When retrospectively analyzing the design process of a creative product, the creative leap or moment of inspiration is often described by the designer in an idealized way' [I]. There is little evidence within literature describing when the ideas behind promising concepts were conceived. This study tracks several real industrial design projects in the early conceptual design phase. The development and manipulation of ideas captured during the initial group brainstorm meeting are assessed in terms of the concepts at the following stage gate meeting. In addition, several different forms of stimulus were introduced to the different groups and compared to a control group. The results showed that the frequency of idea production remained virtually constant for the first 60 minutes. However, the number of ideas to form part of a concept at the stage gate meeting dropped markedly after the first 20 minutes. The frequency of appropriate ideas featuring within stage gate concepts increased with the introduction of stimuli, highlighting the positive effect of introducing stimuli.