Two studies were conducted to investigate the motivational influences of information about task difficulty on task effort. In both studies, an anagram task was used as the experimental task and task motivation was measured with rating scales. In experiment 1, 60 participants were presented anagrams labeled as “easy” or “difficult”, both of which were actually impossible to solve. Results revealed that participants low in intrinsic motivation put in more effort on anagrams labeled “easy” than “difficult”. In experiment 2, 60 participants were assigned to two groups (30 each) and task outcomes were manipulated (positive and negative). Results revealed that participants with positive outcomes could maintain task motivation and put in more effort on the challenging anagrams than those with negative outcomes. These results suggest that information about task difficulty can promote regulation of task effort and task motivation for sustained studying, especially for computer-based learning.