The guards in the Stanford Prison Experiment used several bases of social power to get compliances from their 'prisoners'. First the used both threats and promises. They threatened the prisoners with solitary confinement, push ups and other physical punishments, and denying certain human rights like their use of the toilet being replaced with a bucket in their cells they sometimes weren't able to clean for a while. They used promises when they decided to break solidarity among prisoners, allowing certain prisoners to sleep in 'privileged' cells where they could brush their teeth and eat better higher quality food at meal times. Secondly the guards used legitimate power to gain prisoners' compliance. Even though they weren't real guards, the inmates thought that they were, or were to obey them like they were actually prison guards. 

Police officers and guards are people we generally consider to be in authority over average citizens. We know that they hold the power to issue us tickets or arrest us if we do things that are illegal. For the most part, people accept this because over all it keeps our society as a whole under control, safe, and happy, however power can be abused. As we saw in the Stanford Prison Experiment, the guards started out reasonably giving orders and keeping control, but as the days went on, the began to exercise less and less humane actions towards the prisoners, and maybe even enjoyed doling out these punishments to them because at the end the guards said they mostly didn't want the experiment to be over, whereas the prisoners did. This experiment proved that the prison system is flawed in that it de-humanizes rather than just corrects behavior. And it's not just the prisoners that experience this de-humanizing, but the guards experience it too. 

If I was a prisoner in this experiment I would like to say that I wouldn't have obeyed the unfair things the guards tried to do to the prisoners, and that I would have stood up for myself and others there with me, but I'm sure the situation is much different once your there under the influence of all the different aspects and the environment of the mock prison life. I'm almost sure, then, that I would have reacted much in the same way as these average volunteers reacted because there's a lot going on that is influencing your mind and way of thinking in that situation, things you can't control or avoid, like solitary confinement if they decide you need it, or refusing to feed you well or at all, or making you defecate in a bucket in your own living space and leave it there, all of these things would change you pyschologically. I think the same goes for the role of the guards. Having been given the powers that they were, and being told to exercise those powers over people that they were told to think of as criminals probably put them in a weird position and I won't say I wouldn't become one of the guards practicing unfair treatment to the prisoners because I think it's one of those things you can't judge until you experience it personally, and I think there's a lot more going on in the psyche than meets the eye in this experiment, but I would like to think I'm to nice of a person to treat people that harshly. I think I'm more of a passive person so it would be easier for me to submit in a bilateral situation rather than cause an useless conflict spiral.