Objective measurement of fear-associated learning in dogs

Attempts have been made in many studies to measure canine behavioral traits, but the results cannot be compared, because no standardized methods exist. The purpose of this study was to standardize the fear-eliciting stimuli (i.e., a conditioned stimulus) to assess a particular behavioral trait, namely fearfulness. We applied a Pavlovian aversive conditioning protocol and measured autonomic parameters, in addition to making behavioral observations. Fear-related autonomic responses, such as increased heart rate and increased body temperature, rose consistently in response to a conditioned stimulus, but behavioral changes did not consistently correlate with the physiological responses. Our findings show that dogs clearly respond to conditioned stimuli and that their autonomic reactions assessed in objective indices can be more reliable and consistent measures than some behavioral measures. Based on these results, we propose that associative learning between fear-inducing conditioned and unconditioned stimuli can be assessed accurately in dogs.