People that don't care if they do a good job or not aren't generally motivated by either criticism or praise because they don't care. People that want to do well can be better motivated by praise because criticism can make you nervous and more worried, and being nervous can sometimes cause you to make mistakes.
I feel like praise is better due to the fact that it makes the person want to keep doing a good job and even exceed at what they are doing. On the other hand by fearing criticism people end up just doing enough to not be in trouble instead of continuing to exceed and perform better. By praising you not only help out that person but also the people around them will see it and want to be the same way.
Praise works better for most individuals than fear of criticism does. Positive reinforcement makes most people feel more optimistic and confident. Negative reinforcement (or criticism) affects a person's self esteem and they begin to question whether they are capable of succeeding. A positive environment helps people to succeed; whereas, criticism helps people be unhappy.
Criticism is used to help people as they are told what they are doing wrong, so that they can change that and become even better as they know where to focus their improvements. Do not get me wrong, praise is lovely and a compliment goes a long way, however, it will not improve your work and will not motivate you as much as criticism because you may become lazy because you think you are doing really well if you are given nothing but praise, but criticism allows you to improve and puts you into the mindset of ' this person is telling me what I am doing wrong, I am going to prove them wrong by changing that and making it better'; thus motivating you more.
I think for me its a motivator that people tell me how bad a job I am doing. I usually make it a deal to myself to fix these issues and push for a better outcome. I think the opposite might be true for other people,but for me praise is annoying.