Drawing power of virtual crowds

Abstract

In 1969, social psychologist Milgram and his colleagues conducted an experiment on a busy city street where passers-by witnessed a set of actors spontaneously looking up towards a building. The experiment showed that the crowd's propensity to mimic the actor's gaze increased with the number of actors that looked up. This form of behavioural contagion is found in many social organisms and is central to how information travels through large groups. With the advancement of virtual reality and its continued application towards understanding human response to crowd behaviour, it remains to be verified if behavioural contagion occurs in walkable virtual environments, and how it compares with results from real-world experiments. In this study, we adapt Milgram's experiment for virtual environments and use it to reproduce behavioural contagion. Specifically, we construct a replica of an indoor location and combine two established pedestrian motion models to create an interactive crowd of 60 virtual characters that walk through the indoor location. The stimulus group comprised a subset of the characters who look up at a random time as the participants explore the virtual environment. Our results show that the probability of looking up by a participant is dependent on the size of the stimulus group saturating to near certainty when three or more characters look up. The role of stimulus size was also evident when participant actions were compared with survey responses which showed that more participants selected to not look up even though they saw characters redirect their gaze upwards when the size of the stimulus group was small. Participants also spent more time looking up and exhibited frequent head turns with a larger stimulus group. Results from this study provide evidence that behavioural contagion can be triggered in the virtual environment, and can be used to build and test complex hypotheses for understanding human behaviour in a variety of crowd scenarios.

Contagious yawning in virtual reality is affected by actual, but not simulated, social presence

“…Collectively these data indicate that participants are quite sensitive to the social contagion of yawning within a virtual environment, which is consistent with recent VR research on other forms of contagious/reflexive behavior (i.e., gaze following) 49 . And yet, surprisingly, the participants were immune to the visual social signals of explicit (Experiments 4 and 5) and implied (Experiments 2 and 3) social presence displayed within this setting; but were extraordinarily sensitive to the unseen real presence of an experimenter outside of VR, i.e., in the testing room.…”

Standing out from the crowd: Both cue numerosity and social information affect attention in multi-agent contexts

“…Previous research has emphasized that cue numerosity guides behavioral responses in both human infants (Pun et al, 2016) and primates (Pun et al, 2017) in an effortless and spontaneous manner. Recent work has also shown that group-ratio estimates (e.g., the identification of a group majority vs. minority) dynamically guide human adults' attentional responses in a variety of contexts Gallup et al, 2012;Jorjafki et al, 2018;Sun et al, 2017). Thus, our finding of greater magnitudes of gaze following responses to the gaze direction of the group majority vs. the group minority is consistent with such previous research.…”

The drawing power of crowds revisited: Evidence for a two-step model of social group influence

“…Finally, as a preregistered exploratory analysis, we also looked for non-linear patterns in the data, based on the fact that previous research has mostly found an asymptotic relationship between group size and gaze following (Gallup et al, 2012;Jorjafki et al, 2018;Milgram et al, 1969). Non-linear models were fitted by replacing the linear group size term with a linear b-spline term with a single knot at the average group size (Hastie et al, 2009).…”

“…In one of the first studies to make this point, Milgram, Bickman, and Berkowitz (1969) asked a group of confederates to walk down a New York City street before suddenly stopping and looking up at a tall building. They then measured how often unaware passersby imitated the group's behavior and found a clear positive relationship between the size of the stimulus group and the probability of looking up (see also Gallup et al, 2012;Jorjafki et al, 2018;Knowles & Bassett, 1976).…”

“…But why do we follow the gaze of groups? According to the traditional account, we do so because it is adaptive: when we see a large group of people looking in the same direction, we assume that they must be looking at something important and therefore we decide to follow their gaze as a means to obtain relevant information (Gallup et al, 2012;Jorjafki et al, 2018;Milgram et al, 1969). In other words, the traditional account argues that the influence of groups on attention is driven by top-down, strategic processes (Jorjafki et al, 2018).…”