Nelson Chapter 9 Short Answer Test Answers PDF

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 postural instability: difficulty maintaining an upright posture and a steady balanced position; contributes to gait (walking) disturbances (e.g. apparent in the short, shuffling steps taken and reduced arm swing) and inability to maintain a steady, upright posture (e.g. unable to take a corrective...

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Chapter 9 Test SECTION B Answers: Assessment guide Question 1 (1 mark) Define the meaning of REM rebound.  REM rebound: catching up on REM sleep by spending more time than usual in REM sleep immediately following a period of lost REM sleep when next asleep/during the next NREM/REM sleep cycle (1 mark) Note. Do not award a mark for simply stating catching up on REM sleep or catching up on lost REM sleep.

Question 2 (2 marks) Deep sleep may be defined as starting during NREM stage __________________when a pattern of__________________ brain waves is established.  3 (1 mark); delta/slow/very slow (1 mark)

Question 3 (2 marks) Distinguish between a sleep cycle and a sleep episode.  sleep cycle: a sleep period/phase comprising NREM sleep and REM sleep that occurs during/within a sleep episode (and is normally repeated a number of times, depending on the duration of the sleep) (1 mark)  sleep episode: a sleep period/event, starting with sleep onset and ending with a final awakening, that comprises one or more sleep cycles (but not necessarily complete cycles as a microsleep for a few seconds or a nap may be considered a sleep episode) (1 mark)

Question 4 (3 marks) Describe how eye movements are likely to change across the sleep cycle of a young adult under normal circumstances.  Description should refer to:  NREM stage 1 — initially some slow, rolling eye movements may occur  NREM stages 2–4 — no eye movements  REM period — spontaneous bursts of rapid eye movement during which the eyeballs quickly move beneath the closed eyelids, darting back and forth and up and down in jerky, but coordinated movements. Award 1 mark for each of 3 key points.

Question 5 (2 marks)

Label the two plot lines in the graph below to show which line represents NREM stage 4 sleep and which line represents REM sleep.

REM sleep (1 mark)

NREM stage 4 sleep (1 mark))

Question 6 (4 marks) List four differences in sleep across the lifespan with reference to the total amount of sleep and changes in the pattern and proportions of REM and NREM sleep (including NREM stages).  Differences include:  decrease in total sleep time with age e.g. infants sleep more and people sleep appreciably less as they age  decrease in REM with age then levels out i.e. REM proportion markedly decreases from about 50% between 0–2 years, then stabilises at about 20–25% through to very old age  age-related increase in NREM sleep proportion through infancy and early childhood  decrease in time spent in NREM and REM that persists through to a very old age, especially from birth for REM and early childhood for NREM  decrease in NREM stages 3 and 4 with age i.e. decrease in proportions of NREM stages 3 and 4, especially a marked decrease or disappearance in late adulthood/very old age  in later adulthood, at around 60 or so, sleep is mostly stage 2 light sleep. Award 1 mark for total sleep time and 1 mark for each of three differences associated with change in REM and NREM sleep.

Question 7 (4 marks) Describe two characteristics that best distinguish sleep from any other state of consciousness. Explain with reference to a person in a drug-induced state after having used a potent depressant.  Characteristics are:  reversibility: a sleeper can always be awoken with a strong enough stimulus, such as noise or bodily force, and therefore ‘reverse back’ to the waking state (1 mark); quick reversibility to a wakeful state distinguishes sleep from a drug-induced state after having used a potent depressant; reversibility from this type of drug-induced state occurs, but not as quickly as sleep e.g. if a potent arousal stimulus is used, arousal from sleep will be immediate but not normally so from a severe drug-induced state (1 mark)  perceptual disengagement: a sleeper has no awareness of the external sensory stimuli of which they are usually conscious in the waking state (1 mark); a person in a drug-induced state may have some awareness of external stimuli, especially early in the state (1 mark)  unresponsiveness to environmental stimuli: a sleeper is ordinarily unresponsive to external stimuli; a strong enough sensory stimulus may awaken a sleeper (as per the reversibility characteristic) but the exact nature of the stimulus is not perceived by the sleeping person as it would be by the waking person (1 mark); a person in a drug-induced state may be responsive to environmental stimuli, especially early in the state (1 mark). Award 2 marks for each of two valid characteristics. Although a depressant may induce drowsiness or sleep, this is not considered a key distinguishing characteristic.

