Perception

Perceptual Development- Study 1

Gibson and Walk investigated depth perception in 6-14 month year old crawling babies using a visual cliff apparatus which was created by simulating a steep drop on one side and a shallow surface on the other. Babies were placed on a center-board and were called by mothers to the shallow side then steep side consecutively. They found that all children crawled to their mothers when called from the shallow side but when called from the deep side, children children either crawled to the shallow side or cried because they would not cross the visual cliff suggesting that depth perception is innate.

Cross-Cultural Research of Perceptual Development- Study 1

Turnball found that Bambuti Pygmies who lived in dense forest had not developed size constancy as they did not have experience of looking at objects far away. When one member of the tribe was taken out of the forest and saw buffalo grazing in the distance he perceived these as insects until he got closer and identified them as buffalo. Suggesting that size constancy is learnt.

Bruce and Young's Theory of Face Recognition- Study 2

Young et al conducted an experiment where participants were shown the faces of famous people. One group was asked whether they were familiar, the other were asked whether the face was that of a politician. They found that the first group answered more quickly, supporting the model by suggesting that the face recognition units are activated before the person identity nodes.

Bruce and Young's Theory of Face Recognition- Study 1

Young et al investigated face recognition in ex-servicemen who had missile wounds to the back of the head. Some were poor at familiar face recognition, some poor at matching unfamiliar faces, others couldn't recognise facial expressions suggesting that there are independent systems for different aspects of face recognition.

Perceptual Development- Study 3

Bower investigated shape consistency in two month old babies by training them to turn their head to a rectangle. He found that the babies still responded when the same rectangle was presented at an angle showing that the babies realised it was the same rectangle and therefore had shape constancy, demonstrating that shape constancy is an innate ability.

Gibson's Bottom Up (Direct) Theory of Perceptual Organisation- Study 2

Bower investigated shape consistency in two month old babies by training them to turn their head to a rectangle. He found that the babies still responded when the same rectangle was presented at an angle showing that the babies realised it was the same rectangle and therefore had shape constancy. This study demonstrates that shape constancy is an innate ability, supporting the Bottom-Up theory

Bruce and Young's Theory of Face Recognition- A01

Bruce and Young's Model involves a series of modules that work sequentially and parallel to each-other. When our brain identifies a human face the structural encoding stage begins and a mental representation of the face is produced which allows you to decided if the face is male/female, old/young etc. The face is then compared to face recognition units, which include every face we have stored in memory. If there is a match we can then access the persons identity nodes which are stores of personal information about the people we have stored faces for. Finally we can retrieve the person's name. Another set of processing systems are activated at the same time and include expression analysis, facial speech analysis, directed visual processing, and a cognitive system.

Bruce and Young's Theory of Face Recognition- Issues

Bruce and Young's model has been criticised as being deterministic, in that it is a linear model. This suggests that face recognition can only occur in the order stated. It is possible that this occurs in many different ways, so it is invalid to state that it can only occur in one order. The model also draws on the issue of psychology as a science as the role of the cognitive system is extremely vague. Bruce and Young did not explain the specific function of this system. The model could also be criticised as being descriptive rather than explanatory. It does not for example; explain how expression analysis is initiated, or how we are able to label certain emotions as "happy" or "sad".

Cross-Cultural Research of Perceptual Development- A01

Cross-cultural research are useful as it helps to distinguish between biological and environmental factors (nature and nurture). If perception is consistent across cultures it would imply perceptual development is biological, whereas perceptual inconsistencies would imply that perceptual development is learned/environmental.

Perceptual Development- Study 2

Campos et al compared heart rates of two month year old babies placed on the shallow and deep side of the visual cliff apparatus. He found heart rates decreased on the deep site indicating intrigue, but stayed the same on the shallow side suggesting that babies could distinguish between the two sides supporting the argument that perception is innate. Older babies of nine months however showed an increased heart rate on the deep side, indicating anxiety suggesting that perception may be innate but recognising danger is learned through experience.

