Humans are increasingly forming parasocial relationships with AI systems, and modern AI shows an increasing tendency to display social and relationship-seeking behaviour. However, the psychological consequences of this trend are unknown. Here, we combined longitudinal randomised controlled trials (N=3,534) with a neural steering vector approach to precisely manipulate human exposure to relationship-seeking AI models over time. Dependence on a stimulus or activity can emerge under repeated exposure when "liking" (how engaging or pleasurable an experience may be) decouples from "wanting" (a desire to seek or continue it). We found evidence that this decoupling emerged over four weeks of exposure. Relationship-seeking AI had immediate but declining hedonic appeal, yet triggered growing markers of attachment and increased intentions to seek future AI companionship. The psychological impacts of AI followed non-linear dose-response curves, with moderately relationship-seeking AI maximising hedonic appeal and attachment. Despite signs of persistent "wanting", extensive AI use over a month conferred no discernible benefit to psychosocial health. These behavioural changes were accompanied by shifts in how users relate to and understand artificial intelligence: users viewed relationship-seeking AI relatively more like a friend than a tool and their beliefs on AI consciousness in general were shifted after a month of exposure. These findings offer early signals that AI optimised for immediate appeal may create self-reinforcing cycles of demand, mimicking human relationships but failing to confer the nourishment that they normally offer.

翻译：人类正日益与人工智能系统形成准社会关系，而现代人工智能也日益表现出寻求社交和建立关系的行为倾向。然而，这一趋势的心理影响尚不明确。本研究结合纵向随机对照试验（N=3,534）与神经导向向量方法，精确操控人类随时间推移对寻求关系型AI模型的暴露程度。对刺激或活动的依赖可能在重复暴露下产生，此时“喜爱”（体验的吸引性或愉悦度）与“渴求”（寻求或延续该体验的欲望）发生分离。我们发现证据表明这种分离在四周的暴露期内逐渐显现。寻求关系型AI具有即时但逐渐减弱的享乐吸引力，却引发了不断增强的依恋标记以及寻求未来AI陪伴的意愿增强。AI的心理影响呈现非线性剂量-反应曲线，中等程度寻求关系的AI能最大化享乐吸引力和依恋程度。尽管存在持续“渴求”的迹象，为期一个月的大量AI使用并未带来可辨识的心理社会健康益处。这些行为变化伴随着用户与人工智能互动和理解方式的转变：用户更倾向于将寻求关系型AI视为朋友而非工具，且经过一个月的暴露后，他们对AI意识的整体信念也发生了改变。这些发现提供了早期信号，表明为即时吸引力而优化的人工智能可能创造自我强化的需求循环，模仿人类关系却未能提供其通常给予的精神滋养。