Study of the theory of mind in normal aging: focus on the deception detection and its links with other cognitive functions.

Detection of deception is crucial to avoid negative circumstances (financial frauds, social tricks) in daily living. Considering that this cognitive function is especially supported by the prefrontal cortex of the human brain and that these cerebral regions change with advanced age, deception detection may also change with aging. Our purpose is to study this complex ability and its potential links with other cognitive functions, such as the executive control, in normal aging. Thirty-five young adults (YA) aged from 20 to 40, thirty-five old adults (OA) aged from 65 to 79 and thirty very old adults (VOA) aged from 80 to 95 were involved in this study. We propose a novel neuropsychological test (inspired by Theory of Mind Picture Story task) assessing the ability to understand deceptive and cooperative interactions, and tasks involving executive processes (monitoring, task setting, flexibility) to all participants. Between-group analyses show that older participants performed worse than YA on deceptive, cooperative and mixed situations (involving deception and reciprocity) of our task. Significant correlations exist between the deception-cooperation detection and the executive functions. Our results show that these frontal abilities decline after 65 years, even more after 80 years, and they are involved on the deceptive-cooperative situations. The verbal IQ is also linked with the deception-cooperation detection. This suggests that mixed cognitive trainings would allow older adults to detect more easily bad intentions of others, to adjust their behavior to context and to achieve their goals with less risk.