Intranasal oxytocin, testosterone reactivity, and human competitiveness

Area of Science:

• Neuroendocrinology
• Social Neuroscience
• Behavioral Economics

Background:

• Competitiveness is crucial in social interactions, yet biological underpinnings, particularly hormonal influences, are not fully understood.
• Previous research on sex hormones and competition yielded inconsistent results, necessitating further investigation into other biological factors.

Purpose of the Study:

• To investigate the interaction between intranasal oxytocin (OT) and endogenous testosterone (T) in regulating the willingness to compete.
• To explore the sex-specific effects of oxytocin on the relationship between testosterone reactivity and competitive behavior.

Main Methods:

• A double-blind, placebo-controlled study involving 204 participants (102 females) who self-administered oxytocin or placebo.
• Willingness to compete was assessed using a validated economic laboratory competition paradigm.
• Salivary testosterone concentrations were measured throughout the task to assess endogenous reactivity.

Main Results:

• In females, testosterone reactivity was not associated with competitiveness under either oxytocin or placebo conditions.
• In males, a positive correlation between testosterone reactivity and competitiveness was observed under placebo but not under oxytocin.
• The three-way interaction between oxytocin, testosterone reactivity, and sex on competitive preferences was significant, independent of mediators like self-confidence or risk aversion.

Conclusions:

• Oxytocin modulates the relationship between testosterone reactivity and competitive motivation in males, suggesting a specific role in regulating competitive drive.
• These findings highlight the complex interplay between neuropeptides and hormones in shaping human social behavior, specifically competitive preferences.