Body image perception and sense of agency: notes from the alien hand experiment

  • Marcelle Matiazo Pinhatti Universidade Federal do Rio Grande do Sul
  • Thiago Gomes de Castro Universidade Federal do Rio Grande do Sul
  • William Barbosa Gomes Universidade Federal do Rio Grande do Sul
Palavras-chave: Imagem corporal, Agência, Consciência corporal, Estatística probabilística, Autopercepção.


Body image perception comprises stable and dynamic representational features. Here, we examined whether a stable body image (BI) measure correlates to a dynamic sense of agency (SoA) score. Moreover, we tested whether differential BI perception scores predicts SoA performance under sensory conflict conditions. A total of 21 university students (age M=25.9, SD=9.29) completed the Brazilian version of the Silhouette Figures Scale (SFS) and participated in The Alien Hand Experiment (TAHE). TAHE is a task that manipulates participants’ hand movement SoA. A Bayesian correlation matrix revealed substantial negative correlation probability between BI perception and SoA confidence in accuracy responses, specifically in experimental conditions where agency was manipulated. Based on the SFS scores, participants were divided into groups with and without evidences of BI distortion. Bayesian Independent Samples T-Tests evidenced substantial differential probability between groups. Analyzes confirmed lower SoA confidence among subjects with BI distortion greater than ±3 kg/m².

***Percepção de imagem corporal e senso de agência: notas do experimento da mão alienígena***

A percepção da imagem corporal compreende características representacionais estáveis e dinâmicas. Aqui, examinamos se uma medida estável da imagem corporal (IC) correlaciona com o senso de agência (SA) de movimentos corporais. Um total de 21 estudantes universitários (M=25,9, DP=9,29) completaram a versão brasileira da Escala de Figuras de Silhuetas (EFS) e participaram do Experimento da Mão Alienígena. Uma matriz de correlação bayesiana revelou uma probabilidade de correlação negativa substancial entre a percepção de IC e a confiança em SA, especificamente nas condições experimentais onde o SA foi manipulado pelo experimento. Com base nos escores da EFS, os participantes foram divididos em grupos com e sem evidências de distorção de IC. Testes de comparação de grupos evidenciaram uma diferença substancial entre os grupos de IC. As análises confirmaram uma menor confiança em SA entre indivíduos com distorção de IC maior que ±3 kg/m².


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Como Citar
Pinhatti, M. M., Castro, T. G. de, & Gomes, W. B. (2018). Body image perception and sense of agency: notes from the alien hand experiment. Psico, 49(2), 111-118.