Affect Meaning: To Influence, to Pretend, and a Shown Emotion

Affect meaning: the three senses

1. To influence, to have an impact on. "Higher fuel costs affect almost every business." The thing affected may be a person, a result, a mood or a body part ("a disease that affects the lungs").
2. To move someone emotionally. "The speech deeply affected the audience." Here the impact is on feelings. The adjective affecting means touching, much like poignant.
3. To pretend, to put on. "He affected a calm he did not feel." Someone who affects an accent or a habit is adopting it for show. The noun is affectation, and an affected manner is one that seems false.

The fourth sense is the noun. In psychology and medicine, affect (stressed AF-ekt) is the emotion a person shows through face, voice and body. A doctor might note "flat affect" when a patient shows little emotional expression.

Affect vs effect: the simple rule

For most writing, this works: affect is the action, effect is the result. You affect something, and that produces an effect.

Two memory tricks: A for action (affect) and E for end result (effect). Also, if you can put the or an in front, you almost always want effect: "the effect", "an effect".

Watch the rare verb effect. "The policy will affect change" means it will influence some change that is already happening. "The policy will effect change" means it will cause the change. Most writers mean the second.

Example sentences

• The power cut affected every shop on our street for most of the evening.
• Does the weather affect your mood as much as it affects mine?
• Only two of the forty students were affected by the exam timetable mistake.
• She affected surprise at the party, though she had planned it herself.
• The nurse noted that the patient's affect was flat during the interview.

Grammar notes and word forms

• Transitive verb. You affect something directly, without a linking word: "It affects us", not "It affects on us". (The noun effect is the one that takes on: "an effect on us".)
• Affected can mean influenced ("affected areas after the flood"), emotionally moved, or fake ("an affected laugh").
• Affective means to do with emotions, as in affective disorders in medicine. Do not confuse it with effective, which means working well.
• Common pairings: directly affect, badly affect, adversely affect, seriously affect, be affected by.

Where affect comes from

Both meanings of the verb go back to Latin. Afficere, "to do something to, to act on", gave English the influence sense through its past participle affectus. The pretend sense came by way of the related Latin affectare, "to aim at, to strive after", which also meant to pursue a manner or look. The psychology noun was taken from the older sense of affect as "feeling, emotion". Effect, by contrast, comes from Latin efficere, "to bring about, to complete", with ex- (out) instead of ad-.

So the spelling difference reflects a real difference in meaning: acting on something versus working something out to its result.

Close words and when to choose them

Affect is neutral and works almost everywhere, but other words can be more precise:

• Influence: a gradual or indirect effect, "Her coach influenced her career."
• Impact: a strong effect; as a verb it is common in business writing, "The delay impacted sales." Some editors prefer affected here.
• Alter / change: when you mean the thing is different afterwards.
• Move / touch: for emotional effect.
• Feign: for the pretend sense.

Other word pairs that look alike and cause the same headache include principal and principle and whether and weather. For more, see everyday vocabulary.