Consciousness, Sleep and Drugs
Psychology · Section 2.1 · 18 study cards
Attention and awareness, circadian rhythms, the sleep stages and disorders, theories of dreaming, hypnosis, and the three drug classes.
Practice this set → Spaced repetition, card by card. No account needed.
Method
Consciousness is a spotlight, not a floodlight
Start from the capacity limit. Conscious awareness handles very little at a time, while unconscious processing handles a great deal in parallel. Every phenomenon in the first part of this unit follows from that: selective attention is the spotlight, the cocktail party effect shows the unattended channel is still monitored, and inattentional and change blindness show what falls outside the beam. When a question describes someone missing something obvious, the answer is almost always about where attention was, not about the eye.
Learn the sleep stages by their fingerprint
- N1 is the doorway: slowing waves and the falling sensation.
- N2 is the bulk: sleep spindles and K-complexes. Half the night.
- N3 is the deep one: delta waves, hard to wake, growth hormone, and the stage that owns sleepwalking and night terrors.
- REM is the paradox: waking-like brain activity with a paralysed body, and the vivid story dreams.
Then learn the shape of the night: N3 is front-loaded and vanishes, REM lengthens towards morning. Most exam items about timing are answered from that one sentence.
The trick that sorts every sleep disorder
Ask two questions. Which stage does it occur in, and does the person remember it? Deep N3 events happen early and are not remembered, and can involve movement because REM paralysis is absent. REM events happen late and are remembered, and cannot involve movement. Night terrors against nightmares is the same question in exam clothing.
Drugs: class, mechanism, then consequence
- Name the class. Depressants slow the nervous system, stimulants speed it up, hallucinogens distort perception.
- Name the mechanism at the synapse where the course gives you one, for example alcohol enhancing GABA, or cocaine blocking dopamine reuptake.
- Predict the effects from the class rather than memorising them drug by drug.
- Finish at the reward pathway, which is what every class has in common and what explains tolerance and dependence.
Keep tolerance, withdrawal and the two dependences as four separate definitions; items routinely offer them as alternatives to one another.
Definitions and theorems
Worked example
A sleep clinic records two patients overnight. Patient A sits up in bed about 50 minutes after falling asleep, screams, has a racing heart and rapid breathing, does not respond to her partner, and in the morning remembers nothing of it. Patient B wakes at about 6 am from a frightening and detailed dream that he describes at length, and reports that he could not move for a few seconds afterwards. For each patient, name the phenomenon, the sleep stage involved, and state which stage of the night it occurred in and why that is consistent. Then explain Patient B's brief paralysis.
Apply the recall test to Patient A. High physiological arousal with no memory of the episode is the signature of a night terror, not a nightmare.
Name the stage. Night terrors occur in N3, deep slow-wave sleep, and the timing confirms it: about 50 minutes after sleep onset falls in the first cycle, when N3 periods are longest. N3 dominates the early night and disappears later.
Apply the recall test to Patient B. A detailed frightening dream that is clearly remembered is a nightmare, which occurs in REM sleep.
Check the timing again. Waking at about 6 am is late in the night, which is consistent, because REM periods lengthen across successive cycles and most REM occurs in the final hours before waking.
Explain the paralysis. During REM the voluntary muscles are effectively paralysed so that dream content cannot be acted out. Patient B woke while that atonia was still in place, producing a brief inability to move.
State the general rule the item is testing. Deep N3 events occur early, involve movement or high arousal, and are not remembered; REM events occur late, are vividly remembered, and cannot involve movement. Stage, timing and recall settle every item of this kind.
Common mistakes
- Calling a night terror a nightmare. They differ in stage, timing and memory. Night terrors are N3 events early in the night with no recall; nightmares are REM dreams later in the night that are remembered in detail. Decide on recall first and the rest follows.
- Saying the brain shuts down during REM. The opposite is true: REM brain activity resembles waking, which is why it is called paradoxical. What shuts down is the voluntary musculature. Reserve the idea of the deepest, most slowed sleep for N3.
- Treating alcohol as a stimulant because people get louder. Alcohol is a depressant. The apparent stimulation is disinhibition, the slowing of the controls that normally restrain behaviour. The same reasoning catches items describing increased confidence or talkativeness.
- Confusing tolerance with withdrawal, or physical with psychological dependence. Tolerance is needing more for the same effect; withdrawal is what happens on stopping; physical dependence is using to avoid withdrawal; psychological dependence is using to manage negative emotion. Exams place them as alternatives in the same item precisely because students blur them.
- Claiming hypnosis recovers accurate memories or forces unwilling behaviour. It raises confidence without raising accuracy and cannot override a person's values. Its best-supported use is in reducing the experience of pain, and answers should say that rather than describing hypnosis as a route to the unconscious.
Practice it
Reading the method is not the same as being able to recall it under pressure. This set drills 18 cards one at a time and schedules each card separately, so the ones you keep missing come back sooner.