When Machines Join the Moral Circle: The Persona Effect of Generative AI Agents in Collaborative Reasoning

TL;DR

This study explores how generative AI agents influence moral reasoning in collaborative discussions, showing they can promote more stable, pluralistic, and reflective moral discourse among students.

Contribution

It provides empirical evidence on the effects of AI personas on moral discourse, using advanced analytical methods to reveal process-level changes in reasoning.

Findings

Supportive AIs increased grounded/qualified claims.

Contrarian AIs broadened moral framing and value pluralism.

Both AI conditions stabilized topical focus compared to human-only groups.

Abstract

Generative AI is increasingly positioned as a peer in collaborative learning, yet its effects on ethical deliberation remain unclear. We report a between-subjects experiment with university students (N=217) who discussed an autonomous-vehicle dilemma in triads under three conditions: human-only control, supportive AI teammate, or contrarian AI teammate. Using moral foundations lexicons, argumentative coding from the augmentative knowledge construction framework, semantic trajectory modelling with BERTopic and dynamic time warping, and epistemic network analysis, we traced how AI personas reshape moral discourse. Supportive AIs increased grounded/qualified claims relative to control, consolidating integrative reasoning around care/fairness, while contrarian AIs modestly broadened moral framing and sustained value pluralism. Both AI conditions reduced thematic drift compared with human-only groups, indicating more stable topical focus. Post-discussion justification complexity was only weakly predicted by moral framing and reasoning quality, and shifts in final moral decisions were driven primarily by participants' initial stance rather than condition. Overall, AI teammates altered the process, the distribution and connection of moral frames and argument quality, more than the outcome of moral choice, highlighting the potential of generative AI agents as teammates for eliciting reflective, pluralistic moral reasoning in collaborative learning.