Question 8 (2 marks) If a person’s eyelids are taped open and they fall asleep, explain whether they would stop seeing.  Explanation should demonstrate understanding that the person is asleep (i.e. they fall asleep) so there is perceptual disengagement and therefore ‘seeing’ is not possible e.g. the person will stop seeing because from the moment of sleep onset to the moment the person awakens (1 mark) he or she is essentially blind due to the perceptual disengagement defining characteristic of sleep (1 mark). Note that perceptual disengagement from the environment during sleep is not simply the result of our eyes closing (or blocking our ears etc.).

Question 9 (4 marks) (a) Describe two criteria that could be used to assess whether a biological rhythm could be called a circadian rhythm. 2 marks 

Criteria to be called circadian include:  The rhythm has a duration of about 24 hours and must repeat every 24 hours.  The rhythm persists in the absence of external cues, which distinguishes circadian rhythms from simple responses to daily external cues.  The rhythm can be adjusted to match the local time, e.g. the rhythm can be reset/entrained by exposure to external stimuli (such as a clock or light). Award 1 mark for each of two criteria.

(b) Distinguish between a circadian and an ultradian rhythm. 2 marks  Distinction should refer to cyclical duration i.e.  circadian rhythm: changes in bodily functions or activities that occur as part of a cycle with a duration of about 24 hours (1mark)  ultradian rhythm: changes in bodily functions or activities that occur as part of a cycle shorter than 24 hours (1 mark)

Question 10 (6 marks) Explain how light influences the human sleep–wake cycle with reference to biological structures and processes that regulate the cycle and why sleepiness is highest at night and lowest in the day.  Explanation should:  name the SCN (suprachiasmatic nucleus) (1 mark)  demonstrate understanding of the role of the SCN with reference to both natural and artificial light — monitors light and melatonin output to influence arousal/a biological clock that regulates the timing and activity of the sleep–wake cycle; receives information about the amount of light from the eyes and adjusts the sleep–wake cycle by sending neuronal messages to the pineal gland to secrete more or less melatonin in relation to light intensity; may also adjust through feedback on melatonin level (1 or 2 marks)  name and describe the role of the pineal gland — produces and secretes melatonin into the blood to influence alertness/arousal and help regulate the circadian sleep–wake cycle (1 mark)  name and describe the role of melatonin — a hormone secreted into the blood; the amount that is secreted varies with the amount of light that is detected e.g. higher at night and lower during the day; amount present in the blood is associated with alertness — higher melatonin levels are associated with greater drowsiness and vice versa (1 mark)  demonstrate understanding that sleepiness is highest at night and lowest in the day due to light influencing melatonin level (1 mark) Award up to a total of 6 marks, noting suggested marking allocation above.

Question 11 (5 marks) (a) Name and describe two different theories on the purpose and function of sleep. 3 marks  restoration theory: sleep has a restorative function i.e. opportunity/‘time out’/rest to assist/support recovery of the body (including brain) to full waking capacity/recovery from activities during waking time that deplete bodily resources e.g. sleep enables replenishment of neurotransmitter used up during the day, downtime to repair damaged cells, removal of waste products in muscles etc.  evolutionary/circadian theory: sleep enhances survival of a species by protecting its members through making them inactive during the part of the day when it is riskiest or most dangerous to move about — an organism’s circadian sleep–wake cycle helps ensure its lifestyle and specific activities are synchronised with the day–night cycle of its environment and at the safest times i.e. the sleep–wake cycle is regulated by circadian processes that are tied to light–dark changes and support a safer lifestyle by ensuring the scheduling of activities and biological functions at appropriate times in the daily environmental cycle. Award 1 mark for correctly naming two theories and 1 mark for each description of a study design prescribed theory. (b) What is a limitation of each theory? 2 marks

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Limitations include:  lack of empirical research evidence e.g. for restoration theory, has not been conclusively established in a cause–effect way precisely what, if anything, is actually restored, repaired or revitalised during sleep and at no other time; for evolutionary/circadian theory, primarily relies on animal studies  contradictory evidence e.g. physical activity can hasten sleep onset or improve sleep quality and increase sleep duration, but we do not necessarily need to sleep more than usual after a particularly active day; sleep deprivation studies have failed to provide conclusive evidence for the restorative claim that sleep is essential for the maintenance of healthy bodily functioning — a cause–effect relationship has yet to be established  do not account for individual differences in sleep needs and effects of sleep loss (including no lasting effects), especially among humans  do not adequately account for the ultradian nature of sleep or the patterns and proportions of NREM and REM sleep  evolutionary/circadian theory does not actually explain our need for sleep — why we (and other mammals) must and will eventually sleep, regardless of the environmental circumstances and possibly the danger to which we may be exposed if we fall asleep  evolutionary/circadian theory does not account for the loss of awareness and alertness during sleep, since their loss may place the organism at greater risk  both emphasise biological aspects, overlooking psychological aspects. Award 1 mark for each of two limitations.

