These two words are often confused, just because they look so similar. They are related, but they are also quite distinct.
The first thing to notice is that affect is generally a verb, and effect is generally a noun. There is a noun affect (pronounced with the stress on the first syllable) but it is formal and rather infrequent; it refers to an emotion that changes what you do or think. The verb effect, pronounced the same as the noun, is also formal and means ‘to bring about’.
So the first way to distinguish between these two words is to see whether the one you are looking at is a verb or a noun. If it’s a verb, it almost certainly means ‘to change or influence something’. If it’s a noun, it probably means ‘a change produced in one person or thing by another’. You can see from this what the semantic link between the two words is: if something affects something else, it has an effect on it.
Here are some examples of affect and effect used in context:
Did the newspapers really affect the outcome of the election?
The disease affects (=has a bad effect on) many different organs of the body.
She had been deeply affected by her parents’ divorce.
Scientists are studying the chemical’s effect on the environment.
Any change in lifestyle will have an effect on your health.
East German companies were suffering the adverse effects of economic union.
In each of these example sentences, it is possible to replace the verb affect with a structure containing the noun effect and vice versa:
Did the newspapers really have an effect on the election?
Any change in lifestyle will affect your health. |