Everything for the Psychology lesson on Monday

Question 1

Who is Burgess et al (2003) and what were his findings on jetlag? (EXO)

Answer 1

Found that exposure to bright light prior to an east-west flight decreased the time needed to readjust to local time on arrival.

3 treatment conditions:

1. Continuous bright light-circadian rhythm sifted back 2hrs earlier and woke 2hrs earlier
2. irregular bright light- shifted their rhythms by 1.5hrs
3. Dim light -0.6hrs shift in rhythm

Question 2

What is the name of the External factor that controls the sleep-wake cycle and what is its role?

Answer 2

Exogenous zeitgebers and ‘Time-givers’ are external causes and entrain biological rhythms.

Question 3

What is light responsible for?

Answer 3

For resetting the body clock each day keeping it on a 24-hour cycle. (Entrainment)

Question 4

If we need light to activate our sleep-wake cycle, how can blind people know when to sleep and wake naturally?

Answer 4

Blind people have no visual perception but the connections still exist between the eye and the SCN that do not involve those part of the visual system on which the perception of light depends.

Question 5

What does Micheal Siffre’s research indicate?

Answer 5

That in absence of environmental zeitgebers our endogenous pacemakers can still regulate biological rhythms, although regulation is not perfect.

Question 6

What were Burgess et al’s 3 treatment conditions in his jet lag study? (EXO)

Answer 6

1. Continuous bright light-circadian rhythm sifted back 2hrs earlier and woke 2hrs earlier
2. irregular bright light- shifted their rhythms by 1.5hrs
3. Dim light -0.6hrs shift in rhythm

Question 7

What does Burgess’s study show? (EXO)

Answer 7

That exposure to bright like prior to air travel may help travellers adjust to local daylight conditions more easily. Exogenous zeitgbers are necessary.

Question 8

What is the procedure and findings of Decoursey et al?

Answer 8

• Destroyed the SCN connections in the brains of 30
  chipmunks
• The chipmunks were returned to their natural habitats and observed for 80 days
  Findings:
• Found that the SWC of the chipmunks disappeared and by the end of the study a significant proportion of them were killed by predators.

Question 9

What is the procedure and findings of Ralph et al?

Answer 9

• Bred ‘mutant’ hamsters with a 20-hour SWC
• The SCN cells from the foetal tissue of mutant hamsters were transplanted into the brains of normal hamsters, the cycle of the second ground defaulted to 20 hours.

Question 10

What do Decoursey et al and Ralph et al’s studies demonstrate?

Answer 10

Emphasise the role of the SCN in establishing and maintaining the circadian SWC

Question 11

Who is Aschoff & Wever (1976)?

Answer 11

• P’s spent 4 weeks in a WWII bunker without natural light
• 1 Participant SWC extended to 29 hours however everyone reminded between 24-25 hours. (Suggests that the SN is the biological factor that dictates your cycle)

Question 12

What does Aschoff& Weber’s study suggest?

Answer 12

This suggests that the natural sleep-wake cycle may be slightly longer than 24hrs which makes sense as the length of the day is not exactly 24hrs - depending on the time of year.

Question 13

What does research for artificial light show?

Answer 13

Research shows that artificial light (Especially SW blue light from the screen can keep people awake)

Question 14

What did Czeisler et al (1999) research show about artificial light?

Answer 14

Found that they could adjust p’s circadian rhythm using dim lighting.

Question 15

Why would the use of artificial light be a limitation of these studies?

Answer 15

Social cues would enable people to copy each other.

Question 16

What is a practical application to work?

Answer 16

Research on the sleep-wake cycle has informed people about the negative impacts of shift work, especially night shifts eg reduced concentration at night, HD due to disrupted sleep patterns.

Question 17

What is a practical application to drug treatment?

Answer 17

The pharmaceutical industry can use knowledge of circadian rhythms to decide when the best times for drug absorption is i.e. when digestion is best or when the drug is likely to be the most effective.

Question 18

What is a limitation in research of the sleep-wake cycle?

Answer 18

Research has shown that SWC typically uses small sample sizes which may not be representative of the wider population which is an issue of generalizability.

Question 19

What are the individual differences due to this research of the sleep-wake cycle?

Answer 19

• Not everyone goes to sleep and wakes up at the same time (e.g. early risers, night owls; Duffy et al)
• Both Siffre and Czeisler’s research showed significant variations in peoples circadian rhythms (between 13 and 65 hours in some cases)

Question 20

What did Duffy et al (2001) find?

Answer 20

Duffy et al. (2001) found that ‘morning people’ prefer to rise and go to be early 9about 6 am and 10 pm) whereas ‘evening people’ prefer to wake and go to bed later (10 am and 1 am)

Question 21

What does Duffy et al. (2001)’s study demonstrate?

Answer 21

That there may be innate (key factors) individual differences on the circadian rhythms, which suggests that research should focus on these differences during investigations