The rapid emergence of stimulus specific perceptual learning.

Patrick J Bennett,Zahra Hussain,Allison B Sekuler,Paul V Mcgraw

doi:10.3389/fpsyg.2012.00226

Abstract

Is stimulus specific perceptual learning the result of extended practice or does it emerge early in the time course of learning? We examined this issue by manipulating the amount of practice given on a face identification task on Day 1, and altering the familiarity of stimuli on Day 2. We found that a small number of trials was sufficient to produce stimulus specific perceptual learning of faces: on Day 2, response accuracy decreased by the same amount for novel stimuli regardless of whether observers practiced 105 or 840 trials on Day 1. Current models of learning assume early procedural improvements followed by late stimulus specific gains. Our results show that stimulus specific and procedural improvements are distributed throughout the time course of learning.

Highlights

IntroductionImprovements in perceptual and motor skills often follow a time course comprising steep early gains, followed by gradual increases in performance that accumulate over the course of several hundreds or thousands of trials (Poggio et al, 1992; Karni and Sagi, 1993; Recanzone et al, 1993; Ahissar and Hochstein, 1997; Karni et al, 1998; Wright and Fitzgerald, 2001; Hussain et al, 2009a; Ortiz and Wright, 2009; Agus et al, 2010)
Accuracy of the 40-novel group in Bin 9 was 20% worse than accuracy of the 40-same group [t (13.92) = 3.38, p < 0.01]. These analyses confirm that significant stimulus specific learning occurred in the 40-trials groups
Even small amounts of practice produced stimulus specific learning in a 10-AFC identification task: response accuracy measured on Day 2 was significantly greater in subjects shown a familiar set of faces compared to subjects shown a novel set of faces

Summary

Introduction

Improvements in perceptual and motor skills often follow a time course comprising steep early gains, followed by gradual increases in performance that accumulate over the course of several hundreds or thousands of trials (Poggio et al, 1992; Karni and Sagi, 1993; Recanzone et al, 1993; Ahissar and Hochstein, 1997; Karni et al, 1998; Wright and Fitzgerald, 2001; Hussain et al, 2009a; Ortiz and Wright, 2009; Agus et al, 2010). Stimulus specific learning – the proportion of learning that is specific to the trained stimulus attributes, retinal location, or eye (Fiorentini and Berardi, 1980; Ball and Sekuler, 1987; Poggio et al, 1992; Karni and Sagi, 1993; Ahissar and Hochstein, 1997; Hawkey et al, 2004; Aberg et al, 2009; Hussain et al, 2009a; Ortiz and Wright, 2009; Jeter et al, 2010) – is thought to be a slower process occurring later, after the cumulation of several hundred trials or more, and is associated with different mechanisms of plasticity than those involved in task-related learning (Karni and Bertini, 1997; Zhaoping et al, 2003; Law and Gold, 2009) By this view, the early and late phases of perceptual learning are associated with distinct types of learning. Stimulus-related learning has been reported to emerge early (Hawkey et al, 2004), and one study has shown that late trials contribute to generalizable improvements (Wright et al, 2010)

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Conclusion