Modelling the Effect of Depression on Working Memory

Velde, M.A. van der (2018) Modelling the Effect of Depression on Working Memory. Master's Thesis / Essay, Human-Machine Communication.

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Abstract

Individuals with depression are prone to engage in rumination, a process in which attention turns inwards to narrowly-focused, negative patterns of thought, at the cost of attending to a task. Depression is furthermore associated with certain cognitive deficits, such as increased difficulty inhibiting information that is no longer relevant and increased difficulty switching between task goals. Previous studies have investigated how these factors affect task performance, but their observations have generally only been supported by verbal theories. Here, we present a computational cognitive model of performance on one such task, an n-back task in which the stimuli are faces with different emotional expressions. Depressed participants were previously found to have a stronger attachment to sad faces than to neutral or happy faces. Compared to faces with other expressions, they integrated sad faces into working memory more quickly, while they spent more time disengaging from sad faces that were no longer relevant. By having a perceptual bias towards sad stimuli, and selectively elaborating on sad items as they are removed from working memory, our model is able to reproduce the reaction time effects observed in the original data, as well as accuracy and response rate metrics. This study demonstrates how a cognitive model can serve as an explicit, testable implementation of a verbal theory, providing a deeper understanding of the cognitive processes underlying behaviour.

Item Type:	Thesis (Master's Thesis / Essay)
Degree programme:	Human-Machine Communication
Thesis type:	Master's Thesis / Essay
Language:	English
Date Deposited:	15 Feb 2018 08:35
Last Modified:	15 Feb 2018 08:35
URI:	https://fse.studenttheses.ub.rug.nl/id/eprint/16425

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