—>General rule is that affect is a verb (a word that relays an action) and effect is a noun (a person, place, or thing). However there are uncommon, yet specific instances in which affect is a noun and effect is a verb.
—>Affect as a verb means ‘to influence’ or ‘to change.’
Examples: Her words affected him. She affects him with her words.
—>Effect as a noun means ‘an influence,’ ‘a change,’ or ‘a result.’
Examples: The effect of her words was powerful. His days in the military had a lasting effect.
—>When affect is used as a noun, it means ‘a person’s emotional response’ and is typically only used in regards to psychology.
Examples: Her affect told the doctor that the topic was upsetting. When the man raised his voice, her affect was withdrawn and fearful.
—>When effect is used as a verb, it means ‘to cause’ or ‘to bring about’ and is rarely used except in relation to business or procedure.
Example: The new protocol effected a rise in boycotts.
—>The exceptions may make this seem terribly confusing, but it’s actually fairly simple. Let me show you. Going by the rule that affect is a verb and effect is a noun, you’d assume it would be:
Her effect told the doctor that that the topic was upsetting..
The new protocol affected a rise in boycotts.
—>However in this first sentence, it is not an effect (an influence, change, or result); it is her emotional response- her affect. In the second sentence, the protocol didn’t affect (influence or change) the rise, it effected (caused) the rise. Effect as a verb is a more subtle difference. Remember that something which did not exist before cannot be affected (influenced or changed); it can merely be effected (brought about). When in doubt, replace effect with influence, change, or result; and affect with influenced or changed to see if it still makes sense:
Her influence told the doctor that the topic was upsetting.
Her change told the doctor that the topic was upsetting.
Her result told the doctor that the topic was upsetting.
The new protocol influenced a rise in boycotts.
The new protocol changed a rise in boycotts.
—>Doesn’t sound quite right, does it? That’s how you know you’re using the wrong word.