Biological rhythms: Ultradian rhythm

Question 1

Ultradian rhythm

Answer 1

less than one day/24 hours periodicity - occurs many times during the day
* for example we repeat 4-6 cycles of sleep during the night

Question 2

what are the 5 stages of sleep

Answer 2

stage 1 -4 = non-REM sleep
stage 5= REM sleep
* 90 minute cycle that continues throughout the course of the night

Question 3

Stages 1 and 2

Answer 3

light sleep
* person is easily woken
* beginning of sleep where brainwave patterns become slower and more rhythmic (alpha waves), becoming even slower as sleep becomes deeper (theta waves)
* heart rate decreases
* hypnogogic dreams occur- shortly after drifting off we feel out of control/falling, so we wkae up with a jolt

Question 4

Stages 3-4

Answer 4

deep sleep/slow wave sleep
* delta waves are even slower
* difficult to wake someone up at this point

Question 5

Stage 5

Answer 5

REM sleep
* body is paralysed
* brain activity speeds up in a manner that resembles the awake brain
* REM= rapid eye movement
* REM activity is highly correlated with dreaming
* not all dreaming occurs at this stage

Question 6

Research into sleep

Answer 6

Dement and Kleiman (1957)
* monitores sleep patterns of 9 adults in a sleep lab
* brain activity recorded on an EEG and researchers controlled for the effects of caffeine and alcohol
* REM activity during was highly correlated with the experience of dreaming and ppts woken during sreaming reported very accurate recall of their dreams
* replication of this investigation have noted similar findings

Question 7

Evaluation

Answer 7

-Small sample size
+ standardised procedure
+ other research has demonstrated its reliable

Question 8

small sample size

Answer 8

study used a sample of 9 adults. therfore its low in population validity so findings cannot be generalised to the wider population

Question 9

standardised procedure

Answer 9

the study was conducted in a lab setting and used standardised procedure. this means that it was well controlled

Question 10

BRAC

Answer 10

Basic rest activity cycle
* applies to the 90 minute sleep cycle to waking hours
* similar to 90 minute cycle but occurs in waking hours- its a period of alertness followed by a spell of physiological fatigue occuring in a 90 minute cycle
* supported by anecdotal evidence such as students being unable to focus for 90 mins at a time
* Ericsson et al (1993) conducted a study of violinists and found that the best performers tended to practice for 3 sessions during the cours of the day each session lasting no mor than 90 mins
+ Practical application to school