Impaired sadness recognition is linked to social interaction deficit in autism

Abstract

Can autistic individuals use motion cues to identify simple emotions from 2D abstract animations? We compared emotion recognition ability using a novel test involving computerised animations, and a more conventional emotion recognition test using facial expressions. Adults with autism and normal controls, matched for age and verbal IQ, participated in two experiments. First, participants viewed a series of short (5s) animations. These featured an 'emotional' triangle, interacting with a circle. They were designed to evoke an attribution of emotion to the triangle, which was rated both in terms of anger, happiness, sadness or fear from its pattern of movement, and how animate ("living") it appeared to be. Second, emotion recognition was tested from standardised photographs of facial expressions. In both experiments, adults with autism were significantly impaired relative to comparisons in their perception of sadness. This is the first demonstration that, in autism, individuals can have difficulties both in the interpretation of facial expressions and in the recognition of equivalent emotions based on the movement of abstract stimuli. Poor performance in the animations task was significantly correlated with the degree of impairment in reciprocal social interaction, assessed by the Autism Diagnostic Observation Schedule. Our findings point to a deficit in emotion recognition in autism, extending beyond the recognition of facial expressions, which is associated with a functional impairment in social interaction skills. Our results are discussed in the context of the results of neuroimaging studies that have used animated stimuli and images of faces.

Figure 1

Frame from one of the 12 animations, showing the circle and triangle, and the following question. Eight animations were designed to evoke the attribution of a particular emotion (angry, happy, sad or scared), whereas in the other four the shapes were designed to appear inanimate. Animations were followed by a question in which the participant selected their response from a numerical rating scale.

Figure 2

2a) Mean ratings of the animations by the two participant groups, for either an actual or an alternative emotion. 2b) Computed emotion recognition scores of the autism and control groups, on the animated emotion task. The range of possible scores was from -5 to +5, with a higher score indicating a greater accuracy in correctly identifying the emotion. Error bars indicate standard error. * = p<0.05.

Figure 3

Mean ‘living’ ratings of the autism and control groups for animations representing each of the four emotions. Error bars indicate standard error. Ratings are on a scale from 0 to 5.

Figure 4

Scatterplots indicating correlation between a subject’s RSI score (higher score = more impaired) and their ability to recognise that a ‘sad’ animated triangle is sad (a) or living (b).

Figure 5

Bland-Altmann plot of participants’ scores at time 1 and time 2 in the test - retest paradigm. The x-axis shows the mean score of each subject (maximum score = 5; a score of zero indicates performance at chance). The y-axis shows the difference between that subject’s scores for time 1 and time 2.

Figure 6

Mean scores for autistic and control groups on emotional faces task. The score indicates the number of faces that were assigned the correct emotion, out of the ten presented in each category. Error bars indicate standard error. * = p<0.05.