ENtry, Occupancy, EXit (NOX): A Model of Human-Robot Territorial Dynamics

Paper Title

ENtry, Occupancy, EXit (NOX): A Model of Human-Robot Territorial Dynamics

Publication Info

• Topic area: Human-Robot Interaction (HRI) focusing on socio-spatial dynamics.
• Keywords: Territoriality, Human-Robot Interaction, NOX model, spatial dynamics, friction points, territorial congruence, empirical validation, socio-spatial design, environmental psychology, autonomous robots.

Background and Problem

• Problem / challenge: Existing HRI research largely focuses on proxemics, neglecting territoriality—the social use of space that involves claims, control, and defense. This gap limits understanding of how robots should navigate human territories.
• Significance: Territoriality is critical for harmonious integration of robots into human environments, as violations can lead to negative emotions, defensive behaviors, and reduced acceptance of robots.
• Motivation and related work: Prior studies have acknowledged territoriality but lack a formalized model or shared vocabulary for HRI. Proxemics provides insights into interpersonal distances but overlooks territorial boundaries and expectations. This paper builds on fragmented findings to address the need for a structured approach to territorial dynamics.

Solution

• Proposed approach: The NOX model (Entry, Occupancy, Exit) organizes human-robot territorial interaction into three stages, identifying friction points where incongruence between robot behavior and human expectations may arise.
• Novelty:
  1. Introduces territoriality as a critical socio-spatial dimension in HRI, complementing proxemics.
  2. Provides the first structured, stage-based model (NOX) for territorial interaction, with actionable friction points.
  3. Empirically validates the model through a vignette-based study, demonstrating its utility in predicting territorial infringement responses.
• Procedure and key techniques:
  • Defines territories as interactions between physical spaces and stakeholders.
  • Identifies three friction points per stage: Freedom (permission seeking), Action (behavior), and Status Alteration (impact on stakeholder authority).
  • Conducts a vignette study (N = 290) simulating robot behaviors in a domestic bedroom setting, measuring territorial congruence, emotional responses, and defensive behaviors.

Results

• Concrete findings:
  • Territorial incongruence at friction points elicited negative affect (valence shift from ~+2.5 to ~-1.5), increased arousal (shift from calm to neutral), reduced dominance (shift from ~+2.5 to ~0), and heightened defensive intent (e.g., rule-setting likelihood increasing from ~-2.5 to ~+2.0).
  • Baseline scenarios were rated as appropriate (+2.5), while friction-point vignettes showed reduced appropriateness (-1.7 to ~+0.8).
• Advantage over baselines: The NOX model successfully isolates friction points where incongruence arises, providing targeted insights for design and adaptation.
• Experiments / evaluation:
  • Vignette survey with 10 conditions (baseline + 9 friction-point scenarios).
  • Measures included territorial congruence (expectation-perception alignment), emotional responses (SAM ratings), defensive behaviors, and perceived appropriateness.
  • Sample: 290 participants, predominantly North American, with strong territorial attachment to bedrooms.
• Limitations and future work:
  • Cultural generalizability is limited; future studies should explore cross-cultural norms.
  • Vignette-based design lacks longitudinal data; real-world deployments are needed to capture evolving territorial dynamics.
  • Applicability to non-humanoid robots and multi-stakeholder contexts remains unexplored.

Summary

The NOX model provides a structured framework for understanding human-robot territorial dynamics, dividing interactions into three stages (Entry, Occupancy, Exit) and identifying friction points where incongruence may arise. Empirical validation shows that mismatches between robot behavior and stakeholder expectations at these points trigger typical territorial infringement responses, including negative emotions, defensive behaviors, and reduced appropriateness. By linking abstract territoriality theories to actionable design constructs, NOX offers a foundation for creating socially harmonious robots capable of negotiation, adaptation, and recovery in diverse environments. Future work should extend the model to cross-cultural, multi-stakeholder, and non-humanoid contexts.