The spread of attention and learning in feature search: Effects of target distribution and task difficulty

Merav Ahissar*, Shaul Hochstein

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

75 Scopus citations


We examined the roles of two determinants of spatial attention in governing the spread of perceptual learning, namely, stimulus location distribution and task difficulty. Subjects were trained on detection of a target element with an odd orientation imbedded in an array of light bars with otherwise uniform orientation. To assess the effects of target distribution on attention and learning, target positions were distributed so that attention was allocated not only to the target positions themselves, but also to intermediate positions where the target was not presented. Target detection performance substantially improved and improvement spread to match the induced window of spatial attention rather than only the actual target locations. To assess the effect of task difficulty on the spread of attention and learning, the target-distractor orientation difference and the time interval available for processing were manipulated. In addition, we compared performance of subjects with more versus with less detection difficulty. A consistent pattern emerged: When the task becomes more difficult, the window of attention shrinks, and learning becomes more localized. We conclude that task-specific spatial attention is both necessary and sufficient to induce learning. The spread of spatial attention, and thus of learning, is determined by the integrated effects of target distribution and task difficulty. We propose a theoretical framework whereby these factors combine to determine the cortical level of the focus of attention, which in turn enables learning modifications. Copyright (C) 2000 Elsevier Science Ltd.

Original languageAmerican English
Pages (from-to)1349-1364
Number of pages16
JournalVision Research
Issue number10-12
StatePublished - Jun 2000

Bibliographical note

Funding Information:
We thank Roni Laiwand for technical assistance in performing these studies and the data analysis. We thank Anne Treisman, Robert Shapley and Howard Hock for many helpful discussions of the work. This study was supported by grants from The Israel Institute for Psychobiology (to MA); the US–Israel Binational Science Foundation (BSF) and the Israel Science Foundation of the Israel Academy of Arts and Sciences (to SH).


  • Attention
  • Feature search
  • Learning
  • Perception
  • Pop-out


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