Question 1

What is the difference between Affect and Effect?

Accepted Answer

In almost every sentence you'll write, affect is the verb (the act of changing something) and effect is the noun (the change that results). The exceptions are real but rare: 'effect' as a formal verb means to bring something about ('to effect change'), and 'affect' as a noun is a psychology term for outward emotion.

Question 2

How do I know if I mean Affect rather than Effect?

Accepted Answer

Readers who land here meaning Affect rather than Effect are usually searching for phrases like “affect or effect”, “is it affected or effected”, “the weather affected or effected my mood”.

Aspect	Affect	Effect
Usual part of speech	Verb	Noun
Means	To influence or change	A result or consequence
Example	'Lack of sleep affects my memory.'	'Lack of sleep has an effect on my memory.'
The rare use	Noun in psychology: visible emotion	Formal verb: to make happen ('effect a change')

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Affect

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