Behavioural and neuroscience studies have shown that observing objects activates affordances, evoking motor responses. The aim of the present study is twofold. First, we intend to investigate whether children are sensitive to the distinction between neutral/graspable (affordances) and dangerous objects. Second, we aim to verify whether children's responses are modulated also by the agent who is interacting with the objects (human hand contrasted with robot hand, and male hand contrasted to female hand). We conducted an experiment on school-age children using a priming paradigm: a prime given by a hand or a control object was followed by graspable or dangerous objects. Children were required to categorize them into artefacts or natural objects by pressing two keys on a keyboard. Our results clearly showed that children are able to distinguish between neutral and dangerous objects: the latter produced an interference effect. In addition, we demonstrated that children are sensitive to the difference between actions performed by biological and non-biological agents: responses were faster when the prime was a grasping hand of a human compared to control stimuli. Results were interpreted in terms of gradient of vulnerability (female hand induced the most inhibition, while robot hand induced the least one) and of motor resonance (resonance is higher when the similarity between the hand prime and the participant's hand is higher).