write aa summary for thisSer fr  m se perme:
lbrr epermes
Evidence for the inuence of pheromones on human
behaviour has been inconclusive. There are many
intriguing ndings, but there is always an alternative
explanation or lack of clarity that prevents us from
claiming pheromonal effects with certainty.
For example, Lundstrom and Olsson (2005)
studied the effects of androstadienone—a
derivative of testosterone and one of the
chemical components of sweat. The study
involved studying a woman’s mood after being
exposed to: either androstadienone or control
solution; and in the presence of either a male
or a female experimenter. Results showed that
androstadienone increased women’s mood in the
presence of a male experimenter and had no effect
when the experimenter was female. It is tempting

to conclude that androstadienone as a pheromone
intensies women’s reactions to men, but the study
has important limitations.
● The concentration of androstadienone used in
the study was much higher than the normal
amount found in male sweat—which is a
common feature of pheromone studies.
● It is hard to separate the effects of the
pheromone from the effects of the experimenter.
For example, what if the male experimenter
was simply particularly handsome? Additional
research has to be done in this area.
ATL skills: Thinking and research
As a researcher, how would you overcome the two
problems listed above? Can you decrease the pheromone
concentration? Can you think of a way to quantify and
control attractiveness of the male experimenter?
It is widely recognized that a basic function of a sex
pheromone, whatever other additional functions it
performs, is to signal gender. If a chemical does not
perform gender-signalling function, the chances are
that it will not produce any other gender-related
effects and so it is not a sex pheromone. Therefore,
to prove that androstadienone or any other
chemical is a sex pheromone one needs to show
that it signals gender.
Following this logic, Hare et al (2017)
investigated whether androstadienone (AND)
and estratetraenol (EST)—the best-known
candidates for human sex pheromones—signal
gender and affect mate perception. The experiment
used a repeated measures design. Heterosexual
participants completed two computer-based tasks
twice on two consecutive days. While completing
the task, on one of the days they were exposed
to the putative pheromone (AND or EST) masked
with clove oil, and on the other days they were
exposed to a control scent (clove oil only).
Substances were administered by a cotton ball
taped under the nose throughout the task. The
design was counterbalanced (some participants had
the pheromone on the rst day and the control
substance on the second day, some vice versa). The
rst computer-based task involved showing the
participants ve “gender-neutral facial morphs”,
and participants had to indicate the gender (male
or female). In the second task participants were
shown opposite-sex photographs and asked to rate
89

PhERoMonE S anD BEhav iouR

Results of the rst task revealed no difference
in gender assigned to the morphed faces in the
pheromone versus control condition. Similarly,
results of the second task revealed no difference

in the average attractiveness ratings of opposite-
sex photographs. The authors concluded that

AND and EST do not act as signals of gender
or of attractiveness, which means that they do
not qualify as sex pheromones. Incidentally, the
gender of the experimenter had no effect on
the results.
So far, we have two contradictory studies—
but they are not as contradictory as it seems.
If we assume that the methodological quality
of both studies was high and the ndings
accurately reect reality, we may admit that some
chemicals such as androstadienone inuence
women’s mood. However, these chemicals do
not signal gender and they do not affect mate
perception, so we cannot classify them as a
sex pheromone. Of course there is always an
alternative explanation, which is that one of the
studies was biased in some way.
ATL skills: Communication
If you were to assume that the contradictory ndings in
these two studies were in fact due to the bias present
in one of them, which one would you pick as the more
biased study? Write a short statement explaining your
point of view and giving reasons.
Maybe the problem is that both the studies
concentrated on a very specic behaviour and
in order to clarify the functions of a putative
pheromone we need to look at a wider range
of behaviours. Or maybe the problem is in the
articiality of the experimental tasks.

The following two research studies attempted to
address both the problems—they were conducted
in real-life settings and accounted for a wider range
of behaviours.