22 Understanding Rational Decision Making
business problems outside their function area.^139 Sometimes experts try to apply their schemata
to decisions outside their domain of expertise. But experts’ schemata are domain specifi c and
cannot be used as the basis of expertise in a second domain even when that domain appears to
be similar.^140
Such limitations can lead experts to make biased decisions, particularly if they try to usetheir schemata to make nonroutine decisions or to solve ill-structured problems.^141 In such cir-
cumstances, expert audiences do not necessarily make better decisions than novices.^142 Experts’
schemata can even incline them to overlook information simply because it is not formatted
in the typical way. For example, expert, but nonprofessional, investors have been found to use
comprehensive income information only when it is presented in the format they have come
to expect.^143
The Shared Decision Schemata of Groups
Shared schemata underpin the corporate cultures of diverse organizations^144 and guide the
decision-making processes of effective groups and teams.^145 A study of 25 four- to six-person
groups of business executives making hiring decisions reports that the executives in each group
shared the same schema concerning the characteristics of suitable applicants, tended to search for
the same information about each applicant, mentioned that same information in group discussions,
and used that information to make group decisions. When group members repeated information
during their discussions, they were more likely to repeat information that was schema relevant than
schema irrelevant. Any information that was unshared, or known by only one group member, was
more likely to be mentioned in group discussions if it were schema-relevant information than if
it were schema irrelevant. Finally, the study reports that the most infl uential person in each group
was the group member with the most complete knowledge of information relevant to the group’s
shared schema.^146
Factions within a group who are initially in a minority can successfully advocate their preferredalternative by appealing to shared knowledge structures or schemata upon which all members
agree.^147 Any alternative consistent with the group’s shared schema is easier for the minority to
defend. That alternative is also more likely to be chosen by the group as a whole, although usually
after some delay.^148 The group is more likely to choose that alternative even when it is not demon-
strably correct, as is often the case with jury decisions.^149 However, if group members do not share
a schema, or if they possess multiple and confl icting schemata, the group will tend to choose an
alternative on the basis of majority/plurality rule.^150
Shared mental models, a type of shared schema, predict both team processes and team perfor-mance.^151 They are associated with higher team satisfaction,^152 increased within-team helping
behavior,^153 reduced absenteeism,^154 and greater team effectiveness.^155 They have an even greater
effect on team performance than demographic similarities among team members.^156
The benefi ts of shared schemata or shared mental models arise because they enable teammembers to anticipate each other’s information needs, communicate effi ciently, and work
in sync.^157 In many cases, a shared mental model about the task is necessary if a team is to
complete its task successfully.^158 Furthermore, as the differences among the team members’
mental models decrease, team performance increases. High-performing teams tend to have not
only more widely shared mental models than low-performing teams, but also more elaborate
ones.^159 Teams that fail to develop shared mental models tend to be uncoordinated and to
perform poorly.^160