Is there some scientific methodology for this kind of trial? If I knew I was participating in an experiment and I get presented with this kind of artificial te

Is there some scientific methodology for this kind of trial? If I knew I was participating in an experiment and I get presented with this kind of artificial test then I know they are looking for some kind of response, and my actions are highly liked to be influenced by the fact that I know I am under observation. According to the paper (http://www.rotman.utoronto.ca/newthinking/greenproducts.pdf http://www.rotman.utoronto.ca/newthinking/greenproducts.pdf) the sample sizes seem pretty small. I'm no statistician, but is it really valid to draw conclusion of people's behaviour from a sample size of < 100 people??