Answer:
Confirmation bias
Step-by-step explanation:
Confirmation bias is also denoted as a confirmatory bias in psychology. It is defined as a phenomenon that states an individual tends to believe only on those things or search for those explanations that generally confirms his or her thinking-pattern. It can often lead an individual to possess false beliefs that support his or her beliefs in the absence of any evidence.
In reference to the question, Greg's behavior best illustrates confirmation bias.