Why group decisions may not be the best

We tend to assume that decisions taken by a group of people are optimal because of the varied input and cumulative experience of the group members. As long as all opinions are heard and considered, the outcome is considered as best. Yet, the conventional wisdom may always not hold.

Max Ringelmann was a French engineer who studied the performance of horses when pulling carts. By way of a device he designed, he measured the power output of horses when pulling a cart alone, and when pulling with other horses. Surprisingly he found that two horses pulling individually did not equal the power of the same two horses pulling together.

Intrigued by his results he extended his research to humans and had several people pulling on a rope; first separately to measure their individual strength and maximum power, and then all together where he measured the cumulative pulling power of the group. Sure enough, again he found that on average when two people pulled the rope they expended 93% of their maximum strength, when three pulled together it was 85% and with eight people tugging at the rope the figure dropped to 49%. Scientists call this the social loafing effect.

The same effects were found in tests done where tug-of-war contestants were told to pull on a rope blindfolded not knowing whether they were alone or not. On average, when people only thought (as opposed to definitely knowing) they were pulling within a group, their efforts were 18% less than when they exerted when tugging alone.

Social loafing can often occur when individual performance in a group is not directly measurable or visible and blends into the group output. When people work together the value of each individual’s input tends to diminish the larger the group becomes. In teams we slack off mentally until a group reaches about 20 people or more; when our (reduced) performance plateaus.

A second impediment to optimal group decisions is group-think, a term coined by Irvin Janis, a psychologist from Yale University. Janis defined group-think as : "The mode of thinking that persons engage in when concurrence seeking becomes so dominant in a cohesive in-group that it tends to override realistic appraisal of alternative courses of action."

We may think that problems are easier to solve when a group of people get together and brainstorm a solution, as opposed to trying to find a solution alone. Studies have shown though that brainstorming in a group often does not produce a superior decision. As Walter Lippman said: “When all think alike, no one is thinking”. The desire to appease the leadership of the group, the need to be accepted by the group and the inclination to avoid confrontation, often hinders optimal decision making.

When it comes to group decision making, the collective group output may be much less than the individuals’ outputs had they been able to contribute by themselves. Our tendency to expend less effort in groups than when alone, and our tendency towards group-think may be detrimental in reaching optimal decisions and outcomes.

A possible better way for a group to decide on strategy, problem or outcome is to canvas everyone individually first – ask them what they would do if they alone had to decide. Then have the group discuss the solutions and pick the best alternative.