School group projects are the worst. You’re bound to encounter among your team at least one of these: The procrastinator, the slacker, and the student who has no idea what’s going on the whole time, all of whom over-promise and under-deliver. But when it’s time to present the final project to the teacher for a grade, each student steps up, embellishes the part they played and overclaims their contributions — even if all they did was purchase sharpies for the presentation board. New research published in the Journal of Experimental Psychology: Applied reveals that group size, and egocentrism are responsible for this phenomenon.

Researchers found that over claiming — or taking more credit than is deserved — tends to increase as the size of the group increases. Overestimating contributions correlates with group size because in larger groups people become more egocentric, “and consequently more likely to fail to recall the contributions of their fellow group members,” explained Schroeder, an assistant professor of management at UC Berkeley's Haas School of Business.

“Past research has shown that groups often "overclaim" credit for their contributions. What we find is that, remarkably, the size of the group can influence its members likelihood of overclaiming,” Juliana Schroeder, lead author of the study, told Medical Daily.

Overclaiming isn’t uncommon in group settings. People often overestimate their contributions to group or collaborative endeavors at the workplace, the PTA meeting, and even at home when arguing about the distribution and completion of chores.

“Believing one deserves more credit than others fail to acknowledge can be a source of dissatisfaction and conflict in groups. Although such 'over-claiming' is reliable across many experiments, relatively little is known about what moderates its magnitude,” study authors wrote.

Researchers from University of California at Berkeley conducted four experiments on four different groups of people — MBA students, academic authors, museum visitors, and a large-scale national sample — the sample size increased with each subsequent experiment. Each group was asked to complete a group assignment or task. After each group session, researchers asked participants to report the percentage they personally contributed to the group’s total. The study offered no reward for over-claiming one's contribution. Investigators then calculated the percentages and found that claims of responsibility consistently added up to more than 100 percent, indicating over-claiming.

In addition, researchers also found that an important moderator for over-claiming behavior was group size. The study showed that the bigger the teams, the more individual members of a team “over-claim” their contributions. That means people on large teams, such as big film productions, are more likely to resort to high school antics — overestimate or inflate their contributions while diminishing their team members’ work. However, unlike scheming adolescents, these people sincerely thought their reporting was accurate.

Because people are “naturally egocentric” they tend to focus on their own contributions and not take into account the work of others. This behavior increases with group size because it is harder to consider everyone's contributions when groups are larger, researchers concluded.

"When you have large groups, you might want to consider breaking down the group into smaller teams," Schroeder said. "It is also important to make the workflow very clear. If assignments are clearly divided, it's easier for people to remember who is doing what."

To prevent this from occurring in the real world, researchers urge people to consider others’ contributions alongside their own. If you’re a teacher or manager, you could encourage this among students and employees by asking them to comment on their teammate’s contributions before discussing their own. Researchers say this tends to force people to be a little more accurate about self-reporting.

Schroeder and her colleagues are now searching for other factors that influence egocentrism and overclaiming.

Source: Schroeder J, Caruso E, Epley N. Many Hands Make Overlooked Work: Over-Claiming of Responsibility Increases With Group Size. Journal of Experimental Psychology: Applied . 2016.