Cognitive Evaluation Theory

Cognitive evaluation theory (CET), a subtheory within SDT, provides a more specific explanation of how external influences affect intrinsic motivation (Deci & Ryan, 1985). CET argues that external events influence motivation depending on whether they support or undermine an individual's sense of autonomy and competence. 

External factors such as constructive feedback, autonomy supportive coaching and encouragement can strengthen intrinsic motivation because they reinforce feelings of competence while preserving personal control. In contrast, controlling environments characterised by excessive surveillance, pressure, rigid expectations, or reward-based conditional approval tend to weaken intrinsic motivation by reducing perceived autonomy. 

CET is particularly important in youth sport because it explains why external rewards do not always enhance performance in a meaningful way. While rewards such as trophies, scholarships, rankings, or praise may increase effort in the short term, they can also shift the athlete's focus away from enjoyment and mastery toward external outcomes. Over time, this may reduce intrinsic motivation and undermine long-term engagement. 

This concept is closely linked to the overjustification effect, discussed later in Section 3.3, where external rewards for an already enjoyable activity can diminish intrinsic motivation once those rewards are removed.