Relationships Flashcards
Sexual selection and human reproductive behaviour
Human reproductive behaviour
any behaviour which relates to opportunities to reproduce and pass on our genes
Sexual selection: Mate preference - Inter-section
Sexual selection - Mate competition- Intra-selection
Parental investment
the amount of time, effort and resources which go into reproducing and rearing offspring
Sexual selection
An evolutionary explanation of partner preferences. Attributes/behaviours that increase reproductive success are passed on and may become exaggerated over succeeding generations of offspring
Inter-sexual selection
What?- When members of one biological sex choose mates of the opposite sex to mate with
Who?- Preferred by females - Females choose based on attractiveness and biology
Inter-sexual selection and human reproductive behaviour
Choosiness
Females invest a greater amount of time, energy and resources into raising a child
So they need to be more careful when choosing a partner. They need to be sure their partner will provide the right genetic fit and will be willing to provide resources to support the female and the child.
Runaway process: sexy son hypothesis
The runaway process is that female preference will determine which features are passed on to the offspring. E.g if height is a female preference it will increase in the male population over successive generations leading to this characteristic gradually becoming exaggerated
The sexy son hypothesis
when a female mate will a male who has certain characteristics then their sons will have this ‘sexy’ trait which will make them more likely to be picked as mates by females, so the ‘sexy’ trait is perpetuated.
Why - As females choose based on attractiveness and biology
Robert Trivers - Parental Investment
Male parental investment
- Investment is relatively small
- Large amounts of sperm
- Remains fertile throughout his life
- Capable of many mating’s
- The only limit on the number of offspring he can produce is in the number of available female partners.
Female parental investment
- Investment is substantial
- A limited supply of eggs
- Reproductive life of 30 years
- Carries foetus for 39 weeks
- 1 offspring per year
- Gives birth
- Breastfeed
Supporting evidence for inter-sexual selection
Clark 1989 Hatfield’s 1990
Sent a male and female psychology students across a university campus. They approached other students individually with this question have been noticing you around campus? I find you very attractive. Would you go to bed with me tonight. Not a single female student agreed to the request, whereas 75% of males did immediately.
Supporting evidence for inter-sexual selection
Buss and Schmitt 1993
They asked how many sexual partners people would ideally like over the next 2 years, the next decade and during their lifetime.
On average over the next 2 years
Men would like 8 partners
Women’s 1 partner
On average over a lifetime
18(men)
Between 4 and 5 women
Intra sexual selection
What - Compete with members of the same sex for access to members of the opposite sex.
Who- is preferred by males
Intrasexual selection and human reproductive behaviour
Sexual dirmorphism
Sexual dimorphism means ‘a difference in form between the sexes’. It is a term that describes the fact that in many (but not all) species of insect, bird mammal, reptile and so on, the males and females look different
In physical competition between males for mates, size matters. Large males have an advantage and are more likely to mate.
Dimporhism suggest that males are competing for the attention of females and females do the choosing.
Aggressive behaviour
Many males benefit from behaving aggressively in order to acquire fertile females and protect them from competing males. This leads to the selection of aggressiveness in males.
Preference for youth and fertility
- Males are more likely to want to mate with female that are youthful as younger females are more fertile. E.g in humans, men prefer women with a large wait to hip ratio.
Why - As males compete for females which leads to dimorphism
Supporting evidence
Miller et al
Miller et al
Compared the earnings of lap dancers who were menstruating naturally with those who were on the pill(which stops ovulation)
At non-fertile times, both dancers earned similar money in tips. However, during the fertile phase, the naturally menstruating dancers earned higher tips. Suggesting that women must somehow advertise their fertility to men, who consider them more attractive at that stage.
Supporting evidence
Waynforth and Dunbar 1995
Researched ‘lonely hearts’ columns in american newsapapers and discovered that women tended to describe themselves in terms of physical attractiveness and youth (‘exciting, flirty, curvy’) men on the other hand advertised their resources and intelligence more than women did.
Supporting evidence
Cunningham 1986
Investigated what types of females faces found attractive by males. He found that men were most attracted to features usually associated with young children - large eyes, small noses and chins. Some features associated with maturity such as prominent cheekbones and narrow cheeks were also found attractive and were dilated pupils and wide smiles.
Self penetration theory
- Altman and Taylor’s 1973 social penetration theory of how relationships develop. It is the gradual process of revealing your inner self to someone else, giving away your deepest thoughts and feelings.
- In romantic relationships, it involves the reciprocal exchange of information between intimate partners.
- As they increasingly disclose more and more, romantic partners penetrate more deeply into each other’s lives and gain a greater understanding of each other.
Doing so means that a relationship has reached a certain stage where such self-disclosure will be welcomed and reciprocated.
Breadth and depth of self-disclosure
Depth- how much detail you give
Breadth - how much you reveal
- According to Altman and Taylor, self-disclosure has 2 elements breadth and depth.
As both of these increase, romantic partners become committed to each other.
The breadth of disclosure is narrow because many topics are off-limits early in a relationship. If we reveal too much information too soon, this may threaten the relationship before it can get going.
- However, as the relationship develops, self-disclosure gets deeper, progressively removing more and more layers to reveal our true selves and encompassing a wider range of topics, especially concerning those things that matter to us.
Reciprocity of self-disclosure
As Reis and Shaver 1988 point out, for a relationship to develop, as well as an increase in breadth and depth there needs to be a reciprocal element to disclosure.
Once you have decided to disclose something that reveals your true self, hopefully, your partner will respond in a rewarding way, with empathy and also their intimate thoughts and feelings.
So there is a balance of self-disclosure between both partners in a successful romantic relationship, which increases feelings of intimacy and deepens the relationship.
Social Penetration Theory (AO3)
Sprecher and Hendrick (2004)
- Correlational analysis
- Heterosexual couples
- Strong correlation between satisfaction and self- disclosure
Social Penetration Theory (AO3)
Laurenceau et al (2005)
- Self-report technique- daily writing diary
- Self-disclosure and perception of self- disclosure linked to higher levels of intimacy in long-term married couples
- The reverse was also true
Social penetration theory
Culture bias- ethnocentric:
Tang et al. (2013)
Found that men and women in the USA tended to disclose more sexual thoughts and feelings than romantic partners in China; however, the level of relationship satisfaction was high in both cultures.