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The physiological approach to motivation

Instinct theory

Physiological drives

The structure of the nervous systemHomeostatic drive theory

Temperature regulation

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Instinct Theory

Darwins theory ofevolution as set out in The Origin of

Species (Darwin, 1859)

We are born with instincts, which push us towards

certain forms of behaviour

The most basic of these behaviour is the instinct to

survive : this will prevail at all costs, without it we would

not survive

All behaviour can be seen therefore in the light of this

basic overriding concern: sex, eating, drinking, sleeping

etc

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Instinct Theory (a critical approach)

A very important and influential theory

Whilst instincts do help us to understand basic/early motivated

behaviours, they do not help us to understand the more complex

human activities, like art and culture

In order to understand these activities we need to develop moreinstincts than just those that are directly related to survival

A number of behaviours separate us from animals

We use in an offensive way phrases to suggest that our behaviour

as humans should be different from animals

We are anxious to separate our behaviour from animals behaviour:civilization is an attempt of this kind (Norbert Elias)

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We say

crying like a baby

Humans may be dominated by their instincts in their early

years, but these instincts are either socialised out of usor we are taught, as adults, to hide them better than

children are able to do

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How many instincts?

Try to create your own list of

Biological Instincts Psychological instincts

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Counting instincts

- William James (1890) first attempted to do this

- He tried to relate instincts directly to their evolutionary past studying his ownchildren

- He suggested that humans are more strongly influenced by instinctsbecause we are influenced by psychological as well as biological ones

- McDougall (1908) developed a list of 12 instincts (they were basic andmade little reference to specifically psychosocial motives so further listswere needed

- McClelland (1961) used the same kind of basic instincts but added furtherones that were related to certain needs e.g. the need for achievement andthe need of affiliation

- Lists of this short caused more problems than they solved. Under this vew,instincts doesnt explain motivated behaviour, as they have become littlemore then just meaningless labels

- However: around 15.000 instincts have been identified over the yearsandthere are probably as many that havent been labelled yet

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Physiological Drives

A possible biological alternative to the notion of instincts

A long history in psychology, not confined to purely biological

theories

As an explanation of the biological basis of behaviour, drives take us

into the cellular and neurochemical areas of physiology A drive is determined by certain tissue needs

It is satisfied through the activation of brain receptors leading to the

release of hormones

Hunger, thirst, temperature regulation and sex

Require an understanding of central and autonomic nervous systemoperations, which maintain normal functioning through homeostatic

regulation of the endocrine system

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The structure of the nervous system

Made up of billions of cells called neurons, which havethe ability to transmit electrical impulses. In this wayeach neuron is able to pass messages to and from thebrain

The brain and the spinal cord make up the centralnervous system (CNS), which is the master controlsystem for all actions and reactions in the body

It is connected to the rest of the body through theperipheral nervous system (PNS) , which consists of

nerves that extend from the spinal cord to all parts of thebody

Each nerve is made up of a collection ofneurons

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The brain contains a number of areas that are believed to

be directly responsible for certain forms of behaviour

The raphe nuclei and the reticular formation both

involved in arousal

The hypothalamus involved in homeostatic regulation The cerebral cortex controls higher cognitive

functioning

The limbic system involved in emotional control

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Autonomic Nervous System (ANS)

A branch of the PNS directly involved in the maintenance

of a stable internal statehomeostasis

Transmits information to the organs, glands and smoothmuscles involved in the regulation of the internal

environment of the body

Particularly important in the control of motivationalbehaviours, such as eating and drinking and emotional

behaviours such as fight or flight

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The 2 branches of ANS

The sympathetic and the para-sympathetic

Each keep a separate role but controls the functioning of

parts of the system to achieve stability

They are stimulated by sections of the brain They have a direct effect on all the major organs (e.g.

the heart will be made to beat faster in order to speed up

the supply of oxygen

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Endocrine System

Whilst the ANS involves a speedy an automatic messenger

system for homeostatic activity

The endocrine system is much slower Involves responses stimulated by messengers in the

blood streamhormones

The release of hormones is controlled by the

hypothalamus Hormones are released from various glands in the body,

through the activation of the pituitary gland

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These systems are basic for the

physiological explanation of motivated

behaviours related to instincts and drives,

which push the organism towards certainforms of behaviour in order to maintain

normal homeostatic functioning

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Homeostatic drive theory

Cannon (1929) first put forward the idea thathomeostatic drives (the need to maintain a constant levelof physiological functioning) determine our behaviour

In order to function normally our bodies have certain

physiological needs that must be fulfilled: food, drink,sleep, warmth, shelter etc

When these needs have not been satisfied, physiologicalmechanisms are activated and motivate us to restorebalance

The bodys tendency to maintain a state of balance iscalled homeostasis (like a kind of thermostat in a centralheating system)

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Homeostatic drive theory

It is a regulatory process: involves responses that occurdue to changes in the internal/external environment

Some of these responses are automatic they do notrequire us to do anything in order to restore balance e.g.

when temperature rises, sweating will occur as a normalreaction of the ANS

Some changes require behavioural responses e.g. whentemperature drops we might rub our hands together tokeep warm

Other times is about both automatic and behaviouralresponses e.g. removing an item of clothing andsweating

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Basic features of homeostasis

A set point identifies the ideal range for each component

of the homeostatic mechanism

Each component has to have a detectorto monitor the

set-point maintenance

A correctional mechanism make alterations when the

detectors register a significant deviation from the set

point

The prospective element in homeostasis help all animals

to anticipate future changes that are likely to occur

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Temperature Regulation

Set point : we must try and maintain our core body

temperature at a relatively constant 37o C

Detector: Hypothalamus is involved in homeostasis and

its area that is responsible for this detection is the

preoptic area

Control mechanism: if the preoptic area becomes cold, it

stimulates the sympathetic branch of the ANS that

stimulates the blood vessels to constrict and prevent the

flow of warm blood to the surface of the ski where itwould be cooled.