Temporal Integration and Segregation of Brief Visual Stimuli:...

This experiment is based on the following paper:

Dilollo, V., Hogben, J., & Dixon, P. (1994). Temporal integration and segregation of brief visual stimuli: patterns of correlation in time. Perception and Psychophysics, 55, 373-386. Reprinted by permission of the Psychonomic Society, Inc.


Visible persistence refers to the fact that visual stimuli remain visible for a brief time after the display has been turned off. As the duration of the original stimulus is decreased, the duration of persistence is increased. Various explanations have been made for this “inverse duration effect.”

According to [the] processing hypothesis, visible persistence corresponds to a period of neural activity (which we refer to as the visual response) that starts at stimulus onset and lasts for a fixed period, irrespective of stimulus duration. (p. 373)

When the stimulus is short, the duration of persistence outlasts the physical display, but the longer the stimulus lasts, the more it overlaps with the persistence response of the visual nervous system, thus shortening persistence. For long durations, persistence and the physical exposure completely overlap, and persistence disappears.

When two stimuli are presented in rapid succession they are temporally integrated and seen as a single visual event. Under the processing hypothesis, integration occurs when the visible persistence of the first stimulus overlaps the onset of the second. The only factor affecting whether or not it occurs is the Stimulus Onset Asynchrony (SOA: the time between the onset of the first stimulus and the onset of the second).

A different prediction is made by the temporal correlation model. According to this theory, the correlation between two visual responses is calculated neurally.

According to the processing hypothesis, stimulus duration and ISI are equivalent; increasing the duration of one while decreasing the other by the same amount should have no effect on temporal integration. By contrast, according to the correlational model, temporal integration should be affected more by a change in ISI than by a corresponding change in stimulus duration. (p. 375)

This study was designed to test the predictions of the processing and temporal integration models.


The full text describing the experiment is available here.

The experiments are available below.

dillollo_win.zip (61.8 KB)

dillollo_mac.zip (84.2 KB)