One of the key factors, says Bloom, is the fact that our brains have separate cognitive systems for dealing with living things - things with minds, or at least volition - and inanimate objects.

• 布鲁说，其中一个关键因素便是我们的大脑有两个独立的认知系统：一个处理生命体（指有思想意识，或至少有主观意志的物种）的认知；另一个主管无生命物体的认知。