Words matter. Making subtle changes to a request can dramatically increase the likelihood of persuading others. Behavioural scientists have identified one word that has increased motivational power.

The word in question is BECAUSE. Psychologist Ellen Langer carried out a number of studies testing persuasion. Researchers asked people waiting in line to use a photocopier to let them skip the queue.

Study A

The researcher walked to the top of the queue and ask the person next in line ‘Excuse me, I have five pages. May I use the photocopier?

60% of people approached let the researcher skip ahead and use the machine.

Study B

The researcher changed the wording of the request slightly to include a reason. ‘May I use the photocopier, because I am in a rush?’  The number of people who complied jump to 94%.

This finding is not hugely surprising. After all the researcher gave a reasonable justification for the request.

Study C

In the third variation, the researcher also included the word because but tagged on a weak justification. ‘May I use the photocopier, because I need to make copies?’ Everybody else in line was there for the same reason.

Amazingly even without a valid excuse, 93% of the participants let the researcher skip ahead.


So why did it work?

The persuasive power of the word because comes from association. Typically ‘because’ is followed by a reasonable request or rationale. Sometimes in situations we use mental short cuts when deciding to behave. Simply hearing the word because is enough to suggest we are supporting a reasonable request.


Does it always make us more persuasive?

In each of the scenarios above  the researcher only wanted to make five copies. Maybe people agreed because it was a small request. After all five copies would not really increase the waiting time.

What if you had a large stack of pages to copy when you asked to jump ahead? Could because make a difference in this situation?

In a different set of experimental conditions, the researcher had 20 copies to make. The results

  • When the researcher asked without including because, 24% agreed.
  • When the researcher asked ‘May I use the photocopier, because I need to make copies?’ this did not increase the level of compliance at all.
  • However when the researcher used because and a valid justification ‘because I am in a hurry’, 50% more people agreed to the request.

When we make decisions that impact us more. we tend to fall back to mental shortcuts less. So if you are making a larger request, you need to tag on a good reason.

What does this tell us?

This research serves as a good reminder. If you want to persuade a person to do something they may not choose to do, include a good reason. This might sound obvious. But sometimes we assume others know why something needs to be done. It is implied in our request.

But remember how important it is to say it. Because it works.