Broad bandwidth of perceptual learning in second-order contrast modulation detection

Abstract

Comparing characteristics of learning in first- and second-order systems might inform us about different neural plasticity in the two systems. In the current study, we aim to determine the properties of perceptual learning in second-order contrast modulation detection in normal adults. We trained nine observers to detect second-order gratings at an envelope modulation spatial frequency of 8 cycles/° with their nondominant eyes. We found that, although training generated the largest improvements around the trained frequency, contrast sensitivity over a broad range of spatial frequencies also improved, with a 4.09-octave bandwidth of perceptual learning, exhibiting specificity to the trained spatial frequency as well as a relatively large degree of generalization. The improvements in the modulation sensitivity function (MSF) were not significantly different between the trained and untrained eyes. Furthermore, training did not significantly change subjects' ability in detecting first-order gratings. Our results suggest that perceptual learning in second-order detection might occur at the postchannel level in binocular neurons, possibly through reducing the internal noise of the visual system.

Transfer of visual perceptual learning over a task-irrelevant feature through feature-invariant representations: Behavioral experiments and model simulations

“…One potential influence is the use of a pre-test baseline that included variations in the task-irrelevant feature in our experiments, as one review suggested that the use of pre-test baselines increased transfer compared to designs that did not use pre-tests ( Dosher & Lu, 2020 , chapter 3). However, a study design similar to that of our experiments (pre- and post-tests at multiple spatial frequencies but training at one) in two-interval contrast detection found narrower spatial frequency tuning following training in normal control observers ( Huang et al., 2008 ; Zhou et al., 2015 ).…”