Biased Information Search in Homogeneous Groups: Confidence as a Moderator for the Effect of Anticipated Task Requirements

When searching for information, groups that are homogeneous regarding their members’ prediscussion decision preferences show a strong bias for information that supports rather than conflicts with the prevailing opinion (confirmation bias). The present research examined whether homogeneous groups blindly search for information confirming their beliefs irrespective of the anticipated task or whether they are sensitive to the usefulness of new information for this forthcoming task. Results of three experiments show that task sensitivity depends on the groups’ confidence in the correctness of their decision: Moderately confident groups displayed a strong confirmation bias when they anticipated having to give reasons for their decision but showed a balanced information search or even a disconfirmation bias (i.e., predominately seeking conflicting information) when they anticipated having to refute unterarguments. In contrast, highly confident groups demonstrated a strong confirmation bias independent of the anticipated task requirements

Combined Effects of Knowledge About Others' Opinions and Anticipation of Group Discussion on Confirmatory Information Search

There is conclusive evidence that information search processes are typically biased in favor of the information seeker’s own opinion (confirmation bias). Less is known about how knowledge about others’ opinions affects this confirmatory information search. In the present study, the authors manipulated feedback about others’ opinions and anticipation of group interaction. As predicted, the effect of knowledge about others’ opinions on confirmatory information search depended on whether participants anticipated interacting with these others. Specifically, minority members anticipating a group discussion exhibited a particularly strong confirmation bias, whereas minority members who did not anticipate a discussion predominantly sought information opposing their opinion. For participants not anticipating group interaction, confidence about the correctness of one’s decision mediated the impact of knowledge about others’ opinions on confirmatory information search. Results are discussed with regard to the debiasing effect of preference heterogeneity on confirmatory information search in groups

Beyond group-level explanations for the failure of groups to solve hidden profiles: The individual preference effect revisited

The individual preference effect supplements the predominant group-level explanations for the failure of groups to solve hidden profiles. Even in the absence of dysfunctional group-level processes, group members tend to stick to their suboptimal initial decision preferences due to preference-consistent evaluation of information. However, previous experiments demonstrating this effect retained two group-level processes, namely (a) social validation of information supporting the group members’ initial preferences and (b) presentation of the additional information in a discussion format. Therefore, it was unclear whether the individual preference effect depends on the co-occurrence of these group-level processes. Here, we report two experiments demonstrating that the individual preference effect is indeed an individual-level phenomenon. Moreover, by a comparison to real interacting groups, we can show that even when all relevant information is exchanged and when no coordination losses occur, almost half of all groups would fail to solve hidden profiles due to the individual preference effect

Social validation in group decision making: differential effects on the decisional impact of preference-consistent and preference-inconsistent information

"Shared information has a stronger impact on group decisions than unshared information. A prominent explanation for this phenomenon is that shared information can be socially validated during group discussion and, hence, is perceived as more accurate and relevant than unshared information. In the present study we argue that this explanation only holds for preference-inconsistent information (i.e., information contradicting the group members’ initial preferences) but not for preference-consistent information. In Experiments 1 and 2 participants studied the protocol of a fictitious group discussion. In this protocol, we manipulated which types of information were socially validated. As predicted, social validation increased the decisional impact of preference-inconsistent but not preference-consistent information. In both experiments the effect of social validation was mediated by the perceived quality of information. Experiment 3 replicated the results of the first two experiments in an interactive setting in which two confederates discussed a decision case face-to-face with one participant." [author's abstract

Many Labs 5:Testing pre-data collection peer review as an intervention to increase replicability

Replication studies in psychological science sometimes fail to reproduce prior findings. If these studies use methods that are unfaithful to the original study or ineffective in eliciting the phenomenon of interest, then a failure to replicate may be a failure of the protocol rather than a challenge to the original finding. Formal pre-data-collection peer review by experts may address shortcomings and increase replicability rates. We selected 10 replication studies from the Reproducibility Project: Psychology (RP:P; Open Science Collaboration, 2015) for which the original authors had expressed concerns about the replication designs before data collection; only one of these studies had yielded a statistically significant effect (p < .05). Commenters suggested that lack of adherence to expert review and low-powered tests were the reasons that most of these RP:P studies failed to replicate the original effects. We revised the replication protocols and received formal peer review prior to conducting new replication studies. We administered the RP:P and revised protocols in multiple laboratories (median number of laboratories per original study = 6.5, range = 3?9; median total sample = 1,279.5, range = 276?3,512) for high-powered tests of each original finding with both protocols. Overall, following the preregistered analysis plan, we found that the revised protocols produced effect sizes similar to those of the RP:P protocols (?r = .002 or .014, depending on analytic approach). The median effect size for the revised protocols (r = .05) was similar to that of the RP:P protocols (r = .04) and the original RP:P replications (r = .11), and smaller than that of the original studies (r = .37). Analysis of the cumulative evidence across the original studies and the corresponding three replication attempts provided very precise estimates of the 10 tested effects and indicated that their effect sizes (median r = .07, range = .00?.15) were 78% smaller, on average, than the original effect sizes (median r = .37, range = .19?.50)

How Much Group is Necessary? Group-To-Individual Transfer in Estimation Tasks

G-I transfer denotes an increase in individual performance due to group interaction, for example, because of acquiring certain skills or knowledge from the other group members. Whereas such G-I transfer has been successfully shown for problem-solving tasks, evidence for G-I transfer on quantitative estimation tasks is scarce. We address this research gap with a focus on how often a group has to interact in order to fully exploit the benefit of this learning effect. Results from two experiments support the idea that a single group interaction is sufficient to induce a stable G-I transfer, which reduces group members’ metric error. Smaller metric errors indicate that people improved their representation of the correct upper and lower boundaries, or what range of values is plausible. In contrast to nominal groups, both members of continuously interacting groups and members of groups with only one initial interaction exhibited stable G-I transfer, and the size of this transfer did not significantly differ between the latter two conditions. Furthermore, we found evidence for differential weighting of group members’ individual contributions that goes beyond sheer individual capability gains under certain circumstances, namely in tasks with a population bias

Why dyads heed advice less than individuals do

Following up on a recent debate, we examined advice taking in dyads compared to individuals in a set of three studies (total N = 303 dyads and 194 individuals). Our first aim was to test the replicability of an important previous finding, namely that dyads heed advice less than individuals because they feel more confident in the accuracy of their initial judgments. Second, we aimed to explain dyads’ behavior based on three premises: first, that dyads understand that the added value of an outside opinion diminishes when the initial pre-advice judgment is made by two judges rather than one judge (given that the dyad members’ opinions are independent of each other); second, that they fail to recognize when the assumption of independence of opinions does not hold; and third, that the resistance to advice commonly observed in individuals persists in groups but is neither aggravated nor ameliorated by the group context. The results of our studies show consistently that previous findings on advice taking in dyads are replicable. They also support our hypothesis that groups exhibit a general tendency to heed advice less than individuals, irrespective of whether the accuracy of their initial judgments warrants this behavior. Finally, based on the three assumptions mentioned above, we were able to make accurate predictions about advice taking in dyads, prompting us to postulate a general model of advice taking in groups of arbitrary size