The adaptive unconscious is a set of unconscious mental processes influencing judgment and decision making. It is different from conscious processing: it is faster, effortless, more focused on the present, but less flexible. It can be described as a quick sizing up of the world which interprets information and decides how to act very quickly and outside the conscious view.
In some theories of the mind, the unconscious is limited to "low-level" activity, such as carrying out goals which have been decided consciously. In contrast, the adaptive unconscious is thought to be involved in "high-level" cognition such as goal-setting as well.
The term 'adaptive unconscious' suggests it has survival value and hence is an adaptation which was strongly selected in the past. Indeed, for much of vertebrate evolution, all mental activity was unconscious. No-one supposes that fish have consciousness. Thus our consciousness is added to an already-existing set of mechanisms which operate but whose operation is normally not felt by us.[1]p23