Human-animal interaction research needs to address methodological limitations and expand the focus beyond treatment-outcome studiesHuman-animal interaction (HAI) has a long history as a method of improving mental health and reducing psychological distress. It continues to be used today in widely diverse settings (hospitals, schools, airports, libraries, clinics, etc.) for the purpose of reducing psychological distress. While HAI has widespread popular support, research documenting its effectiveness in reducing psychological distress is inconclusive. This paper reviews the evidence and includes a discussion of the primary limitations and interpretive challenges of the research on HAI. Five common research limitations discussed include (1) extra therapeutic factors, (2) social facilitation, (3) insufficient statistical power, (4) generalization across animals, and (5) publication bias and questionable research practices. Proposed solutions to each of these limitations are offered for future HAI research.
While the research suggests that HAI has a small-to-medium effect on distress, it does not clarify whether animals account for the treatment effects. Other possibilities include the increased social interaction between humans when animals are present and such extratherapeutic factors as the time of day or the passage of time. The author presents several possible rationales for the positive influence of HAI on distress including biophilia (innate affinity for living things), tactile stimulation, coping support, entertainment, social support, and expectancy effects. She notes, however, that there is no conclusive evidence in favor of any of these – or other – proposed mechanisms. She calls for carefully-designed empirical studies to establish the relative contributions of proposed mechanisms.
The author presents additional areas for future work to improve research and practice in HAI and highlights three priority areas: identifying how HAI reduces distress; determining when HAI is most effective at reducing distress; and examining how HAI affects the animals. The various forms of HAI also need to be acknowledged and supported, including interactions between companion animals and their owners; casual interactions in the street; interactions with non-companion animals (e.g., animals at zoos, on farms, and in aquariums); unstructured animal-assisted activities; animal-assisted therapies (in which animals serve as adjuncts in other treatments); and interactions between individuals and their service animals. These various forms of HAI require different types and levels of evidence. Pursuing these areas of research can increase, not only our understanding of the mechanisms of HAI, but also the impact and credibility of HAI as a method of reducing psychological distress.
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