Early Perceptual Development

This theory states that the origin of all knowledge is from sense experience. Experience and evidence, especially sensory perception are emphasised in the formation of ideas.The notion of innate ideas is seen as invalid. In order to build a more complex body of knowledge from these direct observations, induction or inductive reasoning must be used. This kind of knowledge is also known as indirect empirical knowledge.

John Locke (1690) "Tabula rasa": Humans are born as a blank slate - they have no knowledge whatsoever. They learn and acquire ideas from the environment; their blank slate is "written on" as a person lives and experiences. 

William James (1890) "Blooming, buzzing confusion": James used this quote to describe a baby's first experience of the world

Nativism is the theory that certain skills or abilities are "native", or innate to the brain at birth, they aren't learned - they emerge from a mind that is in some way already set up to deal with the environment in which it will develop and function. Language is typically used as a prime example of an innate ability, it is acquired in a way that is largely outside of the child's conscious control.

Kant: The human mind knows objects in innate "a priori" ways

Descartes: Believed that there were some forms of knowledge which are built in to the human psyche

Chomsky: Believed in Nativism in regards to language acquisition. Coined the LAD - a language organ which is hardwired into the brain at birth, thus we are born with the ability to understand and develop language.

This theory proposes that learning is an active, constructive process. Humans actively construct or create their own subjective representations of objective reality. New information is linked to prior knowledge. Knowledge is constructed based on personal experiences and hypotheses of the environment.The learner is not a blank slate, but brings past experiences and cultural factors to a situation.

Vygotsky - Social Development Theory: Social interaction precedes development; consciousness and cognition are the end product of socialisation and social behaviour. Includes 2 key concepts: "the more knowledgeable other" (MKO) and the zone of proximal development (ZPD).

Piaget: "I am a constructivist. I think that knowledge is a matter of constant, new construction, by its interaction with reality, and that it is not pre-formed. There is a continuous creativity".

Eye tracking: Eye tracking techniques can be used to investigate which parts of the stimulus infants attend to. Newborns will turn their eyes and heads in response to an interesting sight or sound - especially human voices or faces.

Habituation techniques: Babies prefer to pay attention to new sights, sounds, smells and temperatures rather than familiar ones. The technique involves repeatedly exposing a stimulus until the infant habituates. Then a novel stimulus is presented, researchers must then observe whether or not attention is reactivated (dishabituation).

Example: Phillips-Silver & Trainor (2005)

• 7 month old babies were bounced in synchrony to one of two rhythmic patterns
• After this, they showed a preference for the pattern they had been bounced to

Expectancy violation: Used to test how well older infants predict events. E.g an infant sees an object appearing in different locations successively. After several repetitions of the sequence the objects appearance in the expected place is delayed. By monitoring eye movements, the researcher can tell if the baby had learned the sequence and could predict the objects next appearance (Wentworth et al 2001).

High amplitude sucking used in habituation studies: Infants can control the rate and pressure of sucking very early on, and will do this when there is no food. Once sucking reaches a predetermined level, stimulus #1 is presented. Once it declines and the infant has habituated, stimulus #2 is presented. If sucking then increases the infant has dishabituated.

Preference paradigm: These techniques can tell us whether the infant can discriminate between two different stimuli and which of the two stimuli they prefer

Conditioned head turning: Used to test hearing thresholds and auditory discrimination in infants. A sound is presented through a speaker away from the infant's gaze. If the infant turns towards the sound, they are rewarded. Once head turning is established the sound can be changed over trials. Head turns to the speaker in the presence versus absense of sounds can then be compared.

Contingency or operant learning techniques: We need to learn that behaviours have consequences. Lewis et al (2004) put infants in a seat and attached a ribbon on an elastic band to their wrist. Base line measures taken of how much infant pulls the band without stimulus, then singing and slides are shown every time the infant pulls. From around 8 weeks, this resulted in increased pulling.

Physiological measures: Cortisol, which is released by the adrenal glands in response to stress, is sometimes swabbed from infant's mouths. Heart-rate changes are reflective of brain activity. Sensors can be placed on the infant's chest and compared with base-line measures.

Number sense

• 6 month old babies discriminate 8 dots vs 16 dots (1:2 ratio), at 9 months they improve at 2:3 but not 4:5 ratios.
• Numerosity discrimination abilities increases with development.

Vision

• Fantz & Miranda (1975) found that one week old infants preferred patterns with curved edges rather than straight
• Fantz (1961) presented 2 different patterns side by side to infants. He found that infants can distinguish between patterns and prefer the more complex ones.
• Brostein, Ferdinandsen & Gross (1981): by 4 months infants prefer symmetrical to asymmetrical patterns. Preference for complexity increases with age (Fantz & Fagan, 1975)
• Fantz (1961): infants preferred looking at a drawing of a face and scrambled face in comparison to a black and white circular drawing.
• Barrera & Maurer (1981): 3-6 month olds can distinguish similing from frowning faces
• Serrano, Iglesis & Loeches (1995): 4 month olds react differently to happy and angry faces

Shape constancy:

• Shape constancy is when people's perception of the shape of an object does not change regardless of changes to the object's orientation. Slater & Morison (1985): newborns shown a shape until they habituated. When it was shown at a novel angle they didn't dishabituate, indicating they have shape constancy

Size constancy:

• Size constancy refers to the fact that our peceptions of the size of objects are relatively constant despite the fact that the size of objects on the retina vary greatly with distance. Newborns prefer stimuli that provides the biggest retinal image. However, infants quickly go beyond retinal image and size constancy develops rapidly in the first year.

Kelman, Gleitman & Spelke (1987) habituated 16 week old infants to a rod that moved back and forward behind a block. Infants then either saw the whole rod (unfamiliar object) or bits of rod which were unobscured by the block (familiar object). Results showed that the infants dishabituated in response to the two parts. This suggests they were aware that there was a whole rod moving behind the occluding block. When the rod didn't move behind the occluding block, the infants didn't appear to perceive it as a whole object.

Johnson (1997) showed that when experimental conditions were optimal, even 2 month olds infants were aware that the rod was a whole piece. Newborns, however, cannot do this.