14 November 2020 | New Scientist | 43
romantic kissing. What’s more, there is
evidence that body odour can communicate
someone’s emotional state and even their
sexual arousal. Our greetings can allow us
to sample this aroma without overtly sniffing
someone’s body, according to research by
Idan Frumin, then at the Weizmann Institute
of Science in Israel.
Frumin was inspired when, at a conference,
he noticed that people often ran their hand
under their nose after shaking hands with
someone else. He wondered whether the
purpose of this “weird ritual” was to get a
whiff of the other person’s natural perfume.
To test the idea, his team covertly filmed
visitors to the lab as they waited to take part
in an experiment. About 3 minutes into the
wait, a scientist of the same gender entered
the room, introduced themselves and then
left. The footage revealed that people were
more likely to bring their hand to their face
if the scientist had shaken it; many directly
touched their noses after the encounter. To
make sure that people were actually sniffing
their hand, Frumin fitted another group
of volunteers with a sensor that measured
species like Guinea baboons, in which males
form closely bonded coalitions. Greetings,
she suggests, help individuals test their trust
in each other and build alliances that could
improve their chances of survival in the
future. “The greetings allow you to touch
base with many individuals in your society,
and in different ways depending on the
relationship you have,” says Dal Pesco.
Similarly intricate behaviours are found
among white-faced capuchins, whose rituals
include finger-clasping, embracing and the
toe-curling practice of sticking a finger into
one another’s eye sockets, sometimes up
to the first knuckle. Like baboons, capuchins
have a complex society in which groups of
males band together – again suggesting that
risky interactions allow the monkeys to test
and affirm their relationships. “It clearly
can’t feel that good to take somebody’s
dirty claw and finger and stick it in your eye
socket,” says Susan Perry at the University
of California, Los Angeles, who has spent
thousands of hours observing these
interactions. “The fact that they can pull
this off really says a lot about their trust.” >
So what can these animal interactions
teach us about ourselves? We too live
in complex societies in which trust and
cooperation are paramount. Of course,
our greetings are imbued with a deeper
symbolism and meaning and they have
enormous variety, from the namaste bow
in India to the hongi of the Maori, in which
two people press their noses together, as
well as handshakes and cheek kisses (see
“A very brief history of greetings”, page 44).
Yet however much more sophisticated
we may seem, the latest research suggests
that many of our gestures serve the same
functions as those in other animals.
Sniffing you out
Any greetings that involve bodily contact
may offer us a way to pick up chemical
cues. Although the existence of human
pheromones is controversial, research
suggests that we may be able to assess
someone’s physical fitness and fertility
from compounds in their saliva – a possible
rationale for the strange phenomenon of
BL
AIN
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AR
RIN
GT
ON
/AG
EF
OT
OS
TO
CK
/AL
AM
Y
The sharing of breath
symbolises unity for
New Zealand’s Maori