The New York legislative session ended last week without action on the HALT bill that would have barred the use of solitary confinement in ways that violate international law.  Even without this action, the debate over solitary confinement is sure to continue in New York State's legislatures and others around the country. It is clear by studying the comparison of the reactions of humans subjected to solitary confinement to the reactions of primates who are held similarly gives important new insight into why solitary confinement must be ended.

One of us has long experience with the practice of solitary confinement in prisons and jails as a litigator, advocate and scholar.  In his work, he has seen how solitary confinement imposes psychological pain which is so great that it often leads otherwise normal human beings who are subjected to it to either become psychotic or if not psychotic to engage in behavior indicative of great mental pain.  People in solitary commit suicide at a rate far in excess of people in any other setting; they engage as well often in other self-destructive behavior including self-mutilation, feces throwing and violence. They lose the ability to concentrate and often act erratically and fearfully.  The physical and psychological damage solitary inflicts is often permanent. Witnessing firsthand the awful consequences of subjecting human beings to solitary confinement and looking into the eyes of those inmates struggling to maintain a foothold on reality and sanity is painful.

The other of us is an expert on animal law. He, too, has seen the pain of solitary albeit in a different setting imposed on a different species. Currently, tens of thousands of primates are held in solitary confinement in scientific laboratories across the United States.  He has observed shockingly similar behavior in those primates to what his colleague and co-author observed in prisoners in solitary. Nonhuman primates in solitary confinement become agitated, confused and distraught. Like humans, they often mutilate themselves, tearing out their hair, and attacking their own bodies. They also scream continuously, beat themselves against their cages and exhibit other self-destructive behaviors. As with humans, solitary confinement is for them a searing experience. It frightens, disorients and shatters well-being.

That solitary confinement can have such a powerful deleterious effect even across species demonstrates that it must end in all its forms. Specifically, the New York legislature next term should return to its consideration of the HALT act and pass it. In addition, laws to reform the use of solitary of non-human animals in laboratories should also be passed. Without waiting a moment longer, moreover, administrators of prisons and labs can take steps themselves to end these practices. These actions would ensure the suffering we impose on hundreds of thousands of defenseless beings is relegated to the past. In short, the lessons we learned from looking closely at the harm inflicted by solitary on creatures we care for should be known to everyone and not be wasted.

Michael B. Mushlin and David N. Cassuto are professors of law at the Elisabeth Haub School of Law at Pace University.