Topic 4: Recognizing Objects

Apperceptive agnosia

Inability to recognize objects or shapes due to a failure in visual perception despite normal eyesight.

Associative agnosia

person can clearly perceive and draw an object, but can't recognize it or tell you what it means.

Bottom-up processing

Processing incoming sensory info as it travels upward from the senses to the brain.

Top-down processing

Using prior knowledge, beliefs, and expectations to interpret incoming sensory info.

Transcranial magnetic stimulation (TMS)

Brain stimulation applied to the 'what system' that can selectively disrupt object recognition by category.

Priming

When prior exposure to a stimulus influences response to a subsequent stimulus without conscious awareness.

(eg, recognize a word more because it's used frequently)

Word frequency effect

High-frequency words are recognized significantly faster and more accurately than low-frequency words.

Repetition priming

Enhanced recognition of a stimulus resulting from recent prior viewing.

P300 wave in repetition

High-frequency repeated words show a reduced P300 in frontal regions, indicating less attentional effort.

N400 wave in repetition

Repeated words show a reduced N400 in parietal regions, reflecting facilitated semantic processing.

Word-superiority effect

The advantage of perceiving a letter faster and more accurately when it is part of a real word, rather than alone or in a random string of words.

Pseudowords

Pronounceable non-words that follow standard spelling rules but have no dictionary definition.

(eg, FISH = GHOTI)

Degree of well-formedness

A measure of how closely a letter sequence conforms to usual language spelling patterns.

Feature nets

Hierarchical cognitive models that explain pattern recognition through layers of conceptual detectors.

Feature nets and errors

Competing activation across multiple letter detectors can lead to errors under quick or unclear conditions.

Bigrams

Pairs of letters that feature nets and the brain track to assist in word recognition.

Distributed representation

Storing infor as a pattern of activity across an entire network rather than one location.

McClelland and Rumelhart model

A recognition model where detectors can act as either excitatory activators or inhibitory suppressors.

Object recognition consensus

Models combine basic feature detection, hierarchical progression, and bidirectional (bottom-up/top-down) flows.

Prosopagnosia

Difficulty perceiving and identifying familiar faces despite having normal general eyesight.

Super recognizers

People who are extremely accurate in facial recognition without special advantages in other perceptual or memory tasks.

Face inversion effect

The psychological phenomenon where people find it much harder to recognize upside-down faces than upright ones.

Fusiform face area

A brain region associated with facial recognition, though it may also help recognize other familiar things.

Holistic facial recognition

Processing faces by relying on overall configuration and proportions rather than smaller parts

Composite face effect

When the brain automatically fuses halves of two different faces, making it hard to recognize either half separately unless misaligned.

Familiar vs unfamiliar face processing

Familiar face recognition relies on internal features, while unfamiliar recognition relies on outer parts like hair and head shape.

Familiarity vs race effect

Individual familiarity completely eclipses the own-race effect in facial recognition.