Developmental Psych (UnitII: Visual Cliff and Summary)

Review of Language Development - Any language capabilities/critical period

• Babies are pre-prepared to learn any language - research in Canada looked at words that English speakers cannot differentiate between - used these words to see when the reorganization happens in infant brains after which those exposed to English can no longer differentiate such phonemes - this happens at ~ 10-12 months

Experiment #3: Deprivation pf Experience

• Case study: Handicapped infant who did not begin locomotion until 8.5 months • Did not show HR acceleration until 20 months • Conclusion: offeres converging evidence that locomotor experience is an antecedent of the emergence of weariness of heights

Experiment #1

• Compared HR and facial expressions of pre-locomoting and locomoting (locomotion for an average of 5 weeks) 7.5 month old infants when lowered by a female researcher onto the shallow and deep side of a visual cliff apparatus • Age held constant design • Results: - Significant difference in HR response when lowered onto deep side of visual cliff; facial expression did not differentiate among groups - Both groups of infants showed visual placing response (both groups perceived depth) - Pre-locomoting infants don't show fear while locomoting infants do = locomotion seems to causes wariness of heights

Conclusion

• Locomotor experience paces the onset of weariness of heights • This is due to learning from experience that crawling leads to falling, but more importantly, by the fact that infants catch fears from their parents

Experiment #4: Age of Onset and Locomotion and Locomotor Experience

• New Dependent Variables: - Avoidance of descending on 1st trial - Latency to decent (shallow trials vs. deep trials) • Independent Variables - Age of onset of crawling (early, normative, late) - Duration of locomotor experience (11 vs. 41 days) • Results: Locomotor experience, regardless of the onset of crawling, predicts latency to descend, not age of onset - due to greater time navigating environment

Visual Cliff Research: Overview

• Research with the visual cliff illustrates the interdependence of different domains of development • Using the visual cliff, Gibson and Walk found that 6- 14-month-old infants received and understood the significance of the depth cue of relative size • Subsequently work by Campos and his colleagues using heart rate deceleration as the dependent measure indication that pre-locomoting infants could perceive the difference in depth but showed no fear of the deep side • Locomoting infants show fear • In a series of studies, the researchers found that the experience of moving themselves in the environment plays a very important role in babies' developing understanding of the significance of differences in the height of surfaces.

Summary Video

• Stage 1 : Preverbal - sounds that have no meaning but are used to communicate needs - sounds produce an effects on the world arena them - mothers con somewhat differentiate between these noises for their own baby • In the 1st year - show increasingly recognizable emotions - Birth = general distress - 2 mo = enjoyment - 3 mo = fun - 14 weeks = laughter - 3-4 mo = anger - cry with eyes open - 6 mo = joking amusement - 6 mo = wariness - 9 mo = expression of fear • Stage 2: Babbling - 9-12 weeks - over time babbling will develop to reflect sounds of the native language - Deaf children babble later • 10 mo = 1st word - Avg. age = 13.6 mo as infants move out of the preverbal stage - generally say names for familiar objects and people • At 1 year language development pauses to focus on other aspects of development - crawling and walking • Stage 3: Single word stage - 1 word for an entire sentence - children are generally with expressive or referential - tend to overgeneralize • Words then gain symbolism - can use words out of context • Making connections between objects, actions, and words - knowledge of social routines - visual context of word learning - parents saying what an object is or what a child is doing • Skinner believed - imitation - operate conditioning - not whole story - children create original sentences • Chomsky • Integrationist

Unresolved Issue

• The underlying causal mechanism is ambiguous. It could be that self-produced locomotion is causing the development of weariness of heights - Alternatively, the development of locomotion and the emergence of weariness of heights may be jointly determined by a third factor that brings about both changes - i.e brain development • in experiment 1 relationship between self-locomotion and fear is only correlational

Experiment #: Enrichment Manipulation

• True manipulation experiment • Experimental Groups (provided with 32 hours of voluntary forward movement in the device - baby walker) - pre-locomotor infants - locomotor infants • Control group - Pre-locomotor matched controls - Locomotor matched controls • Results: - The three groups of infants with any type of locomotor experience showed evidence of HR acceleration - pre-locomotor control infants did not - The experimental groups of locomotion infants who received a "double dosage" of locomotion experience showed a significantly higher HR acceleration than the other groups of infants • Conclusion: Locomotor experience appears to be an antecedent of the emergence of weariness of heights L --> Fear

Campos et. al. 1992

• Used Programatic research • Asked what the relationship between self-locomotion and the development of fear of heights is • Operational definitions (how they measured it) - Depth perception: visual placing responde - the extension of the arms and hands in anticipation of contact with the shallow, but not the deep surface, of the cliff - Emotional Response/Fearfulness: Heart rate response (HR) in the first 3 second period of descent onto the surface of the cliff --> HR deceleration = index of interest --> HR acceleration = index of fear - Facial expression - wasn't very reliable

Design

• Used a series of converging operations, • Programmatic research that built of each result