Guess Who? Understanding lifelong face blindness

The most natural way to identify people we know is by recognising their face, but imagine if you were unable to recognise the familiar faces of family and friends, or even your own reflection. This is often the case for people with Developmental Prosopagnosia (DP) or lifelong face blindness. DP is a neurodevelopmental condition characterised by lifelong difficulties in facial recognition that are not associated with broader problems with vision or memory. DP has negative effect on well-being, tends to run in families, and may affect up to one in fifty people with varying severity. DP research has made progress in recent decades, but our knowledge remains limited and patchy because most DP studies rely on small samples of participants (10-20 people per study).

Supported by a Marsden Fund Fast-Start, Dr Tirta Susilo's team in the School of Psychology at Victoria University of Wellington are using the power of the internet to access much larger samples of people with DP (100+ people per study). Because their studies run online, the team can work with affected people anywhere in the world. This approach has enabled them to collect more DP data than ever before and develop a more coherent picture of the condition.

After initial surveys, participants who satisfy diagnostic criteria for DP are invited into studies focusing on a variety of issues associated with DP. These include examining which aspects of face processing people with DP have trouble with; which cognitive and brain mechanisms are atypical in DP; whether DP tends to co-occur with other neurodevelopmental conditions; and whether we can find ways to improve the face recognition skills of people with DP.

In recent studies, the team confirmed that people with DP are less able to analyse faces as a whole. Rather, they tend to recognise faces based on specific features - such as  eyes, mouth or nose – in isolation (see Figure 1). This result suggests that DP is linked to a deficit in the way that the brain integrates visual information across the whole face. The team have also demonstrated that people with DP have more difficulty processing facial identity than facial expression. This result indicates that DP problems do not affect all aspects of face processing, but specifically affect the ability to process information about identity. These studies have begun to clarify the nature of DP and pave the way for future research towards a better understanding of DP at the cognitive, neural, and even genetic level.

Figure 1: For typical observers, determining which of the three faces on the right matches the face on the left is much easier when the faces are shown upright. This is because face recognition involves specialised brain procedures that result in a holistic impression of the face, which are not accessible when faces are shown upside-down. People with DP have trouble with these procedures, and so they show reduced benefit from seeing faces upright compared to upside-down. 

 

You can find out more about DP from Dr Susilo’s webpage and the Prosopagnosia Research Centre. If you think you may have DP and are interested in participating in research, you can fill out an initial survey. The team will then send you a link to a battery of tests for DP diagnosis, and give you individualised feedback upon completion.

Additional information: Vision and Cognition Group, at Victoria University of Wellington