“Body odor sampling is an essential tool in human chemical ecology research.”
– explain the authors of a recent research project undertaken jointly by the Department of Anthropology, Faculty of Humanities, at Charles University, Prague, Czech Republic, and the Evolutionary Psychology and Behavioural Ecology Research Group at the School of Biological Sciences, University of Liverpool, UK. But it’s not always convenient, or even practical, to take on-the-spot axilliary (armpit) odor samples for use in human cognition experiments. Therefore, the investigators decided to find out if it might be possible to deep-freeze Body Odor (BO) samples as a way of preserving them. Pointing out that “…almost no studies test validity of current methods”.
“In 2 experiments, we tested whether axillary odors were perceived differently by raters when presented fresh or having been frozen and whether several freeze–thaw cycles affected sample quality.”
The series of controlled tests, which deep-froze the BO at –32 °C for up to 6 months, had significant results:
“We found no differences in ratings of pleasantness, attractiveness, or masculinity between fresh and frozen samples. Similarly, almost no differences between repeatedly thawed and fresh samples were found.”
It’s hoped that this new approach will enhance standardisation in future studies on the social impact of human odors.
The study: Methods of Human Body Odor Sampling: The Effect of Freezing. is published in Chemical Senses 34, 127-138, 2009. And can be read in full here