It's a very good joke, but I'm afraid you're both wrong . Having "cause" in there is irrelevant:

What part of the brain is affected by cannibalism?
The tasty part.

Which part of the brain is responsible for cannibal jokes? The part that tastes funny.

Why do cannibals laugh during dinner?

Someone always has a gag

Firemen arrive in the nick of time as guy fawkes up bonfire.

Wowcher has 80% off.

The Prophet Muhammad and three disabled children walk into a bar

And the barman says "Woah I don't want anything to do with this joke!"

If Ched Evans returns to football one wonders how the commentators will feel when they have to say 'and its Evans coming in from behind' ...

And Evans managed to squeeze one in in the box.

What do you call short rubbish jokes? Bin liners.

My girlfriend got sick of me taking the piss out of her.

So I bought her a catheter.

What's the difference between virgin olive oil and regular olive oil?

Popeye's knob

thats pretty good

What is a golfers favourite festive staple?

Christmas Putting

That's a cracker.

I had a one night stand with a girl who works at Kwik Fit. She serviced me all night and I woke up tyred and exhausted.