# The subjective value of genuine smiles guides real-world social behaviour

## TL;DR

People who value genuine smiles more in the lab respond more to them in real-life interactions, leading to better social outcomes.

## Contribution

Shows that lab-measured subjective value of genuine smiles predicts real-world social responsiveness and interaction quality.

## Key findings

- Higher subjective value of genuine smiles correlates with stronger attention to faces previously associated with smiles.
- Faster smile reciprocity in real interactions is linked to higher interaction quality ratings from partners.
- Lab-based valuation of smiles influences natural social behavior and outcomes.

## Abstract

The mechanisms that underpin human social behaviour are poorly understood, in part because natural social behaviour is challenging to study. The task of linking the mechanisms thought to drive social behaviour to specific social behaviours in a manner that maintains ecological validity poses an even greater challenge. Here we report evidence that the subjective value people assign to genuine smiles, as measured in the laboratory, determines their responsiveness to genuine smiles encountered in a naturalistic social interaction. Specifically, participants (university undergraduates; age 17 to 36) who valued genuine smiles to a greater degree also showed stronger attention capture effects to neutral faces that were previously associated with genuine smiles and faster reciprocity of a social partner’s smiles in a real social interaction. Additionally, the faster participants responded to the partner’s genuine smiles the higher the partner’s ratings of interaction quality were after the interaction. These data suggest that individual differences in subjective value of genuine smiles, measured in the lab, is one element that underpins responsiveness to natural genuine smiles and subsequent social outcomes.