Sex Differences and the Modulating Effects of Gonad Intactness on Behavioral Conformity in a Mouse Model

Chianfang G. Cherng ； Lung Yu

《The Chinese Journal of Physiology》 62卷6期 (2019/12) Pp. 245-255

https://doi.org/10.4103/CJP.CJP_42_19

摘要

Although gender differences in conformity are noticed in human studies, cultural norms and psychosocial factors inevitably affect such differences. Biological factors, especially the gonadal hormones and the brain regions involved, contributing to the sex differences in behavioral conformity remained scarcely explored. To prevent psychosocial and cultural norm confounds, intact and gonadectomized male and female mice were used to assess the modulating effects of gonadal hormones on behavioral conformity and such conformity-related brain regions using an approach of choice paradigm. Intact and gonadectomized mice' choices for the nonrewarded runway were assessed when these experimental mice were alone versus with a group, consisting of three same-sex noncagemates choosing the respective experimental mice' nonrewarded runway, in a double-J-shaped maze test. Although male and female mice exhibited comparable rewarded runway choices at the conclusion of the operant training procedures and in the test individually, male mice demonstrated greater conformity index as compared to female mice when group tested. Gonadectomy, done at their 4 or 9 weeks of age, decreased males' conformity index but did not affect females' when both sexes were group tested. Such gonadectomy did not affect the conditioning or conformity index when tested individually in either sex. Female mice had higher serum corticosterone (CORT) levels when group tested as compared to the female mice tested individually and male mice. Finally, the number of FOS-staining cells in high conformity-displaying mice was found less than it in the low conformity-performing mice in the nucleus accumbens. Taken together, we conclude that testis-derived hormones, at least, play a role in enhancing behavioral conformity in male mice. CORT and nucleus accumbal neuronal activity deserve further investigation for their involvement in behavioral conformity.

關鍵字

Conformity ； decision-making behavior ； glucocorticoids ； operant conditioning ； orchidectomy ； ovariectomy ； sex difference

參考文獻

Asch SE. Effects of group pressure on the modification and distortion of judgements. In: Guetzkow H, editor. Groups, Leadership and Men. Pittsburgh: PA Carnegie Press; 1951. p. 177-90.

Asch SE. Studies of independence and conformity. A minority of one against a unanimous majority. Psychol Monog 1956;70:1-70.

Sherif M. A study of some social factors in perception. Arch Psychol 1935;187:60.

Cherng CG, Wang CY, Lai YT, Tzeng WY, Chen LH, Tsai YN, et al. Anticipated, intense risk enhances behavioral conformity in a mouse model. Ethology 2014;120:1035-43.

Baron RS, Hoppe SI, Kao CF, Brunsman B, Linneweh B, Rogers D. Social corroboration and opinion extremity J Exp Soc Psychol 1996;32:537-60.