Multisensory integration of social information in adult aging

Efficient navigation of our social world depends on the generation, interpretation and combination of social signals within different sensory systems. However, the influence of adult aging on cross-modal integration of emotional stimuli remains poorly understood. Therefore, the aim of this PhD thesis is to understand the integration of visual and auditory cues in social situations and how this is associated with other factors important for successful social interaction such as recognising emotions or understanding the mental states of others. A series of eight experiments were designed to compare the performance of younger and older adults on tasks related to multisensory integration and social cognition. Results suggest that older adults are significantly less accurate at correctly identifying emotions from one modality (faces or voices alone) but perform as well as younger adults on tasks where congruent auditory and visual emotional information are presented concurrently. Therefore, older adults appear to benefit from congruent multisensory information. In contrast, older adults are poorer than younger adults at detecting incongruency from different sensory modalities involved in decoding cues to deception, sarcasm or masking of emotions. It was also found that age differences in the processing of relevant and irrelevant visual and auditory social information might be related to changes in gaze behaviour. A further study demonstrated that the changes in behaviour and social interaction often reported in patients post-stroke might relate to problems in integrating the cross-modal social information. The pattern of findings is discussed in relation to social, emotional, neuropsychological and cognitive theories