In this 2019 bibliographic analysis, Alexandra Horowitz and B. Franks examined 481 canine cognition studies published between 2008 and 2018 across 13 scientific journals. Although dogs are known to rely predominantly on their sense of smell, the authors discovered that most studies did not account for olfactory cues or implement scent-related controls during experimental design.
The study highlights a pervasive issue in comparative cognition research: anthropocentric sensory bias, particularly the tendency to prioritize visual cues—despite many animals, including dogs, relying primarily on olfaction, auditory, and chemical communication. As a result, data interpretation in dog cognition studies may be skewed, as researchers often overlook the influence of scent on behavior, attention, learning, and decision-making.
Horowitz and Franks argue that methodological reproducibility is compromised when scent variables are ignored. Without controlling or at least acknowledging the presence of odors—such as human scent traces, previous dog markings, or environmental odors—researchers may inadvertently affect experimental outcomes.
To address this gap, the authors propose a simple reporting rubric for canine cognition research. This framework encourages researchers to document: (1) whether scent variables could have influenced the outcome, (2) how olfactory cues were controlled, masked, or measured, and (3) how dogs’ sensory priorities were considered in study design.
The study emphasizes that appreciating dogs’ olfactory umwelt—their sensory-perceptual world—is crucial for accurately interpreting their cognitive behavior. Incorporating scent awareness not only improves research quality but also deepens understanding of how dogs think, communicate, explore, and make decisions.
Horowitz and Franks conclude that recognizing olfaction as a primary cognitive and communicative modality is essential for advancing canine cognition research, making future studies more accurate, ecologically valid, and meaningful.
Source: Horowitz, A., & Franks, B. (2019). What smells? Gauging attention to olfaction in canine cognition research. Animal Cognition. Published October 12, 2019.
