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

Simple Summary Animal-assisted interventions (AAIs) have been receiving ever-increasing attention from both practitioners (including psychologists, educators, social workers, and physicians) and clients alike. However, despite this interest, the literature does not provide an unanimous support for including dogs, horses, cats, or other animals in interventions. The present work analyzes whether or not this lack of support could be understood as the result of inconsistencies and/or biases present in the literature, analyzing the definition of AAIs, the role of animals in interventions, the relationship among AAIs and the way humans relate to non-human animals, and the way in which researchers study these phenomena. The present comment provides some clues on how to improve the development of the field, including the following: giving more prominence to cultural, anthrozoological aspects of AAIs; considering AAIs as modalities of well-known interventions, avoiding their representation as alternative, new, or groundbreaking; and making changes to the study and intervention of designs, thus making it easier to demonstrate the impact of human-animal interactions on improving outcomes. 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.