All the participants (undergraduate students) were exposed sequentially (one by one) to 5 brief descriptions of different actions constituting criminal offences according to the Spanish Penal Code. Each description was accompanied by the specific name of the offence, and the range of the jail sentence length (in months) that might be imposed for the offence according to this penal code. The participants were asked to choose within this range a penalty for each case as a function of the severity that was perceived in the description of the facts. The participants in Group SEVERE were initially exposed to the descriptions of four relatively severe offences. The participants from Group MILD, however, were initially exposed to four less severe offences. The fifth offence to which the participants were exposed was the same in both groups–a description of a violent robbery. It was observed that participants in Group SEVERE imposed lighter penalties for the robbery with violence than participants in Group MILD. These results indicate that our perception of the severity of a criminal offence can be modulated by the severity of other actions to which we have previously been exposed.