In this work, we investigated the possible interaction between item format and conative aspects of the results obtained by the examinees in knowledge tests. For the study we used three questions in multiple choice format, short-answer and open response, respectively, and a series of questions designed to collect noncognitive information about volitional and conative aspects of the examinee. Through the development of logistic regression models were concluded that conative aspects (motivation and volition) are factors to be considered in the assessment of learning through problem solving and behavior examined in relation to these variables is differential depending on the format in which to respond to the question.