Oxford Companion to the Affective Sciences

A cognitive bias is any systematic deviation from a normative criterion that affects thinking, often leading to errors in judgment. Affect, in particular, may bias cognition, both by altering the depth of cognitive processing and by impacting the content of cognitions. A useful example of emotion altering depth of processing appears in studies by Bodenhausen et al (1994). Happy individuals demonstrated less depth of processing than individuals in a neutral affective state, as evidenced by their reliance on simple mental categories rather than on complex stimuli. A useful example of emotion altering the content of thought appears in studies on the affect-asinformation model (see affect-as-information). Individuals in a positive mood judged their overall life satisfaction more positively than did individuals in a negative mood. That is, their temporary positive mood altered the content of their thoughts about satisfaction as a whole.