ISSN 0439-755X
CN 11-1911/B

中国科学院心理研究所

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### 基于成本最小化信息的社会性意图识别：来自脑电和行为的证据

1. 1. 宁波大学
2. 宁波大学教师教育学院
• 收稿日期:2020-08-29 修回日期:2021-08-13 出版日期:2021-08-27 发布日期:2021-08-27
• 通讯作者: 尹军
• 基金资助:
国家自然科学基金面上项目;国家自然科学基金青年基金项目

### The recognition of social intentions based on the information of minimizing costs: Evidence from modulation of μ oscillations

• Received:2020-08-29 Revised:2021-08-13 Online:2021-08-27 Published:2021-08-27

Abstract: The recognition of intentions of observed actions or behaviors is one of important social functions in human’s visual system. Previous research has invested much effort on how human’s vision system recognizes object-directed intentions of actions (i.e., actions are implemented to approach the physical objects without influencing the others). However, actions are also directed to social entities or agents, as to impacting others, which is termed as social intentions (or social interaction intentions). This paper was aimed to investigate how the vision system recognize social intentions. On the basis of elaborating the properties that two individuals involved in social interaction are rational and should maximize the utility of actions in the overall level, this paper proposed a hypothesis that when the costs of Agent A helping Agent B to achieve the goal state are less than the costs of Agent B acting alone to achieve this goal state (short for, information of minimizing cost), these two agents are recognized with social intentions. To test the above hypothesis, we manipulated the information of minimizing costs by presenting cartoonized animations about how two agents move and influence each other. Specifically, the movable Agent A placed an apple to Agent B who always keeps still, but at the front of Agent B a fence was set or not, to operationalize the cost of Agent B achieving the target of this apple. In this case, when a fence was placed at the front of Agent B, his path of achieving the target of apple was blocked, and accordingly when Agent A pushed the apple to the front of Agent B and helped Agent B to achieve this target, the costs of Agent B (i.e., path) to obtain the apple were less than when Agent B achieved the apple alone. Whereas, when there was not a fence at the front of Agent B, the costs of Agent B achieving the apple alone were less than the costs of Agent A helping Agent B to achieve this target. In brief, only when there was a fence at the front of Agent B, the actions of Agent A placing the apple at the front of Agent B meet with the information of minimizing costs, they should be recognized with a social intention; when there was not a fence at the front of Agent B, the object-directed intention should be attributed, as Agent A approached the target of apple. To identify the recognized intentions of actions, we measured μ suppression (electroencephalogram oscillations within the 8–13 Hz range in the sensorimotor regions; namely, C3 and C4 channels) related to action understanding. It was suggested that the functional grouping of two individuals in social intentions should induce greater suppression that the representation of individual object-directed actions. To control for the possible low-level differences strictly, the action of Agent A placing the apple at the front of Agent B (i.e., transferring action) was paired with the action of Agent A placing the apple at the front of stone (i.e., disposing action), which was typically recognized as an object-directed intention, either when the fence was present or not. Each of the actions lasted 2 seconds, and participants were asked to count the fillers (i.e., incomplete actions) when watching actions presented on the screen. It was found that in Experiment 1 when the fence was present at the front of Agent B, the transferring action (M = -17.3% relative to the baseline) induced more μ suppression than the disposing action (M = -8.5%). Importantly, the occipital α with the same frequency band as μ was not modulated by the action type, but this component was suggested to be functional with the attentional mechanisms. These results were further confirmed by cluster-based permutation tests without selecting interested channels. In Experiment 2, to test whether the effect in Experiment 1 was dependent upon the information of minimizing costs, the fence was removed and accordingly the critical information was absent. We found that the difference in μ suppression between transferring and disposing actions was insignificant when the fence was not present. To further test the hypothesis proposed in this study, we also used a behavioral indicator (i.e., measuring the sensitivity of changes). We manipulated the information of minimizing costs just as being done in Experiment 1 and 2, but participants engaged in a change detection task, in which a set of identical actions were memorized in sequence, and were required to detect whether anything changed in the test animation compared to those previously memorized. It has been suggested that the chunking resolves in more efficient processing of the configuration (e.g., encoding of interactants’ identity), but involves a cost for the individuating parts within it, showing a memory confusion effect. Hence, if Agent A is perceived as having a social intention toward to Agent B, they should be chunked in the memory, and accordingly participants would be less likely to detect changes within the interaction (i.e., the roles of A and B in an interaction were swapped during test; termed as role swap), but would be more likely to detect changes in pair composition (i.e., the recipient in an interaction was replaced by the recipient from another interaction; termed as structure change) relatively to kinematically identical non-social transferring actions. It was found that in Experiment 3a when the fence was presented in the front of Agent B, in the role swap condition, participants were more sensitive to such change to the disposing action (M = 1.96; SE = 0.25) than to the transferring action (M =1.38; SE = 0.24); in contrast, in the structure change condition, the sensitivity of detecting such change to the transferring action (M = 2.04; SE = 0.21) was higher than to the disposing action (M = 1.51; SE = 0.23). In Experiment 3b, when there was not a fence in the front of Agent B, even participants were more sensitive to the role swap change than the structure change, but it was not influenced by the action type. It has been widely suggested that the disposing action was widely suggested to be attributed with an object-directed intention, regardless whether the fence was present or not, and the recognized social intention should induce greater suppression and higher sensitivity for a structure change and lower sensitivity for a role swap change than the recognized object-directed intention. Hence, we concluded that the results, in which the transferring action induced more μ suppression and higher sensitivity for a structure change and lower sensitivity for a role swap change than the disposing action when the fence was present, were reasoned by that the transferring action was recognized as having a social intention. But this recognition depends on the information of minimizing costs; otherwise, the difference of μ suppression and different sensitivities of changes between transferring and disposing actions should be observed as well when the fence was not present. Hence, this paper provides solid evidence supporting that when the costs of Agent A helping Agent B to achieve the goal state are less than the costs of Agent B acting alone to achieve this goal state (short for, information of minimizing costs), they are recognized with social intentions.