PSYC 4415: Intro to Perception

Chapter Objectives

• Explain the seven steps of the perceptual process.

• Differentiate between "top-down" and "bottom-up" processing.

• Describe how knowledge influences perception.

• Understand perception by analyzing relationships between:

  • Stimulus and behavior

  • Stimulus and physiology

  • Physiology and behavior.

• Explain "absolute threshold" and methods for measuring it.

• Describe methods for measuring perception above threshold.

• Distinguish between physical stimuli and perceptual responses.

Sensation vs. Perception

• Sensation: Detection of information from the environment by sense organs.

• Perception: Interpretation of sensory signals.

• Sensory transducers convert energy forms.

The Perceptual Process

• Seven steps, including knowledge, illustrate perception:

  1. Distal stimulus (environmental object).

  2. Proximal stimulus (representation on receptors).

  3. Receptor processes (transduction of energy).

  4. Neural processing (signal transformation in neurons).

  5. Perception (awareness of stimuli).

  6. Recognition (categorizing stimuli).

  7. Action (response to stimuli).

  8. 

Distal and Proximal Stimuli

• Distal Stimulus: All environmental features available to an observer;
  selective attention to specific objects.

• Proximal Stimulus: The internal representation of the stimulus on receptors.

Knowledge in Perception

• Bottom-up Processing: Driven by stimuli from the environment.

• Top-down Processing: Influenced by prior knowledge and expectations.

Studying Perception

• Components include:

  • Stimulus (distal, proximal)

  • Physiology (receptors, neural processing)

  • Behavior (perception, recognition, action)

Measuring Perception

• Absolute Threshold: Minimal energy required for detection.

• Classical methods include:

  • Method of limits

  • Method of constant stimuli

  • Method of adjustment

• Assessments: Difference threshold (DL), magnitude estimation, reaction time, and phenomenological reports.