A nutshell summary of modern Darwinism is this: An organism is an integrated
collection of problem-solving devices—that is, adaptations—that were
shaped by natural selection over evolutionary time to promote, in some specific
way, the survival of the genes that directed their construction. The “specific way”
that an adaptation was designed to promote gene survival is that adaptation’s
function (or goal or purpose). The function of the heart is to pump blood, the function
of pancreatic beta cells is to secrete insulin, and so forth. Unlike nonliving
matter, living matter is not just complexly organized, it is functionally organized.
The specific aspects of the environment to which an adaptation is adapted and on
which its normal functioning and development depend are sometimes called its
environment of evolutionary adaptedness (EEA).

The second lesson that I draw from T. antennifer’s sex life is that it is logically
impossible to describe an adaptation without (at least implicitly) describing the
adaptation’s EEA. Without the EEA, there is no science of adaptation. Any scientifically
useful description of T. antennifer’s flower will necessarily include a description
of the morphology of certain female flies and the mating psychology of
male flies found in T. antennifer’s natural habitat, the high-altitude cloud forests
of Ecuador. Moreover, my brief description of T. antennifer’s flower would be intelligible
only to those who already understood the nature and purpose of flowers
and their evolved relationships with environmental vectors such as insects.
The EEAs of the vast majority of human adaptations still exist today and usually
are too obvious to merit explicit mention. For example, a neurophysiologist
describing the function of a certain component of the human visual system probably
will simply assume that his or her colleagues know: (1) a great deal about the
nature of electromagnetic radiation and (2) that the (natural) light falling on
human retinas today is essentially identical to the light that fell on our ancestors’
retinas during the evolution of our visual system. But human environments, especially
those of modern industrialized societies, have changed in many ways in
the brief period since the origin of agriculture 10,000 years ago, and some of these
changes potentially affect the functioning of human mating adaptations. Darwinian
students of human mating psychology thus have another advantage over other
researchers: The Darwinian is alert to potentially significant differences between
current and ancient environments, and this “EEA mindedness” can inform hypothesis
formation. In some cases, it can even lead the Darwinian to posit the existence
of adaptation where others perceive pathology or folly.

For example, a striking feature of human courtship—in its broadest sense—is
the powerful effect that fear of rejection has on behavior. Sexual/romantic rejection
hurts; the memory of being rejected hurts; the thought of being rejected hurts;
hence, it is not surprising that the possibility of being rejected affects most people’s mating behavior. Yet, on the face of it, fear of rejection seems to be astonishingly
dysfunctional. The potential benefits of propositioning an attractive member of the
other sex, which include everything from a sexual fling to a lifetime mateship,
would appear to vastly outweigh the potential costs, which seem to consist mainly
of a small amount of wasted time.

The potent effect that fear of rejection has on human courtship should inspire
students of human mating psychology to consider whether this fear might have
been adaptive during the vast majority of human evolution, even if it is not adaptive
in many current environments. In other words, being rejected might have entailed
real and significant costs in the human evolutionary past that it does not
usually entail today. I propose the following hypothesis. During most of human
evolutionary history, our ancestors lived in relatively small, face-to-face groups
wherein sexual/romantic rejections were very likely to become common knowledge.
When Ann the gatherer rejected Andy the hunter’s proposition, everyone
in their community probably found out about it before long (assuming that our
ancestors were no less interested in other people’s sex lives and no less prone to
gossip than we are). The information that Ann had rejected Andy could diminish
his perceived mate value in the eyes of others, including other potential mates
(Ann may have rejected Andy because she had acquired mate-value-relevant information
about him that others were not privy to). On a modern university campus,
with thousands of students and enormous scope for anonymity, Bob’s
anxiety at the prospect of hitting on Bobbi is, perhaps, “irrational” in the sense
that he has little to fear but fear itself; but the underlying motivational system
may have been shaped by selection to function in an environment in which rejection
had substantial costs.