Because people with autism are also strongly obsessional, meaning that they pursue their current interest to extraordinary detail and lengths and in great depth, they can develop 'tunnel vision' that prevents them from seeing the bigger picture, including the repercussions of their current actions.

Like any skill, systemising occurs on a bell curve in the population, with some people being faster at spotting patterns than others. Autistic people are often strong systemisers. Indeed their attention is often described as 'obsessive' as they check and recheck the patterns of a system.

Autistic people's disabilities are widely known, but one of their best-established strengths is their attention to detail.

Simon Baron-Cohen Quotes