Sensation and perception flashcards

Sensation is the process by which sensory receptors detect physical stimuli from the environment and convert them into neural signals, while perception is the brain's active interpretation of those signals into meaningful experiences. Students must understand transduction, the major senses and their receptor mechanisms, and key thresholds including absolute threshold and difference threshold (just noticeable difference). Signal detection theory explains how factors beyond sensitivity, such as motivation and expectation, influence detection. Perceptual organization principles from Gestalt psychology, depth cues (monocular and binocular), perceptual constancies, and top-down versus bottom-up processing are all essential. Students should also understand how sensory adaptation, selective attention, and prior experience shape what we ultimately perceive.

1. Card 1

   What is the difference between sensation and perception?

   Sensation is detecting raw stimuli through sensory receptors; perception is the brain's active interpretation of those signals into meaningful experiences.

2. Card 2

   What is transduction in the context of sensation?

   Transduction is the conversion of a physical stimulus (light, sound, pressure) into an electrochemical neural signal that the brain can process.

3. Card 3

   Define absolute threshold.

   The absolute threshold is the minimum stimulus intensity needed for a person to detect it 50% of the time under controlled conditions.

4. Card 4

   What is the difference threshold (just noticeable difference)?

   The difference threshold (or just noticeable difference) is the smallest change in stimulus intensity a person can detect 50% of the time.

5. Card 5

   What does Weber's Law state?

   Weber's Law states that the just noticeable difference is a constant proportion of the original stimulus, not a fixed absolute amount.

6. Card 6

   How does signal detection theory differ from simple threshold models?

   Signal detection theory holds that detecting a stimulus depends on both sensory sensitivity and non-sensory factors like motivation, expectation, and response bias.

7. Card 7

   What is sensory adaptation and why does it occur?

   Sensory adaptation is the decrease in sensitivity to a constant, unchanging stimulus over time, freeing attention for new or changing stimuli.

8. Card 8

   Distinguish top-down from bottom-up processing.

   Bottom-up processing builds perception from raw sensory data; top-down processing uses prior knowledge, context, and expectations to interpret incoming information.

9. Card 9

   Name two Gestalt principles of perceptual organization.

   Figure-ground (separating an object from its background) and proximity (grouping nearby elements together) are two key Gestalt principles of organization.

10. Card 10

    What is the difference between monocular and binocular depth cues?

    Binocular cues (like retinal disparity) require both eyes; monocular cues (like linear perspective or interposition) allow depth perception with one eye.

11. Card 11

    What is perceptual constancy? Give one example.

    Perceptual constancy is perceiving an object as stable despite changing sensory input, e.g., size constancy keeps a car's perceived size stable as it drives away.

12. Card 12

    What role do feature detectors play in visual perception?

    Feature detectors are specialized neurons in the visual cortex that respond selectively to specific stimulus features such as edges, angles, or movement.

• Students often confuse sensation and perception, treating them as the same process rather than recognizing that sensation is passive detection while perception is active interpretation by the brain.
• Many students incorrectly assume the absolute threshold is the point at which a stimulus is always detected, forgetting that it is defined as detection 50% of the time under controlled conditions.
• Students frequently mix up monocular and binocular depth cues, incorrectly classifying retinal disparity as a monocular cue when it actually requires input from both eyes to compare slightly different images.

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