Two cases requiring external reinforcement in perceptual learning

Aaron R. Seitz, Jose Nanez, Steve Holloway, Yoshiaki Tsushima, Takeo Watanabe

Research output: Contribution to journalArticlepeer-review

51 Scopus citations


The role of external reinforcement is an issue of much debate and uncertainty in perceptual learning research. Although it is commonly acknowledged that external reinforcement, such as performance feedback, can aid in perceptual learning (M. H. Herzog & M. Fahle, 1997), there are many examples in which it is not required (K. Ball & R. Sekuler, 1987; M. Fahle, S. Edelman, & T. Poggio, 1995; A. Karni & D. Sagi, 1991; S. P. McKee & G. Westheimer, 1978; L. P. Shiu & H. Pashler, 1992). Additionally, learning without external reinforcement can occur even for stimuli that are irrelevant to the subject's task (A. R. Seitz & T. Watanabe, 2003). It has been thus hypothesized that internal reinforcement can serve a similar role as external reinforcement in learning (M. H. Herzog & M. Fahle, 1998; A. Seitz & T. Watanabe, 2005). This idea suggests that perceptual learning should occur in the absence of external reinforcement provided that easy exemplars are utilized as a basis for the subject to generate internal reinforcement. Here, we report results from two studies that show that this is not always the case. In the first study, subjects participated in two sessions of a motion direction discrimination task with low-contrast dots moving in directions separated by 90°. In the second study, subjects participated in 12 orientation-discrimination sessions using oriented bars (oriented either 70° or 110°) that were masked by spatial noise. Trials of different signal levels (yielding psychometric functions ranging from chance to ceiling) were randomly interleaved. In both studies, subjects experiencing external reinforcement showed significant learning, whereas subjects receiving no external reinforcement failed to show learning. We conclude that while internal reinforcement is an important learning signal, the presence of easy exemplars is not sufficient to generate reinforcement signals.

Original languageEnglish (US)
Article number9
Pages (from-to)966-973
Number of pages8
JournalJournal of Vision
Issue number9
StatePublished - Aug 22 2006


  • External reinforcement
  • Feedback
  • Internal reinforcement
  • Motion discrimination
  • Orientation discrimination
  • Perceptual learning

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems


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