Recognition of Rotated Letters: Extracting Invariance Across Successive and Simultaneous Stimuli

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Response time (RT) for identifying single letters is usually indifferent to disorientation, but in Experiment 1 RT increased with the angular deviation from that of the preceding letter (ADP). This occurs only when the same letter is repeated, which suggests a process of backward alignment. RT again increased with ADP when the same letter was repeated in the same format (normal or mirror-reflected; Experiment 2). These findings were replicated for a same-different task by using 2 simultaneously presented letters (Experiment 3). Experiments 4 and 5 focused on stimuli that are related by a rotation in depth and suggested that transformation in the depth plane may facilitate judgments of sameness and that backward alignment can occur for different views of the same three-dimensional shape. The results suggest the operation of a pattern-recognition mechanism that relies on the extraction of invariance over temporally or spatially contiguous events.

Original languageEnglish
Pages (from-to)444-457
Number of pages14
JournalJournal of Experimental Psychology: Human Perception and Performance
Issue number2
StatePublished - May 1991

ASJC Scopus subject areas

  • Experimental and Cognitive Psychology
  • Arts and Humanities (miscellaneous)
  • Behavioral Neuroscience


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