Question 12 (15 marks) To test the effectiveness of a new sleeping pill, a researcher conducts an experiment at the participants’ homes rather than in a sleep laboratory. Eighteen volunteer adult participants, who reported that they have been suffering from sleep-onset insomnia (i.e. difficulty falling asleep) for more than a year, are each given a packet of 14 pills and asked to take one each night for 14 consecutive nights, 15 minutes before their usual sleeping time. They are also given a special apparatus to record the time they fall asleep. The apparatus, worn on the body, measures various physiological responses associated with sleep–awake states, has a timing device and has been reported by participants in previous studies as not being uncomfortable in any way. Researchers have also found it to be far more valid and reliable than similar measures devised as smart phone apps. The participants do not know that they have been randomly allocated to either of two groups. The researcher’s assistant is also unaware of the group to which each participant has been allocated. Group 1 has 9 participants whose pills are arranged in the pack so that pills 1 to 7 are the new sleeping pills, and pills 8 to 14 look and taste like the sleeping pills but do not contain the sleep-inducing ingredient. Group 2 also has 9 participants, but their pills are arranged so that pills 1 to 7 are the fake pills and pills 8 to 14 are the new sleeping pills. The results are shown in the following table.

(a) Identify the operationalised independent and dependent variables.  IV: sleeping pill (1 mark)  DV: time taken to fall asleep (minutes) (1 mark)

2 marks

(b) Name the experimental design.  repeated measures (1 mark)

1 mark

(c) Explain the meaning of the term counterbalancing with reference to how it was used in this particular experiment. 2 marks  Explanation should demonstrate understanding that each group experienced both conditions but the order of treatment was different. Treatment for Group 1 involved active sleeping pill first and the placebo second, whereas for Group 2 the order was placebo first and active sleeping pill second. Award 1 or 2 marks. Do not award 2 marks for a generic explanation that does not refer to the particular experiment. (d) What was counterbalancing used to control in this experiment?  potential order effects of sleeping pill/placebo conditions (1 mark)

1 mark

(e) Identify the experimental and control groups, if any. 2 marks  Groups 1 and 2 are exposed to both the experimental (active pill) and control (placebo) conditions. Award 1 or 2 marks. (f) Explain the difference between a placebo effect and an experimenter effect in relation to this particular experiment. 2 marks  A placebo effect refers to any improvement in sleep-onset time due to the participants’ belief that the treatment to which they are exposed has been effective e.g. taking a ‘sleeping pill’ believed to have an active ingredient but which is actually fake. In this experiment, using a placebo helps determine whether participants’ responses are due to the treatment (active sleeping pill) or the placebo (fake pill) alone. (1 mark)  An experimenter effect occurs when there is a change in a participant’s response due to the researcher’s expectations, biases or actions, rather than to the effect of the independent variable. In this experiment, the research assistant is not privy to which group is receiving the pill first and cannot unduly influence participant responses. (1 mark) (g) Name and describe the procedure(s) used to control placebo and experimenter effects in this experiment. 2 marks

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double-blind procedure (1 mark) The participants did not know that they had been randomly allocated to either of two groups. The researcher’s assistant was also unaware of the group to which each participant had been allocated. (1 mark)

(h) What conclusion can be drawn from the results? 1 mark  Conclusion should demonstrate understanding of no difference given Group 2 results i.e. sleeping pill not effective in inducing sleep onset. (1 mark) (i)

Identify a relevant extraneous or confounding variable that may have affected the results of the experiment. 1 mark  Consider variables other than sleeping pill ingestion that can affect sleep-onset, particularly as the experiment is conducted in volunteer participants’ homes. (1 mark)

(j) Explain a way in which this variable may have been minimised or controlled in the experiment. 1 mark Award 1 mark for a valid explanation of the answer to question i above....