"Love is a wondrous state, deep, tender, and rewarding. Because of its intimate and personal nature it is regarded by some as an improper topic for experimental research. But, whatever our personal feelings may be, our assigned missions as psychologists is to analyze all facets of human and animal behavior into their component variables. So far as love or affection is concerned, psychologists have failed in this mission. The little we know about love does not transcend simple observation, and the little we write about it has been written better by poets and novelists."

“Because that's how it feels when you're depressed.”

“The effects of 6 months of total social isolation were so devastating and debilitating that we had assumed initially that 12 months of isolation would not produce any additional decrement. This assumption proved to be false; 12 months of isolation almost obliterated the animals socially.”

“hereas Milgram’s findings need constant reiteration in every generation, Harlow’s research no longer surprises us. One might say that its very success has made teaching it unnecessary: No one would argue against Harlow’s findings, as many students always want to do with Milgram’s.”

“In our study of psychopathology, we began as sadists trying to produce abnormality. Today, we are psychiatrists trying to achieve normality and equanimity.”

“The only thing I care about is whether a monkey will turn out a property I can publish. I don't have any love for them. Never have. I don't really like animals. I despise cats. I hate dogs. How could you like monkeys?”

“In the first place I have an enormous regard for common sense. Any time we discover some great thing and it contradicts common sense, we better go back to the laboratory and check it.”