Laboratory experiments have also been done to study people’s reactions to TV by monitoring brain waves by the use of EEG (electroencephalograph). Those who participated in the study carried a beeper. They were signaled six to eight times a day randomly over the period of a week. When they heard the beep, they were to write down what they were doing and how they were feeling. People who were watching TV when beeped reported feeling relaxed and passive. The studies showed less mental stimulation as measured by alpha brain-wave production during viewing TV than if these participants had been reading. After the television set was turned off, this study showed the participants were still very relaxed and passive as if all energy had left them.