Examining the myth of perceptual tropism or the moth-to-flame phenomena: Myth busted!

Perceptual tropism related to a crash scenario is when a driver is inexplicably drawn towards the lights of a stopped vehicle. The analogy used is that a driver is drawn to the lights like a moth. Actually tropism suggests there is an instinctual attraction. Helandar (1978) suggested that perceptual tropism is the reason why drivers' crash into the rear of stopped vehicles at night. Summala et al pointed out that Helander's was measuring a corrective action after drivers had overcompensated for the unknown light. Essentially, there is no evidence that driver's are drawn toward lights. While some studies show that drivers may drive slightly closer to an unidentified light than if the light was not present, there is no indication that drivers will travel directly toward a light. Other explanations could include confusion due to a poor light pattern, an inability to judge depth cues and in some circumstances, inattention to the forward field while driving. The argument proposed by many is that perceptual tropism occurs with Intoxicated drivers. However, intoxication influences a driver's ability to judge depth, contrast, (light) patterns and their search patterns are closer to the front of their vehicle than normal. Therefore, there are always other explanations (that are empirically supported) while there is no credible empirical support for a theory that claims that drivers drive toward lights at night. (A)


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Media Info

  • Pagination: 64-8
  • Serial:
    • IMPACT
    • Volume: 13
    • Issue Number: 3
    • ISSN: 0959-4302

Subject/Index Terms

Filing Info

  • Accession Number: 01012324
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: Dec 20 2005 3:24PM