Basic Cognitive Processes - 2

Psych. 414

Prof. Jessica Sommerville

Infant perception

• Visual perception

• Auditory perception

• Intermodal perception

Face perception

• By 3 months look longer at face than non-face, and show a preference for familiar faces

• After 6 months face perception becomes more adult-like– Orientation, gender, emotional expression, attractiveness

• Faces as preferred stimuli from birth?– Preferential tracking of faces from birth

– Innate template for detecting faces based on configurational elements

Auditory perception

• Head-turn paradigm

• HAS paradigm

Head-turn paradigm

•Hear noise

•Reinforced for turning head in particular direction

High-amplitude sucking (HAS) paradigm

• Baseline sucking• Reinforced for increases in sucking rate• Sucking wanes with repeated presentation (habituation)• Different sound: increased sucking?

Speech perception

• Preferences:– Speech over non-speech; infant-directed speech– Preference for mother’s voice: due to

familiarity • From birth: Cat in the Hat study (DeCasper &

Spence, 1986; txt p. 49-50)

Speech perception

• Discriminations:– Categorical speech perception: differences between

speech sounds are continuous -- we perceive them as categorical

• Present in adults and infants• Initially discriminate speech sounds across all languages• Decline in non-native contrasts between 6 and 12 months of

age• Matter of degree not overall loss• Categorical perception not unique to humans or speech

Intermodal perception

• Recognition of common source of sensation; ability to match information across senses

• Sights and sounds– By 3 months match voice to face based on sex, age, and

mouth movements

• Sights and feels– Match visual impression to touch by 1 month– Imitation (at birth)

Memory development:The traditional view

TIME

Recognition

Applying schemas to objects

Habituation/dishabituation

Operant conditioning

18 months

Recall

Requires mental representation

Deferred imitation

Recognition

• Familiarity with a reencountered stimulus• Habituation paradigms

– Infants habituate to a repeated stimulus and dishabituate to a novel stimulus from birth

– 5 month-olds show a novelty preference for new faces and new objects after two weeks (Fagen, 1973; Fantz et al., 1975)

– 6 month olds remember dynamic stimulus from 3 months ago (Bahrick & Pickens, 1995)

Recognition

• Operant conditioning paradigms (Rovee-Collier and colleagues)

– Mobile task: 3 minute baseline (no reinforcement); 9-minute reinforcement period; expose babies to mobile later

– 3 month-old infants remember for 2 weeks– Initially, memories are highly specific

Recall

• The ability to retrieve a representation from memory in the absence of cues

• Measured via deferred imitation- Infant watches action (no immediate imitation is allowed)- Given opportunity to reproduce action at a later point in time

• Piaget – Not until 18 months of age– Relies on mental representation

Recall

• But emerging evidence suggests that it develops earlier– First evident in 6-month-olds– By 9 months infants can reproduce an action

they say 24 hours earlier (a subset up to 1 month)

– 23 month-olds imitate actions they saw modeled 1 full year ago

Memory development and the brain

• Age-related changes between 6 months and 2 years in deferred imitation linked to brain development

• Hippocampus– Develops early – Underlies deferred imitation of simple actions at 6

months

• Long-term recall of more complex actions requires additional brain areas– Prefrontal lobe, temporal lobe