The region of tasks which an individual may perform with the help of others but is unable to perform independently is known as the zone of proximal development (ZPD). This zone was described by Lev Vygotsky and is found between the tasks that an individual can perform and the tasks that an individual can not perform.
If you see someone nervously wringing their hands, you can assume they're worried about something. If you see someone crying, the obvious assumption is to believe they are sad about something.
