ABSTRACT
This chapter describes sensorimotor and ecological implications of visual direction illusions to everyday life. It details how Minor Motor Anomalies frequently affect performance in nonlaboratory situations like batting in baseball. Minor Motor Anomalies have many possible physiological determinants. They could be caused by fluctuations in intramuscular temperature as the result of changes in local circulation and metabolic levels. They could also be caused by electrophysiological phenomenon common to all cholinergic transmission: depression, facilitation, and post-tetanic potentiation. Minor Motor Anomalies induce constant errors rather than random errors and they are induced by common conditions, which have been available to pressure the evolution of perceptual mechanisms. According to sensorimotor theories, the constant error induced by Minor Motor Anomalies should have been manifested equally in dark and light conditions. According to ecological theories, the visual direction illusion observed in the dark should be eliminated in the lighted condition that provided structural overlap, visible body parts, and static perspective, plus expectations.
