Purpose: We measured performance on a battery of visual form perception tasks for adults sampled evenly from each decade of adult life from 20 to 80 years.
Methods: Measures were included that are considered to reflect processing at early through intermediate stages of the form processing pathways: collinear facilitation, center-surround contrast effects, global shape discrimination of contours of elements embedded in noise elements, and global shape discrimination in texture (Glass patterns). A total of 38 women and 20 men (mainly Caucasian, low refractive error) participated, aged between 20 and 82 years.
Results: With advancing age, contrast sensitivity decreased linearly (B = 0.009, t(56) = 8.14, P < 0.001), perceptual surround suppression of low contrast stimuli embedded in higher contrast surrounds increased (B = -0.006, t(56) = -3.32, P < 0.01), and coherence thresholds for detecting form in Glass patterns increased (B = 0.14, t(56) = 2.53, P = 0.02). Performance between tasks was not correlated.
Conclusions: Several aspects of form perception alter gradually throughout the adult lifespan, namely context-dependent perception of contrast, and the extraction of global shape from texture. Our results suggested age-dependent differences under natural viewing conditions that are not predictable by standard clinical measures of visual function, and point to changes in neural function that are ongoing throughout adult life.