Let’s break down one of the study design dot points in Unit 4, AOS 1 of VCE Psychology. The dot point is centred on the concept of sleep, as shown below.
So, some things to take note of here:
Sleep is an altered state of consciousness.
We need to know about both circadian and ultradian rhythms.
We don’t need to know about corresponding brain wave patterns.
Let’s look at each of these points briefly in turn.
1. Sleep is an altered state of consciousness.
Earlier in Unit 4, you would have looked at the concepts of Normal Waking Consciousness (NWC) and Altered States of Consciousness (ASC).
Sleep is a naturally occurring altered state of consciousness.
This means that it is characterised by all the general effects of an ASC, such as reduced perception, a distorted sense of time and reduced limitations on the contents of consciousness (such as your dreams, which can be pretty wacky).
2. We need to know about both circadian and ultradian rhythms.
Circadian and ultradian rhythms can be a tricky concept.
Circadian rhythms are cycles that repeat every 24 hours. The overall human sleep-wake cycle is a circadian rhythm, as it follows a 24-hour pattern.
Ultradian rhythms are cycles that repeat in less that 24 hours. Each individual sleep cycle, which lasts for about 90 minutes and consists of both REM and NREM sleep, is an ultradian rhythm.
These ultradian rhythms (sleep cycles) change over the course of a sleep episode (which is the entire time that you’re asleep):
They tend to increase in length throughout the night (e.g. from ~80 minutes to ~100 minutes)
The amount of REM sleep increases with each ultradian rhythm
The amount of NREM 3 + 4 sleep decreases with each ultradian rhythm
If you’re still confused, I suggest you look at some graphs of the stages of sleep that a person experiences throughout the night, I found them really helpful!
3. We don’t need to know about corresponding brain wave patterns.
Brain wave patterns during different sleep stages were a big part of the previous study design, so they still tend to appear in textbooks and undoubtedly many teachers are still teaching them.
We don’t need to know about these for the exam.
All you need to know about for brain wave patterns is how they relate to different levels of consciousness (e.g. beta = focused, alpha = relaxed, theta = just asleep, delta = deep sleep) and how they are affected by stimulants and depressants.
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