Affective relates to emotions and feelings, as in affective disorders. Effective means producing the intended result, as in an effective treatment. The two are easy to confuse because they look alike, but affective is about affecting the emotions, while effective is about actually working.
The core difference
Affective concerns emotions; effective concerns results.
- affective — relating to or influenced by the emotions: the study looked at the affective response to sad music.
- effective — producing the intended result: the new medication proved effective against the infection.
- effective — also means officially in force: the new rules are effective from next Monday.
How to tell them apart
Affective traces back to Latin afficere, to affect or influence, which is why the word stayed close to feelings and mood: psychology and medicine use it for anything to do with emotion, such as an affective disorder. Effective has a different history, coming through French effectif from Latin efficere, to bring about or accomplish, which is why it is the word for results, from effective marketing to an effective date.
A quick check: if you could swap in the word emotional without changing the meaning, affective is correct. If you could swap in successful or in force, reach for effective instead.
