Are you affected by someone's behaviour? Or is the behaviour effecting a response? So, but like, what's the overall effect of it all? Here Helen breaks down the mystery of the affect vs effect conundrum.
There's a lot about English 'rules' that I can let go of. But when it makes the meaning actually unclear? That's when I start getting my red pen out. Affect vs effect is one of those ambiguity-creating conundrums.
Affect and effect can be a verb or a noun in your sentence.
If it’s a noun in your sentence, you’ll almost certainly need 'effect'. (The only exception is when you're a psychiatrist talking about a patient's symptoms).
So that bits easy – it's 'a rainbow effect', and 'an effect of the light'.
If it’s a verb things get murkier. What is correct comes down to what you need to say. So remember this. If you mean 'accomplish', use 'effect'. If you mean 'influence', use 'affect'.
Sometimes you might even seen a sneaky adjective form of effect and affect, and the same rules apply. If the speech was effective it accomplished something. If it was affecting it was influential.