ULTRADIAN RHYTHM

Ultradian = less than a day (sleep stages)  Infradian = a day > a year (menstrual cycle, SAD) 

5 stages of sleep: NREM four stages --> relaxed state easily woken (alpha waves) --> brain waves slow down (SWS: slow wave sleep) body repair, growth hormones ---> REM sleep (paradoxical sleep) brain & eyes active body paralysed --> brain activity resembles awake brain --> each sleep cycle 90 minutes--> 90min 'clock' ticks throughout day - BRAC --> Friedman & Fisher psychiatric patients --> H/W institutionalised --.> may have cues (exogenous) to eat & drink .. mentality not the same as 'normal'

 DEMENT and KLEITMEN: est. REM sleep was a sperate sleep stage & dreaming takes place here --> This shows that sleep has distinct stages -->  H/W correlation of REM & dreaming not necessarily cause and effect. -->  lab expt. --> high control .. replicable --> use of EEG objective, scientific evidence -->H/W lacks ecological validity as sleep not 'normal' & may have had an effect... --> small sample not reflectvie of general population

Infradian rhythm: menstrual cycle --> lasts 20 days

Pituitary gland releases FSH and LH which stimulates a follicle in one ovary to ripen an egg --> also triggers release of oestrogen --> once ripened, ruptured follicle secretes progestorone causes lining womb prepare for pregnancy.. if no fertilisation w/in 2weeks progestorone levels drop and lining shed

 Menstrual cycle found in many mammals .. biological evidence proves it is controlled by hormones & pituitary gland --> H/W exogenous cues influential --> RUSSEL: daily samples of sweat 1group smeared on another group .. although separated menstrual synchronised --> suugests external factors PHEROMONES have an effect --> Field study = high external valdity .. H/W small sample .. generalisability

PMS (premenstrual syndrome).. week before menstruation.. high levels of progesterone: symptoms - acne, fatigue, mood swings and aggression --> Case study: woman commited manslaughter but given probation b/c argued caused by biology (biologically determined) --> Extremely contentious issue: women argue against diminished responsibility --> lead to discrimination .. e.g. employability --> Some women PMS serious condition .. many women have 'free will' to find ways to deal with it

 Monthly male cycle--> EMPSON 21 male P's 40 - 100 days --> found 20 day cycle variation of both temp. & alertness --> Methodology: reliable, scientifi but self-subjective report