Browsing by Subject "Perceptual learning"
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Item Open Access Deleterious effects of roving on learned tasks(Elsevier, 2014) Clarke, Aaron; Grzeczkowski, L.; Mast, F.; Gauthier, I.; Herzog, M.In typical perceptual learning experiments, one stimulus type (e.g., a bisection stimulus offset either to the left or right) is presented per trial. In roving, two different stimulus types (e.g., a 30′ and a 20′ wide bisection stimulus) are randomly interleaved from trial to trial. Roving can impair both perceptual learning and task sensitivity. Here, we investigate the relationship between the two. Using a bisection task, we found no effect of roving before training. We next trained subjects and they improved. A roving condition applied after training impaired sensitivity.Item Open Access Task difficulty and expertise mediate the effects of roving on perceptual performance(Bilkent University, 2019-01) Ceylan, GizayExperience-dependent improvement of perception, known as perceptual learning, is possible in the absence of feedback, but feedback enables faster progress as demonstrated by both unsupervised and supervised learning mechanisms. Perceptual learning models have shown that mixing these two learning mechanisms may potentially cause synaptic drift and disruption of learning. Models predict this disruption in simultaneously learning two tasks with differing difficulty levels, but not for tasks of equal difficulty. The roving, randomly intermingling of two different tasks, has thus sometimes been found to disrupt learning, but not always. Interestingly, the deleterious effect of roving may occur not only during learning but also even after a task has been learned. In this study, we examine roving's effects based on task difficulty as a function of expertise level. Subjects were trained with a vertical line bisection task, where they were asked to decide if the central line was offset to the left or right outer lines. Following training, the trained stimulus was roved with a narrower untrained bisection stimulus; half of the subjects were exposed to the roved stimuli, which were equated for difficulty using an adaptive staircase method, while other half were exposed to stimuli made to differ in difficulty levels using different staircase procedures for each. We demonstrated that performances improved with training. Moreover, roving deteriorated performance for the trained task under mixed difficulty conditions but not under matched difficulty conditions. Training participants over multiple days further revealed that roving's deleterious effects decreased with increasing expertise levels.Item Open Access Trait anxiety and post-learning stress do not affect perceptual learning(Elsevier, 2012) Aberg, K.; Clarke, Aaron; Sandi, C.; Herzog, M.While it is well established that stress can modulate declarative learning, very few studies have investigated the influence of stress on non-declarative learning. Here, we studied the influence of post-learning stress, which effectively modulates declarative learning, on perceptual learning of a visual texture discrimination task (TDT). On day one, participants trained for one session with TDT and were instructed that they, at any time, could be exposed to either a high stressor (ice–water; Cold Pressor Test; CPT) or a low stressor (warm water). Participants did not know when or which stressor they would be exposed to. To determine the impact of the stressor on TDT learning, all participants returned the following day to perform another TDT session. Only participants exposed to the high stressor had significantly elevated cortisol levels. However, there was no difference in TDT improvements from day one to day two between the groups. Recent studies suggested that trait anxiety modulates visual perception under anticipation of stressful events. Here, trait anxiety did neither modulate performance nor influence responsiveness to stress. These results do not support a modulatory role for stress on non-declarative perceptual learning.