Explanations of Prosopagnosia- Study 2

Case studies of Prosopagnosia have provided evidence for prosopagnosia being due to brain damage. WJ developed prosopagnosia following a series of strokes. He was unable to recognise the face of a famous person when shown alongside unfamiliar faces. He later became a sheep farmer and although he was unable to recognise human faces he could recognise sheep which are seen as objects. This is further supported by PET scans and MRI scans which provide evidence that the right fusiform gyrus is more active during face recognition than during object recognition. Therefore we can assume that damage to this area will affect face recognition.

Gibson's Bottom Up (Direct) Theory of Perceptual Organisation- Study 1

Gibson and Walk's visual and cliff study supports Gibson's Bottom up theory as they found that babies crawled to their mothers when called from the shallow side of the visual cliff, but when called from the deep side, children children either crawled to the shallow side or cried because they would not cross the visual cliff suggesting that depth perception is an innate ability and not learned as other theories would suggest.

Gibson's Bottom Up (Direct) Theory of Perceptual Organisation- A01

Gibson argued that perception is not the result of learning but is a natural/automatic process. The environment provides a rich source of information that the brain can perceive directly with little processing and unambiguous data, as it would not make evolutionary sense to evolve a perception system that involved guesswork. Optic flow are changes in the optic array due to movement. Gibson believed that movement was vital in perception and these changes give us information about our position, direction and speed. He also believed that the perceptual system has evolved uses (affordances) of objects. Objects have characteristics that we can perceive a potential use for- and can be described as 'action possibilities'.

Gibson's Bottom Up (Direct) Theory of Perceptual Organisation- Issue 2

Gibson's Bottom up theory which would suggest that all people view the world in much the same way, and that perception is innate and forged by evolution, suggesting perception is vital for survival supporting the nature side of the nature-nurture debate. However there is strong evidence to show that the brain and long term memory can influence perception. In this case, it could be said that Gregory's theory is far more plausible.

Gibson's Bottom Up (Direct) Theory of Perceptual Organisation- Issue 1

Gibson's ideas may have applications in artificial intelligence. Recent research has used information from the optic array and affordances to design robots capable of advanced movement. Airport runways have lights to enhance optic flow patterns for pilots and road markings as we approach roundabouts become closer together to increase drivers' perception of speed and make them slow down.

Gregory's Top down (Constuctivist ) Theory of Perceptual Organisation- Issue 1

Gregory's Top down theory shows how perception is influenced by a number of cognitive, environmental, emotional and motivational factors. It offers an explanation for why people can perceive things differently in contrast to Gibson's Bottom up theory which would suggest that all people view the world in much the same way- supporting the nurture side of the nature-nurture debate.

Explanations of Prosopagnosia- Study 1

Grueter et al studied between 2 and 4 generations of 7 affected families and found 38 cases of prosopagnosia. This suggests a significant genetic contribution to face recognition skills, and prosopagnosia can therefore be explained by the mutation of a single gene.

Explanations of Prosopagnosia- A02

In many studies participants ability to recognise unfamiliar faces is measured. These lack ecological validity since the processing of unfamiliar faces is different to processing familiar faces, and in the everyday lives of prosopagnosics the inability to recognise familiar faces is the most problematic making this area of research more important.

Cross-Cultural Research of Perceptual Development- Issues

Issue of Cultural bias in research by conducting the study in a way which is disadvantageous to other cultures. A study on a group of Ethiopians were shown pictures of animals on paper. The Ethiopians did not seem to perceive the animals but were more interested in the paper itself which was unfamiliar to them. When the animals were printed on cloth they recognised the pictures, demonstrating how there is risk of misinterpreting results in a way that makes our own culture appear better.

Perceptual Development- Issue 2

Issues with studying neonates is that due to physical and cognitive constraints babies can only produce a limited range of observable behaviours- and it might be that they cannot demonstrate all of their abilities.

Perceptual Development- Issue 1

Many Babies used in research into perceptual development may have already have had time to learn perception making it difficult to disentangle the effects of maturation of the visual system (nature) and the effects from experience (nurture). Although animal studies have been found to support studies by Gibson and Walk and that depth perception is innate, it can be argued that animal studies are ungeneralisable to humans as there is less need for humans to be born with depth perception as humans are not mobile from birth.

