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Nestor Matthews, Jenna Kelly; Laterality-Specific Perceptual Learning on Gabor Detection. Journal of Vision 2010;10(7):1145. doi: 10.1167/10.7.1145.
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© ARVO (1962-2015); The Authors (2016-present)
Introduction: Several studies have demonstrated visual performance advantages for stimuli distributed across the left and right hemi-fields (bilateral stimulation) versus stimuli restricted entirely within one lateral hemi-field (unilateral stimulation) (Awh & Pashler, 2000; Alvarez & Cavanagh, 2005; Chakravarthi & Cavanagh, 2009; Reardon, Kelly, & Matthews, 2009). In the present perceptual learning study, we investigated the extent to which practice-based improvements in peripheral Gabor detection are specific to –versus generalize across- bilateral and unilateral training regimens. Method: Twenty Denison University undergraduates completed the study. The independent variables were training group (bilateral training versus unilateral training), session (pre versus post), Gabor target laterality (bilateral versus unilateral), and Gabor distracter (present versus absent). Each trial began with a pair of bilateral or unilateral cues indicating the peripheral positions (14.55 deg diagonally from fixation) at which a Gabor target would appear, if present. Half the trials contained Gabor distracters positioned between cued target positions. After correctly identifying a foveally flashed letter, participants judged whether a Gabor target had been present or absent at either cued peripheral position. For each participant, bilateral and unilateral performance was measured before and after five laterality-specific (i.e., bilateral only or unilateral only) training sessions. Results: Signal detection analyses revealed laterality-specific improvements in the proportion of hits (i.e., “present” responses on target-present trials) when distractors were present (F(1,18) = 8.833, p = 0.008, partial eta-squared = 0.329), but not when distracters were absent (F(1,18) = 0.002, p = 0.963, partial eta-squared <0.001). There was no evidence for laterality-specific improvements in the proportion of false alarms (i.e., “present” responses on target-absent trials) whether distractors were present (F(1,18) = 0.006, p = 0.939, partial eta-squared <0.001) or absent (F(1,18) = 0.257, p = 0.619, partial eta-squared =0.004). Conclusion: The findings are consistent with lateral hemi-field constraints on attentional selection.
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