Proxemics and Permeability of the Pedestrian Group

TL;DR

The paper investigates how pedestrian groups establish proxemic behavior and permeability in crowds by treating groups as emergent agents and formalizing a group-proxemics framework. It combines a hierarchical, game-theoretic modeling approach with naturalistic crowd datasets to define group zones (convex hull and circle) around groups and to measure zone occupancy and outsider clearance. Empirically, it finds that outsiders intrude into group zones in a minority of encounters and spend little walking time inside, while groups intermittently adjust their zones during transient states, revealing a progressive permeability. The work advances crowd dynamics and human-robot interaction research by providing quantitative metrics, a formalized group-agent perspective, and a data-driven basis for simulating and predicting group-aware pedestrian behavior in real-world settings.

Abstract

People tend to walk in groups, and interactions with those groups have a significant impact on crowd behavior and pedestrian traffic dynamics. Social norms can be seen as unwritten rules regulating people interactions in social settings. This article studies people interactions with groups and the emergence of group proxemics. Group zones, zone occupancy counts and people clearance from the group are studied using naturalistic data. Analysis indicate potential presence of three different zones in addition to the public zone. People tend to remain in the public zone and only progressively get closer to groups, and those closer approaches happen in a low frequency and for brief periods of time.

Figures (8)

• Figure 1: People as individuals as well as groups could be seen as agents. With the emergence of intelligent machines, those could be seen as agents as well. Multi-agent interactions between any of such agents influence their behavior and would be essential in the design of intelligent behavior in machines.
• Figure 2: Structure of mutual expectations in the interaction between pedestrian and groups in crowd. When a group is formed, group proxemics emerge. The group is expected to maintain their formation and walk as to protect their zones, while outsiders to the group would avoid intrusions so long as the group maintain its part of this shared mutual expectations.
• Figure 3: Hall hall1966hidden coined the term "proxemics" in his studies of interactions between individuals. Group proxemics could be seen as an extension to account for proxemics in the interaction between outsiders with a pedestrian group as a collective.
• Figure 4: Group permeability indicates active zones with associated intrusion avoidance social norms from more flexible inactive zones.
• Figure 5: An image representing a general scene of observations with extracted pedestrian trajectories and group labeling (trajectory color). This is a sample from Student003 dataset lerner2007crowds, with group annotation and illustration from solera2013structured. This figure is borrowed from solera2013structured.