What are the 4 theories as to why

animals sleep in the Evolutionary theory?

(Initials: EC, FR, PA, WT)

Energy Conservation

Foraging Requirements

Predator Avoidance

Waste of Time

Describe the Energy Conservation Theory in 4 points

in the Evolutionary theory?

1/ Warm-blooded animals use a lot of energy in order to maintain a constant body temperature.

2/ Smaller animals with high metabolic rates therefore need to use a lot more energy and so sleep more.

3/ Sleep helps us conserve energy due to inactivity.

4/ Webb described this as the Hibernation Theory.

Name the Psychologist who described Energy Conservation as the Hibernation Theory?

(Initials: W)

Webb

Describe Foraging Requirements in the

Evolutionary Theory?

Some animals sleep less due to their need to look for food. Herbivores must spend more time eating as plants do not provide enough nutrients in small quantities. Therefore herbivores have less time to sleep whereas predators who eat high-nutrient meat can sleep more.

Describe Predator Avoidance in the

Evolutionary Theory?

Predators can sleep for longer whereas prey must remain vigilant in order to look out for possible predators hunting them.

Describe the Waste of Time hypothesis in the

Evolutionary Theory?

Meddis suggested sleep helps animals stay out of the way of predators at times of the day when they are most vulnerable such as in darkness.

Name the Psychologist who suggested the Waste of Time hypothesis in the Evolutionary Theory?

(Initials: M)

Meddis

Name 3 Psychologists (one repeated twice) who support the Evolutionary theory?

(Z&R, A&C, C, C)

Zepelin & Rechtschaffen

Allison & Cicchetti

Capellini et al.

Capellini et al.

Why do Zepelin and Rechtschaffen support the

Evolutionary Theory?

Found that smaller animals with higher metabolic rates, sleep more than larger animals - with the exception of sloths (who are large yet still sleep loads).

Why do Allison & Cicchetti support the 

Evolutionary Theory?

Found that species who were more likely to be hunted, sleep less in order to watch out for predators - with the exception of rabbits who sleep lots yet are at high risk.

Why does Capellini et  al. support Foraging Requirements in the Evolutionary Theory?

Argues that previous research was flawed as the methods were not standardised between species. Analysed data which was approved valid and found support for foraging requirements.

Why does Capellini et al. support Phylogenetic Signals in the Evolutionary Theory?

Found mammals who are genetically close, tend to have similar sleeping platterns. This means they have a strong phylogenetic signal.

Name a Psychologist who criticised the 

Evolutionary Theory and 2 flaws?

(C, E, CE)

Capellini et al.

Exceptions

Cannot explain

Why does Capellini et al. criticise the

Evolutionary Approach?

Found negative correlation between small animals with high metabolic rates and the duration of sleep they have. Contrasts with the energy conservation theory.

Why are 'Exceptions' a flaw in the

Evolutionary Approach?

Both Rabbits and Sloths are exceptions to the findings by Zepelin&Rechtschaffen and Allison&Cicchetti. Rabbits are at high risk yet sleep lots and sloths are large and have small metabolic rates, yet sleep lots.

What can the Evolutionary Theory

not explain?

Why we have such a strong drive for sleep when

we are sleep deprived.