SENSORY DEVELOPMENT

Sensory Development

Can see and hear Can see and hear

Follow moving objects with eyesFollow moving objects with eyes

10% of time ‘quietly alert’ – scanning for 10% of time ‘quietly alert’ – scanning for interesting stimuliinteresting stimuli

Can feel pain, detect mother’s odour, show Can feel pain, detect mother’s odour, show taste and flavour preferencestaste and flavour preferences

Visual Perceptual Abilities

Born with ability to perceive movement and some Born with ability to perceive movement and some degree of depth degree of depth

Visual cliff experiment (Gibson and Walk, 1960)Visual cliff experiment (Gibson and Walk, 1960)

By 2 months, discern colour and brightnessBy 2 months, discern colour and brightness

4 months – 35% scanning time and ability to focus 4 months – 35% scanning time and ability to focus at varying distances is almost as good as adultsat varying distances is almost as good as adults

Narrow peripheral vision at birth – more than Narrow peripheral vision at birth – more than doubles between 2 and 10 weeks of agedoubles between 2 and 10 weeks of age

Habituation

Hearing abilities often studied through Hearing abilities often studied through habituationhabituation

Baby becomes used to a stimulus and stops Baby becomes used to a stimulus and stops responding to it. When a new stimulus is responding to it. When a new stimulus is presented, the response (e.g. sucking on presented, the response (e.g. sucking on comforter) resumes, indicating differencecomforter) resumes, indicating difference

As early as 3 daysAs early as 3 days

Preference

Amount of time looking at different sights tell Amount of time looking at different sights tell us about visual preferencesus about visual preferences

4 months, show a preference for red and blue4 months, show a preference for red and blue

Babies prefer curved lines to straight, complex Babies prefer curved lines to straight, complex patterns to simple, three dimensional to two patterns to simple, three dimensional to two dimensional objects, pictures of faces to dimensional objects, pictures of faces to pictures of other things, new sights to familiar pictures of other things, new sights to familiar ones.ones.

Face recognition

Maurer and Salapatek (1976) – 1 and 2 month Maurer and Salapatek (1976) – 1 and 2 month babies shown three expressionless faces: their babies shown three expressionless faces: their mother’s, a strange woman’s and a strange man’s.mother’s, a strange woman’s and a strange man’s.

1 month tended to look away, particularly from 1 month tended to look away, particularly from faces of their mother.faces of their mother.

Eyes focused on borders of the faces – recognition Eyes focused on borders of the faces – recognition based on chin or hairline distinctiveness.based on chin or hairline distinctiveness.

Auditory

Better developed than visualBetter developed than visual

Inner and middle ears reach nearly adult size and shape Inner and middle ears reach nearly adult size and shape in the wombin the womb

Startled by loud noisesStartled by loud noises

Turn in direction of soundsTurn in direction of sounds

Can distinguish between varying lengths and intensity Can distinguish between varying lengths and intensity

By 3 days, recognises difference between mother’s By 3 days, recognises difference between mother’s voice and other women voice and other women

Discriminative sucking

1 month old discriminates between two sounds as 1 month old discriminates between two sounds as close as ‘bah’ and ‘pah’ (1971)close as ‘bah’ and ‘pah’ (1971)

Special nipples, when sucked, turn on recording. Special nipples, when sucked, turn on recording.

At first, vigorous sucking for ‘bah’. Then slowed At first, vigorous sucking for ‘bah’. Then slowed down.down.

When ‘pah’ replaced ‘bah’, strong sucking When ‘pah’ replaced ‘bah’, strong sucking returned.returned.

Mother’s voice – recording of storytellingMother’s voice – recording of storytelling

24% more sucking when it was the mother’s voice.24% more sucking when it was the mother’s voice.

Taste

Can discriminate between different tastesCan discriminate between different tastes

Rejects bad-tasting foodRejects bad-tasting food

Prefer sweet tastes to sour or bitter onesPrefer sweet tastes to sour or bitter ones

Sweeter the fluid, the harder they suck and more they Sweeter the fluid, the harder they suck and more they drink.drink.

By four months, most favour salty over sweet tastesBy four months, most favour salty over sweet tastes

Useful to parents and medical practitioners – add saltUseful to parents and medical practitioners – add salt

Smell

One of the most highly developed in One of the most highly developed in newbornsnewborns

Preferences show within first weeks, Preferences show within first weeks, including a preference for the odour of including a preference for the odour of breast milkbreast milk

Helps recognise mother – mother and Helps recognise mother – mother and other women wore pads close to their other women wore pads close to their breast. The two pads were then placed breast. The two pads were then placed either side of an infant’s head. Even 2 wk either side of an infant’s head. Even 2 wk infants were more likely to orient to the infants were more likely to orient to the pad with their mother’s unique scent.pad with their mother’s unique scent.

TOUCH

Touching increases positive emotions and causes Touching increases positive emotions and causes babies to gaze and smile at adult carersbabies to gaze and smile at adult carers

Haptic perception – children use touch to explore Haptic perception – children use touch to explore and discover sensory qualities of objects.and discover sensory qualities of objects.

First few months, oral explorationFirst few months, oral exploration

Manual manipulation - newborn infants wooden Manual manipulation - newborn infants wooden cylinder/prism experiment show discriminationcylinder/prism experiment show discrimination