Section 6 : Biopsychology - Biological Rhythms

Question 1

what are the three types biological rhythms

Answer 1

• Circadian Rhythms
• Infradian Rhythms
• Ultradian Rhythms

Question 2

what are circadian rhythms

Answer 2

cycles that generally occur once every 24 hours e.g. sleep wake

Question 3

what are infradian rhythms

Answer 3

cycles that occur less than once a day e.g. menstrual cycle

Question 4

what are ultradian rhythms

Answer 4

cycles that occur more than once every 24 hours e.g. in the sleep cycle we have several repeating stages of light and deep sleep

Question 5

what did sabbagh and barnard 1984 find

Answer 5

when women live together their menstrual cycle may synchronise, not clear why but could be due to pheromones

Question 6

how are the timings of these biological rhythms determined

Answer 6

by factors inside and outside our bodies

Question 7

what is the SCN

Answer 7

the suprachiasmatic nucleus, in the hypothalamus which acts as an internal clock to keep the body on a 24hr sleep wake cycle

Question 8

what are endogenous pacemakers

Answer 8

biological structures and mechanisms that set the rhythms within the body such as the SCN in the hypothalamus

Question 9

what is the SCN sensitive to

Answer 9

the SCN is sensitive to light and regulates the pineal gland which secretes melatonin. when there is less light more melatonin is produced and the other way around.

Question 10

what are exogenous zeitgebers

Answer 10

influences outside the body that act like a prompt why may trigger a biological rhythm

Question 11

what is the most important zeitgeber

Answer 11

light

Question 12

what was siffre 1975

Answer 12

michel siffre spent six months in a cave. no clocks or natural light as zeitgebers. as a result his sleep wake cycle extended from 24hrs to a 25-30hr cycle. therefore seemed that natural light is needed to fine tune our normal 24hr cycle

Question 13

what did penegelly and fisher find

Answer 13

that squirrels will hibernate even when kept in a lab conditions very different from their natural environment. this shows that in some cases endogenous factors may completely determine a cycle

Question 14

what other factors can affect biological rhythms

Answer 14

• cultural factors e.g. Eskimos live in permanent night or day time and can maintain regular sleep cycles
• individual factors e.g. Aschoff and Wever found that some ppl isolated from daylight maintained daily sleep cycles but other members displaye their own extreme idiosyncrasies

Question 15

what happens if u disrupt biological rhythms

Answer 15

negative effects e.g. slower reaction time, impairing problem solving skills, limiting ability to concentrate. changes such as light levels in winter and summer dont negative effects tho

Question 16

Does jet lag have an effect in biological rhythms

Answer 16

Yes, you would be out of sync with the local timing as you would be waking up and falling asleep earlier.

Question 17

What did Wegman et al find

Answer 17

That travelling east to west seems easier to adapt than travelling west to east

Question 18

What did Schwartz et al find

Answer 18

Found that baseball teams from the east coast of USA got better results travelling to play in the west teams than teams based in the west when travelling to play in the east

Question 19

Did shift work disrupt people’s sleep cycle

Answer 19

Yes

Question 20

What was Czeisler et al 1982

Answer 20

• studied factory workers who shift patterns appeared to cause sleep and health problems
• the researchers recommended 21-day shifts (allowing more time for workers to adapt) and changing shifts forwards in time (phase delay).
• after implementing the changes productivity and job satisfaction increased

Question 21

What are the limitations of research on biological rhythms

Answer 21

• findings from animal studies can’t accurately be generalised (humans have greater adaptability)
• studies of deprived humans of natural light allowed artificial light; reduces validity of studies as the artificial light can give benefits of the natural light
• studies into individual differences need further studies
• if we understand what causes problems linked to jet lag and shift work we can minimise and avoid work place accidents.

Question 22

Why does there need to be more research into individual differences in the affect of rhythms

Answer 22

Some people are more alert early in the day and other later on, and the speed with which we adapt to disruption vary. It’s difficult to determine whether a person’s lifestyle is a cause or effect of their biological rhythms