Some psychologists believe that there are two systems in the human brain, namely system 1 and system 2. System 1 runs unconsciously and quickly. It is not very laborious. It is completely in an autonomous control state. System 2 diverts attention to Brain-intensive brain activities that are required, such as complex computing. The operation of System 2 is often associated with subjective experiences such as behavior, selection, and concentration. According to the definition above, which of the following is behaviors caused by the operation of System 2? ['Detecting unfriendliness in tone.', 'Determine the source of the sudden sound.', 'The disgusted expression after seeing the horror picture.', 'Observe if you are decent in social situations.']