Psychology Revision cards

Circadian Rhythm;

A Circadian Rhythm takes place approximately every 24hours. An example of a Circadian Rhythm is the sleep/wake cycle, and this is a prime example of how endogenous (internal clock) and exogenous (light) factors can affect our biological rhythms.

In the Michael Siffre case study where he lived in a cave for about 6 months with no natural light or indication of time in the outside world, he fell into a 25hour Circadian rhythm which tells us there is an biologically innate clock which controls our Circadian Rhythm, an endogenous factor.

Also in the study of the blind man (Miles et al), he formed a 24.9hour Circadian Rhythm. He had to take stimulants and sedatives to reprogramme his innate clock. This suggests there are individual differences, but that we have a natural rhythm of 25hours but to stay in time with the world this is reset by light, an exogenous factor affecting our Circadian Rhythm.

Infradian Rhythm;

An Infradian Rhythm is one which occurs more than every 24hours, but less than yearly, and a perfect example is the menstrual cycle. The menstrual cycle occurs every 28days, although this can vary, and is controlled by the hormones oestrogen and progesterone. This cycle prepares the female body for fertilisation. It is controlled mainly by endogenous factors but exogenous factors do affects it also.

Mc Clintock found that there was synchronisation of menstrual cycles in girls boarding schools. He concluded that this was to do with the release of pheromones. These are biochemical substances which are released into the air and act as chemical messengers co-ordinating the menstrual cycles of the girls. He also found that women who work with men have much shorter menstrual cycles as the male pheromones reset the woman's clock, and this leads to increased ovulation.

There are many studies that have tried to explain the nature of sleep, and from them we can conclude that it is due to a range of factors; biological clocks, the SCN and the pineal gland, and biochemicals e.g. melatonin.

Melatonin influences the production of serotonin which makes us sleepy. Serotonin accumulates in the raphe nuclei in the hindbrain, near the pons, and stimulates the shutting down or the RAS (reticular activating system), which is closely linked with brain activity.

Jouvet has identified the role of noradrenaline as a biochemical affecting sleep. It accumulates in the locus coeruleus in the pons, and if this area is damaged, noradrenaline levels fall and REM sleep is impaired. He concluded that different areas of the brain, and the corresponding neurotransmitters, controlled the two types of sleep; REM and NREM. The raphe nuclei and it's serotonin pathway controls NREM sleep; the locus coeruleus and noradrenaline pathway control REM sleep.

Andenosine is another biochemical which affects sleep. It builds up during wakefulness and is then broken down during sleep. It's been suggested that the build up causes drowsiness and could switch the brain into preparing for sleep mode.

Reward/Need Satisfaction Theory ;

Based on the concept of learning and stated that we form relationships which provide rewards (sex, money, comfort) and satisfy our needs. Both operant and classical conditioning are influential.

Classical conditioning - We come to like people with whom we associate enjoyment and satisfaction, even if they are not directly responsible for the positive experience.

Operant Conditioning - We like thoses who directly provide us with rewards.

Griffit and Guay's study on, "the bogus stranger" is an example of classical conditioning. Someone gave a reward/punishment to participants in the presence of a by-stander. Afterwards it was revealed that the by-stander was like more by those who were rewarded rather than those who were punished.

Economic Theories ;

Social Exchange Theory (SET) - Assumes relationships provide both reward and costs, and humans try to maximise these rewards whilst minimising the costs.

Thibaut and Kelley explained there were 4 stages to any relationship that take place when the rewards and costs are established and entrenched; sampling, bargaining, negotiation and institutionalisation.

Satisfaction depends on what individuals have come to expect from previous relationships - CL (comparison level), and the rewards and costs involved if they were to form another relationship - CLalt (comparison level for alternatives)

Equity Theory - People only consider a relationship to be satisfactory if what they gain from it reflects what they put into it (this is more important at the beginning of a relationship).

Walster et al concluded that if gain doesn't equal input, distress and relationship breakdown will result.

Gender Dysphoria, also known as gender identity disorder, is a condition in which people are uncomfortable with the gender to which they have been assigned (dysphoria means unhappiness).

In extreme cases this can lead to transsexualism which is a desire to change your sex. It is a more common issue in boys but it can occur in girls also.

There are two theories to explain Gender Dysphoria; a biological explanation to do with prenatal hormones, and family constellations (relationships with the parents).

The causes if gender dysphoria are unclear as no single explanation can be applied to every single individual who has the condition.

There are two theories which make an attempt to explain the condition known as Gender Dysphoria; Biological Theory and Family Constellations Theory.

Biological Theory - This theory believes GD is caused by unusual development in parts of the brain before birth.

There are small areas in the brain that differ in males and females.The biological theory claims that GD is caused by one of these areas developing in a way that corresponds to the opposite sex characteristics. This area is then not constant with the genitalia and chromosomes.

Kruijiver et al claims males have twice as many somatostatin neurons than females. He found that in individuals with GD, these neurons corresponded to their desired sex. This therefore points to a neurobiological basis of GD.

Zhou et al also studied one of the brain structures which was different in men and women and found that in 6 male-to-female transsexuals, this followed a purely female pattern.

Family Constellations Theory - Stoller pointed out that certain family conditions are associated with GD. Boys with an over-close relationship with the mother and a distant father figure are likely to develop GD. Girls who have a depressed mother in the first few months of their life and a father who is either not present or does not support the mother and leaves the child to try and control the mother's depression, are likely candidates of GD.

Rekers links GD to the absence of a father figure physically or psychologically.

De Cegile suggests that parents have a strong desire for a child of the opposite sex and, not necessarily deliberately, reinforce gender-inappropriate behaviour.

Biller and Hamilton investigated boys with GD and found they often had fathers who were absent either physically or psychologically.

When the egg and sperm mix the zygote that is formed will either have ** chromosomes (girl), or XY chromosomes (boy). For 7 weeks the development of a boy and girl are identical. The Y chromosomes induces the release of testosterone, if this is not released, the foetus develops female sex organs. In the rare chance, genetic males are insensitive to male hormones and do not develop male genitalia. They are born looking like girls and often brought up as girls, and this condition - complete androgen insensitivity syndrome - is not usually detected until puberty.

The Y chromosome which releases testosterone in the developing foetus, is 1/5 of it's size, hence males carry less genetic material than females. Montagu listed 62 specific disorders that are mostly in males e.g. haemophillia or red/green colour blindness. This is the role that genes play in gender development.

The role of hormones is extremely important. Each sex has identical sex hormones, the only difference is the amount they produce. Females produce oestrogen, oxitocin and progesterone; males produce a collection of male hormones and testosterone being most important.

Young et al demonstrated that pregnant monkeys injected with androgens have given birth to females with masculinised genitalia and who act in masculine ways, such as being threatening and aggressive, engaging in rough-and-tumble play, and mounting females.