It is mine! Using clicker training as a treatment of object guarding in 4 companion dogs (Canis lupus familiaris)

Aggressive behaviors in companion dogs are a serious problem to owners, which often result in important physical and emotional damage on the victims. Aggressive incidents frequently happen during human-dog interactions (i.e., reaching toward the dog or petting it) while the dog is engaging with a preferred item (e.g., a toy, sock, or shoe). The present study investigated whether a clicker-training approach, backward chaining, could decrease the frequency of category II (e.g., ears flattened and/or hovering over the object) and category III (e.g., staring and/or stiffening up) behaviors by establishing an alternative target response of releasing preferred item on cue. Four dogs were exposed to the intervention using a nonconcurrent multiple-baseline single-case experimental design. Each dog experienced a total of 14 conditions, including baseline conditions (i.e., rates of preferred item release on request before any training), treatment conditions (i.e., different steps of the backward chaining procedure, such as release or place, sit), and probe conditions (i.e., same procedure as baseline but conducted after varying steps during treatment condition). Success rates of the target response more than doubled in all dogs after implementation of the backward-chaining procedure, ranging from 2% to 85%. Rates for category II responses showed an important reduction in 3 of the 4 dogs ranging from 39% to 55%. In the case of category III aggressive responses, there was a reduction in frequency relative to baseline rates ranging from 58% to 69% across all dogs. During follow-up probes conducted 3 months after the intervention ended, average rates of category II behaviors decreased by 23% for the dog in human-dog dyad 1 and 35% for the dog in dyad 2, whereas rates of category III responses reverted back to baseline levels in dogs in dyads 01 (D01) and 02 (D02). Success rates during follow-up probes more than doubled for dog D01 from 2% to 45% and reverted to baseline levels for D02. Overall, the present study showed that backward chaining is an effective procedure to teach dogs to release a highly preferred item on cue and importantly reduce category II and III behaviors, at least short term. Considering the scarcity of studies on the effectiveness of backward chaining in aggression-related behaviors, further research could extend these promising findings, including determining whether ongoing maintenance training would extend this effect, and addressing the present study's limitations (e.g., using a refined categorization of aggressive responses).