Are faces special? Critically evaluate the evidence that we have evolved a specialised neural network dedicated to processing faces. Brian Marron, 11461992, SF TSM. INTRODUCTION
Processing faces is extremely important to humans as social beings. We are able to put and identity on thousands of faces (Gazzaniga, 2002) with ease, something we might take for granted. The value of this ability can be better understood when the world is viewed through the eyes of somebody with prosopagnosia, the inability to recognise faces. The following quotation from David Fine, a prosopagnosic describing the difficulty associated with the disorder. “I often fail to recognise my children or even my wife … I have failed to acknowledge friends and, more distressingly, those in authority. At school I would get lines for not raising my cap to a teacher. As a young man I ignored girls whom I had met the night before – not a good mating strategy. I find networking all but impossible, and social situations … may cause acute anxiety.” (Fine, J. R. 2011 pp 455) Face processing is something that almost all of us can do yet exactly how we process faces is not yet known. In this essay I will examine one of the most heatedly debated topics of face processing: Are faces special? That is to say, are faces processed in a special way compared to non-face stimuli and have humans evolved a specialised neural network to achieve this? The two sides of the argument have been debated for a long time and there is still no clear answer. (Hole & Byrne, 2010) Research from both sides will be critically evaluated. Initially, evidence from psychological studies will be explored in an attempt to address whether faces are processed in the same way as non-face stimuli. After that the question of whether humans have evolved a specialised network dedicated to processing faces will be considered, drawing on evidence from studies of brain damage and neuroimaging. If faces and only were processed in a different way to non-face stimuli, it would greatly support the argument that faces are special. Yin carried out a very influential experiment in 1969. He presented participants with photos of faces, stickmen drawings, planes and houses. The task involved participants recognizing the stimuli presented inverted or “right-way-up”. Yin found that inversion decreased people’s ability to recognise all categories of stimulus. However, inversion impeded performance by 3 times as much for faces compared with other non-face stimuli. Yin also collected oral feedback. The results and feedback suggested that faces and non-face stimuli were processed differently. After many more very influential studies, such as the Thatcher Illusion (Thompson, 1980), the Composite Face Effect (Young et al. 1987), blurring facial features (Collinshaw and Hole, 2000) and many more, it was concluded that faces were processed in a different way to non-face stimuli. Specifically, faces are processed holistically with a dependence on configural information whereas non-face stimuli are processed using featural information in a peicemental way. It was concluded that because faces were processed differently they are special. Diamond and Carey disagreed (1986) that face and non-face stimuli were processed differently faces were special. They put forward the expertise hypothesis in a much cited paper in 1986. They said the Face Inversion Effect found by Yin was not a result of using different sources of information (configural and featural) but that it was a result of expertise with faces. They based their assertions on evidence from their experiment with dog experts. Dog experts and non-experts were given a similar inversion test to Yin’s, with photos of dogs as well as faces (1969). Again they were asked to recognise the dogs and human faces while upright or inverted. Understandably, Yin’s Inversion Effect was found for faces. Interestingly, the dog experts showed a similar inversion effect for dogs while the...
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