A2 Psychology

Circadian Rhythm

The Sleep - waking cycle

• Repeats in cycle once every 24 hours.
• mammals possess about 100
• Sleep - waking cycle is a good example; illustrates that circadian rhythms depend on an interaction of physiological and psychological processes. Our fairly consistent sleep patterns suggest an internal/ endogenous mechanism. Can be overidden by psychological factors. Eg:anxiety.
• Effected by both endogenous and exogenous factors. Endogenous refers to innate mechanism that sets timing of biological rhythms. Exogenous factors are things such as light and time cues from the outside world.

Research

• Siffres 'cave study' - 2 months in a dark cave. In absence of light developed sleep wake cycle of 25 hours. Close to standard of 24 hours, suggesting influence of endogenous factors.

Infradian Rhythm

The menstrual cycle

• involves a cycle greater than 24 hours.
• Human menstrual cycle occurs every 28 days and is controlled by the hormones oestrogen and progestrone, causes release of egg etc.
• it is seen as an endogenous mechanism, as it is controlled mainly by internal biological factors but exogenous factors (external cues) can also effect the rhythm

Research

• McClintock - women/girls who live or spend considerable time together can have synchronized menstrual cycles. This may be due to pheromones, biochemical substances that act like hormones but are released in the air rather than the blood stream - 'chemical messengers' which may co ordinate synchronization.

Insomnia: problems falling asleep/ staying asleep, sleep tends to be not deep & easily disturbed. Linked with: fatigue, poor attention, impaired judgement, decreased performance, being irritable & increased risks of accidents.

It is not a single condition, there are different forms based on degrees of severity (mild, moderate, severe, acute and chronic)

Primary vs Secondary ; depends on cause.

Primary is the most common form and has no clear underlying cause. There is a sleep problem but no physiological or psychiatric cause, likely as a result of maladaptive behaviours or learning.

Clinical characteristics; individual has suffered insomnia for at least a month, but this wouldn't be linked with other sleeping disorders (eg parasomnia, narcolepsy OR clinical depression, medication or substance abuse)

Worrying about it can lead to an unending cycle = focus on problem.

Secondary insomnia = has a specific cause

Examples of such causes : sleep apnoea, restless legs syndrome, circadian rhythm disorders (due to night shiftwork), various medical/ substance use and emotional problems.

Factors effecting insomnia: (interfere with natural progression of brain activity, from day time functioning to slowing down)

• Environmental factors; bright lights, loud noises, hot/cold, uncomfortable bed, snoring companion = interfere with brains natural calming down. Even change of location.
• Stress; acute stress (exam, job change) as brain activity is heightened, the sympathetic ans is active = parasympathetic cant switch. when stressor is over normal sleep should resume, unless chronic stressor = long term disruption.
• Sleep Hygiene/Bedtime Behaviour; patterns tat promote the calming of the brain in preparation for sleep. Poor hygiene = habits that obstruct this (caffiene, alcohol, nicotene. Similarly activities that take place in bedroom; tv, on the phone,homework, night fears.

Sleepwalking

Somnambulism; relatively common (1 in 10). Eyes are open, glazed and staring. Most likely to occur in NREM sleep staged 3 and 4, in slow wave sleep. Tends to be earlier rather than later & is most common in childhood. Episode may only last a few seconds, but can also last hours, when awake the individual will have no recollection. Causes include: a genetic predisposition, fatigue, lack of previous sleep, stress or anxiety, alcohol/drugs also act as triggers.

Genetic element supported by Hublin et al (1997) who used the Finnish twin cohort. Found gentic contribution:

• Children = 66% male & 57% female
• Adult = 80% male & 36% female

Szelenberger, Niemcewicz and Dabrowska offer explanation to sleepwalking = low & declining levels of delta waves - could be signs of chronic inability to sustain slow wave sleep.

