The literature on entrepreneurial intent assumes that having the intent to start up a company is often sufficient to predict effective new venture start-up. However, half of the nascent entrepreneurs do not succeed in getting their venture off the ground. The extant literature gives a number of reasons for this phenomenon, many of which are attributed to the uncertain environment in which the founder starts. In such an uncertain environment, the founder needs to have a so-called conscientious personality to succeed. Conscientious individuals have a high need to achieve and are dependable to work with. Yet, it is not only personality that counts. Rather, ‘cognitions’ may be complementary to personality types. Cognitions are decision heuristics used to make sense of the environment. Personalities tend to be stable over time, but cognitions can be trained and may change. An individual’s ability to adapt cognitions (decision heuristics) to feedback from the environment has been called his/her cognitive adaptability. Novice nascent entrepreneurs who do not possess cognitions developed in a previous venture context, might particularly need a fair amount of ‘cognitive adaptability’ to turn intent into effective start-up.