Training under attentional competition produces learned biases in visual appearance.

Selective attention can momentarily alter visual appearance, but can such effects be learned? We tested whether training attention under sustained sensory competition produces learned changes in perceived contrast. Across 7 days, participants trained on an orientation discrimination task in which the target appeared at a fixed spatial location, either with or without a salient distractor in the opposite hemifield. Before and after training, we measured perceived contrast using psychophysical estimates of the point of subjective equality. Training under competition produced a reliable opponent shift in relative perceived contrast between the two tested locations: lower physical contrast was required for stimuli at the trained location, whereas higher physical contrast was required for stimuli at the opposite/untrained location, to appear equivalent to the standard. In contrast, training without distractors improved discrimination accuracy but did not alter appearance. These shifts were observed at post-test, replicated across judgment formats designed to minimize response bias, and generalized partially to stimuli differing in orientation and contrast. Together, the findings demonstrate that repeatedly resolving attentional competition does not merely enhance performance but recalibrates the perceptual weighting of visual information, altering how the visual world is experienced.