Sensory traces versus the psychological moment in the temporal organization of form.

Visual stimuli were constructed so that any given stimulus by itself appeared to be a random collection of dots. However, when 2 corresponding stimuli were superimposed by means of a 2-field tachistoscope, a 3-letter nonsense syllable was perceived. When a temporal interval was introduced between the presentation of the corresponding stimulus halves, organization in perception was found to be a decreasing function of interstimulus interval over a range in excess of 100 msec. The applicability of a concept of a decaying sensory trace in accounting for the integration of form perception over time was investigated. Clear evidence of a decaying sensory trace was found; however, this concept was unable to account for all aspects of the data. The applicability of a psychological moment acting in conjunction with a decaying sensory trace was considered as was also the possibility of discontinuity detectors which inhibit or break up temporal organization.