Roscoe G. Bartlett lays out his case:

We also know more about the consequences of invasive research on the animals themselves. Biomedical procedures that are simple when performed on humans often require traumatizing restraint of chimpanzees to protect human researchers from injury, as chimpanzees are five times stronger than humans. For instance, acquiring a blood sample from a chimp can require a “knockdown,” or shooting it with a tranquilizer gun. If you’ve seen video of a knockdown, you know it is clearly frightening and stressful.

Moreover, even the mere confinement in laboratory cages deprives chimpanzees of basic physical, social and emotional sustenance. Numerous peer-reviewed studies of chimpanzees in sanctuaries who had previously been confined in laboratories have documented behavioral symptoms associated with post-traumatic stress disorder. Chronic and traumatic stress harms chimpanzees’ health and compromises the results of experiments conducted on them.

There is no question that chimpanzees experience pain, stress and social isolation in ways strikingly similar to the way humans do. James Marsh’s recent documentary, “Project Nim,” chronicles the 27-year life of Nim Chimpsky, a chimpanzee who was the subject of a controversial research project that involved raising him as though he were a human. Nim was taught sign language — and he used those signs to tell his human interlocutors that he was traumatized by his living conditions.