Psychology of communication must do everything is possible to promote an adequate perception of risk. This is particularly true when it comes to transmitting statistical and probabilistic data to an audience of non-experts, inevitably conditioning their perception of risk. Data are all available, but subjects are able to understand them in the specific meanings proper to a specialized language, only if they are adequately transmitted. And we find these phenomena in the difficulty in representing the trend of, for instance, Covid-19 (...) contagion, based on probability of contagion and mortality. In general, then, when we communicate scientific terms or data we should re-introduce the psychological aspects which characterize communication. The nudging strategies can be considered as a prototype of approach to overcome risky behaviours, which takes into account the cognitive characteristics of the human system. This strategy acts on different levels, using implicit factors, bypassing defensive attitudes and exploiting adaptive inferential processes, without overloading the cognitive system. But from a communicative point of view, nudge, as well as any other type of intervention, is not a general ‘recipe. The acceptance of the suggestion, the effectiveness of the nudging implies the congruity with the system that receives it: the “way of reasoning”, and its implicit layer has to be taken into account. The right combination of the source, the adopted message and the decisional setting could improve the efficacy of the public policies. (shrink)