In the listed examples, the institutions that sponsored these experiments were not looking to harm the participants, they were simply trying to understand the social world around them; however, in every situation in life, work, extracurricular activities, etc. , a cost and benefits analysis must be conducted. Inflicting harm to participants can alter their perception of the world around them. It can cause momentary and possibly lasting psychological or physical ailments.
After the experiment, the participant should feel the same psychologically and physically, just as they felt coming into the experiment, there should be no negative altering of their bodies and minds. Boundaries are set up, such as the Belmont Report, Office for Protection from Research Risks in the National Institutes of Health, etc. , to protect, minimize harm, analyzing cost and benefits of research in this field. This is done to protect participants from negative effects from research.
I also believe rules, regulations, and boundaries have to be set up regarding this issue due to the principle of legality. If harm is afflicted either psychologically or physically or both to the participants it will inevitably effect the results, the experiment may not even be carried out to completion. This causes wasted time, energy, thought, and money on an experiment that could e used on an ethical experiment to further the understanding of science.
I also believe if participants feel abused or mistreated during an experiment, they will not view science the same way again. They will no longer respect science and perhaps discredit what it has already accomplished through experiments. They also may not want to help by participating or funding research thereafter. Science must set a high, ethical standard to be respected, and perhaps the moral gesture will be reciprocated from individuals in their everyday life or field of study.