Personal context-specific experience can affect how a designer evaluates a design problem and proposes solutions. However, this effect was seldom discovered in a quantitative manner in problem-solving design tasks. This paper uses empirical evidence and quantitative methods to show the effects of novice designers' contextual experience on design tasks, particularly as it relates to the design process and design outcomes. Thirty-three people performed two design tasks while their cognitive states were assessed using electroencephalography (EEG). Moreover, the objective ratings (i.e., quantity, novelty and quality) from prospective users were analyzed to gauge the effect of contextual experience on design outcomes. Results suggest that during ideation, contextual experience has a negative effect on mental states associated with creativity and also on the novelty evaluations of the proposed solutions in the tested design tasks. This research advances the development of design methods for novice designers.