Narcolepsy

Rare but characterised by chronic sleepiness - individual may fall asleep at any time. Short naps of 10-20 mins are common, after which sleepy feeling is temp reduced (only to reappear with 2 to 3 hours)

• Cartaplexy can also occur - muscles lose strength when strong emotions occur. body may droop, sag, collapse as if paralysed. No loss of consciousness, individual doesn't faint. Usually over in seconds/minutes.
• Sleep Paralysis - occurs at beginning/end of sleep and is a brief loss of the ability to move (apart from breathing/eye muscles). Usually lasts a few minutes & is very distressing, accompanied by sense of fear. Individual thinkin they are dead, even hallucinations.
• Sleep hallucinations - may occur when dropping off or when awakening.

Research has established that in non humans (dogs and mice) that narcolepsy = caused by genetic mutation. Mignot discovered that in dogs mutation also produced a deficiency in a receptor for the neurotransmitter hypocretin - blocks communication between neurones, particularly messages to when the body should wake. (hard to generalise)

Reward/need satisfaction theory

Based on learning theory - states we form relationships that provide rewards (reinforcement) and satisfy our needs. rewards such as sex, money & status

Both operant & classical conditioning are influential

• Classical - Byrne; come to like people we associate enjoyment and satisfaction, even if they aren't directly responsible for positive experiences. Enjoyable experiences = positive feelings = positive affect.

• Operant - we like those who provide us with rewards. dislike those whose presence is unpleasant. Eg: tedious, argumentative.

Economic Theories Social exchange theory. Relationships provide both rewards and costs - minimise costs, maximise rewards. Thibaut and Kelly - long term friendships go through 4 stages; sampling, bargaining, negotiating, institutionalisation. Level of satisfaction will depend on costs and rewards if they were with someone else 'comparison levels for alternatives' (Clalt) Equity theory Extension of social exchange - Basic assumption; people only consider relationship satisfactory if what they gain reflects what they give - one person contributes more, they get more out of it. However this is more important at the start, negotiation to produce fairness.

Gender dysphoria

aka gender identity disorder = condition which people are not comfortable with the gender to which they have been assigned.

In extreme = lead to transsexualism - desire to change gender. More common in boys but occurs in both sexes.

Biological explanation: influence of prenatal hormones.

Girls = ** chromosomes, boys = XY. One explanation = unusual development in parts of the brain before birth. Small areas different between males & females. one area has developed in a way that corresponds with the opposite sex therefore the brain has not developed in a way that corresponds to the gender assigned to the child at birth.

Zhou et al (1995) - studied one of the brain structures that is different in men and women and found that in 6 male to female transsexuals this followed a totally female pattern.

Family Constellations

Stoller (1968) points out certain family conditions associated with gender dysphoria. For boys who want to be girls = overly close r.ship with mother & distant father. Girls who want to be boys = depressed mother in 1st few months of life & a father who isnt present/ doesnt support the mother, leaves child to try to control mother depression.

Rekers linked gender dysphoria in boys to absent father figure (physically/psychologically).

Bleiberg, Jackson and Ross have linked development of GD with an inability to mourn a parent or important attachment figure in early life.

De Ceglie (2000) suggest parents have a strong desire for child of opposite sex & unintentionally reinforce gender inappropriate behaviour. Research; In the case of James, developed dysphoria after death oh his grandmother who raised him. After therapy, where he had to talk about her condition gradually went away.

Prenatal Sexual Development

Sequence of sex development after fertilisation.

• 7 weeks virtually indentical; boys and girls.
• Y chromosome then induces release of testosterone - stimulates growth of male sex organs. no testosterone = develops as female
• Rare condition; Androgen sensititvity syndrome; genetic males = insensitive to male hormones & don't develop male genitalia. Born looking and raised like girls, detected in puberty.

Influence of sex chromosomes. Y chromosome is 1/5 of its size, boys carry less genetic material than girls = males are more vulnerable. Montagu listed 62 disorders due to sex linked genes, found mostly in males eg haemophilia.

The role of hormones

Each sex has identical sex hormones, difference is amount they produce. Normal biological development females produce female sex hormones = oestrogen and progestrone. Males produce androgens = collection of male hormones mainly testosterone.

Up to about the age 8-10 negligible amounts are produced, from 11+ increase, girls produce more than boys.

Research;

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