Emotional influences on the kinematics of interactions between two walkers: preliminary results on angriness

International audienceBACKGROUND AND AIM: Gait kinematics are influenced by the emotional state [1] or the emotional context [2]. Observers recognize emotions from the whole body motion [1,3]. We investigated the influence of emotions on the kinematics of interactions between two walkers. We focused on the specific case of walking together. METHODS: 2 professional actors walked in an 8m circular area. They were first asked to walk alone in a neutral or angry emotional state. Then they walked simultaneously: individually or together. For these 2 situations, either both actors had a neutral emotional state or one or both of them experienced angriness with variations: transitive or not (Tr/NTr) and with or without talking (D/ND). Alone and individual situations were used as controlled tasks. Each task was 1' long and repeated 3 times. We focused on walking speed, relative angle and distance between actors. RESULTS: In neutral state, walking speed depended on the situation (H=8.9, p<0.05). It was slower when actors walked together: neutral gait may not be modified by the presence of another walker but by the interaction itself. No difference was observed between the 3 situations for one angry actor (NTr-ND). Nevertheless, when walking together the actor in neutral state walked faster when the other was angry NTr-ND (U=1114, p<0.001). The neutral actor may adapt his speed to follow the angry actor. For together situation, results showed that walking speed was slower when angriness was transitive (U=38472, p<0.001) or when actors spoke (U=35713, p<0.001) and faster when both actors were angry (U=36792, p<0.001). Moreover, the distance between actors was higher when angriness was transitive (U=14406, p<0.001) and when both actors were angry (U=21214, p<0.001) and lower when they spoke (U=21377, p<0.001). There was no difference between relative angles when both actors were neutral or angry NTr-ND but when only one actor was angry NTr-ND, he walked ahead. When one actor was angry, he also walked more ahead in NTr variation compared to Tr one (U=7553, p