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Nitzan Censor, Dov Sagi; Practice little, gain much: Short training enables long-term resistance to perceptual deterioration. Journal of Vision 2008;8(6):974. doi: 10.1167/8.6.974.
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© ARVO (1962-2015); The Authors (2016-present)
Intensive training or testing reduces performance on perceptual tasks. These effects are specific to basic image features, implicating early stages of the visual stream rather than general fatigue (Mednick, Nakayama, et al., 2002; Ofen, Moran & Sagi, 2007). Here we show, for the texture discrimination task, that such adaptation-like performance decrements are practically eliminated following practice with a small number of trials and sleep. Texture stimuli were presented for 40 ms and backward masked (Censor, Karni & Sagi, 2006). Observers decided whether an array of 3 diagonal bars embedded in an array of horizontal bars (1919) was horizontal or vertical. In each session the SOA (target-mask asynchrony) decreased gradually to obtain a psychometric curve. One group of observers practiced the texture discrimination task with 12 trials/block of SOA (∼450 trials/session), showing low thresholds (112.3±3.5 ms, mean±SE). A second group practiced the task with 50 trials/block (∼1600 trials/session), showing higher thresholds (174.8±7.2 ms). Both groups returned for intense test-sessions with 50 trials/block. Results showed that the average threshold in the 50 trials/block test-sessions was significantly lower for the observers trained with short 12 trials/block sessions (117.8±5.0 ms), as compared to those trained with 50 trials/block (158.3±6.3 ms). This learning effect was long-term, observed even when training and test were separated by nine months, and was not found when training and test were not separated by sleep. Thus, short training produces consolidation of an effective memory within the visual neural network, resistant to the performance decrements that are induced by intensive testing. We suggest a link between perceptual deterioration and learning: best performance is achieved with short training while further training leads to decrements due to connectivity saturation. Resistance is achieved by sleep dependent consolidation of unsaturated connectivity. This link may have an important role in the underlying mechanisms of perceptual learning.
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