Human tears contain a chemosignal.
Level 2 - randomized trial
Controlled experimental laboratory study evaluating physiological, behavioral, and neuroimaging responses in humans.
PubMed 21212322 · doi:10.1126/science.1198331
What was done
Men sniffed odorless negative-emotion-related tears collected from female donors. Researchers evaluated the effects of tear sniffing on men's ratings of sexual appeal attributed to photographs of women's faces, self-rated sexual arousal, physiological indicators of arousal, testosterone levels, and neural activation using functional magnetic resonance imaging (fMRI).
What was found
The abstract reports no numerical values, effect sizes, or confidence intervals. It states that sniffing women's emotional tears led to reductions in the sexual appeal men attributed to women's faces, decreased self-reported sexual arousal, diminished physiological arousal measures, lower testosterone levels, and selectively reduced fMRI activity in brain regions associated with sexual arousal.
Why it matters
This study provides evidence that human emotional tears may function as chemical signals that modulate behavioral, endocrine, and neural responses in conspecifics, specifically dampening sexual arousal.
Limits
The abstract does not state the sample size (n), participant selection criteria, or the specific control substance used. Only the effect of female tears on male subjects was evaluated, leaving other donor-recipient sex combinations unaddressed. No quantitative data or statistical precision metrics are reported in the abstract.
Cited by
- supports Scientific research shows that human tears affect hormone levels in people around them.