Research over the last 5 decades has suggested that negative affective states narrow cognitive scope, whereas positive affective states broaden cognitive scope. An examination of this past research, however, reveals that only negative affects of high motivational intensity (e.g., fear, stress) and positive affects of low motivational intensity (e.g., gratitude, amusement) may have been examined. Consequently, over the last 5 years, research has examined positive and negative affects that are low (e.g., sadness) versus high (e.g., desire) in motivational intensity. This research has found that affects of low motivational intensity broaden cognitive scope whereas affects of high motivational intensity narrow cognitive scope, regardless of the positivity or negativity of the affective state.
Harmon-Jones, E., Gable, P. A., & Price, T. F. (2013). Does negative affect always narrow and positive affect always broaden the mind? Considering the influence of motivational intensity on cognitive scope. Current Directions in Psychological Science, 22(4), 301-307.