The masking effect due to noise manifests itself not only on auditory warning signals, but also verbal communication. Communication in noise increases both the workload of the person who sends and the one that receives; indeed, the first must raise their voices, the second attention makes an effort to understand the message. This difficulty understanding increases when the operator must pay attention simultaneously to the verbal message and signals from other sources. In this case, the focus of attention on the verbal message reduces the attention span and therefore the operator's ability to meet competing demands.