The present study attempted to determine the optimal difficulty level of some occupational problems for students with varying interests and ability levels. Some 288 high school boys were presented with simulated vocational problems in sales, medical laboratory technology, and x-ray technology. The criterion for a successful performance was set at three levels of difficulty. Each subject was assigned at random a problem in one occupation and at one of the three levels of difficulty. Subject variables were grade level, grade point average, and initial occupational interest as measured on the Holland Vocational Preference Inventory. Criterion measures of three types were taken: expressed interest in the occupation, scores on an information test covering the occupation simulated, and incidents of information seeking during the week following treatments. Analysis of variance was used to test the main effects and all interactions. Difficulty level was not found to produce differences on the measures used, but did significantly interact with initial vocational interest pattern. The simulated problems in each occupation did generate interest and exploration in that occupation. Most students reacted favorably to the experience. (Author)