What the exam asks
- Distinguish processing types: Identify whether a scenario relies on raw sensory features (bottom-up) or prior knowledge and expectations (top-down).
- Analyze internal and external filters: Explain how schemas, perceptual sets, immediate context, and cultural background shape what a person perceives.
- Apply organization and depth cues: Match visual scenarios to the exact Gestalt principle, binocular cue, or monocular cue defined in the course framework.
- Explain attention failures and illusions: Differentiate inattentional blindness from change blindness, and explain how perceptual constancies and apparent movement can trick the visual system.
Core ideas
Top-down and bottom-up processing
Sensation is the detection of physical energy by sensory receptors, whereas perception is the brain’s cognitive interpretation of those signals.
- Bottom-up processing begins at the sensory receptors and works up to higher levels of integration. You use it when encountering something unfamiliar—piecing together individual lines, angles, and colors to figure out what an object is.
- Top-down processing constructs perceptions from sensory input by drawing on your prior experiences, expectations, and knowledge.
Your top-down filters come from both internal and external sources:
- Internal factors: Schemas (cognitive frameworks that organize information) and perceptual sets (a mental predisposition to perceive one thing and not another). For example, if you expect a new dish to be bitter, your perceptual set makes you perceive a mild flavor as unpleasant.
- External factors: Immediate context (a between and is read as the letter ), past experiences, and cultural expectations (such as growing up in an environment with carpentered corners versus circular architecture, which alters susceptibility to visual illusions).
Attention and awareness
- Selective attention: Focusing conscious awareness on a particular stimulus while filtering out others.
- Cocktail party effect: The ability to attend to one voice among many in a noisy room, while still instantly noticing a personally meaningful stimulus (like your own name) spoken in an unattended conversation.
- Inattentional blindness: Failing to see visible objects when our attention is directed elsewhere (such as counting basketball passes and missing a person in a gorilla suit).
- Change blindness: Failing to notice a distinct change in the environment after a brief visual interruption (such as not realizing a stranger you are giving directions to was swapped for a different person while a door was carried between you).