根据以下内容回答题：It is well known that when an individual joins a group he tends to accept the group’s stand-ards of behavior. and thinkin9．He is expected to behave in accordance with these norms——in other words the group expects him to conform．Many illustrations could be given of this from everyday life，but what is of particular interest to psychologists is the extent to which people’s judgments and opinions can be changed as a resuh of group pressure． In a typical experiment，the experimenter ask for volunteers to join a group whicii is inves tigating visual perception．The victims are not，therefore，aware of the real purpose of the ex-periment．Each volunteer is taken to a room where he finds a group of about seven people who are collaborating with the experimenter．The group is shown a standard card which contains a single line．They are then asked to look at a second card．This has three lines on it．One is ob-viously longer than the line on the first card，one is shorter and one the same length．They have to say which line on the second card is the same length as the line on the standard card．The other members of the group answer first but what the volunteer does not know is that they have been told to pick one of the wrong lines．The volunteer sees that the other members of the group unanimously choose a line which is obviously not the same length as the one on the standard card． When it is his turn to answer he is faced with the unanimous opinion of the rest of the gmup—all the others have chosen line A but he quite clearly sees line B as correct．What will he do?According to Asch，more than half of the victims chosen will change their opinion．What is equally surprising is that，when interviewed about their answers，most explained that they knew the group choice was incorrect but that they yielded to the pressure of the group because they thought they must be suffering from an optical illusion．

Psychologists are interested in__________ ．