Common and unique effects of HD-tDCS to the social brain across cultural groups

ABSTRACTCultural background influences social cognition, however no study has examined brain stimulation differences attributable to cultural background. 104 young adults [52 South-East Asian Singaporeans (SEA); 52 Caucasian Australians (CA)] received anodal high-definition transcranial direct current stimulation (HD-tDCS) to the dorsomedial prefrontal cortex (dmPFC) or the right temporoparietal junction (rTPJ). Participants completed tasks with varying demands on self-other processing including visual perspective taking and episodic memory with self and other encoding. At baseline, SEA showed greater self-other integration than CA in the level one (line-of-sight) VPT task as indexed by greater interference from the alternate perspective. Anodal HD-tDCS to the dmPFC resulted in the CA performing closer to the SEA during egocentric perspective judgements. Baseline performance on level two (embodied rotation) VPT task and the self-reference effect in memory (SRE) was comparable between the two groups. In the combined sample, HD-tDCS to the rTPJ decreased the interference from the egocentric perspective during level two VPT and dmPFC HD-tDCS removed the SRE in episodic memory. Stimulation effects were comparable when baseline performance was comparable. When baseline performance differed, stimulation differences were identified. Therefore, social cognitive differences due to cultural background are an important consideration in social brain stimulation studies.HIGHLIGHTSCompared with Caucasians, South-East Asians were influenced by the alternate perspective to a greater extent during level one visual perspective takingAnodal HD-tDCS to the dmPFC shifted Caucasians closer to the baseline performance of South-East AsiansAnodal HD-tDCS to the dmPFC removed the self-reference effect in episodic memory in both cultural groupsAnodal HD-tDCS to the dmPFC reduced overall memory performance in the South-East Asians but not in the Caucasian groupAnodal HD-tDCS to the rTPJ reduced egocentric interference in a level two visual perspective taking task in both cultural groups

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Group membership and the effects on visual perspective taking

10.31234/osf.io/wnrk6 ◽

2018 ◽

Author(s):

Dana Schneider ◽

Anne Grigutsch ◽

Matthias Schurz ◽

Romi Zäske ◽

Stefan R. Schweinberger

Keyword(s):

Theory Of Mind ◽

Mental State ◽

Perspective Taking ◽

Visual Perspective ◽

Interference Effects ◽

Social Categories ◽

Visual Perspective Taking ◽

Mental State Ascription ◽

Ethnic Nationality ◽

Level 1

It has been hypothesized that visual perspective-taking, a basic Theory of Mind mechanism, might operate quite automatically particularly in terms of ´what´ someone else sees. As such we were interested in whether different social categories of an agent (e.g., gender, race, nationality) influence this mental state ascription mechanism. We tested this assumption by investigating the Samson level-1 visual perspective-taking paradigm using agents with different ethnic nationality appearances. A group of self-identified Turkish and German participants were asked to make visual perspective judgments from their own perspective (self-judgment) as well as from the perspective of a prototypical Turkish or German agent (other-judgment). The respective related interference effects - altercentric and egocentric interferences - were measured. When making other-judgments, German participants showed increased egocentric interferences for Turkish compared to German agents. Turkish participants showed no ethnic group influence for egocentric interferences and reported feeling associated with the German and Turkish nationality to a similar extent. For self-judgments, altercentric interferences were of similar magnitude for both ethnic agents in both participant groups. Overall this indicates that in level-1 visual perspective-taking, other-judgments and related egocentric interferences are sensitive to social categories and are better described as a flexible, controlled and deliberate mental state ascription mechanism. In contrast, self-judgments and related altercentric interference effects are better described as automatic, efficient and unconscious mental state ascription mechanisms. In a broader sense the current results suggest that we should stop considering automaticity an all-or-none principle when it comes theory of mind processes.

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