A-level Biology/Mammalian Physiology and Behavior/Behavior

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Behaviour[edit]

Behaviour is everything an animal does, and is influenced by both nature (genes) and nurture (envrionment).

Innate[edit]

Innate (instinctive) behaviour is defined as inherited, pre-set behaviour that doesn't require learning or practice.

Genes[edit]

You'll remember the concept of alleles being selected for in a population as part of natural selection - the same is true for alleles for evolutionary-advantageous behaviour, and so the behaviour becomes more common. However, a lot of behaviour we used to consider completely innate we are now not so sure about - an animal's genes produce the basic structure of its body, and the behaviour it shows is an interaction between these features and the environment that the animal has developed in.

Reflexes[edit]

Reflexes are rapid, automatic responses to stumulus, such as pulling your hand away when you touch something hot - the signals are not passed to the brain before we act, as to speed up our reaction. Removing your hand from something hot, or ducking when you see something flying toward you are examples of innate reflexes. We can also develop condition reflexes, as shown by Pavlov's dogs for example.

Experience[edit]

Innate behaviour can be influenced by experience, for example in birds that feed their young by fetching food for them and putting it in their beaks. To begin with the chicks just open and close their beaks but after a few days they learn how to twist their heads in order to grab the parent's beak to get at the food quicker - the basis is innate, but the refinement is learning.

The Nature of Learning[edit]

Learning is a change in behaviour as the result of experience, and you are required to know three case studies on learning performed in the last century.

Skinner[edit]

B.F. Skinner became well known for studying operant conditioning with the use of his 'Skinner box', which isn't as dangerous as it sounds. It is a cage in which an animal is placed, and inside the cage there is a lever that can be depressed that will produce a reward. At first, the animal wanders around looking for a way out, but by accident hits the lever and food appears. After a few times of doing this, the animal begins to purposefully press the lever, and this shows that the animal has learned to associate the behaviour with the reward.

Pavlov[edit]

Ivan Pavlov worked on classical conditioning, with dogs as the subject of his experiments. Pavlov measured the salivation of dogs when meat powder was puffed into their mouths, and then began to introduce some other stimulus right before the food - a bell. The bell was rung, and the food was given, and after several occurrences of this the dog began to salivate upoun just hearing the bell - classical conditioning.

Initially the dog had a reflex, producing saliva in response to food, an unconditioned stimulus, but the sound of the bell that was associated with the food is known as the conditioned stimulus. The response, combined with the stimulus is known as a conditioned reflex.

Advantages[edit]

The adapative value of conditioning can be valuable indeed - the animal learns to change it's behaviour based on a reinforcer, a reward or a negative event that tells it to do or not to do the action. This can be seen for example with animals who might try and eat a wasp, and be stung. The yellow and black colours of a wasp will in the future cause the animal to back off since it has learned that it will be hurt if it does try to eat the wasp.

Kohler[edit]

Kohler worked on more complex types of learning than simple association, known as insight learning. He studied primates, chimpanzees. A chimp with a stick inside it's cage and a banana outside of the cage quickly learned to use the stick to reach the banana to eat it - a reward. Once this had been learnt, the chimp was given two sticks that fit together end to end, and the banana was placed such that it would require both sticks to reach it. The chimp attempted to reach it with just the one but could not, and quickly gave up.

The chimp then began to play with the sticks, and during this realised that he could fit the two sticks together, and immediately rushed back to the banana and retrieved it with the extended stick. This is known as insight learning - applying one situation to another, since the chimp was not doing something directly related to food but connected it to food.