Gregory's Top down (Constuctivist ) Theory of Perceptual Organisation- Study 2

Minturn and Bruner showed that the middle figure was more likely to be seen as the number 13 when presented with 12 and 14, but more likely to be seen as a B when presented with A and C supporting a top down approach as it shows we interpret data in relation to context etc.

Perceptual Development- A01

Neonates have been studied in order to establish whether or not perceptual abilities are innate or whether they develop from exposure to the environment. Can be monitored by: 1) Eye-movement monitoring- If the infant appears only to focus on certain features of the stimulus, it suggests that the whole stimulus cannot be perceived. 2) Heart and breathing Rate- If there are changes in rate when novel stimuli are presented it is assumed that the baby can distinguish between them, 3) Preferential looking- If a baby looks at one distinctive stimuli more than the other, the experimenter can assume they can tell the difference between them and has a preference for one over the other.

Gregory's Top down (Constuctivist ) Theory of Perceptual Organisation- Study 1

Palmer showed participants a familiar scene such as a kitchen. He then flashed an object onto the screen which was either: An object appropriate to the scene (bread) or an inappropriate object to the scene (drum). The loaf of bread was correctly identified 84% of the time, but the drum was identified less than 50% of the time. This supports a top down approach as it suggest perception is not just influenced by the sensory data but by the person's interpretation of the data due to expectation, context etc. It is what the brain does with the information that is vital, not just the information itself.

Gregory's Top down (Constuctivist ) Theory of Perceptual Organisation- A01

Perception is an active process whereby our past experience, knowledge, expectations and motivations can affect how we interpret the visual information we receive. This takes place rapidly however sometimes our senses present us with ambiguous data, and perception is slowed down. Perceptual set is a bias or readiness to perceive some things rather than others. The brain is pushed or 'set' into perceiving things in certain ways due to factors such as experience, context, motivation etc. Gregory believes the brain creates a hypothesis to explain sensory data. Visual illusions demonstrate how we can be misled and draw the wrong conclusions about what we see.

Explanations of Prosopagnosia- A01

Prosopagnosia is a disorder of face perception where the ability to recognise faces is impaired, while the ability to recognise other objects may be relatively intact. However some have problems with this as well. Acquired prosopagnosia is a condition following acute damage to the part of the brain specialised for processing faces. Evidence suggests that the part of the brain dealing with the face recognition units is called the right fusiform gyrus. If it finds a match then the anterior temporal cortex brings up a store of facts about the person which assists with the identification process. With prosopagnasia the third step of face recognition is not functioning properly and it is likely that damage to the right fusiform gyrus is responsible for failure to recognise faces.

Gregory's Top down (Constuctivist ) Theory of Perceptual Organisation- Issue 2

Research draws on the issue of psychology as a science as studies are criticised for lacking validity as visual illusions involve very artificial two- dimensional stimuli that give very little information and are often only displayed for a short amount of time, therefore it is no wonder that top-down guess work comes into play.

Explanations of Prosopagnosia- Issue 1

Research into prosopagnosia has applications to real life as it has helped therapists design new ways of helping sufferers to recognise faces. Prosopagnosics are now encouraged to use other non-facial cues such as voice, clothes etc. They are also encouraged to devise a mental checklist for familiar people, (E.g. blue eyes, brown hair, freckles = ____) and run through this when they meet someone.

Cross-Cultural Research of Perceptual Development- Study 2

Seagall investigated how different cultural groups responded to visual illusions. 2000 adult/child participants from 14 non-European groups and 3 European groups were shown various straight lined illusions. He found that European groups were more susceptible to the Muller-Lyer illusion than non-Europeans and tried to perceive it as a 2D representation of a 3D object. It was argued that this was a result of mis-applied size constancy suggesting that perception is learned, because people from a 'carpentered' environment are used to seeing geometric shapes/angles and have learnt to perceive the angles as parts of buildings, whereas those from a 'non-carpentered' environment took the picture at face value.