• Elton H. Matsushima
  • Fabiana F. G. da Silva
  • Aline P. A. de Gouveia
  • Rodrigo R. M. Pinheiro
  • Nilton P. Ribeiro-Filho
  • José A. da Silva


The present investigation aimed to provide a psychophysical account of visually directed actions. Seven different studies produced during the last eight years by our research group were submitted to Stevens’ power law analytical procedures. Those studies were conducted in different experimental environments, under different cue conditions, measuring perceived distance through visually directed walking task and variations of it, e.g., visually directed fractionation. One of these studies also addressed developmental issues. Therefore, many variables that potentially influence exponents of power law were controlled in these studies. Psychophysical analyses showed a general tendency to perceptual constancy, exponents equal to one. The cognitive demands of experimental tasks, the complexity of walking paths, the observers’ perceptual tendencies, and some developmental variable, have influences on exponents, usually leading to perceptual underconstancy. The presented results support the validity of visually directed actions, at least for visually directed walking, as a true measure of perceived distance.

Author Biographies

Fabiana F. G. da Silva

Rodrigo R. M. Pinheiro

José A. da Silva

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