Overview
A stimulus is any change in an organism’s environment that causes to the organism to react. It is a fancy way of saying ‘cause’.
A response is how the organism reacts to a stimulus and results in a change in behaviour. It is a fancy way of saying ‘effect’.
Plants also respond to their environment. They are called tropisms.
Example:
You are hungry, so you eat some food.
Stimulus: You are hungry Response: So you eat some food.
External Stimuli and Internal Stimuli
Internal stimulus
An external stimulus is a stimulus that comes from outside an organism.
Example:
- You feel cold so you put on a jacket.
- A snake lunges at a rabbit so it runs away.
External stimulus
An external stimulus is a stimulus that comes from inside an organism.
Example:
- You feel hungry so you eat some food.
- A cat feels thirsty so it drinks water.
Responding to stimuli
Animals can respond to stimuli in two ways:
- In a way that they learned. We call this learned behaviour.
- In a way that they were just born knowing how to do. We call this instinct.
Learned behaviour
Learned behaviour is a response to a stimulus that an animal was taught.
Example:
- Chimps and monkeys learning to use tools
- Bear teaching her cubs to fish