The word is 'because' (and the submission title linkbait).

>If you read the entire paper, she basically obliterates the notion that humans behave rationally. Through a series of experiments, she proves that whenever a “because” is appended to a request...

The blog author does not understand the paper. The paper argues people comply because a reason is given. Not because they used the word "because". The paper does not "prove" that the word 'because' is any more special than providing a reason, or using a synonym in general, such as 'since'.

Also saying the paper "proves" something is a misunderstanding of these papers & science in general. The experiments only provide support for a hypothesis, they don't prove it.