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 Uses operant conditioning -- esp useful for localization and discrimination 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 Recognition Recall Applying schemas to objects Requires mental representation Habituation/dishabituation Deferred imitation Operant conditioning TIME 18 months

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