The case of the disappearing bone: Dogs’ understanding of the physical properties of objects

Kristina F. Pattison, Holly C. Miller, Rebecca Rayburn-Reeves, Thomas Zentall

The case of the disappearing bone: Dogs’ understanding of the physical properties of objects

Behavioural Processes, Volume 85, Issue 3, October 2010, Pages 278–282

Abstract

To assess dogs’ memory for an occluded object, a gaze duration procedure was used similar to one often used with nonverbal infants. A bone shaped dog biscuit was placed behind a solid screen that then rotated in the depth plane through an arc front to back. Dogs were shown either of the two test events. In one event (the possible event), the screen rotated until it reached the point at which it would have reached the bone and then stopped (about 120°); in the other event (the impossible event), the screen rotated through a full 180° arc, as though it had passed through the bone. The dogs looked significantly longer at the impossible event. To control for the differential time it took for the screen to move, for a control group, a bone was placed behind the screen and the screen was rotated either 60° or 120° (both possible events). No difference in looking time was found. To control for the movement of the screen through 120° or 180° when both were possible, for a second control group, the bone was placed to the side of the screen rather than behind the screen and the screen was moved 120° or 180°. Again, no significant difference in looking time was found. Results suggest that much like young children, dogs understand the physical properties of an occluded object. That is they appear to understand that an object (such as a screen) should not be able to pass through another object (such as dog bone).

Figurative and spatial information and search behavior in dogs (Canis familiaris)

Claude Dumas

Figurative and spatial information and search behavior in dogs (Canis familiaris)

Behavioural Processes, Volume 42, Issues 2–3, February 1998, Pages 101–106

Abstract

Domestic dogs (Canis familiaris) were administered a variant of the delayed matching-to-sample task in which they had to recover a hidden object and in which both spatial and figurative information were kept constant at the outset of each trial. Thereafter, either spatial (i.e. spatial condition) or figurative cues (i.e. figurative condition) became relevant to solve the task. The results revealed that dogs rapidly associated a spatial cue with the recovery of the object. The discussion emphasizes the role of cognitive and ecological constraints to account for the fact that figurative information was not readily used as a cue to guide search behavior.

What do dogs know about hidden objects?

Holly C. Miller, Rebecca Rayburn-Reeves, Thomas R. Zentall

What do dogs know about hidden objects?

Behavioural Processes, Volume 81, Issue 3, July 2009, Pages 439–446

Abstract

Previous research has found that dogs will search accurately for an invisibly displaced object when the task is simplified and contextual ambiguity is eliminated [Doré, F.Y., Fiset, S., Goulet, S., Dumas, M.-C., Gagnon, S., 1996. Search behavior in cats and dogs: interspecific differences in working memory and spatial cognition. Animal Learning & Behavior 24, 142–149; Miller, H., Gipson, C., Vaughan, A., Rayburn-Reeves, R., Zentall, T.R., 2009. Object permanence in dogs: invisible displacement in a rotation task. Psychonomic Bulletin & Review 16 (1), 150–155]. For example, when an object is placed inside an occluder, one of which was attached to each end of a beam that could be rotated 90°, dogs search inside of the appropriate occluder. The current research confirmed this finding and tested the possibility that the dogs were using a perceptual/conditioning mechanism (i.e., their gaze was drawn to the occluder as the object was placed inside and they continued looking at it as it rotated). The test was done by introducing a delay between the displacement of the object and the initiation of the dogs’ search. In Experiment 1, during the delay, a barrier was placed between the dog and the apparatus. In Experiment 2, the lights were turned off during the delay. The search accuracy for some dogs was strongly affected by the delay, however, search accuracy for other dogs was not affected. These results suggest that although a perceptual/conditioning mechanism may be involved for some dogs, it cannot account for the performance of others. It is likely that these other dogs showed true object permanence.