Decision making

What is ‘decision making’ referring to? 

Decision making requires the use of knowledge and experience of a context in order to choose a course of action. The ability to autonomously make decisions is referred to as their decisional capacity. Effective decision-making aims to increase the likelihood of a favourable outcome in the relevant context, selecting responses that avoid unfavourable or harmful outcomes.

An experimental tool used to examine decision-making is the Iowa Gambling Task. On each trial, participants choose a card from one of four decks and receive a monetary gain or loss. Two decks (A, B) are disadvantageous and two decks (C, D) are advantageous. The decks also differ according to the amount of immediate gain, the relative frequency of gains vs. losses and the relative number of net losses. The goal is to maximize monetary outcome through adaptive decision-making across many trials.

Another experimental tool is the MacArthur Competence Assessment Tool, which assesses the ability to understand the relevant information, the ability to reason rationally, the ability to appreciate a situation and its consequences, and the ability to communicate a choice.

What is the evidence for decision making?

High quality evidence finds medium to large impairments in understanding, appreciation and reasoning decision-making and a small impairment in expression of a choice decision making. Effect sizes were smaller in studies using enhanced informed consent for people with schizophrenia.

Moderate to high quality evidence found poorer performance on the Iowa Gambling Task, with more A and B deck choices and fewer D deck choices. There were also fewer C deck choices, although this was not significantly different to controls.

Moderate quality evidence finds more severe psychotic symptoms and poorer verbal cognitive functioning are associated with reduced decision-making ability about treatment (small to medium-sized effects).

July 2019

Last updated at: 4:13 am, 30th July 2019
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