Dominance and Hormones Flashcards
What are hormones and what organs are they produced in?
1) Chemical messengers produced by the endocrine system that regulated metabolism and behaviour
2) By hypothalamus, testes/ovaries, pancreas, pituitary gland, thyroid gland, thymus, adrenal glands, pineal gland
What are the 2 effects of hormones?
1) Organizational = during development; irreversible structural change
2) Activational = in mature individuals; temporary effects on the body and brain
What is an example of organizational (long-term) hormone effects?
Testosterone during development results in masculine genitals
What is an example of activational (short-term) hormone effects?
Surges of testosterone correlate to muscle building, aggression (responses to dominance), and libido
What are the 2 types of hormones?
1) Steroid hormones (sex hormones and glucocorticoids)
2) Peptide hormones (insulin)
What are some examples of sex hormones?
Estrogens (estradiol) and androgens (testosterone)
What is an example of a glucocorticoid?
Cortisol (stress hormone)
What is the difference between the 2nd and 4th digit of primates?
The 4th digit has more steroid receptors than the 2nd digit
What does high testosterone result in?
Males, as they have higher testosterone, they have a low 2D:4D ratio (4D is longer)
What does low testosterone result in?
Females, as they have higher estrogen than testosterone, have 2D >= 4D
What does a longer 4th digit relative to the 2nd digit (low 4D:2D) indicate?
Higher prenatal androgen exposure (PAE)
What does having equal-length 2nd and 4th digits (or a bigger 2nd digit) indicate?
Lower prenatal androgen exposure (PAE)
What is the relationship between PAE and mating systems?
In more monogamous societies, where male aggression is less frequent (less intrasexual selection), the 2D:4D ratio is ~1 (equal length)
What is the 2D:4D ratio in species with high intrasexual selection?
The 2D:4D ratio is lower (i.e., the 4D is longer than 2D - higher PAE)
What are some examples of monogamous species?
Gibbons, siamang, humans