Smelling human sex hormone-like compounds affects face gender judgment of men

Gyula Kova, Balazs Gulya, Ivanka Savic,David I. Perrett,R. Elisabeth Cornwell,
Anthony C. Little, Ben C. Jones, D. Michael Burt, Viktor Gal and Zoltan Vidnyanszky

Processing in a given sensory modality is affected by the
information that is processed simultaneously in other
modalities. Cues from different senses interact and are
integrated by the brain to evoke the most efficient and
appropriate behavioral responses. Intensive research has
recently provided evidence that cross-sensory interactions
between vision, audition and somatosensation occur at the
early stages of sensory processing both in macaques [1] and
in humans [2]. We know little, however, about how
chemosensory information may affect sensory processing
in other modalities. Although it has been shown that odors
modulate the efficiency of learning and recall of sensory
information provided by other modalities [3], evidence
regarding the cross-sensory effects of odors on the sensory
processing itself are lacking.

In the present study we investigated the effect of passive
inhalation of sex hormone-like steroids 5-a-androgenst-16-
en-3-one (androgen) and oestra-1, 3, 5 (10), 16-tetraen-3-ol
(estrogen) on the visual face gender discrimination in men.
There are two major reasons behind our choice of the
specific chemosensory and visual stimuli. First, in a
previous study by two of the present authors [4] it was
found that smelling sex hormone-like compounds activates
of the fusiform gyrus, a brain region that was shown to be
involved in the processing of visual faces [for reviews see 5–
7]. Second, our goal was to choose sensory modalities which
may naturally be associated during ontogenesis.We selected
female and male human faces and gender-specific odorous
substances, based on the assumption that there is a prolonged and pronounced association between the
gender-specific cues of different sensory modalities.