Same-different conceptualization in dogs (Canis familiaris).

Abstract

concept formation was once thought to be a uniquely human ability. An increasing variety of nonhuman species have demonstrated aspects of this ability, however, suggesting that conceptualization is a widely shared aspect of cognition. The capacity to form a concept of same-different, in particular, has now been shown in pigeons, primates, bottlenose dolphins, sea lions, and more. Traditional methods of studying abstract concept formation include matching-to-sample (MTS), same/different (S/D), and relational-matching-to-sample tasks, tasks that typically require animals to discriminate sets of planar images. Some of these methods may actually test familiarity, memory, associative learning, or other phenomena rather than a concept of same-different. In the current study, we tested same-different concept formation in domestic dogs using a variation on the S/D task that required subjects to discriminate sets of three-dimensional objects. This method avoids some pitfalls of matching-to-sample and S/D tasks that use two-dimensional images and thousands of training trials. Dogs were able to learn to classify sets of objects as “same” and “different” and proved to be able to immediately transfer this ability to novel sets, including sets of only two objects. Domestic dogs are promising subjects for future studies of same-different conceptualization due to their widespread availability and willingness to work cooperatively with humans.

The Perception of Similarity, Difference and Opposition

“…In relational match-to-sample tasks, participants are cued with a pair of stimuli that exhibit a given relationship (e.g., sameness, i.e., AA) and are then asked to match these with a target pair that exhibits an identical relationship (i.e., BB, not CD). These methods have frequently been used to test the perception and conceptualization of sameness and difference in non-human animals (for an overview, see Cook and Qadri 2021 ; Diaz et al 2021 ; Lazareva and Wasserman 2017 ; Scagel and Mercado 2023 ; Wasserman et al 2017 ). Based on the results of these studies, it is acknowledged that many species of animals are capable of learning concepts that presuppose detecting and classifying sameness and difference; examples of these animals include bottlenose dolphins (e.g., Mercado et al 2000 ), sea lions (e.g., Kastak and Schusterman 1994 ), parrots (e.g., Pepperberg 1987 ), primates (e.g., Wright and Katz 2006 ), pigeons (e.g., Cook and Brooks 2009 ), dogs ( Scagel and Mercado 2023 ), bumblebees ( Brown and Sayde 2013 ) and honey bees ( Giurfa 2021 ).…”

“…These methods have frequently been used to test the perception and conceptualization of sameness and difference in non-human animals (for an overview, see Cook and Qadri 2021 ; Diaz et al 2021 ; Lazareva and Wasserman 2017 ; Scagel and Mercado 2023 ; Wasserman et al 2017 ). Based on the results of these studies, it is acknowledged that many species of animals are capable of learning concepts that presuppose detecting and classifying sameness and difference; examples of these animals include bottlenose dolphins (e.g., Mercado et al 2000 ), sea lions (e.g., Kastak and Schusterman 1994 ), parrots (e.g., Pepperberg 1987 ), primates (e.g., Wright and Katz 2006 ), pigeons (e.g., Cook and Brooks 2009 ), dogs ( Scagel and Mercado 2023 ), bumblebees ( Brown and Sayde 2013 ) and honey bees ( Giurfa 2021 ). This suggests that the ability to detect sameness and difference, and also the ability to transfer this abstract concept from training stimuli to novel stimuli, are not dependent on language competence.…”

A preliminary investigation to establish conceptual behavior in gray wolves (Canis lupus)

“…The dogs successfully learned the match‐to‐sample task, and the researchers demonstrated abstract‐concept learning of sameness through novel odor trials in which the subjects successfully transferred match‐to‐sample responding to novel stimuli. Scagel and Mercado (2023) focused on same–different concept formation to train six domestic dogs of varying breeds and backgrounds to distinguish between visual stimuli. The authors successfully trained the dogs to make a response of “same” or “different” when presented with sets of nine objects, depending on whether the nine items were identical or mismatched.…”