Chapter 5 Flashcards
5.1; 5.2; 5.4 (41 cards)
What is Male sexual behavior and what regulates it?
All behaviors necessary to deliver sperm to female gametes, regulated by sex steroid hormones
Describe the difference between Male Sex drive, sex performance and sexual arousal
Sex drive (Sexual motivation): The motivational force that compels males to seek sexual union
Primitive and strong in most species
Influenced by hormones and environment
Sexual performance: Execution of behaviors leading to copulation
Influenced by similar hormones, although distinct from sex drive
Sexual arousal: Genital blood flow, erection
Historically equated with motivation (Beach, 1942)
How are puberty, castration and androgen replacement therapy evidence that testosterone and other androgens are critical for sexual motivation and behavior?
- Puberty coincides with increased sexual interest
- Castration==>reduced sexual behavior
- Androgen replacement therapy restores sexual behavior
As we have seen, androgens do not “cause” sexual behavior. What does it do instead?
Lower the threshold for sexual responses
[bring together behavior and context…hormones interact with experience and social context]
What are the neural mechanisms of hormonal effects?
Androgens affect
- NT levels (ex: dopamine, serotonin)
- Availability of NT receptors
- Other proteins that regulate neural activity
How do rodents and primates (including humans) differ in Hormonal control of sexual behavior?
Rodents: Strong dependence on hormones for sexual behavior. Ex: rats require testosterone
Primates: More influenced by socialization and
learning. Can engage in sexual behavior despite hormonal fluctuations/absence
The Red-sided garter snake exhibits mating behavior independent of hormones. What does this show?
Different species exhibit varying degrees of hormonal dependence.
Etymology of “Testicle”
Latin testiculus (diminutive of testis, meaning “witness”).
Ancient Roman witnesses swore oaths by placing their hands on their testes, symbolizing the link between virility and truth.
In the 19th century, what was thought to be activating male sexual behavior?
a. Testosterone
b. Seminal vesicle swelling
c. Androgens
d. Corticosteroids
b. Seminal vesicle swelling
*based on the discovery of neural stretch receptors in the 1880s
(Refuted by experiments showing sexual behavior persisted even when seminal vesicles were emptied)
How does sexual experience affect responses to castration (experimented vs not)?
Inexperience male rats: Stop mating within 2 weeks of castration
Experimented male rats: Show variation. Some stop mating quickly, others continue for weeks
Impact of experience on postcastration sexual behavior.
- Tomcats neutered after sexual experience may still attempt copulation for months.
- Aristotle observed that castrated bulls sometimes continued mating.
- 19th-century records indicate that some men who lost their testes due to injury or disease maintained sexual function indefinitely.
What did Pfüger (1877) suggest to explain human persistence in sexual behavior post-castration?
Could be explained by unique cognitive faculties (e.g., imagination, memory).
What did Eugen Steinach’s research emphasize?
The importance of sensory information regulating sexual behavior
Remember Berthold’s earlier studies (chicken castration). What did he demonstrate, relative to sexual behavior?
Testicular hormones, rather than neural inputs, drive sexual motivation
Brown-Séquard believed in a particular myth regarding hormones. Name it and explain his reasoning.
Claimed that testicular extracts had
rejuvenating effects–>Injected himself with a solution from dog and guinea pig testes.
Later found that his method was ineffective,
as androgens are lipid-soluble and not
water-soluble
Name an implication of the Hormonal Rejuvenating Myth.
- Commercial exploitation…charlatans marked endocrine extracts “treatments”
- Led to scientific interest in sex steroid hormones
When studying the onset of male rats copulation, what did Calvin P. Stone find?
- First copulation occurred around 50 days
- Showed variation in how long sexual behavior persisted post-castration
What theory shaped North American Psychology of sexual behavior?
Drive Theory and Motivation testing (1920s)
Which is NOT a key research question addressing the Drive Theory?
a. Do animals prioritize sex drive over hunger or thirst?
b. How much effort will an individual exert to gain access to a mate?
c. How much pain will an animal endure to satisfy sexual motivation?
d. What are the main hormones regulating sexual drive?
d. What are the main hormones regulating sexual drive?
What led researchers to test lipid-based extracts from testes? What breakthrough led them closer to discovering testosterone?
Discovery that ovarian estrus-inducing hormone was lipid-soluble
Breakthrough: Bull testis extract dissolved in oil rapidly restored comb growth in capons
When was Testosterone first identified?
Pure crystalline testosterone was identified in 1935
What was the purpose of the Beach & Holz-Tucker (1949) experiment?
a) To test the effects of estrogen on female rat behavior
b) To study the impact of testosterone on sexual behavior in castrated male rats
c) To analyze the effects of food intake on mating behavior
d) To examine how rats interact in social groups
b
In Beach & Holz-Tucker (1949) experiment, what happens to mating behavior in male rats after castration?
a) It remains the same
b) It increases significantly
c) It declines
d) It varies randomly
**How does testosterone treatment affect mating behavior in castrated rats
c
**It maintains it
What was the minimum dose of testosterone required to maintain sexual behavior at precastration levels (Beach & Holz-Tucker (1949))?
a) 10 μg/day
b) 50 μg/day
c) 100 μg/day
d) 500 μg/day
c
*Only rats receiving testosterone doses of 100
μg/day or greater displayed sexual behavior at precastration levels
