The site is credible because the illusions are explained by Associate Professor of the Department of Psychology in the American University in Washington DC. The site also allows you to alter the illusion to help you understand how it's formed.

Only watch from 9:10 to 41:00 This video talks about many different things. From the Nature vs. Nurture debate, epigenetics, addicts, and it also talks about the important psychological needs of young children and even the needs of a fetus in the womb of their mother.