Task: Categorize the tweet based on the intensity of the specified emotion E, capturing the tweeter's mental state. 0: no E can be inferred. 1: low amount of E can be inferred. 2: moderate amount of E can be inferred. 3: high amount of E can be inferred.
Tweet: Positive #psychology research shows salespeople who score in the top 10% for #optimism have 88% &gt; sales than those in top 10% for pessimism.
Emotion: joy
Intensity class: 
0: no joy can be inferred