Improved performance on simple or well learned tasks in the presence of others. Social loafing: where people in a group exert less effort when pooling their efforts to attain a common goal then if they are working. Deindividuation: often occurs when group participation makes people feel aroused and anonymous leading to a loss of self-restraint (inhibitions are reduced) Group polarization: beliefs/ attitudes that we bring to a group grow stronger as we discuss them with like-minded people. When examining brain waves: amplitude= refers to how tall the wave is, frequency= the frequency of the waves. Hypnic jerk (were your entire body jerks while you are asleep) Their eyes rapidly move back and forward. 5 % of total sleep is spent in stage 1. 50% of total sleep is spent in stage 2. 20% of total sleep is spent in deep sleep (stage 3 and 4) 25% of the night is spent in rem sleep.