Abnormal evidence accumulation underlies the positive memory deficit in depression

Area of Science:

• Cognitive Psychology
• Clinical Psychology
• Neuroscience

Background:

• Healthy adults exhibit enhanced memory for positive stimuli compared to negative stimuli.
• Depression is known to disrupt this positive memory advantage, but underlying mechanisms remain unclear.
• Previous research is limited by small sample sizes and insufficient analytical depth.

Purpose of the Study:

• To investigate the psychological mechanisms behind the positive memory advantage and its disruption in depression.
• To analyze these effects in a large, well-controlled sample using advanced modeling techniques.
• To clarify how depression impacts memory retrieval processes for emotional information.

Main Methods:

• Recruited 1,358 participants who completed the Beck Depression Inventory-II (BDI-II) and an emotional memory task.
• Employed a multistaged analysis including recall, recognition, and source memory tests.
• Utilized hierarchical drift diffusion modeling (HDDM) to analyze evidence accumulation during memory retrieval.

Main Results:

• Replicated the positive memory advantage and its reduction in individuals with higher depression scores across memory tasks.
• HDDM revealed that higher BDI-II scores correlated with more efficient evidence accumulation for negative words in recognition and source memory.
• Evidence accumulation for positive words was unaffected by BDI-II in recognition but became less efficient in source memory as BDI-II scores increased.

Conclusions:

• Depression significantly reduces the positive memory advantage in a large sample.
• Findings suggest depression differentially affects the speed of evidence accumulation for positive versus negative memories during retrieval.
• Diffusion modeling provides precise insights into the cognitive mechanisms underlying depression's impact on emotional memory.