Abney, D., Conlee, K., Cunneen, M. et al. 2006. Human-animal relationship in the research lab: a discussion by the Refinement and Enrichment Forum. Animal Technology and Welfare 5(2), 95-98.

The question was asked: "Does the regular, affectionate interaction with adult animals help the subject overcome the fear of humans, and hence buffer the stress response to being handled during experimental procedures?" I think an affectionate human-animal relationship makes a huge difference for the animals because it helps them overcome anxiety and fear in disturbing or distressing situations. The stress resulting from a neutral or negative relationship between investigator/technician and animal is bound to affect the research data collected from the animal subject, but the research industry is not yet taking this methodological flaw seriously.