EXPRESS: Interference effects between hand posture and manipulation dimensions during action tool knowledge retrieval

Understanding how components of action tool knowledge are organized and interact is crucial for elucidating the cognitive and neural basis of tool use. In this study, we examined the relationship between two key dimensions: hand posture and manipulation. Forty-eight participants made similarity judgments based on these dimensions across pairs of familiar tools. Results revealed an asymmetrical interference pattern: judgments about manipulation were significantly influenced by hand posture, whereas the reverse effect was weaker. This asymmetry was modulated by perceptual similarity, particularly when participants attended to hand posture, suggesting a dynamic interaction between perceptual and conceptual features. Notably, perceptual similarity judgments were not solely explained by low-level visual features but were also influenced by stored action tool representations. This indicates that participants spontaneously activated integrated tool knowledge even during perceptual tasks. These findings support a model of action tool knowledge, with hand posture emerging as a primary dimension that influences and potentially precedes manipulation. Together, these results provide new insights into the cognitive architecture of tool knowledge and offer a foundation for future studies exploring the interaction between perceptual, motoric, and conceptual dimensions in action tool knowledge.