Orientation discrimination in 5-year-olds and adults tested with luminance-modulated and contrast-modulated gratings.
We compared thresholds for discriminating orientation by 5-year-olds and adults for first-order (luminance-modulated) and second-order (contrast-modulated) gratings. To achieve equal visibility, we set the contrast for each age and condition at a fixed multiple of the contrast threshold for discriminating horizontal from vertical gratings. The minimum tilt that could be discriminated from vertical was four to five times larger in 5-year-olds than in adults, even when the noise was removed from the first-order stimuli and amplitude modulation increased to 0.90. Thresholds at both ages were significantly worse (1.2-1.5 times worse) for second-order modulation than for equally visible first-order modulation, and 5-year-olds were equally immature for both types of pattern. Together, the findings suggest that orientation discrimination is slow to develop and worse for second-order than first-order patterns in both children and adults.
Lewis
Terri L
TL
Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON, Canada. LewisTL@mcmaster.ca
Kingdon
Andrea
A
Ellemberg
Dave
D
Maurer
Daphne
D
D000328:Adult; D016477:Artifacts; D002675:Child, Preschool; D015350:Contrast Sensitivity; D004192:Discrimination, Psychological / Q000502:physiology*; D006801:Humans; D008027:Light; D009949:Orientation / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods*; D012684:Sensory Thresholds; D014796:Visual Perception / Q000502:physiology*