Of all the word pairs separated by a single vowel, this pair is the worst for native speakers and language learners alike. Between the two words, there are four different meanings: Affect is both a verb (to influence) and a noun (emotional expression), and effect is both a verb (to make happen) and a noun (impact).
- Ooh, I love those sound affects.
- Their son didn’t consider whether eating that much candy might effect him.
- It is time for us all to affect change in our own lives.
About 80 percent of the time, you can trust that affect is a verb. “Eating a lot of candy might affect you. It affected me greatly.” Similarly, effect is usually a noun. If you love a particular sound effect such as a cowbell, that effect is a single item — a noun (a cowbell, in this case). An effect is an impact: “Wow! That cowbell had quite the effect on the audience!”
MORE TO KNOW
In spite of the tempting rule that affect = verb and effect = noun, there are exceptions. Affect is also a noun, and effect is also a verb. Affect (noun) is used in psychology, and refers to emotional display. People with “flat affect” appear emotionless, even if they aren’t. To effect (verb) is to bring about or make happen. You, too, can effect change in your life.