Effect of time limits on problem solving I recently took part in psychological testing as part of a recruitment process to a job. I was not happy about the evaluation I got and I asked for a feedback discussion with the psychologist. The psychologist told me (among other things), that I could perform well in a situation that was undisturbed, when I could concentrate and when there was no time limit. But isn't that true about all people? 


Do there exist individuals, who start performing better when there is time pressure? 
Of course there may be such individuals, but what would be a general rule that would apply to most normal mortal individuals? 


The scores I got were slightly above average in IQ tests (there were also personality tests). So I should not have problems with solving problems fast, too. At least I performed like other normal average people do. Still the psychologist wanted to stress the fact that I can perform well when I can concentrate and there is no time limit.

There were no tests in which I would have been disturbed in any manner. The tests were largely automated and the test room was a quiet classroom. Other applicants, other test subjects like me, were all also doing their tests quietly in front of computers. As far as I can recall, most IQ tests did have a time limit.
This ted talk video would probably interest you. 

It seems the current understanding is that it would depend on both the individual, and the type of task they are performing. Here are the general tendencies I've seen/been taught.

For physical tasks or tasks where the important factor is strength and effort, time constraints and rewards tend to increase the pace at which someone finishes the task. A simple example is track and field, where the contestants are generally able to perform better with the added pressure/motivation of the competition. No records are made in practice.

For more mental and creative tasks, time constraints and rewards tend to diminish one's ability to finish a task. For instance, musicians rarely make great music when they are told they have to. 

Both of the above situations however, can be affected by the person completing the task. If youlook at sporting events with very tense situations, there is an understanding that some players "rise to the occasion" and some "shrink under pressure." One's anxiety level and self confidence will affect the psychology of how they approach a task, which will certainly affect the result of that task.