Lecture 19 Flashcards
Discuss colour, pattern and depth perception in children
These are all categorisations of stimuli
Colour perception: At one week of age they are able to distinguish some colours but not all. This ability becomes similar to an adults ability by 2 months.
Pattern perception: There’s a test with three pacman like shapes forming the points of an invisible triangle. Newborns are able to see the triangle if motion cues are present, however, they can understand the illusion without motion cues by 7 months.
Depth perception: At 1 month of age, babies are seen to blink when they see an object expanding and they can perceive a visual cliff by 6 months of age.
Discuss visual acuity in children
Most of an adult’s cortex is involved with visual processing and visual acuity can be tested via habituation paradigms. However, it’s been found that the visual acuity of newborns is much poorer because their cones aren’t fully developed so only 2% of the light hits the fovea. But by 8 months, visual acuity is almost as good as adults.
Why is the categorisation of visual stimuli important?
Because it reduces the complexity of the environment, reduces the need for constant learning, allows us to have appropriate actions and it enables us to order classes of objects.
Define categorisation
The ability to render different things as equivalent, therefore allowing us to respond to them in terms of their class.
Do we have innate knowledge of sound categories?
Unborn children have a preference towards their mother’s voice and can discriminate their language from others. They can also discriminate other sounds from birth and there is left hemisphere action for normal speech compared to backwards speech.
Additionally, 1 year olds have phonemic categorisation; they can discriminate between a and i and they lose discriminations of sounds that aren’t part of their language. They also have content categorisation; preference for their own language and preferring content words over function words.
Discuss innate face processing
At three days of age, infants have a preference for their mother’s face and at 9 days, they have a preference for a schematic face as opposed to a scrambled face. However, evidence has shown that this predisposition might not be accurate as it could just be a preference for more information at the top of the image.
Children become fully capable of face processing at 10 years of age. Also, face processing is an extremely holistic thing, this means that if one aspect is changed, the whole face looks different. Also, it allows the inverted face illusion to occur.
Discuss the holistic processing of face processing
Holistic processing begins between 4 and 6 years of age and they still rely on other features more like clothing. The activation of both brain hemispheres is consistent when looking at inverted faces and upright faces. However, in adults, there’s a specific activation when viewing upright faces. The activation is in the fusiform gyrus aka the fusiform face area.
What are the methods we use to categorise stimuli?
Perceptual categorisation: categorising objects by similarities in appearance. 3 month old babies have shown this via habituation; they categorise cats which excludes lions and dogs. They can also show shape categories with letters via operant conditioning.
Conceptual categorisation: categorising objects by similarities in function. Motion information contributes to category information and specific attributes are also categorised. Younger et al. found that conceptual categorisation is closely linked to perceptual categorisation and as one gets older, their conceptual categorisation skills increase. This was shown when the children were presented with different shapes that degraded in appearance, some shapes were harder to begin with and the children got better at categorising what shape it was as they aged. However, there are examples of conceptual categorisation over-ruling perceptual as children age so it isn’t fully known which is more dominant.
The two types emerge at different levels and are both very distinct but the development of them is still unknown.
Discuss the categorisation of stimuli in autistic children
Autistic children have an enhanced ability to discriminate between features but this can lead to difficulties in processing similarities. Therefore, it allows us to test how much perceptual categorisation effects conceptual categorisation as their conceptual categorisation should also be impaired if it relies on perceptual categorisation. Semantic categorisations of words enhanced their memory recall ability showing how their conceptual categorisation isn’t impaired. Additionally, their performance on a test of recognising objects after an appropriate or inappropriate context was the same as typically developing children (slower recognition when there’s an inappropriate context).
