Abstract
Perceptual learning is typically highly specific to the stimuli and task used during training. However, recently it has been shown that training on global motion can transfer to untrained tasks, reflecting the generalising properties of mechanisms at this level of processing. We investigated if a) feedback was required for learning when using an equivalent noise global motion coherence task, and b) the transfer across spatial frequency of training on a global motion coherence task, and the transfer of this training to a measure of contrast sensitivity. For our first experiment two groups, with and without feedback, trained for ten days on a broadband global motion coherence task. Results indicated that feedback was a requirement for learning. For the second experiment training consisted of five days of direction discrimination on one of three global motion tasks (broadband, low or high frequency random-dot Gabors), with trial-by-trial auditory feedback. A pre- and post-training assessment was also conducted, consisting of all three types of global motion stimuli (without feedback) and high and low spatial frequency contrast sensitivity. We predicted that if learning involves low level processing, then based on the frequency specificity of the lower level areas, transfer would be contingent on the frequency of training. However, if learning involves a higher, global level of processing, more selective transfer would occur that matches the broadband tuning of the higher processing levels. Our training paradigm was successful at eliciting improvement in the trained tasks over the five days. However, post-training assessments found learning and transfer exclusively for the group trained on low spatial frequency global motion. This group exhibited increased sensitivity to low spatial frequency contrast, and an improvement for the broadband global motion condition. Our findings are consistent with perceptual learning which depends on the global stage of motion processing in V5.
