Assumptions of equality lead to poorer group decision

People of differing competence tend to give each other's views equal weight, preventing them from making the best group decisions, finds new UCL-led research. This suggests that people with similar levels of competence make the best decision-making groups, as otherwise the tendency to assume equal competence can give undue weight to the opinions of less capable members. The new study investigated how pairs of people with differing competence weighted their own judgements against each other's. Researchers split 98 men from Denmark, Iran and China into pairs and asked them to complete a visual perception task, repeated 256 times per pair. Participants were asked to look at a screen for two consecutive intervals, with a subtle target appearing in either the first or second interval. Each person, separated from the other by a screen, indicated whether they thought the target was in the first or second interval and how confident they were. When they disagreed on where the target was, one of the pair was randomly assigned as arbitrator and asked to make the final joint decision.