The social science studies aspects of a human society. Economics, which studies how people deal with scarcity, is an example of social science. Other examples of social sciences are anthropology (study of human culture), sociology (study of humans in groups), and linguistics (study of natural language). It should be noted that economics is in no way an exact science.
Similar to psychology it is based solely on theories and has not produced any scientific "laws". There are theories, but there are normally exceptions to be found. Economics, as well as other similar kinds of social sciences, are affectionately labeled "soft" sciences. There has been real life situations, though that suggest that these theories are correct or a better word logical. (Despite this, many mathematical economic relationships are absolutely true, though not absolutely "scientific", such as the relationships between ATC and MC)
Throughout the history of economics and the study of human behavior, models have been created that appear to accurately describe human behavior for only a short period of time. As time goes on, those models become obsolete with increasing levels of abnormalities and exceptions. Therefore, the science of human behavior is ever changing; we may never understand human behavior in the long run.