The Organization of The Organization of BehaviourBehaviour

Psychology 3106Psychology 3106

IntroductionIntroduction

Animals can do many thingsAnimals can do many things ForageForage DefendDefend Look for mates, etc…Look for mates, etc…

The Problem: When do you do what?The Problem: When do you do what? Usually, only a single behaviour is doneUsually, only a single behaviour is done Usually maladaptive to do two things at onceUsually maladaptive to do two things at once Probably maladaptive to do things in the Probably maladaptive to do things in the

wrong orderwrong order

IntroductionIntroduction

There must then be some sort of central There must then be some sort of central control mechanism that determines when control mechanism that determines when an animal does what and in what order.an animal does what and in what order.

Good examples of control mechanisms Good examples of control mechanisms can be found in many homeostatic can be found in many homeostatic systemssystems

ThermoregulationThermoregulation

Set

PointEffectors Controlled

Variable

FeedbackGain:

Vasoconstriction

Shivering

Loss

Dilation

Sweating

panting

Feedback mechanisms can be + or – or both

What about behaviour?What about behaviour?

Ya!Ya!OK, the Behaviour Systems approach OK, the Behaviour Systems approach says that there are different systems that says that there are different systems that serve different functionsserve different functions Feeding, mating, grooming etcFeeding, mating, grooming etc The system is put into action by releasing The system is put into action by releasing

stimuli (environmental factors) and also by stimuli (environmental factors) and also by internal mechanismsinternal mechanisms

A classic approach to ethologyA classic approach to ethology

ExamplesExamples

Dust bathing in Burmese Red JunglefowlDust bathing in Burmese Red Junglefowl Ancestor of our KFCAncestor of our KFC

Function of the behaviour is to clean out Function of the behaviour is to clean out oil from the feathers and to get rid of oil from the feathers and to get rid of parasites.parasites.

Some birds bathe in water, others in dustSome birds bathe in water, others in dust

Animal starts out by fluffing up some dust

Next is a bill scratch, which gets the dust up onto the neck

Lots of scratching goes on to work up a bit of a cloud really

DustbathingDustbathing

This is actually pretty This is actually pretty complex beahaviourcomplex beahaviourVestergaard, Hogan Vestergaard, Hogan and Krujt (1990) and Krujt (1990) found that junglefowl found that junglefowl don’t need dust!don’t need dust!Hogan and Van Boxel Hogan and Van Boxel (1993) found that (1993) found that dustbathing was dustbathing was already rhythmic at 14 already rhythmic at 14 days post hatchdays post hatch

Circadian RhythmsCircadian Rhythms

Most activities that animals engage in are Most activities that animals engage in are temporally organizedtemporally organized Dust bathing is just one of many examplesDust bathing is just one of many examples

Circadian (from the Latin, about a day) Circadian (from the Latin, about a day) Rhythms show up in not only most Rhythms show up in not only most animals, but most living thingsanimals, but most living things

Makes a lot of sense, as the environment Makes a lot of sense, as the environment changes on a rhythmic schedulechanges on a rhythmic schedule

You can tell that these crickets’ chirping is a You can tell that these crickets’ chirping is a circadian rhythm, it will run free in constant circadian rhythm, it will run free in constant conditions, then it will become entrained to lightconditions, then it will become entrained to light

ConclusionsConclusions

Behaviour is controlled by internal Behaviour is controlled by internal mechanismsmechanisms

Behaviour is controlled by external Behaviour is controlled by external mechanismsmechanisms

Behaviour is controlled by complex Behaviour is controlled by complex interactions of internal and external interactions of internal and external mechanismsmechanisms