What specific science discipline do most social engineering attacks rely on when they are being used?

The answer is: Psychology

Social engineering is a form of crime that's being done by tricking someone into giving a crucial information that can endanger them to other person.

Since this require the victim to be the one that give the information to the perpetrator, this type of crime require the perpetrator to have a good understanding in human psychology and how to influence other people's behavior.

answer; i believe the correct answer is (4) flip a coin as each participant arrives,heads indicates assignment to the first group: tails indicates assignment to the second group;