  What happen in the brain when human beings play games with computers? Here a
simple zero-sum game was conducted to investigate how people make decision via
their brain even they know that their opponent is a computer. There are two
choices (a low or high number) for people and also two strategies for the
computer (red color or green color). When the number selected by the human
subject meet the red color, the person loses the score which is equal to the
number. On the contrary, the person gains the number of score if the computer
chooses a green color for the number selected by the human being. Both the
human subject and the computer give their choice at the same time, and subjects
have been told that the computer make its decision randomly on the red color or
green color. During the experiments, the signal of electroencephalograph (EEG)
obtained from brain of subjects was recorded. From the analysis of EEG, we find
that people mind the loss more than the gain, and the phenomenon becoming
obvious when the gap between loss and gain grows. In addition, the signal of
EEG is clearly distinguishable before making different decisions. It is
observed that significant negative waves in the entire brain region when the
participant has a greater expectation for the outcome, and these negative waves
are mainly concentrated in the forebrain region in the brain of human beings.
