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 mission 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. But of greater concern is the fact that psychologists tend to give progressively less attention to a motive which pervades our entire lives. Psychologists, at least psychologists who write textbooks, not only show no interest in the origin and development of love or affection, but they seem to be unaware of its very existence.



So begins Harry Harlow's classic paper The Nature of Love, delivered to the Annual Convention of the American Psychological Association in Washington DC in 1958. And so begins too The Harry Harlow Project, James Saunders' fascinating theatrical examination of Harlow's controversial experiments on baby rhesus monkeys.

The irony - more, the perversity - of Harlow's experiments is that, while they were driven by Harlow's almost lyrically expressed desire to understand something as unscientific as love, they were exemplary in their cruelty. He radically demonstrated the importance of maternal love - the security of physical affection - to the physical and psychological development of an infant by showing what happened to monkeys that received no affection and no socialisation. The result, unsurprisingly, was psychotic monkeys.

Then he went further, producing babies by forcing female monkeys raised in isolation - and who were so asocial they couldn't mate - into what he unblinkingly called his "rape pack", a wire restraining device which he used to force-mate females. Finally, he created his most notorious experiment,the "pit of despair", a cage of total isolation in which monkeys were sometimes confined for two years, with which he deliberately engineered clinical depression.

Aside from their ingenious cruelty, it's not difficult to discern a disturbing subtext of misogyny beneath some of these experiments: Harlow's "hostile mother", a machine of teeth and spikes that shot cold air on the unfortunate babies, seems like a caricature of a pathology. Yet these experiments revolutionised contemporary attitudes towards child rearing, changing practice in orphanages and rewriting the book on infant psychology. And he initiates a theory of fatherhood - "It is cheering ... to realize that the American male is physically endowed with all the really essential equipment to compete with the American female on equal terms in one essential activity: the rearing of infants," he noted at the end of his paper - which still has reverberations today.

In Harlow's day, childrearing authorities recommended that one should never kiss a child good night, but shake his or her hand. A generation of mothers listened in anguish to their crying babies, sure that should they obey their instincts and comfort them, they should be bad mothers. Harlow changed all that, legitimising human affection as more than mere "indulgence". For all that, it's hard to contemplate these experiments with any sense of ease. And it's hard to escape the thought that, by scientifically proving that maternal love was necessary to develop a healthy child, Harlow convinced the men in white coats of wisdoms that women in so-called "primitive" societies have known since, well, the beginning of time.

It's an ambiguous heritage, and James Saunders accesses much of its bleak emotional resonance in The Harry Harlow Project, which manages to be at once harrowing and funny without either cancelling the other out. The stage becomes a slapstick simulacra of Harlow's psyche, with some deft video work by Martyn Coutts and a subliminally disturbing score by Kelly Ryall framing a bravura performance by Saunders. The conceit - a just one, since in later life Harlow had ECG treatment for depression - is that in his increasingly sadistic experiments Harlow is enacting his own mental distress.

As a theatrical evocation of the hell of alienation, parts of this show are hard to beat. The stage - a white box scattered with minimal props - is fronted by sound and lighting boards, with the artists, their backs to the audience, orchestrating the show like lab technicians. A sequence where the actor interacts with his life-size projection - reaching out, like Michelangelo's God, to his fleshly human image, but finally unable to touch - is masterly. It's set up by an earlier sequence where Saunders is interviewed by a television, a device that works seamlessly through split-second timing but which here is comedic. Saunders' performance invokes the damaged monkeys through physical movement, which itself also presages Harlow's death through Parkinson's disease.

The narrative is told through fragmentary episodes that examine the experiments in tandem with glimpses of Harlow's personal life. At one point Saunders puts on a wig and becomes his own biographer; at another, he becomes Harlow's son. Curiously, in both these enactments he doesn't cease to be Harry Harlow: these other characters seem like mere projections. Perhaps what I found most interesting is how Lipson's direction coins a kind of dramaturgy of anxiety: from the beginning the comedy is uneasy, and despite the explosive release of laughter the tension subliminally winches up, not permitting any release, until the show is over. It left me with all that anxiety still in my body, bleeding out a slow release over the following days.

Perhaps because its black and white aesthetic so successfully evokes the sixties, it got me in personal places that I wouldn't have predicted from its set-up or subject. It made me think of how my father was sent to boarding school when he was four years old, and of my mother's unhappiness, raising babies alone in a mining village at the same time as Harlow was torturing monkeys. It made me think of the post-war scientist-god, certain that all human knowledge can be dissected and measured, sure in his march towards the ultimate good of Progress. It made me ponder again how such smart animals as human beings can get things so wrong.

Picture: James Saunders as Harry Harlow. The Harry Harlow Project, written and performed by James Saunders, directed and designed by Brian Lipson. Composition and sound design by Kelly Ryall, video art by Martyn Coutts, dramaturgy by Kate Sulan. Full Tilt, Fairfax Studio, Victorian Arts Centre until December 5.