Perceptual learning without feedback in non-stationary contexts: Data and model

Abstract

The role of feedback in perceptual learning is probed in an orientation discrimination experiment under destabilizing non-stationary conditions, and explored in a neural-network model. Experimentally, perceptual learning was examined with periodic alteration of a strong external noise context. The speed of learning, the performance loss at each change in external noise context (switch cost), and the asymptotic accuracy d' without feedback were very similar or identical to those with feedback. However, lack of feedback led to higher decision bias (error responses matching the external noise context). In the model, the stimulus representations are constant, whereas the read-out connections to a decision unit learn by a Hebbian plasticity rule that may be augmented by additional feedback input and criterion control of decision bias.

Perceptual learning leads to long lasting visual improvement in patients with central vision loss

“…Indeed there is psychophysical evidence that inner reward/feedback can improve performance (Gibson & Gibson, 1955;Herzog & Fahle, 1998;Petrov, Dosher, & Lu, 2006;Shibata, Yamagishi, Ishii, & Kawato, 2009;Sasaki, Nanez, & Watanabe, 2010). For example Shibata et al (2009) found that also a "fake" feedback indicating a larger performance improvement facilitated learning compared with genuine feedback.…”

Perceptual learning and representational learning in humans and animals

“…In perceptual learning paradigms, the subject is presented with a well-defined task explained verbally by the experimenter-orientation discrimination, for example (Fiorentini & Berardi, 1980;Furmanski & Engel, 2000;Petrov, Dosher, & Lu, 2006), texture discrimination (Ahissar & Hochstein, 1997;Karni & Sagi, 1991), motion direction discrimination (Matthews, Liu, Geesaman, & Qian, 1999), or a hyperacuity test (Poggio, Fahle, & Edelman, 1992). After repetitive training (typically including feedback), the subject's performance improves as quantified by threshold or reaction time measures.…”

The other kind of perceptual learning

“…It "... encompasses parts of the learning process that are independent of conscious forms of learning and involve structural and/or functional changes in the primary sensory cortices" (Fahle and Poggio, 2002). In perceptual learning paradigms, the subject is presented with a well-defined task, such as orientation discrimination (Fiorentini and Berardi, 1980;Furmanski and Engel, 2000;Petrov, Dosher and Lu, 2006), texture discrimination (Ahissar and Hochstein, 1997;Karni and Sagi, 1991), motion direction discrimination (Matthews et al, 1999) or hyperacuity test (Poggio, Fahle and Edelman, 1992) that is explained verbally by the experimenter. After a repetitive training (typically including feedback), the subject's performance improves as quantified by threshold or reaction time measures.…”