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Benjamin van Buren, Tao Gao, Brian Scholl; What are the underlying units of perceived animacy?: Chasing detection is intrinsically object-based. Journal of Vision 2016;16(12):394. doi: https://doi.org/10.1167/16.12.394.
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© ARVO (1962-2015); The Authors (2016-present)
One of the most foundational questions that can be asked about any visual process is the nature of the underlying 'units' over which it operates — e.g. features, objects, or spatial regions. Here we address this question — for the first time, to our knowledge — in the context of the perception of animacy. Visual processing recovers not only low-level features such as color and orientation, but also seemingly higher-level properties such as animacy and intentionality. Even simple geometric shapes may appear to be animate (e.g. chasing one another) when they move in certain ways — and this appears to reflect irresistible visual processing, occurring regardless of one's beliefs. What are the underlying units of such processing? Do such percepts arise whenever any visual feature moves appropriately, or do they require that the relevant features first be individuated as discrete objects? Observers viewed displays containing several moving discs. Most discs moved randomly, but on chasing-present trials, one (the 'wolf') chased another ('the sheep'), by continually updating its heading in the direction of the sheep. On chasing-absent trials, the wolf instead chased the sheep's mirror-image (thus controlling for correlated motion). Observers' task on each trial was simply to detect the presence of chasing. Critically, however, two pairs of discs were always connected by thin lines. On Unconnected trials, both lines connected pairs of distractors; but on Connected trials, one line connected the wolf to a distractor, and the other connected the sheep to a different distractor. Signal detection analyses revealed that chasing detection was severely impaired on Connected trials: observers could readily detect an object chasing another object, but not a line-end chasing another line-end — even when both were easily discriminable. We conclude that the underlying units of perceived animacy are discrete visual objects.
Meeting abstract presented at VSS 2016
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