Component processes of human face perception in typical and atypical individuals

Face perception is an essential component of human social interaction. It guides how we interact with others by enabling us to recognize individuals, identify their emotional state, and judge their attractiveness and trustworthiness. Because face perception operates so effortlessly and reliably, we rarely give it a second thought. But in fact, face perception and recognition are difficult achievements that are based on complex and poorly understood mechanisms. The real difficulty of face processing only becomes apparent when meeting people without any general perceptual or intellectual impairment, and without any history of neurological damage, who find it extremely hard to recognize family and friends from their faces. Behavioural tests of various aspects of face processing conducted by us and by other groups have shown that many of these people with developmental prosopagnosia (DP) have no comparable problems with object recognition, which indicates that faces and non-face objects are processed by different mechanisms. All DPs show severe deficits in the processing of identity, but other aspects of face processing, such as the perception of face parts and face configurations or the processing of emotional facial expression, can be intact or impaired, suggesting that DP is a heterogeneous condition.
In our current ESRC-funded research project, we use a combination of behavioural and electrophysiological measures (event-related brain potentials, ERPs) to gain new insights into which aspects of face processing are damaged in DP. Our results so far point to early visual-perceptual stages of face processing as a major cause of the face recognition problems that affect individuals with DP. For example, people with intact face perception process upright faces and inverted faces very differently, which is interpreted as evidence that the perception of upright faces is "configural" or "holistic", whereas inverted faces are processed in a qualitatively different "part-based" fashion. We have found that people with DP do not show these typical processing differences between upright and inverted faces, indicating that their ability to process upright faces in a configural/holistic fashion did not develop properly.
To find out more precisely how face perception differs between DPs and people with intact face processing, we will conduct a series of experiments with face and non-face stimuli that are specifically designed to engage different aspects of face processing (e.g., the perception of salient face parts such as the eyes, the processing of facial configurations, perceiving faces from different viewpoints, using face perception to remember individual faces), to find out which processes operate normally and which are impaired in people with DP. We will also study whether DPs and non-impaired people look at faces differently, and whether they use different parts of a face when trying to identify it.
Finding out which aspects of face perception work well and which are impaired in DPs will have important implications for our understanding the mechanisms that underlie face perception in people with intact face processing abilities. It will also greatly expand our knowledge of why some people have severe deficits in face recognition. Such deficits can have an enormous impact on their social lives. Many have difficulty maintaining friendships due to perceived snubs and their recognition difficulties at work can be extremely troubling.

Developmental prosopagnosia (DP) is surprisingly common and can cause serious social difficulties. Individuals affected by this condition formed contact groups aimed at providing assistance and support, increasing public understanding of DP, and supporting research aimed at uncovering the causes of DP. Our current ESRC-funded project is at the centre of these activities in London and south-east England. The London-based group of DPs involved in our research is the world's largest group, and has become a focal point for formal and informal contacts between DPs, and for a series of initiatives that go well beyond our core research into DP, as listed below. We will further develop and increase these
and related impact activities in the coming years,

- Organisation of an annual face-blindness Open Day Event at Birkbeck, aimed to provide people with prosopagnosia in the London area with an opportunity to meet each other and to learn about recent research findings. Our first Open Day held on 20 September 2011 was attended by about 40 DPs, representing the largest meeting of DPs ever. See article in the face-to-face newsletter edition: http://www.faceblind.org/links/Face%20to%20Face%20Newsletter%20-%20Winter%202012.pdf

- Contributions to a bi-annual newsletter ("Face-to-Face"), available at faceblind.org (4 issues to date). Its aim is to keep DPs and interested members of the public updated about the latest prosopagnosia research, about our ongoing and planned research studies, and to share stories and experiences. We are currently planning the first edition of our own London-based newsletter.

- Maintaining a dedicated facebook page for London-based DPs: http://www.facebook.com/permalink.php?story_fbid=173408949437929&id=100003064768549#!/groups/117013401655030/


- Contributing to meetings of the London-based DP support group and hosting it on a quarterly basis at the Henry Wellcome Building. We will provide drop-in and information sessions, which are particularly important for those DPs recently diagnosed so that they meet other people similarly affected and to get a more in-depth understanding of their condition. These sessions will be open to those currently attending the London Faceblind group at its location at the Westminster Pastoral Foundation building in Central London, recently diagnosed participants that were tested in our lab, and other DPs that we will notify of the group via both the faceblind.org website and the DP facebook group.

In addition to providing a forum for individuals with DP, we also aim to contribute to the public understanding of DP and its nature as a common and serious condition by communicating our research findings to the media, and facilitating contacts between the media and individuals with DP that will increase public understanding of this condition. Recent press coverage on DP includes articles in the The New York Times (26 December 2011), Sunday Times (20 November 2011, The Daily (8 June 2011), the British Medical Journal (23 March 2011), the Daily Record (20 March 2011), Science News (10 December 2010), and The New Yorker (30 August 2010).