Leveraging Monte Carlo Tree Search for Group Recommendation

Group recommenders aim to provide recommendations that satisfy the collective preferences of multiple users, a challenging task due to the diverse individual tastes and conflicting interests to be balanced. This is often accomplished by using aggregation techniques that select items on which the group can agree. Traditional aggregators struggle with these complexities, as items are chosen independently, leading to sub-optimal recommendations lacking diversity, novelty, or fairness. In this paper, we propose an aggregation technique that leverages Monte Carlo Tree Search (MCTS) to enhance group recommendations. MCTS is used to explore and evaluate candidate recommendation sequences to optimize overall group satisfaction. We also investigate the integration of MCTS with LLMs aiming at better understanding interactions between user preferences and recommendation sequences to inform the search. Experimental evaluations, although preliminary, showed that our proposal outperforms existing aggregation techniques in terms of relevance and beyond-accuracy aspects of recommendations. The LLM integration achieved positive results for recommendations’ relevance. Overall, this work highlights the potential of heuristic search techniques to tackle the complexities of group recommendations.