Are people motivated more by fear or reward?



Fear.

Here's a prime example. Let's say you have 15 days to come up with your rent money. You're going to bust your ass.

On the inverse, let's say you're sitting on $10,000 in the bank. You're not going to worry about paying bills, so you're not going to be as motivated.
 
On the flip side it's also easy to motivate people with fear, ie. which of the following is more effective - (a) telling someone you'll kill his sister if he doesn't do what you say, or (b) telling someone you'll give him a million dollars if he DOES do what you say? In most cases, the first example would motivate him a whole lot more, regardless of how "good" the second example's reward is.

I've split tested using fear vs. reward and so far fear is much more effective. Many times with fear, you don't need as much credibility as you would with reward.

In that example, if a random stranger said they'd give you $100 or $1M, you wouldn't believe the person. If they said they were going to kill/hurt a family member of yours, they don't need credibility because the risk goes straight to your emotions.