A major cause of this ambiguity is the emergence over the past two decades of studies suggesting that many disorders of the brain or mind bring with them strengths as well as weaknesses. People diagnosed with autism spectrum disorder (ASD), for example, appear to have strengths related to working with systems (e.g., computer languages, mathematical systems, machines) and in experiments are better than control subjects at identifying tiny details in complex patterns [1]. They also score significantly higher on the nonverbal Raven’s Matrices intelligence test than on the verbal Wechsler Scales [2]. A practical outcome of this new recognition of ASD-related strengths is that technology companies have been aggressively recruiting people with ASD for occupations that involve systemizing tasks such as writing computer manuals, managing databases, and searching for bugs in computer code [3].
Valued traits have also been identified in people with other mental disorders. People with dyslexia have been found to possess global visual-spatial abilities, including the capacity to identify “impossible objects” (of the kind popularized by M. C. Escher) [4], process low-definition or blurred visual scenes [5], and perceive peripheral or diffused visual information more quickly and efficiently than participants without dyslexia [6]. Such visual-spatial gifts may be advantageous in jobs requiring three-dimensional thinking such as astrophysics, molecular biology, genetics, engineering, and computer graphics [7, 8]. In the field of intellectual disabilities, studies have noted heightened musical abilities in people with Williams syndrome, the warmth and friendliness of individuals with Down syndrome, and the nurturing behaviors of persons with Prader-Willi syndrome [9, 10]. Finally, researchers have observed that subjects with attention deficit hyperactivity disorder (ADHD) and bipolar disorder display greater levels of novelty-seeking and creativity than matched controls [11-13].
Such strengths may suggest an evolutionary explanation for why these disorders are still in the gene pool.