Relationships Flashcards
What is sexual selection?
An evolutionary explanation of partner preference, proposed by Darwin (1871). Attributes which increase reproductive success are passed on, and may become exaggerated over succeeding generations of offspring.
Some physical characteristics, such as a male peacocks tail, are a sign of genetic fitness
Other characteristics, such as aggressiveness, are adaptive. They provide an advantage for male animals over their competitors.
What is Anisogamy?
The differences between male and female sex cells (gametes).
Male gametes (sperm) - small, highly mobile, created continuously in vast numbers from puberty to old age, do not need much energy to be produced
Female gametes (eggs/ova) - relatively large, static, produced at intervals for a limited number of fertile years, and require a significant amount of energy
A consequence of anisogamy is that there is no shortage of fertile males, but a fertile female is a much rarer ‘recourse’. Anisogamy is important for partner preference as it leads to the two types of sexual selection
What are the two types of sexual selection?
. Inter-sexual selection - To do with characteristics that improve desirability - Females are choosier and look for recourses
. Intra-sexual selection - To do with characteristics that aid success in competition - Males compete to mate with as many females as possible
What is Inter-sexual selection?
. Tends to be the preferred strategy of females when choosing a partner
. Trivers (1972) - pointed out that a female makes a greater investment of time, commitment and other recourses before, during and after the birth of her offspring
. Both sexes are choosy, as both stand to lose if they invest in substandard partners, but the consequences of choosing the wrong partner are worse for females
. Females must be more selective, choosing a genetically fit partner with the best recourses
. It is female preference which determines what traits will be passed on in offspring - eg. if a female favours height, this will increase in the male population over time - as females will select the tallest male, so the characteristic gradually becomes exaggerated (a runway process)
. Fisher (1930) - sexy sons hypothesis - the genes we see today are those which have enhanced reproductive success. Females mate with males with particular, desirable characteristics. It is then more likely that her son will inherit this ‘sexy trait’. This then means that her son is more likely to be selected by females who will mate with her offspring. Therefore the preference for this ‘sexy trait’ is perpetuated
What is Fisher’s ‘sexy sons’ hypothesis?
. Fisher (1930) - sexy sons hypothesis - the genes we see today are those which have enhanced reproductive success. Females mate with males who have particular, desirable characteristics. It is then more likely that her son will inherit this ‘sexy trait’. This then means that her son is more likely to be selected by females who will mate with her offspring. Therefore the preference for this ‘sexy trait’ is perpetuated
What is Intra-sexual selection?
. Focuses on strategies and characteristics that aid reproduction within a sex
. It is the preferred strategy of males, who are said to prefer quantity over quality - they are more concerned with beating out other males to get a female and reproduce than selecting the most desirable female
. There is competition between males to be selected to mate with a female. The winner of this competition reproduces, so the characteristics which have contributed to this win may be passed onto his offspring. Losers do not pass on ‘loosing characteristics’ as they do not reproduce to do so.
. Intra-sexual selection can affect the physical characteristics of a population (dimorphism) and behavioural characteristics
What is Dimorphism (physical consequences of Intra-sexual selection)?
The idea that males and females end up looking physically different because of intra-sexual selection. In any physical competition between males, size tends to matter - larger males have the advantage, and so are more likely to reproduce.
On the other hand, females don’t have to compete for reproductive rights, so there is no evolutionary drive towards favouring younger, more fertile women. Youthfulness may be desirable to males because they are seen as more fertile, but this is not a physical, evolutionary change
What are the behavioural consequences of Intra-sexual selection?
Characteristics that allow a male to outcompete his rivals are those that are passed on. These can include deceitfulness, intelligence and aggression. Eg. males may benefit from acting aggressively in order to acquire fertile females and protect them from competing mates, leading to aggressiveness in males.
What are some strengths of evolutionary explanations for partner preferences?
+ Research support for inter-sexual selection, in particular the concept of female ‘choosiness’ - Clark and Hatfield (1989) conducted research on university students. Male and female psychology students approached other students and said: ‘I have been noticing you around campus. I find you to be attractive. Would you go to bed with me tonight?’. No female students agreed to the request, while 75% of male students did. This supports the view that females are choosier than males in choosing sexual partners, and that males have developed a different strategy to ensure reproductive success.
—- COUNTER —- The argument that males and females have adopted different methods of sexual selection is arguably too simplistic. Buss and Schmidt (2016) proposed the ‘sexual strategies theory’ which argues that both males and females adopt similar strategies in seeking long-term partners, in which both are choosy and look for qualities such as kindness, loyalty ect. They suggest that strategies differ according to the desired length of relationship. As such, Clark and Hatfield’s study can only be used to support arguments about sexual selection when discussing it in the very short term, and as such is limited, lacking nuance.
+ Research support for intra-sexual selection - Buss (1989) carried out a survey of over 10,000 adults in 33 countries, asking them questions related to a variety of attributes that evolutionary theory predicts are important in partner preference. Females were found to place greater value on recourse related characteristics eg. ambition, good finances, while males placed greater value on physical attractiveness and youth. These findings are consistent with predictions from sexual selection theory, strengthening its reliability.
What are some limitations of evolutionary explanations for partner preferences?
- Evolutionary theories often underestimate the influence of social and cultural factors over partner preference - rapidly changing social norms in the last century will naturally have an impact on partner preference. These norms have developed much faster than evolutionary timescales would imply, due to changing cultural factors such as attitudes towards reproduction, women’s role in the workplace, homosexuality etc.. Bereczkei et.al (1997) argued that women’s greater role in the workplace (and in turn them becoming less dependent on men) has consequences for their mate preference, which may no longer be resource orientated. Partner preference today is likely to be a combination of evolutionary and cultural influences. The evolutionary explanation arguably lacks temporal validity and is outdated, limiting its value as an explanation.
What factors affect attraction?
. Self-disclosure
. Physical attractiveness
. Filter theory
What is self-disclosure?
Revealing personal information about yourself to a partner, such as your feelings, attitudes, beliefs, memories etc.. This allows partners to understand each other better, strengthening romantic bonds. Partners tend to be cautious about what they disclose initially, but may reveal more over time.
What is social penetration theory (Altman and Taylor)?
. Proposed by Altman and Taylor in 1973
. It is a theory of how relationships develop
. It describes the gradual process of revealing your inner self to someone else, including your deepest thoughts and feelings
. In romantic relationships, it involves the reciprocal exchange of information between partners. By revealing information, partners indicate trust.
. As partners disclose more and more, they penetrate more deeply into each others lives and gain a greater understanding of each other
. Disclosure signals that the relationship has reached a level where self-disclosure will hopefully be welcomed and reciprocated
What did Altman and Taylor say were the two basic elements of self-disclosure?
Breadth and Depth
As both of these increase, partners become more committed to each other
What is meant by Breadth and Depth of self-disclosure?
Altman and Taylor used the metaphor of an onion to describe self-disclosure.
We describe a lot about ourselves at the start of a relationship, but what is revealed tends to be surface level and superficial. Breadth of disclosure is narrow, as there is a narrow range topics considered acceptable.
As the relationship develops, self disclosure becomes deeper, with progressively more and more ‘layers’ removed to reveal our true selves. A wider breadth of topics are discussed. Eventually, we reveal deeper, intimate, high-risk information eg. painful memories, strongly held beliefs, secrets