A six-year-old explained she cries when angry because crying makes her sister comfort her, while anger makes everyone run away. This reveals a fundamental social dynamic: we learn to express sadness to draw people in, while suppressing anger to avoid pushing them away, which can create a disconnect from our true feelings.

Unlike a spoken apology ("cheap talk"), a blush is an uncontrollable physiological response. It credibly signals to others that you acknowledge breaking a social norm, establishing common knowledge of your remorse and your acceptance of the norm itself. This makes the "apology" authentic.

Emotions are not superfluous but are a critical, hardcoded value function shaped by evolution. The example of a patient losing emotional capacity and becoming unable to make decisions highlights this. This suggests our 'gut feelings' are a robust system for guiding actions, a mechanism current AI lacks.

Your internal emotional state is transmitted to others, even when you try to hide it. Behavioral investigator Vanessa Van Edwards found that subtle micro-expressions induce the same feelings in others, causing them to form a negative or positive opinion about you within the first few seconds of an interaction.

Tears are an evolutionary tool for those in a weaker position (less physically formidable, lower status). Crying signals to a more powerful person that they are either imposing a cost that is too high or delivering a benefit that is exceptionally valuable, serving as a potent negotiation tactic.

A key tell for distinguishing authentic from manipulative crying is the crier's behavior. A manipulator needs their tears to be seen to have an effect and will display them openly. Someone genuinely overwhelmed by emotion often tries to hide their tears, viewing them as a sign of vulnerability.

Emotions act as a robust, evolutionarily-programmed value function guiding human decision-making. The absence of this function, as seen in brain damage cases, leads to a breakdown in practical agency. This suggests a similar mechanism may be crucial for creating effective and stable AI agents.

When women get angry and cry simultaneously, it reflects an internal conflict. The anger is a desire to impose costs on another person, but the tears signal that they are in a 'lower-leveraged' position and lack the perceived power to do so effectively. It's a blend of aggression and vulnerability.

Trust isn't built on words. It's revealed through "honest signals"—non-verbal cues and, most importantly, the pattern of reciprocal interaction. Observing how people exchange help and information can predict trust and friendship with high accuracy, as it demonstrates a relationship of mutual give-and-take.