Tell it apart
| 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') |
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.
What it doesn't mean
It is, just a formal one: to effect something is to make it happen. 'The new manager effected real change' means she brought change about, not that she influenced it.
What it really means
Affect and effect sound almost the same, sit in the same kinds of sentences and come from related Latin roots, so it's no surprise they get swapped. The working rule is short: affect is the verb, effect is the noun. Something affects you; it has an effect on you.
The rule bends in two places, which is where careful writers get caught. First, effect can be a verb, but only in the formal sense of bringing something about. "The minister effected reforms" means she made the reforms happen; "the minister affected reforms" would mean she influenced reforms that already existed. Second, affect can be a noun, but almost only in psychology, where it names the emotion a person shows on the outside.
There's also an older, quieter verb sense of affect: to put on a feeling or style you don't really have, as in "he affected a bored tone". That sense gives us the adjective affected, for someone whose manner seems staged.
Memory trick. A comes before E in the alphabet, and the cause comes before the result. Affect is the action that comes first; effect is the end result that follows. If you can put an or the in front of the word, you're holding the result, so write effect.
In real life
- Right: The rail strike affected thousands of commuters. (verb: it changed their day)
- Right: The rail strike had a huge effect on commuters. (noun: the result)
- Wrong: The new rules will effect everyone. (Use 'affect' unless you mean the rules will bring everyone into being.)
Questions
Q01What is the difference between affect and effect?
Affect is usually a verb meaning to influence or change something ('the noise affected my sleep'). Effect is usually a noun meaning the result ('the noise had an effect on my sleep'). If you can put 'an' or 'the' in front of it, you almost always want effect.
Q02Is it 'affected' or 'effected'?
Nearly always affected: 'Thousands were affected by the flooding.' Effected is correct only when you mean 'brought about': 'The treaty effected a ceasefire.'
Q03Can affect be a noun?
Yes, in psychology, where affect means a person's observable emotional response; a 'flat affect' is a face that shows little feeling. Outside that technical use, the noun you want is effect.
Q04What else can affect mean?
In formal English it can mean to put on a manner or feeling you don't really have: 'She affected indifference.' That's where the word 'affected' (meaning showy or unnatural) comes from.
Sources
- Affect or effect? — Cambridge Dictionary, English Grammar Today.
- effect (verb), with the affect / effect usage note — Oxford Learner's Dictionaries.
- affect (verb), including the 'pretend' sense — Cambridge Dictionary.
- Affect vs. Effect — Dictionary.com.