Week 4 - learning to perceive

• fantz concentrated on babies looking time on objects to measure their perceptual abilities at certain ages
• fantz made looking behaviour has become the most popular way of investigating perception in infants
• Slater (1983): newborn infants can discriminate shapes, but they could be doing this in lots of ways – configural shape, contour density, orientations of lines.
• Cohen and Younger (1983) showed that the way infants discriminate forms changes in the first months
• 1.5 month olds dishabituate to novel orientation
• 3.5 month olds dishabituate to novel angle
• Yang, 2014 showed that infants perceive the lightness properties of objects similar to adults
• 3-4mo infants detected changes in light field but not surface reflectance (glossiness)
• 7-8 mo infants detect changes in surface reflectance (glossiness) but not light field
• alan slater famous for demonstrating size, shape and constancy in newborn infants
• slater showed infants could discriminate shapes on basis of angular configuration using fixed familiarisation
• contrary to cohen and younger, slater believed infants can perceive configural shape when that is made salient to them in the environment
• he used fixed trial familiarisation to demonstrate that newborns could perceive objects of constant size, shape and form in the first days of life
• baillargeon showed how infants looked longer at impossible events despite its perceptual familiarity
• (Spelke, 1983) Habituated 4-month-olds demonstrated to a partially occluded rod -> looking preference for a broken rod over a complete rod. This is evidence for innate understanding that common motion signifies that the object is unified behind the occluder
• piaget observed that infants show a striking neglect of objects once hidden (object permanence)
• spelke argued we have an innate neural system that provides us with core knowledge about the world such as object permanence
• spelke proposed infants understand solidity at 2.5 mo
• reciprocal organisation of sensorimotor schemas - sensory information and motor actions are closely intertwined
• multi-sensory info arrives at the senses at different latencies (times), acuity (sharpness) and in different spatial formats
• common to argue infants have multi-sensory abilities due to amodal properties of multi-sensory stimulation
• amodal info is multisensory info which is the same across modalities and coded in a common representational format
• arbitrary correspondences - multisensory correspondences which carry distinct info in separate modalities
• Gogate and Bahrick (1998), Slater et al. (1999): Amodal audiovisual presentations assist (newborn) infants learning of arbitrary relations
• in severely visually impaired individuals localisation of touch in somatosensory co-ordinates is intact or enhanced compared to sighted infants showing they may have enhanced areas such as auditory spatial abilities
• SVI individuals show more accurate and faster responses to audiotacticle than audio or tactile only showing they have faster multisensory integration
• auditory system functions before birth as foetuses startle in response to loud sounds
• evidence infants can distinguish many phonemes by 1 and 2 months of age
• perceptual narrowing is the idea that our sensitivity to perception reduces in tasks with irrelevant domains explaining why sometimes infants perceptual discrimination worsens
• the brain areas involved in face processing continue to develop across childhood and adolescence - this is shown in several fmri studies
• preferences to look at faces has not been confirmed until 2 months of age whereas preferential tracking of faces is available immediately postnatally or perhaps before
• sub cortical face system mediates preferential tracking
• cortical face system which develops later mediates face preferences
• greater blood flow in TPJ in response to visual observation of actions correlated with fine motor skill
• there is evidence newborn infants identify faces as special and possibly even available prenatally
• an ability to differentiate individual faces becomes more specialised t human and upright faces across the first year
• Johnson explains our perceptual abilities of faces in terms of an innate face orientating mechanism which gives rise to the experience dependent specialisation of the cortex for encoding and recognising faces
• olfaction may be particularly important given early exposure to this sense channel
• piaget believed infants take a big step in terms of thinking about objects and perceptions at around 4 months
• amodal properties are ones which are not tied to a specific sensation but rather invariant over them