threat actually served to increase the child's interest in the toy, which was previously undesirable to the child in the absence of threat. Advantages of extrinsic motivators are that they easily promote motivation to work and persist to goal completion. Rewards are tangible and beneficial. A disadvantage for extrinsic motivators relative to internal is that work does not persist long once external rewards are removed. As the task is completed for the reward, the quality of work may need to be monitored, and it has been suggested that extrinsic motivators may diminish in value over time. Flow theory Flow theory refers to desirable subjective state a person experiences when completely involved in some challenging activity that matches the individual's skills. Mihaly Csikszentmihalyi described Flow theory as "A state in which people are so involved in an activity that nothing else seems to matter; the experience is so enjoyable that people will continue to do it even at great cost, for the sheer sake of doing it." The idea of flow theory was first conceptualized by Csikszentmihalyi. Flow in the context of motivation can be seen as an activity that is not too hard, frustrating or madding, or too easy boring and done too fast. If one has achieved perfect flow, then the activity has reached maximum potential. Flow is a part of something called positive psychology of the psychology of happiness. Positive psychology looks into what makes a person happy. Flow can be considered as achieving happiness or at the very least positive feelings. A study that was published in the journal Emotion looked at flow experienced in college students playing Tetris. The students that were being evaluated on looks then told to wait and play Tetris. There were three categories; Easy, normal, and hard. The students that played Tetris on normal level experienced flow and were less stressed about the evaluation. Csikszentmihalyi describes 8 characteristics of flow as - the complete concentration on the task, clarity of goals & reward in mind and immediate feedback, transformation of time (speeding up/slowing down of time), the experience is intrinsically rewarding, effortlessness & ease, a balance between challenge and skills, merged actions and awareness, loss of self-conscious rumination and a feeling of control over the task. The activity no longer becomes something seen as a means to an end and it becomes something an individual wants to do. This can be seen