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Dave Ellemberg, Terri L. Lewis, Bryan Lee, Daphne Maurer; Motion detection and velocity discrimination are still immature in 5-year-olds. Journal of Vision 2002;2(7):646. doi: 10.1167/2.7.646.
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© ARVO (1962-2015); The Authors (2016-present)
We compared motion detection and velocity discrimination in 5-year-olds and adults (n = 18/grp). With a 10 deg Gabor and the method of limits, we measured the minimum velocity required to detect movement. With 10 × 10 deg sine-wave gratings and a 2 interval forced-choice procedure, we measured velocities that were just noticeably faster than 1.5 and 6 deg/sec.
Results. A t-test revealed that 5-year-olds needed a significantly greater velocity than adults in order to detect movement (2 times faster than adults; p < 0.001). An ANOVA on the velocity discrimination thresholds revealed an interaction between age and velocity (p < 0.001). Five-year-olds were significantly worse than adults for both velocities (ps < 0.01), with significantly worse discrimination thresholds at the slower (1.5 deg/sec) than at the faster velocity (6 deg/sec) (p < 0.001). Five-year-olds were about 7 times worse than adults at 1.5 deg/sec and 3 times worse than adults at 6 deg/sec.
Conclusions. The mechanisms underlying motion detection and speed discrimination are less sensitive in 5-year-olds than in adults. Further, in 5-year-olds, the velocity discrimination mechanisms are even less sensitive at the slower than at the faster velocities. These results complement the findings that the direction of motion for slower velocities matures less rapidly than that for faster velocities (Aslin & Shea, Vision Research 1990; Ellemberg et al, ARVO 2000). This suggests that the mechanisms underlying sensitivity to the direction of motion and sensitivity to differences in velocity operate under similar principles.
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