For almost a century, millions of cats, dogs, monkeys, and other laboratory animals have fallen victim to the misguided notion that by torturing animals we may someday find the golden key that unlocks the dark corners and passageways of human psychology. Heedless of any relevance the experiments may have to the human condition or of the differences between humans and other animals, experimental psychologists are exercising unbridled on animals the whole range of suffering, from emotional trauma, like that experienced by the doomed infant monkey, to outright physical torture. Animals have been blinded and returned to the wild to test their ability to survive. They've been placed in tanks of water to record how long they will struggle against an inevitable drowning. They have been subjected to all manner of unnatural conditions, stress, and pain to see how much they can take before being driven to cannibalism. And, because their behavioral response to the agony that is deliberately inflicted upon them is the important factor in the researchers' observations, the hapless victims are denied painkillers. These outrages have been repeated, with only minor variations, over and over again.
Experimental psychology is particularly fiendish because it's the only area of research in which animals are deliberately tortured as part of the experiment's design. And it is the area of research where the greatest suffering is created for the least amount of good.
The Humane Society of the United States, "The HSUS Condemns Psychological Experimentation on Animals" (1984). CUP. 16.