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HK Falkenberg, WA Simpson, V Manahilov; Development of Sampling Efficiency and Internal Noise in Motion Detection and Discrimination . Invest. Ophthalmol. Vis. Sci. 2002;43(13):4727.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose:In an ideal observer framework, human performance is limited by suboptimal sampling efficiency and by additive internal noise. The aim of this study was to investigate how these limiting factors changed over development in motion perception. Methods:We measured the energy contrast threshold as a function of the external dynamic noise level in three tasks: detection of a drifting grating, direction discrimination of oppositely drifting gratings, and detection of the sum of two oppositely drifting gratings. Thresholds were measured in three age groups: 9-10 years, 13-14 years, and adults. Results:The three tasks share a common source of internal noise. The internal noise level does not change with age. The sampling efficiency for discriminating motion direction is much lower than that for the other tasks. Moreover, it increases with age. in the near-adult range tested so far, sampling efficiency for detection and summation tasks does not change over development. Conclusion:We conclude that motion direction discrimination is a difficult task for the visual system: its absolute efficiency is very low and its development takes a long time.
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