Page "Interactive evolutionary computation" Paragraph 1

The number of evaluations that IEC can receive from one human user is limited by user fatigue which was reported by many researchers as a major problem.

In addition, human evaluations are slow and expensive as compared to fitness function computation.

Hence, one-user IEC methods should be designed to converge using a small number of evaluations, which necessarily implies very small populations.

Several methods were proposed by researchers to speed up convergence, like interactive constrain evolutionary search ( user intervention ) or fitting user preferences using a convex function ( Takagi, 2001 ).

IEC human-computer interfaces should be carefully designed in order to reduce user fatigue.