Testosterone change after losing predicts the decision to compete again

Area of Science:

• Behavioral endocrinology
• Social neuroscience
• Human evolutionary biology

Background:

• Testosterone (T) levels are known to fluctuate with competitive outcomes.
• Previous research has not empirically investigated if post-competition T changes predict subsequent human social behaviors.
• Understanding the link between hormonal changes and behavior is crucial for social neuroscience.

Purpose of the Study:

• To investigate whether changes in testosterone levels after losing a competition predict the decision to compete again.
• To examine the relationship between hormonal fluctuations (testosterone and cortisol) and behavioral choices in a competitive context.
• To explore the role of testosterone dynamics in status-related social behaviors following a loss.

Main Methods:

• Sixty-four male participants engaged in a rigged one-on-one competition.
• Saliva samples were collected immediately before and 15 minutes after the competition to measure testosterone and cortisol.
• Participants then decided whether to compete again against the same opponent.

Main Results:

• While winners did not show increased testosterone relative to losers, hormonal changes were influenced by pre-competition levels and cortisol dynamics, particularly in losers.
• Crucially, changes in testosterone levels predicted the decision to compete again among losers.
• Losers who experienced an increase in testosterone were significantly more likely to opt for a rematch compared to those whose testosterone decreased.

Conclusions:

• This study provides novel empirical evidence in humans that testosterone level changes following a status loss predict subsequent social behavior.
• The findings suggest that short-term testosterone fluctuations play a role in mediating responses to competitive setbacks and influence decisions related to status-seeking.
• These results have significant theoretical implications for understanding the interplay between hormonal changes and status-related behaviors in humans.