Contribution of bottom-up and top-down motion processes to perceived position

Area of Science:

• Visual perception
• Cognitive neuroscience
• Psychophysics

Background:

• Perceived object position is influenced by various visual scene factors, notably motion.
• High-level motion perception, involving top-down processes like attention, demonstrably affects perceived object location.

Purpose of the Study:

• To determine if high-level motion perception alone is sufficient to alter perceived position.
• To investigate whether attention to or awareness of motion direction is necessary for positional displacement.

Main Methods:

• Experiment 1: Assessed positional shifts when motion perception occurred without physical motion.
• Experiment 2: Evaluated positional influence when motion direction was indiscernible despite physical motion.

Main Results:

• Perception of motion, even in the absence of physical movement, was sufficient to shift perceived position.
• Objects' apparent locations were influenced even when participants could not identify the direction of a present motion stimulus.

Conclusions:

• Motion influences perceived position via at least two independent processes: a preattentive, passive mechanism and a top-down process requiring awareness of motion direction.
• Both mechanisms contribute to perceived position, operating distinctly from one another.