Ability of adults with a learning disability to recognise facial expressions of emotion: is there evidence for the emotion specificity hypothesis?
Aims Research suggests that people with a learning disability have difficulty processing and interpreting facial expressions of emotion. Emotion recognition is a fundamental skill and impairment in this area may be related to a number of negative, social and functional outcomes including increased frequency of aggressive behaviour, failure of community-based placements and mental illness. This thesis therefore had three aims: to review systematically the evidence for the presence of emotion recognition impairments in adults with a learning disability compared with the non-learning disabled population; to evaluate the emotion specificity hypothesis (which states that people with a learning disability perform less well on emotion recognition tasks as a result of a specific impairment in emotion recognition competence) and to evaluate the relationship between cognitive processing style and emotion recognition in people with a learning disability. Methods The first paper is a systematic review of studies that compared the performance of adults with a learning disability with that of a non-learning disabled control group on tasks of facial emotion recognition. The second paper reports on an empirical study that compared the performance of adults with a learning disability (n = 23) with adults (n = 23) and children (n = 23) without learning disability on tasks of facial emotion recognition and control tasks. The third paper reports further results from the empirical study which looks at cognitive processing style of adults with a learning disability and non-learning disabled children and adults. Results The systematic review found that all of the included studies reported evidence to support the proposal that adults with a learning disability are relatively impaired in recognising facial expressions of emotion. There are significant limitations associated with the research in this area and further studies are required in order to provide insight into the possible causes of emotion recognition deficits in this group of people. In the empirical study, adults with a learning disability were found to be relatively impaired on both emotion recognition and control tasks compared with both adult and child control groups. The availability of contextual information improved emotion recognition accuracy for adults with learning disability. The demands of the task also had an effect: identifying a target emotion from a choice of two images, rather than a choice of nine or naming the emotion also improved accuracy. Adults with learning disability were more likely to adopt a local processing style. A global processing style was associated with greater accuracy on the emotion recognition tasks. Conclusions Adults with learning disability are relatively impaired in facial emotion recognition when compared with non-learning disabled adults and children. This relative impairment was also evident on control tasks and therefore no evidence for the emotion specificity hypothesis was found. A number of issues in relation to future research are raised, specifically regarding the development of control tasks with comparable levels of difficulty to emotion recognition tasks.