all high-level aftereffects are equal.
Part of the Person Perception Seminar series, ARC Centre of Excellence in Cognition and its Disorders
Rm 2.33, North Block, Psychology Buidling, UWA Crawley Campus
: 6488 3573
Thu, 27 Sep 2012 12:00
Thu, 27 Sep 2012 13:00
Linda Jeffery <[email protected]>
Wed, 05 Sep 2012 10:23
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