 Abraham Maslow is a very well-known humanist psychologist with his work on hierarchy needs, in which he states that humans have basic needs, and if they are not satisfied, those individuals will not desire anything else.Maslow also claims that humans are never really satisfied, in that their needs are never fully fulfilled, therefore, this can affect how people can behave (e.g., if people's needs are never fully satisfied, then they might not always behave well, even if they do get a treat for good behavior.