1. Friendships and Social Dynamics
- Sex-Differentiated Friendship Structures: Male friendships are typically less emotionally close, looser, and multi-male, often described as "shoulder-to-shoulder" relationships that focus on coalitional and social support, and shared activities. In contrast, female friendships are generally more emotionally intense, close, and dyadic ("face-to-face"), emphasizing emotional support and detailed discussions. Men also tend to stand at an open angle (around 120 degrees) when conversing to avoid confrontational cues, whereas women are comfortable facing each other directly.
- Fragility and Intimacy in Female Friendships: Female friendships tend to be shorter-lived and more fragile due to their emotional intensity and the sharing of intimate details. This shared information can become "ammunition" if the friendship breaks, leading to significant grief.
- Adaptive Reasons for Female Friendship Styles: Possible adaptive explanations for the depth and dyadic nature of female friendships include the high stakes of allo-parenting (shared childcare requiring high trust) and patrilocality (females often leaving their natal groups to join a partner's kin, necessitating the formation of kin-like bonds with non-kin).
- Social Signalling and Alliance Manipulation: Women use detailed self-disclosure, including sensitive social information or secrets, to build trust and closeness, signalling "you can trust me". Venting, which involves complaining about a third party in an agitated or frustrated manner, is a key tactic for women to manipulate alliances. This allows them to harm the target's reputation without appearing aggressive or manipulative themselves. Sharing privileged information with a close friend can also bolster that friend's perceived value within one's social network.
- Friend Guarding: Similar to mate guarding, friend guarding serves as an adaptive function, signalling the value placed on a friend. However, it requires careful "calibration" to avoid being perceived as too needy or jealous. People, particularly women, are often hesitant to introduce friends from different groups due to the fear of being displaced. This emotion, often stigmatised, is widespread in social animal species (e.g., horses, cows, dolphins, lions) and likely serves an adaptive purpose to prevent the loss of valued relationships.