Twice the negativity bias and half the positivity offset: Evaluative responses to emotional information in depression

Background and objectives Humans have the dual capacity to assign a slightly pleasant valence to neutral stimuli (the positivity offset) to encourage approach behaviors, as well as to assign a higher negative valence to unpleasant images relative to the positive valence to equally arousing and extreme pleasant images (the negativity bias) to facilitate defensive strategies. We conducted an experimental psychopathology study to examine the extent to which the negativity bias and the positivity offset differ in participants with and without major depression. Method Forty-one depressed and thirty-six healthy participants were evaluated using a structured clinical interview for DSM-IV Axis I disorders, questionnaires, and a computerized task designed to measure implicit affective responses to unpleasant, neutral, and pleasant stimuli. Results The negativity bias was significantly higher and the positivity offset was significantly lower in depressed relative to healthy participants. Limitations Entry criteria enrolling medication-free participants with minimal DSM-IV comorbidity may limit generalizability of the findings. Conclusions This study advances our understanding of the positive and negative valence systems in depression, highlighting the irregularities in the positive valence system.