Study shows how social observation shapes decision making

People tend to adjust their choices between a safe and risky decision based on their perception of an observer’s opinion, according to new research.

The study, published today as a Reviewed Preprint in eLife, is described by the editors as an important contribution to the field of social decision making, with solid evidence to show a differentiated adjustment of choices, and not just a universal behaviour of making riskier choices when under observation, as has been claimed in previous studies.

It is well known that people often make choices differently when around others, often mimicking the choices of their social peers. Previous research, particularly in teenagers, has suggested that the mere presence of an observer can make people more likely to take risks. Further studies have shown that this also holds true for adults.

“Those studies suggest that people actively process information about their social environment when making decisions. We speculated that people’s beliefs about their observers, which can be shaped by experience, may play a central role in their decision-making process,” explains HeeYoung Seon, a graduate student in the Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, South Korea. Seon served as a co-author of the current study alongside Dongil Chung, Associate Professor in the Department of Biomedical Engineering, UNIST.

To test their hypothesis, Seon and Chung recruited 43 healthy participants (25 male and 18 female) to take part in a three-phased gambling task. Each participant chose between a safe and a risky option represented as pie charts: the safe option offered a guaranteed payout, while the risky option displayed two probabilities for high and low payouts.

In the first, ‘solo’ phase of the task, participants were asked to make a series of choices between the two options alone. In the second, ‘learning’ phase, they were partnered up with two other participants and asked to predict the choices their partners would make. Unbeknownst to them, one of the partners was determined by the first phase to be a risky player, and the other a safe player. In the third, ‘observed’ phase, participants were given the same set of gambling choices as in the first phase, but were informed that some of their choices would be used for one of the partners’ learning phase. Through this design, participants underwent two types of trials where their choices would be observed by a partner, and one where their choices would be made alone. By examining their choices during the learning phase, Seon and Chung gained insights into how the presence of an observer affected each participant’s decision making. 

Supporting previous research, they found that participants initially believed others would make riskier decisions than themselves. However, after each guess participants were given feedback on the accuracy of their predictions, and were eventually able to correctly predict the choices of their partners. This suggests that, independent of their initial beliefs about social peers, individuals can learn about others’ preferences through experience. 

During the observed phase, participants were shown to be affected by the preferences they learned of their partners. When observed by the ‘safe’ partner, participants were less likely to choose the risky option. Conversely, under the gaze of the ‘risky’ partner, they were swayed towards making riskier choices. These results confirm that social observation influences a person’s decision making and suggests that the direction of this influence depends on the individual’s beliefs about their observer. 

The researchers also investigated the brain regions responsible for an individual’s differentiation of choices while under observation. They used an imaging technique called blood-oxygen-level dependent (BOLD) signalling during the ‘solo’ and ‘observed’ phases of the trials to identify brain regions with increased activity during decision making. They found that a region called the temporoparietal junction (TPJ), which is known to play a role in social cognitive functions, was activated when the individual was observed. This finding suggests that the TPJ is responsible for mentally simulating other people’s choices and using that information to inform the individual’s own decisions.

“Our study provides further understanding for how the presence of others affects an individual's decision-making behaviour,” Chung concludes. “In the modern world, almost every choice we make is seen by others. In this environment, taking the perspectives of others into account is an essential ability to empathise with one another, make prosocial choices and follow social norms. Our data shed light on the flip side, showing how and why incorrect beliefs about others may lead to more risky or maladaptive behaviours, such as the formation of extremely polarised opinions.”

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