He claims that in order to achieve flow, there needs to be the correct balance between the challenge of a task and the skills of the individual performing it. If a lack of challenge is matched with a low skills level, then it leads to a sense of apathy. On the other hand, if the challenge is high and the skill level is low it can lead to anxiety. In order for flow to occur, there must be a demanding challenge and the skills of the individual must also be high.