It seems the women have different stress reaction, which promote defending ofsprings and strengthening the social ties, so that the group can be stronger<ref>[http://scholar.harvard.edu/sites/scholar.iq.harvard.edu/files/marianabockarova/files/tend-and-befriend.pdf Behavioral responses to stress in females: Tend-and-Befriend not Fight or Flight, 2000, Taylor et al. ''psycological review'' 107(3), 411-29]</ref>. I suggest that such a reaction also exists in men, and it help them tight social bonds wthin the group, and though, strengh [[social capital]], and strength the group abilities to attack or defend as a whole<ref>Geary, D.C., & Flinn, M.V. (2002). Sex differences in behavioral and hormonal response to social threat: Commentary on Taylor et al.(2000). ''Psychological Review'', 109, 745–750.</ref><ref>Kenrick, D.T., & Johnson, G.A. (1979). Interpersonal attraction in aversive environments: A problem for the classical conditioning paradigm? ''Journal of Personality and Social Psychology'', 37, 572–579.</ref><ref>Taylor, S.E., Klein, L.C., Lewis, B.P., Gruenewald, T.L.,Gurung, R.A.R., & Updegraff, J.A. (2000). Biobehavioral responses to stress in females: Tend-and-befriend, not fight-orflight. Psychological Review, 107, 411–429.</ref>. The group become more conformtive (I belive it is because of FFFF reaction inhibiting the [[ACC]])<ref>Griskevicius, V., Goldstein, N.J., Mortensen, C.R., Sundie, J.M.,Cialdini, R.B., & Kenrick, D.T. (2009). Fear and loving in Las Vegas: Evolution, emotion, and persuasion. Journal of Marketing Research, 46, 384–395.</ref><ref>Griskevicius, V., Goldstein, N., Mortensen, C., Cialdini, R.B., & Kenrick, D.T. (2006). Going along versus going alone: When fundamental motives facilitate strategic (non)conformity. Journal of Personality and Social Psychology, 91, 281–294.</ref><ref>Griskevicius, V., Tybur, J.M., Sundie, J.M., Cialdini, R.B.,Miller, G.F., & Kenrick, D.T. (2007). Blatant benevolence and conspicuous consumption: When romantic motives elicit strategic costly signals. Journal of Personality and Social Psychology, 93,85–102.</ref>.

===Brain Mechanism===

==Related subjects==