The recent review by Scotland et al. (2015) noted that methodological differences between the studies precluded any firm
conclusions as to the specific nature and cause of the deficit in facial emotion recognition that people with ID were found to
have relative to those without ID. There are two main proposals that attempt to explain why people with ID are impaired in
recognising facial expressions of emotion. The first, the ‘emotion specificity hypothesis,’ argues that impaired performance
on emotion recognition tasks is a reflection of a specific impairment in emotion-perception competence, i.e. that cannot be
fully explained by cognitive-intellectual deficits alone (Rojahn, Rabold, & Schneider, 1995). The second proposal is that basic
emotion perception is intact in people with ID and, instead, that poor performance on emotion recognition tasks is a
consequence of poor IQ-related information processing abilities (Moore, 2001).