This is part of the phenomenon of "Perceptual constancy".
Perceptual constancy, likewise called Object Constancy, or Constancy Phenomenon, the inclination of creatures and people to see recognizable questions as having standard shape, size, shading, or area paying little heed to changes in the point of viewpoint, separation, or lighting.
I believe the answer is: Cognitive dissonance
In psychology, cognitive dissonance refers to a situation when an individual is having inconsistent thought, behaviors, or principles.
Cognitive dissonance is much more common among people in teenage-young adults when their moral compass is still not fully developed yet.
Experimental. Dr James used an experimental model of research for his study which involved facial symmetry. Experimental studies basically comprise of an independent and dependent variable. The goal is to observe if the independent variable has an effect on the dependent variable, and if it has how strong and where is it heading? This is how an experimental study is performed.