The necker cube : a new perspective

Attempts to explain any perceptual phenomena usually do so exclusively in terms of neurophysiological mechanisms on the one hand, or in terms of inferred cognitive processes on the other. Alternative theoretical approaches offer a combination of these positions. The realisation that numerous phenomena can be accounted for by both major theories has lead to confusion of interpretation. One example is the reduction of dominance of a percept of a reversible figure after prolonged exposure to an unambiguous stimulus. Typically, the percept which resembles the unambiguous stimulus is seen for a smaller proportion of the subsequent viewing period. The neurophysiological account of this phenomenon holds that the groups of cells responding to the unambiguous stimulus become fatigued during adaptation so that during subsequent viewing of the ambiguous stimulus the most active group of cells will dominate. The alternative, cognitive explanation proposes that one of the effects of prolonged viewing or adaptation may shift the rate of accumulation of evidence for a particular perspective interpretation. Within this cognitive context one may speculate that prolonged inspection of an unambiguous stimulus simply creates a preference for whichever interpretation of the ambiguous stimulus is the more novel. Proponents of these dichotomous approaches believe that every perceptual phenomena need only be explained by one theory. However, as some phenomena can be explained by both approaches, an integrated approach in which visual processing at a physiological level is influenced by cognitive processes may be warranted. A modified experimental procedure to enable the independent manipulation of the physiological and cognitive components of this visual effect, was suggested.