Cite as:
Bachmann K, Hommuk K, 2007, "Impairment of in-stream target identification when stream items appear perceptually individuated as an invariant, static stimulus token" Perception 36 ECVP Abstract Supplement
Impairment of in-stream target identification when stream items appear perceptually individuated as an invariant, static stimulus token
K Bachmann, K Hommuk
When successive targets are presented within a stream of spatially overlapping, formally invariant items, 20-Hz condition involving perceived flicker allows higher rate of correct target identification than 60-Hz condition without flicker (Bachmann and Sikka, 2005 Acta Psychologica 120 19 - 34). This effect can be related to higher apparent contrast of stream items in the 60-Hz condition or to static appearance of stream-item tokens. Here, we normalised the stream-item contrast so that stream items in the 60-Hz condition appeared as having equal apparent contrast to those of the 20-Hz condition. Target-identification rate in the 60-Hz condition with normalised contrast-level increased compared to high-contrast-level condition, but it remained lower than in the 20-Hz condition of flickering presentation of stream items. Results show a difficulty in target identification when stream-item tokens appear subjectively as a static, invariant object extended in time. Difficulty of target token individuation in stream impairs type identification. When targets are presented within the first epoch of stream (50 - 80 ms from onset), first target unusually prevails over second target.
[Supported by Estonian Science Foundation grant #5778.]
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