Perception of Motion and Illusions

Introduction to Motion Perception

• Humans have specialized motion detectors in the brain.
• Apparent Movement: Perception of movement in stationary objects (e.g., IMAX movies, being in a stationary car).
• Both real and apparent movements are significant in psychology.

Perceptual Constancies

• Perceptual Constancy: Ability to maintain a stable perception of an object despite changes in sensory input.
• Types of Perceptual Constancies:
  • Size Constancy: Perceiving objects as constant in size despite changes in distance (e.g., a person walking away).
  • Shape Constancy: Recognizing objects as the same shape despite changes in orientation (e.g., doors and coins).
  • Color Constancy: Perceiving the color of an object as constant despite changes in lighting (e.g., a banana in different lighting).

Perceptual Illusions

• Interpretation of sensory stimuli can lead to misperceptions, known as perceptual illusions.
• Müller-Lyer Illusion: Lines of the same length appear different due to angles at the ends.
• Vertical Horizontal Illusion: Vertical lines appear longer than horizontal lines of the same length.
• Ames Room Illusion: Distorted perception of size due to a slanted room structure.
• Ponzo Illusion: Size perception influenced by background cues, such as linear perspective.
• Zollner Illusion: Overlapping patterns cause parallel lines to appear misaligned.

Illusions of Movement

• Beta Movement: Perception of continuous motion from quick sequential images (e.g., animated films).
• Phi-Phenomenon: Perception of movement from sequential lighting (e.g., Christmas tree lights).

Conclusion

• Perception is an interpretation of sensory stimuli and can differ from reality.
• Context, experiences, and expectations significantly influence perception.
• Stationary objects can seem to move, and distant objects can appear near due to contextual cues.