Leadership ability, a specific form of creative behavior, appears to be relatively resilient with age. Two different aspects of cognition are crystallized or accumulated knowledge and fluid ability reflecting reasoning, memory, and speed. Our fluid ability peaks before age 30, yet the peak age for CEOs is 60. Accumulated knowledge increases with age until roughly age 60, after which it declines modestly, while fluid ability, such as novel problem solving, declines more steeply with age after its early age peak.
What accounts for the mismatch between declining fluid intelligence and work performance is unclear but may reflect at least four factors, including 1) one seldom needs to perform at their maximum level, 2) there is a shift with age from novel processing (fluid problem solving) to greater reliance on accumulated knowledge, 3) cognition may not be the only determinant of success ("can do, will do, have done"... the latter two represent temperament and experience), and 4) accommodations can be made for some declining skills (Annu. Rev. Psychol. 2012;63:201-26). A fifth possibly related factor may be that older-appearing individuals are preferred as leaders during times of intergroup conflict (PLoS One 2012;7:e36945), a state in which most companies find themselves most of the time.
However, group members who are not in leadership positions may not be as fortunate. Few things are the same now as they were 10 years ago, and the rate of change has accelerated in the computer-catalyzed information age. Biological evolution may be slow, but ideas evolve quickly.
Meme evolution eventually results in meme speciation, with the consequence that memes of different species can no longer interbreed. Consider the example of subspecialization in medicine. We all begin as medical students with a common knowledge base and vernacular, but with subspecialization a child psychiatrist no longer has anything in common with a transplant surgeon. Even within neurology, there is little knowledge shared between epileptologists and neuroimmunologists.
Older individuals who failed to align themselves with one meme line (or physicians who failed to specialize) may find their ideas can no longer "interbreed" with the new meme species (or currently practiced medical specialties). Even within a field, those who fail to keep up with evolving technology will find themselves left behind, such as an aging surgeon who may not have mastered new robotic techniques or an aging secretary who may not understand the latest software. Add to this state of brain affairs, the prevalent ailments of the aging body such as arthritis, hypertension, and deconditioning, and we find that our workforce is not simply getting older, it actually is at risk of becoming obsolete.
And so the effects of age upon our creative behavior are varied and determined not only by our neurobiology, but also by our health (both physical and mental), our family and friends, and our fortune (or lack of it). Next month, we will conclude our 2-year series on creativity and its disorders.
Dr. Caselli is medical editor of Clinical Neurology News and is a professor of neurology at the Mayo Clinic, Scottsdale, Ariz.