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Category: Project

Description: Cognitive Bias Modification (CBM) is an overarching term for various computerized training protocols developed to change automatic information processing patterns (cognitive biases) trough repeated practice on tasks designed to reward response tendencies associated with more desired information processing patterns. Target cognitive biases include those believed to be involved in anxiety, depression, addiction, and eating disorders, and CBM protocols are commonly regarded as potential new treatments. Most CBM forms rely on a (hidden) contingency between stimulus valence and rewarded response. In CBM studies, active training conditions are typically contrasted with control conditions lacking the contingency, often called 50/50 placebo. This report focusses on the wide-spread, and intuitive, notion that pre-existing bias may affect the contingency experienced by an individual engaging in a 50/50 placebo control condition, inadvertently rendering the intended placebo condition more potent. Employing probabilistic arguments, we conclude that, contrary to the often-forwarded notion, pre-existing bias cannot increase the potency of a 50/50 placebo condition. In contrast, we arrived at the unforeseen conclusion that lack of pre-existing bias may render an active training condition functionally similar to a placebo condition. In this project we develop these arguments, review literature, and discuss implications. associated app: https://awkruijt.shinyapps.io/mechanics-of-CBM-app/ (runs in internet browser - limited hours/month available) To run the app locally (and unlimited - in your own Rstudio): shiny::runGitHub("AWKruijt/CBM_contingency_app")