Stimulus expectation prolongs rather than shortens perceived duration: Evidence from self-generated expectations

Area of Science:

• Cognitive Psychology
• Neuroscience
• Perception

Background:

• Previous studies suggested unexpected stimuli are perceived as longer (temporal oddball effect).
• Prior research often used stimulus repetition or probability to manipulate expectation, potentially confounding results.
• A novel paradigm is needed to isolate expectation's effect on duration perception.

Purpose of the Study:

• To isolate the effect of stimulus expectation on perceived duration, independent of repetition and probability.
• To investigate how self-generated expectations influence temporal judgments.
• To re-evaluate the role of stimulus expectation in temporal perception.

Main Methods:

• Participants vocalized their expected stimulus (color or shape) before presentation.
• A temporal bisection task was used to assess perceived duration of presented stimuli.
• Two experiments were conducted, one with color stimuli and one with shape stimuli.

Main Results:

• Longer perceived durations were found when stimulus expectations were met compared to when they were violated.
• This effect was consistent across both color and shape stimuli.
• Results contrast with prior findings suggesting expectation shortens perceived duration.

Conclusions:

• Higher-level stimulus expectation enhances stimulus processing, prolonging subjective duration.
• The findings challenge the notion that expectation primarily shortens perceived duration.
• The study questions the assumption that higher-level expectation is the main driver of the temporal oddball effect.