Their content was playboy or playgirl models; one
rated highly by males and lower by females (female
models) and the second rated highly by females and
lower by males (male models). These five emotional
categories (B, P, D, FM and MM) were then used in a
series ERP studies designed to manipulate “emotional
value” while “task relevance” was held constant.
One large study involved two groups of subjects:
one group (10 male, 10 female) was required to predict
the category of a slide (B, P, D, FM or MM), whereas
the second group (10 male, 10 female) was instructed
to simply count the total number of different emo-
tional pictures. ERPs were recorded after every slide
presentation. First of all, in agreement with prior stud-
ies, the only P3 difference between the two groups was
due to disconfirmed predictions evoking larger P3s
than confirmed predictions, in the predicting group of
subjects. All of the other results were directly related to
the emotional value of the stimuli. For all subjects, the
P3 amplitude evoked by the pleasant (B), neutral (P)
and unpleasant pictures (D) formed a U shaped func-
tion, with pleasant and unpleasant slides evoking
larger P3s than the neutral slides. Furthermore, for
male subjects the playboy models (FM) evoked a larger
P3 response than male models (MM), whereas in fe-
male participants the P3 was larger for the MM than
the FM category. Since all stimuli were equally proba-
ble and task relevant within each group, these findings
are compelling support for interpreting P3 amplitude
as an index of emotional value. This conclusion pro-
vides a solid foundation for using P3 amplitude as a
measure of the emotional response of human males
when they are exposed to female facial images that
vary in features and proportions.
Computer software was used to generate 64 facial
images (32 male, 32 female). The configuration of the
32 female faces was based on prior studies that estab-
lished the average (Av) and the attractive (At) features
of five facial components (Figure 1illustrates these dif-
ferences). All combinations of female faces possessing
one of two possible eye sizes (Av and At), two jaw
widths (Av and At), two lips sizes (Av and At), and two
chin lengths (Av and At), were generated. The two hair
types (black/blond) were arbitrary. For control pur-
poses, 32 male facial images were also constructed
based on all combinations of the same set of facial com-
ponents, but now using the average male features and
proportions, as well as male faces modified in exactly
the same manner as that used to produce attractive fe-
male faces. ERPs were collected from 25 male volun-
teers during three experimental sessions. During each
session the participants were only instructed to focus
on each of the 64 slides as they were presented in a ran-
dom order. In a final session, the participants were re-
quired to rate each face for its degree of attractiveness.
This study revealed that the amplitude of the P3
component of ERPs recorded from the male partici-
pants was highly correlated with their attractiveness
ratings of the female, but not the male, faces. Most
remarkably, out of all the many possible combina-
tions of male and female features and proportions,
the largest P3 response was evoked by female faces
displaying the combination of larger than average lips
and a shorter narrower chin. As noted earlier, this
combination of full lips (a marker of high estrogen
levels) and a short narrower chin (a marker of low
androgen levels) has been shown to be associated
with high fecundity. So from a biological perspective,
it appears that adult females, not unlike other female
primates, are continuously displaying highly visible
facial cues that are capable of evoking an emotional
response in the brain of male observers.
Over the course of human history, discriminating
ancestral males who were attracted by such cues un-
doubtedly enjoyed more reproductive success than
non-discriminating males. This is the functional value
of facial beauty. In some respects, however, beauty is
like the sweetness of sugar. Throughout our hunter-
gatherer history this rich source of ATP was only ob-
tainable from ripe fruit or honey. But in the modern
world, with sugar refineries that separate the sugar
from its nutritional source, the sweet taste of sugar is
no longer a reliable index of a healthy diet. Similarly, in
the modern world, artificial insemination, contracep-
tion, plastic surgery, and fertility drugs, have all signifi-
cantly reduced the validity of beauty as a reliable index
of fecundity. Nevertheless, just like sugar, it will proba-
bly continue to enchant and allure humans for some
time to come.volume 25 number 1 2020 W W W. S K E P T I C. C O M 2 1- Johnston, V. S. 2019. “Darwinian Goggles.” SKEPTIC,
Vol. 24, No. 3, 24. - Johnston, V. S., and Franklin, M. 1993. “Is Beauty
in the Eye of the Beholder?” Ethology and Sociobi-
ology, 14(3), 39-42. - Zaadstra, B.M. et al. 1993. “Fat and female fecun-
dity: prospective study of effect of body fat distribu-
tion on conception rates.” British Medical Journal,
306(6876), 484-487. - Johnston, V. S., Burleson, M., and Miller D. 1987.
“Emotional value and late positive components of
ERPs.” Current Trends in Event-Related Potential
Research, E.E.G. Supp. 40. - Johnston, V. S., and Oliver-Rodriguez, J.C. 1996.
“Facial Beauty and the Late Positive Component of
Event-Related Potentials.” Journal of Sex Research,
34(2), 188-198.
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