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The perceived duration of gratings
J A Baro1, L J Brzezicki, S Lehmkuhle
1School of Optometry, University of Missouri-St Louis 63121.
Perception
|January 1, 1992
Summary
Perceived duration of visual gratings does not change with spatial frequency, despite longer visible persistence at higher frequencies. Reaction times revealed consistent overestimation of duration, independent of spatial frequency.
Area of Science:
- Visual perception
- Spatial frequency processing
- Psychophysics
Background:
- Visible persistence of grating patterns increases with spatial frequency.
- Perceived onset of gratings is delayed at higher spatial frequencies.
- Visible persistence alone cannot determine perceived duration.
Purpose of the Study:
- To estimate the perceived duration of gratings across a range of spatial frequencies.
- To investigate the relationship between spatial frequency and perceived visual duration.
- To resolve discrepancies with previous findings on visible persistence and perceived duration.
Main Methods:
- Measuring reaction times (RTs) to grating onsets and offsets.
- Utilizing a range of spatial frequencies for grating stimuli.
- Calculating perceived duration as the difference between offset and onset RTs.
Main Results:
- Perceived duration was consistently longer than physical duration.
- Estimates of perceived duration did not significantly vary with spatial frequency.
- Onset and offset reaction times showed spatial frequency-dependent effects.
Conclusions:
- Perceived duration of gratings is independent of spatial frequency.
- Methodological differences, particularly in measuring perceived offset, explain discrepancies with prior research.
- Reaction time measurements provide a more robust estimate of perceived visual duration than visible persistence.