Making the world better, one answer at a time. Deodorant was around in ancient times but modern day deodorant was invented in 1888 by an inventor in Philadelphia, Pennsylvania.
Behavioral observations are a key component of cognitive psychology. Behavioral observations give cognitive psychologists a means of testing and evaluating theories about behaviors and a means of testing any predictions about those behaviors.
Non-participant observation is observation with limited interaction with the people one observes. For example, some observational data can be collected unobtrusively (e.g. worn out carpet as indicators of high use areas in a physical setting).