Functions of sleep

Question 1

what are the 5 topics for the ecological theory?

Answer 1

predator avoidance and waste of time, energy conservation, foraging for food, unilateral sleep, phylogenetic scale

Question 2

whats predator avoidance?

Answer 2

suggests that predators can afford to sleep longer, however prey must stay vigilant to avoid risk of predators

Question 3

Whats the waste of time hypothesis?

Answer 3

Meddis (1975) suggested prey sleep to avoid predators when they have nothing better to do. by sleeping in a safe place they have a better chance of survival

Question 4

whats the evidence for predator avoidance/waste of time hypothesis?

Answer 4

Allison (1976) found usually the more predators an animal has the less it sleeps. however there are some exceptions for example rabbits sleep as much as moles, this could be supporting the waste of time hypothesis.

Question 5

what is the energy conservation explanation and who proposed it?

Answer 5

Webb (1982) - warm blooded animals need energy to maintain a consistent body temp, energy conservation is important. however small animals sleep more as activities require more activity due to their high metabolic rates. sleep acts as a period of enforced inactivity (hibernation theory)

Question 6

whats the evidence for the conservation of energy explanation?

Answer 6

Zeplin (1974) found smaller animals (eg bats - 20hrs) sleep longer than larger animals (e.g. elephants - 4hrs). however sloths sleep for 20 hours a day and so this theory is ungeneralisable

Question 7

whats the argument against the energy conservation explanation?

Answer 7

energy conservation is only 5-10% higher during sleep compared to during rest. therefore other factors must be benefited from sleep as well.

Question 8

what is the foraging for food explanation?

Answer 8

herbivores need to spend longer eating (e.g. sheep) than carnivores (e.g. cats)

Question 9

whats the opposing research to the foraging for food explanation?

Answer 9

Capellini et al (2008) studied mammals using standardised procedures and found a negative correlation between metabolic rate and sleep which doesn’t support this theory. they also found sleep could depend on environmental factors, e.g. location of the animal; making this theory reductionist.

Question 10

whats a limitation to the forraging for food explanation?

Answer 10

it cant be applied to humans e.g. vegetarians

Question 11

whats the study for the phylogenetic scale?

Answer 11

Capellini et al (2008) mammals genetically close to each other have similar sleeping patterns than expected by chance.

Question 12

whats unilateral sleep?

Answer 12

a sleep adaptation where one hemisphere in the brain is asleep whilst the other is awake. e.g. dolphins

Question 13

Restoration: what are the effects of slow wave sleep?

Answer 13

growth hormones, the immune system

Question 14

Restoration: whats the effects of REM sleep?

Answer 14

brain growth, neurotransmitters, memory

Question 15

Restoration: whats the study for growth hormones?

Answer 15

Cauter (1996) found GH corrloate with SWS

Question 16

Restoration: whats the study for brain growth?

Answer 16

Seigel (2003) relationship between REM and maturity. eg patypus 8hrs REM, dolphins have none.

Question 17

Restoration: whats the study for memory?

Answer 17

Stickgold (2005) found sleep is used to consolidate memories.
REM = procedural
SWS = semantic

Question 18

Restoration: whats the study for micro sleep?

Answer 18

Williams (1959) found after 72 hours people have microsleep whilst appearing awake. EEG recordings show this is the same as normal sleep.

Question 19

Restoration: what are the 2 case studies for sleep deprivation?

Answer 19

DJ Tripp (201 hours)
Randy Gardner (260 hours)

Question 20

Restoration: who used a non-human study?

Answer 20

Rechtshaffen et al (1983) forced rats to stay awake, after 33 days they all died

Question 21

Restoration: who studied REM deprivation?

Answer 21

Empson (2002) in recovery they increase REM up to 50%

Question 22

Restoration: whats the study for exercise and sleep?

Answer 22

Shapiro et al (1981) found marathon runners sleep for 1 hour more after a race. particularly SWS