The Organization of Behaviour Psychology 3106

Introduction Animals can do many things Forage Forage Defend Defend Look for mates, etc… Look for mates, etc… The Problem: When do you do what? Usually, only a single behaviour is done Usually, only a single behaviour is done Usually maladaptive to do two things at once Usually maladaptive to do two things at once Probably maladaptive to do things in the wrong order Probably maladaptive to do things in the wrong order

Introduction There must then be some sort of central control mechanism that determines when an animal does what and in what order. Good examples of control mechanisms can be found in many homeostatic systems

Thermoregulation Set Point EffectorsControlled Variable Feedback Gain: Vasoconstriction Shivering Loss Dilation Sweating panting Feedback mechanisms can be + or – or both

What about behaviour? Ya! OK, the Behaviour Systems approach says that there are different systems that serve different functions Feeding, mating, grooming etc Feeding, mating, grooming etc The system is put into action by releasing stimuli (environmental factors) and also by internal mechanisms The system is put into action by releasing stimuli (environmental factors) and also by internal mechanisms A classic approach to ethology

Examples Dust bathing in Burmese Red Junglefowl Ancestor of our KFC Ancestor of our KFC Function of the behaviour is to clean out oil from the feathers and to get rid of parasites. Some 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

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

Circadian Rhythms Most activities that animals engage in are temporally organized Dust bathing is just one of many examples Dust bathing is just one of many examples Circadian (from the Latin, about a day) Rhythms show up in not only most animals, but most living things Makes a lot of sense, as the environment changes on a rhythmic schedule

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

Conclusions Behaviour is controlled by internal mechanisms Behaviour is controlled by external mechanisms Behaviour is controlled by complex interactions of internal and external mechanisms