The Past, Present, and Future of Hormones

The activities of all living organisms are functionally dependent upon the
biochemical reactions that make up life itself. Since the evolution of the first
eukaryotic cells more than one billion years ago, hormones have been utilized
in cell-to-cell communication. In vertebrate animals (fish, amphibians,
reptiles, birds, and mammals), endocrine systems have evolved into highly
complicated nervous systems. These nervous systems are even evident in the
invertebrate arthropods (crustaceans, spiders, and so on), especially among
the social insects, such as ants. The endocrine and nervous systems are intricately
interconnected in the control of animal physiology and behavior.

Psychologists are interested in the chemical basis of human behavior and
therefore are interested in human and mammalian hormones. Such hormones
control a variety of behaviors, such as maternal imprinting (in which
an infant and mother bond to each other), courtship and mating, territoriality,
and physiological responses to stress and danger. Animal behaviorists
and psychologists study the connection between hormones and behavior in
humans, primates, and other closely related mammalian species. They identify
similarities in behaviors and hormones among a variety of species. They
also recognize the occurrence of abnormal behaviors, such as antisocial behavior
and sexual deviance, and possible hormonal imbalances that contribute
to these behavioral anomalies.

While the biochemistry of hormones and their effects upon various behaviors
have been established in considerable detail, numerous behaviors
that are probably under hormonal influence have yet to be critically analyzed.
Among them are many subtle pheromones that affect a person’s interactions
with other people, imprinting pheromones that trigger attraction
and bonding between individuals, and hormones that link together a variety of bodily functions. These hormones may number in the hundreds, and
they represent a challenging avenue for further research. Unraveling the relationships
between hormones and behavior can enable researchers to gain
a greater understanding of the human mind and its link to the rest of the
body and to other individuals. These studies offer potential treatments for
behavioral abnormalities and for mental disturbances created by the physiologically
disruptive effects of drug use, a major problem in American society.
They also offer great promise in the alleviation of stress, another major social
and medical problem.