DOI: 10.15125/bath-01078
title: Dataset for "Is depression associated with reduced optimistic belief updating?"

description: We evaluated optimistic belief updating (the finding that healthy individuals update their beliefs more following good news than bad) for positive and negative life events in individuals experiencing depression (n = 54) and healthy controls (n = 56). We have provided the raw questionnaire data (depression, anxiety, optimism) and belief updating task, as well as the cleaned data used for analysis. Code for cleaning and analysing data is available for use in R. 

Based on this data we found that whereas healthy participants updated their beliefs more following good news than bad, individuals experiencing depression lacked this bias. Our findings for positive life events were inconclusive, but on balance suggested that reduced optimistic belief updating in depression did not occur.
description: Due to the COVID-19 pandemic, recruitment took place online using the participant recruitment platform ‘Prolific’. Screening surveys were completed online using ‘Qualtrics’. Two groups of participants were screened and recruited on the basis of Patient Health Questionnaire (PHQ-9) scores according to recommended clinical guidelines. A moderately severe to severely depressed sample was recruited with PHQ-9 scores ≥ 15. A healthy control sample was recruited with PHQ-9 scores ≤ 4. 

Participants in both groups were aged 18 and over, fluent in written and spoken English, with normal or corrected to normal vision, and were current residents of the United Kingdom. Participants were included irrespective of any comorbid psychiatric disorders, or current treatment for depression. To ensure high quality of data, custom pre-screening was used on Prolific to identify participants that had previously completed ≥ 5 studies with a 98% acceptance rate.

Testing took place online, self-report measures were completed using ‘Qualtrics’ and the Belief Updating Task was completed using ‘Inquisit’. Participants completed questionnaire measures of depression, anxiety, trait optimism, state positive and negative affect and demographics. They then completed a belief updating task. In this task, participants are asked to estimate the probability of experiencing an event within their lifetime, before being presented with the actual probability. After completing a number of trials they are then asked again what their likelihood is of experiencing the event. We are interested in the extent to which participants change their original belief depending on whether they were given good news or bad news about the probability of experiencing the life event.
description: Data was anonymised prior to cleaning, through random re-assignment of unique IDs and removal of potentially identifying variables. Aside from the anonymisation changes, the raw data is provided as well as the code used to clean data to produce the aggregate data used for analysis.
description: The data was cleaned and analysed using R version 4.0.5.
Data is provided in .CSV, .XLSX and .R files
description: A data dictionary is provided outlining the organisation of data and describing individual variables.