Ultradium Rhythms Flashcards
(5 cards)
AO1: Ultradium rhythms
An ultradian rhythm is a biological rhythm that occurs more frequently than once every 24 hours.
One example is the stages of sleep which occurs more frequently than once every 24 hours as there are 5 distinct stages that a person cycles through up to 5 times a night.
Research, using EEG, into ultradian rhythms has shown that there are 5 distinct stages to sleep. These are characterised by differences in brain, muscle and eye activity during NREM and REM sleep stages. It is argued that ultradian rhythms are under endogenous control as there are 5 distinct stages of sleep which last 90 minutes each.
Stage 1 and 2 is NREM, this is light sleep where a person may be easily woken and show alpha brain waves. Stage 3 and 4 is NREM known as deep sleep and brain waves are delta waves. It’s difficult to wake someone at this point. In stage 4 the body repairs the muscles. Stage 5
(REM), the body is paralysed. Brain activity closely resembles that of the awake brain (theta). Dreams are often experienced in this stage. The function of stage 5 is to
repair the brain e.g. replenishing neurotransmitter levels.
However, evidence shows the role of exogenous factors can impact the consistency of ultradian rhythms.
Exercise is an exogenous factor as individuals who run ultra-marathons spend longer in stage four of sleep, which has been found to aid
physical recovery to repair the muscles. Likewise, mental health conditions can act as an
exogenous factor as individuals with depression have been found to enter stage 5 (REM) earlier than the average person and will show increased REM sleep duration during the night.
Therefore, shows that exogenous factors are influencing
the stages of sleep and will that this will impact the
regulation of consistent sleep patterns.
What are the evaluations? (3)
1) Practical applications
2) Scientific methods
3) Ecological validity
AO3: Practical applications
A strength of research investigating ultradian rhythms is that it has practical applications in understanding age-related changes in sleep. The knowledge that growth hormone is produced during stage 4 of sleep (slow wave sleep) has been associated with sleep deficit in old age as research has found older people experience less stage 4 sleep. As a result of this research, medication and relaxation techniques have been developed to increase stage 4 sleep in older individuals and therefore, prevent some issues associated with old age such as reduced alertness. Therefore, research investigating ultradian rhythms is an important part of applied psychology.
AO3: Scientific methods
In addition, a further strength of research into ultradian rhythms is that it uses scientific methods. This is because it is based on objective and empirical techniques such as EEGs to measure brain activity and controlled lab settings. These scientifically measure the activity of the brain throughout the five stages of sleep to identify the length of the rhythm and how many times the rhythm occurs throughout the duration of sleep whilst excluding extraneous variables that may affect sleep such as noise and temperature. Thus, psychologists would argue that this increases the overall internal validity of research investigating the role of endogenous factors in ultradian rhythms, therefore, raising Psychology’s scientific status.
AO3: Ecological validity
However, the research into endogenous and exogenous factors in ultradian rhythms may have low ecological validity. Research on ultradian rhythms is conducted in an artificial setting and so the sleep experienced by participants in these studies may not reflect their genuine sleep patterns, governed by exogenous pacemakers, due to the unfamiliar surroundings and because they are attached to electrodes (which are examples of exogenous zeitgebers). This may alter the length of the ultradian rhythm, making it difficult to generalise findings to explain how ultradian rhythms work in real life. Therefore, reducing the external validity of research into endogenous and exogenous factors in ultradian rhythms.
