Keeping track of invisible individuals while exploring a spatial layout with partial cues

Location-based and deictic direction-based strategies

Nicolas Bullot*, Jacques Droulez

*Corresponding author for this work

Research output: Contribution to journalArticle

4 Citations (Scopus)


In contrast to Constructivist Views, which construe perceptual cognition as an essentially reconstructive process, this article recommends the Deictic View, which grounds perception in perceptual-demonstrative reference and the use of deictic tracking strategies for acquiring and updating knowledge about individuals. The view raises the problem of how sensory-motor tracking connects to epistemic and integrated forms of tracking. To study the strategies used to solve this problem, we report a study of the ability to track distal individuals when only their directions can be perceived and not their locations. We introduce a new experimental paradigm named the 'Modified Traveling Salesman Problem' (MTSP), which requires subjects to visit n invisible targets in a 2D display once each. Surprisingly, subjects are competent at this task for up to 10 targets. We consider two types of tracking strategies that subjects might use: 'location-based' strategies and 'deictic direction-based' strategies. A number of observations suggest that subjects used the latter, at least for larger numbers of targets. We hypothesize that subjects used perceptual-demonstrative reference and deictic strategies (i) to perform the sensory-motor tracking of directional segments, (ii) to bind the segments with their updated status in the task, and (iii) to perform the epistemic tracking of invisible targets by means of perception-based inferences.

Original languageEnglish
Pages (from-to)15-46
Number of pages32
JournalPhilosophical Psychology
Issue number1
Publication statusPublished - Feb 2008


  • Deictic Strategies
  • Demonstrative Reference
  • Direction
  • Identification
  • Location
  • Perceptual Inference
  • Predicate
  • Spatial Memory
  • Tracking

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