This is kind of interesting because remember divergent thinking on Word Analogies showed great on the left:
The most creative thinkers, then are those who are able to use both their right and left prefrontal areas well.
Another aspect of the first study is that they were looking at group of "schizotypic" (eccentric personality disorder) subjects compared to normal controls and diagnosed schizophrenics.
Schizotypic traits are features thought to be somewhat on the border between normalcy and disease (e.g. odd speech, "cognitive disorganization", unusual perceptual experiences, magical thinking, social non-conformity). Interestingly, in this study, the schizotypes had slightly higher IQs, higher levels of education, and better fluency scores with letters, categories, and designs. The schizophrenics (IQ-matched to controls) had no "creativity advantage" here - they were significant lower on letter and category fluency, although they matched normal controls with the task of design fluency.
A final interesting tidbit, from the bottom link -children seem to lose their ability to think divergently with time. On a test of divergent thinking, researchers followed the same children over a period of 10 years. At age 3-5 years old, 98% were able to generate divergent answers, 5 years later, only 32% were answering divergently, and 5 years after that (now teens age 14-15), only 10% were good divergent thinkers.
Creativity, Schizotypy, Divergent Thinking
Fluid Analogies and fMRI
Cognitive Features of the Schizotypal Personality
Teaching Divergent Thinking - Design & Engineering
Divergent Thinking Lost As Children Grow Up