Biological rhythms: Ultradian rhythm Flashcards
Ultradian rhythm
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
what are the 5 stages of sleep
stage 1 -4 = non-REM sleep
stage 5= REM sleep
* 90 minute cycle that continues throughout the course of the night
Stages 1 and 2
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
Stages 3-4
deep sleep/slow wave sleep
* delta waves are even slower
* difficult to wake someone up at this point
Stage 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
Research into sleep
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
Evaluation
-Small sample size
+ standardised procedure
+ other research has demonstrated its reliable
small sample size
study used a sample of 9 adults. therfore its low in population validity so findings cannot be generalised to the wider population
standardised procedure
the study was conducted in a lab setting and used standardised procedure. this means that it was well controlled
BRAC
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