Larger effect of aging on the perception of higher-order stimuli.
Widespread deficits are known to accompany normal aging. Contrast thresholds of older and younger observers were measured for static and drifting gratings defined by luminance (first-order) or by contrast (second-order), and for a temporally segmented second-order motion stimulus. Results showed that older individuals had a larger threshold elevation for the perception of second-order stimuli than for the perception of first-order stimuli. This suggests a dissociation between the mechanisms underlying the perception of first and second-order stimuli, and demonstrates that aging may affect the more numerous processing steps required for the analysis of higher level stimuli.
Habak
C
C
School of Optometry, Université de Montreal, C.P. 6128 succ. Centre-ville, Montreal, Canada. habakc@magellan.umontreal.ca
Faubert
J
J
D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D016477:Artifacts; D001288:Attention / Q000502:physiology; D015350:Contrast Sensitivity / Q000502:physiology; D006801:Humans; D008029:Lighting; D008875:Middle Aged; D009039:Motion Perception / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods; D011601:Psychophysics; D012684:Sensory Thresholds / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*