animals Review What’s in a Click? The Efficacy of Conditioned Reinforcement in Applied Animal Training: A Systematic Review and Meta-Analysis Nicole Pfaller-Sadovsky 1,*, Camilo Hurtado-Parrado 2,3 , Daniela Cardillo 4, Lucia G. Medina 3 and Susan G. Friedman 5 1 School of Biological Sciences, Queen’s University Belfast, Belfast BT95AJ, UK 2 Department of Psychology, Troy University, Troy, AL 36082, USA;
[email protected] 3 Faculty of Psychology, Fundación Universitaria Konrad Lorenz, Bogota 110221, Colombia;
[email protected] 4 Green Dogs, Via Dante Alighieri 7, 23814 Cremeno, Italy;
[email protected] 5 Department of Psychology, Utah State University, Logan, UT 84322, USA;
[email protected] * Correspondence:
[email protected]; Tel.: +43-664-4226-538 Received: 14 August 2020; Accepted: 25 September 2020; Published: 28 September 2020 Simple Summary: Conditioned reinforcement, for example, clicker training, has become increasingly popular in recent decades. Hence, questions about the effectiveness of the conditioned reinforcer have become prominent in the animal training arena. This article summarizes the scientific literature on conditioned reinforcement in applied animal training settings (e.g., homes). It was found that dogs and horses were the most frequently studied animals. Clickers and food were the most often used training stimuli. Effect size analysis found a medium effect of clicker training. The literature reviewed here shows that conditioned reinforcement is an effective approach to change animal behavior; however, sizable information potentially related to its effectiveness was not clearly reported in the studies (e.g., food preferences). Although this review fills in a gap in the literature, it also points to the need for more research to further the understanding of conditioned reinforcement phenomena.