Coolidge effect
Encyclopedia
In biology
and psychology
, the Coolidge effect is a phenomenon—seen in nearly every mammalian species in which it has been tested—whereby males (and to a lesser extent females) exhibit continuous sexual activity if they are introduced to receptive sexual partners, but will eventually stop having sex if the partner has already been copulated with.
is credited with naming the "Coolidge effect" in 1955, after one of his students suggested the term at a psychology conference. He attributed the neologism to:
The joke appears in a 1978 book (A New Look at Love, by Elaine Hatfield and G. William Walster, p.75), citing an earlier source (footnote 19, Chapter 5).http://books.google.com/books?id=VBZgXsk-gsAC&pg=PA75&dq=coolidge+hen+rooster&hl=en&ei=jCf8TbG5CIjFswbW0YDwDQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CCkQ6AEwAA#v=onepage&q=coolidge%20hen%20rooster&f=false
.
Human males experience a post-ejaculatory refractory period
after sex. They are temporarily incapable of engaging in sex with the same female after ejaculation and require time to recover full sexual function. In popular reference, the Coolidge effect is the well-documented phenomenon that the post-ejaculatory refractory period is reduced or eliminated if a novel female becomes available. This effect is cited by evolutionary biologists as one reason why males are more likely to desire sex with a greater number and variety of partners than females, though of course sometimes human females are known to copulate with multiple and novel partners as well.
While the Coolidge effect is usually seen demonstrated by males—that is, males displaying renewed excitement with a novel female—Lester and Gorzalka developed a model to determine whether or not the Coolidge effect also occurs in females. Their experiment, which used hamsters instead of rats, found that it does occur to a lesser degrees in females.
species confirmed the validity of the Coolidge effect in freshwater snail Lymnaea stagnalis
. Biomphalaria glabrata
, another simultaneous hermaphrodite freshwater snail, does not exhibit sex-specific effects of partner novelty, and thus there is no Coolidge effect in the species.
Biology
Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...
and psychology
Psychology
Psychology is the study of the mind and behavior. Its immediate goal is to understand individuals and groups by both establishing general principles and researching specific cases. For many, the ultimate goal of psychology is to benefit society...
, the Coolidge effect is a phenomenon—seen in nearly every mammalian species in which it has been tested—whereby males (and to a lesser extent females) exhibit continuous sexual activity if they are introduced to receptive sexual partners, but will eventually stop having sex if the partner has already been copulated with.
Origin of the term
Ethologist Frank A. BeachFrank A. Beach
Frank Ambrose Beach, Jr. was an American ethologist, best known as co-author of the 1951 book Patterns of Sexual Behavior.-Biography:...
is credited with naming the "Coolidge effect" in 1955, after one of his students suggested the term at a psychology conference. He attributed the neologism to:
The joke appears in a 1978 book (A New Look at Love, by Elaine Hatfield and G. William Walster, p.75), citing an earlier source (footnote 19, Chapter 5).http://books.google.com/books?id=VBZgXsk-gsAC&pg=PA75&dq=coolidge+hen+rooster&hl=en&ei=jCf8TbG5CIjFswbW0YDwDQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CCkQ6AEwAA#v=onepage&q=coolidge%20hen%20rooster&f=false
Empirical evidence
The original experiments with rats applied the following protocol: A male rat was be placed into an enclosed large box with four or five female rats in in heat. He immediately began to mate with all the female rats again and again until eventually, he became exhausted. The females continued nudging and licking him, yet he did not respond. When a novel female was introduced into the box, he became alert and began to mate once again with the new female. This phenomenon is not limited to common rats. The Coolidge effect is attributed to an increase in dopamine levels and the subsequent effect upon an animal's limbic systemLimbic system
The limbic system is a set of brain structures including the hippocampus, amygdala, anterior thalamic nuclei, septum, limbic cortex and fornix, which seemingly support a variety of functions including emotion, behavior, long term memory, and olfaction. The term "limbic" comes from the Latin...
.
Human males experience a post-ejaculatory refractory period
Refractory period (sex)
In sexuality, the refractory period is the recovery phase after orgasm during which it is physiologically impossible for an individual to have additional orgasms. Most men are unable to maintain or achieve an erection during this time, and many perceive a psychological feeling of "satiation" and...
after sex. They are temporarily incapable of engaging in sex with the same female after ejaculation and require time to recover full sexual function. In popular reference, the Coolidge effect is the well-documented phenomenon that the post-ejaculatory refractory period is reduced or eliminated if a novel female becomes available. This effect is cited by evolutionary biologists as one reason why males are more likely to desire sex with a greater number and variety of partners than females, though of course sometimes human females are known to copulate with multiple and novel partners as well.
While the Coolidge effect is usually seen demonstrated by males—that is, males displaying renewed excitement with a novel female—Lester and Gorzalka developed a model to determine whether or not the Coolidge effect also occurs in females. Their experiment, which used hamsters instead of rats, found that it does occur to a lesser degrees in females.
On simultaneous hermaphrodites
A 2007 study focusing on the Coolidge effect in simultaneously hermaphroditicHermaphrodite
In biology, a hermaphrodite is an organism that has reproductive organs normally associated with both male and female sexes.Many taxonomic groups of animals do not have separate sexes. In these groups, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which both...
species confirmed the validity of the Coolidge effect in freshwater snail Lymnaea stagnalis
Lymnaea stagnalis
Lymnaea stagnalis, better known as the great pond snail, is a species of large air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Lymnaeidae.-Distribution:The distribution of this species is Holarctic...
. Biomphalaria glabrata
Biomphalaria glabrata
Biomphalaria glabrata is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails....
, another simultaneous hermaphrodite freshwater snail, does not exhibit sex-specific effects of partner novelty, and thus there is no Coolidge effect in the species.