The English words affect and effect are often confused by native speakers – don’t let their mistakes affect your English.
Affect is a verb with several different meanings.
1. To have an influence on, contribute to a change in
What you do affects all of us
This decision will affect the outcome of the elections
Inflation is affected by natural disasters
2. To touch, move; to act on the emotions of
I was profoundly affected by this movie
His actions were not affected by her pleas
3. To simulate
He likes to affect a British accent
She always affected her eccentricity
In psychology, affect is a noun which refers to a "feeling" or "emotion":
Your son’s lack of affect explains why you find it difficult to gauge his moods.
Effect is most commonly used as a noun, and has three meanings.
1. Result, something brought about by someone or something
What was the effect of her decision?
Side effects include nausea and fatigue
I don’t think it will have any effect on the outcome
The law will go into effect tomorrow
You can clearly see the cause and effect
2. Something that gives the impression/sense of something else
The special effects were amazing
Mirrors will give the effect of a larger space
He said that just for effect
3. Effects can refer to belongings
Did you bring any personal effects
As a verb, to effect means "to bring about, lead to a result"
The only way to effect change is to participate
What is the best way to effect these improvements?
This should effect a whole new way of thinking about it
The Bottom Line
The confusion between affect and effect comes out of the fact that affecting something leads to an effect. The two questions "How were you affected?" and "What was the effect on you?" mean almost exactly the same thing.
When you want to use one of these words as a noun, the one you want is probably effect. When you want a verb, most of the time you want affect. Effect is used as a verb only when it has a direct object and only when you mean "to bring about, lead to."
The difference between to affect and to effect can be seen here:
To affect the results – To influence, have an impact on the results
To effect the results – To bring about, lead to the (desired) results