Chimpanzee research should be permitted only on animals maintained in an ethologically appropriate physical and social environment or in natural habitats. Chimpanzees live in complex social groups characterized by considerable interindividual cooperation, altruism, deception, and cultural transmission of learned behavior (including tool use). Furthermore, laboratory research has demonstrated that chimpanzees can master the rudiments of symbolic language and numericity, that they have the capacity for empathy and self-recognition, and that they have the humanlike ability to attribute mental states to themselves and others (known as the “theory of mind”). Finally, in appropriate circumstances, chimpanzees display grief and signs of depression that are reminiscent of human responses to similar situations. It is generally accepted that all species, including our own, experience a chronic stress response (comprising behavioral as well as physiological signs) when deprived of usual habitats, which for chimpanzees includes the presence of conspecifics and sufficient space and environmental complexity to exhibit species-typical behavior. Therefore, to perform rigorous (replicable and reliable) biomedical and behavioral research, it is critical to minimize potential sources of stress on the chimpanzee. This can be achieved primarily by maintaining animals on protocols either in their natural habitats, or by consistently maintaining with conspecifics in planned, ethologically appropriate physical and social environments...You can read the report here.
This resulted in the National Institutes of Health deciding to move toward the elimination of funding for most research using chimpanzees and to move toward the elimination of NIH-funded colonies by not funding any breeding. The news was instantly cheered by most informed people and also instantly criticized by some who "earn" a living by experimenting on animals. The primate vivisectors were particularly outraged.
As they feared, the NIH decision regarding chimpanzees has caused at least a few people to begin wondering about monkeys as well. See Medical Experimentation on Chimps Is Nearing an End. But What About Monkeys? and If We’re Retiring Research Chimps, Why Are We Excluding Monkeys?
Here's a piece I wrote in 2002, asking the same question: How Like Us Need They Be?