Current Status of Animal-Assisted Interventions in Scientific Literature: A Critical Comment on Their Internal Validity

Abstract

Many meta-analyses and systematic reviews have tried to assess the efficacy of animal-assisted interventions (AAIs), reaching inconsistent conclusions. The present work posits a critical exploration of the current literature, using some recent meta-analyses to exemplify the presence of unattended threats. The present comment illustrates that the field (1) comprehends inconsistencies regarding the terms and definitions of AAIs; (2) pays more attention to the characteristics of the animals than to the action mechanisms of AAIs; (3) does not provide a clear connection between anthrozoology (how humans and non-human animals interact in communities), benefits of the human–animal interaction (HAI), and the design of AAIs; and (4) implicitly reinforces these phenomena through research designs. Thus, some conclusions extracted from these meta-analyses need further discussion. Increasing the internal validity of AAIs in empirical studies is an urgent task, which can be addressed by (1) developing a better understanding of how anthrozoology, the HAI, and AAIs relate to each other; (2) highlighting the mechanisms that explain the results in an empirical and specific way; and (3) changing the design of interventions, adopting a component-centered approach, and focusing on the incremental efficacy and efficiency of AAI programs.

Effectiveness of animal-assisted interventions for children and adults with post-traumatic stress disorder symptoms: a systematic review and meta-analysis

“…For most of the studies, detailed information regarding the study design, methodology or the intervention itself was missing. It is important to know in what way the animal was integrated (animal just being present, animal embedded in a therapeutic narrative, amount of physical contact or even riding if horses were present) as this is an important aspect of the intervention and needs to be systematically investigated rather than the presence of an animal itself (Lopez-Cepero, 2020 ). For example, the study by Dietz and colleagues revealed greater positive outcomes when a dog was integrated into the intervention via using therapeutic stories about the dog compared to the dog just being present during the intervention (Dietz et al, 2012 ).…”

“…The results of these studies only allow measurement of the impact of the intervention as a whole but not the individual effect of its components, e.g. the effect of the human–animal contact, the effect of the psychotherapeutic intervention, or the interaction of both (Lopez-Cepero, 2020 ). Accordingly, the selection of an appropriate control group for future research is crucial.…”

Animal-Assisted Intervention in Speech-Language Pathology: Practical, Clinical, and Theoretical Considerations

“…The limits of the evidence base also reflect some of the research design challenges AAI investigators need to overcome. An exhaustive account of the limitations of the evidence base is beyond the scope of this review, 15 21 31 32 33 34 but it is important to highlight some of those of particular relevance for guiding clinical consumers. Sample sizes in studies of AAT are comparatively small, which can limit the (statistical) power of the study for detecting treatment effects.…”

Animals in higher education settings: Do animal-assisted interventions improve mental and cognitive health outcomes of students? A systematic review and meta-analysis

“…One example of a benefit derived from the connection between humans and animals is animal-assisted interventions (AAIs). The term “AAI” has become an umbrella term in the human-animal interaction (HAI) field, referring to all interventions that incorporate some element of HAI to achieve the desired outcome [3,4]. Based on the definition presented by López-Cepero, in this review AAIs are defined as any intervention that incorporates an element of HAI with an unfamiliar animal, with the aim of improving a human health outcome [4].…”