Abstract
Research has demonstrated widespread age-related declines in visual function. Previous research has shown that perceptual learning (PL) techniques can be used to help counteract these age-related declines, and have been successfully used to improve motion discrimination (Bower & Andersen, 2012), as well as fine orientation discrimination in older individuals (DeLoss, Watanabe & Andersen, In Press, Vision Research). The present study examined whether contrast sensitivity could be improved in older adults using a coarse orientation discrimination task. Eight older individuals (mean age 72.13, range 67-84) and eight younger individuals (mean age, 21.29, range 19-23) participated in the experiment, which consisted of seven 1.5-hour sessions. A two-interval forced choice procedure was used during which two sequentially presented Gabor patches were presented. Participants indicated whether the Gabor in the second interval was rotated clockwise or counter-clockwise relative to the first, this rotation was set to a constant of 15 degrees. On days 1 and 7 pre-training and post-training contrast thresholds were determined using QUEST for a trained and an untrained standard (+/- 25 degrees off vertical), both measured at five different levels of external noise. Testing order and trained standard were both counter-balanced across subjects. During days 2 through 6 participants completed 750 trials at their assigned orientation standard, with 150 trials at each of the five levels of external noise presented on the testing days. Results showed improved contrast sensitivity for younger and older individuals for their trained standard. However, older individuals showed significant and nearly complete transfer to the untrained orientation, while younger individuals showed no significant transfer to their untrained orientation. The significance of these findings for perceptual learning, and specificity, in both younger and older individuals will be discussed.
Meeting abstract presented at VSS 2014