When all glasses look half empty: a computational model of reference dependent evaluation to explain depression

Abstract

Computational proposals argue that impairments in evaluation are central to depression. At the same time, contemporary theories of evaluation highlight its reference dependent nature: when attributing value to an outcome, our brain automatically assesses the outcome relative to its context. Yet, reference dependent processes underlying evaluation remain to be explored in the context of depression. To fill this gap, here we develop a computational model of reference dependent evaluation to explain the disorder. The model proposes that early-life stress (combined with genetic predispositions) impairs the ability to adjust to environmental changes. After experiencing stress later in life, such inability to adapt would result in excessive standards to which life outcomes are compared. This model explains diverse affective aberrations observed in the disorder, including low mood, poor self-esteem, reduced controllability, and blunted emotional reactivity. Our proposal raises the possibility that abnormal reference dependent evaluation might be a critical process underlying depression.

A formal theory of mood instability

“…In this case, the reference point is higher than all life outcomes (μ > R), casting all such outcomes in a negative light. This scenario has been argued to explain depression and addiction, whereby a high reference point---that could be expressed either psychologically in terms of an unrealistic standard for rewards or neurobiologically in terms of an altered neuromodulatory setpoint---could result in persistently negative affect: Most stimuli pale in comparison to the high reference point and are thereby experienced negatively (Rigoli, 2022;. The exact opposite scenario has been proposed to reflect (hypo)mania: If an agent's reference point is smaller than the average of one's contextual distribution (e.g., μ=0 rather than μ=40), then most (and, in this case, all) stimuli will be experienced positively, yielding persistently inflated subjective values (see figure 1).…”