Most skilled artists are good at abstract reasoning. Most skilled artists are famous. All people who are good at abstract reasoning are very creative. Some skilled artists are not famous.
Cognitive psychologist: The majority of skilled artists are very creative people, and all people who are very creative are also good at abstract reasoning. However, not all skilled artists are famous. It follows that some people who are good at abstract reasoning are famous.
The cognitive psychologist's conclusion follows logically if which one of the following is assumed?