Unusual phenomena (spontaneous destruction of objects in an empty wooden box) were demonstrated to 6- and 9-year-old children and to adults. These were accompaniedby actionswhichhadno physicallinktothedestroyedobject butcould suggest either scientifically based (the effect of an unknownphysical device) or nonscientifically based(the effect of a parapsychological 'effort of will' or a 'magic spell') causal explanations of the event. Contrary to the expectation that scientifically based explanation would prevail in older children's and adults' judgments and behaviours, the prevalence was only shown in participants' verbal judgments and not in their actions. In their actions, 9-year-olds showed a higher credulity towards the magical effect than towards the effect of a physical device. Adult participants showed an equal degree of credulity towards the effect of both the device and magic in both high- and low-risk conditions. However, when the risk of disregarding the possible causal effect of accompanying actions was high, the overall degree of credulity towards possible effects of the device and magic spell, as judged by specific behavioural patterns, was significantly higher than when the risk was low. The replacement of non-scientific causal explanations by scientific ones does indeed take place with age. However, the replacement model only captures the development of verbal judgments. In participants' actual behaviour the coexistence of alternative causal modes was observed.