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).

Dogs choose a human informant: Metacognition in canines

Shannon McMahon, Krista Macpherson, William A. Roberts

Dogs choose a human informant: Metacognition in canines

Behavioural Processes, Volume 85, Issue 3, October 2010, Pages 293–298

Abstract

The presence of metacognition in animals has been suggested by the observation that non-human primates will seek out information about the location of a hidden reward before responding. In experiment 1, dogs failed to make an information-seeking response that involved re-positioning themselves in space so that they could view a cue that indicated the location of food. In experiments 2 and 3, dogs were allowed to choose between two people, an informant that pointed to the location of food and a non-informant that provided no information. Dogs showed a clear preference for the informant, even when choice of the informant led to no greater chance of reward than choice of the non-informant. In a procedure that involves human communication, dogs show information-seeking behavior.

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.

The breakfast effect: Dogs (Canis familiaris) search more accurately when they are less hungry

Holly C. Miller, Charlotte Bender

The breakfast effect: Dogs (Canis familiaris) search more accurately when they are less hungry

Behavioural Processes, Available online 29 September 2012

Abstract

We investigated whether the consumption of a morning meal (breakfast) by dogs (Canis familiaris) would affect search accuracy on a working memory task following the exertion of self-control. Dogs were tested either 30 or 90 min after consuming half of their daily resting energy requirements (RER). During testing dogs were initially required to sit still for 10 min before searching for hidden food in a visible displacement task. We found that 30 min following the consumption of breakfast, and 10 min after the behavioral inhibition task, dogs searched more accurately than they did in a fasted state. Similar differences were not observed when dogs were tested 90 min after meal consumption. This pattern of behavior suggests that breakfast enhanced search accuracy following a behavioral inhibition task by providing energy for cognitive processes, and that search accuracy decreased as a function of energy depletion.

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.

Learning and owner–stranger effects on interspecific communication in domestic dogs (Canis familiaris)

Angel M. Elgier, Adriana Jakovcevic, Alba E. Mustaca, Mariana Bentosela

Learning and owner–stranger effects on interspecific communication in domestic dogs (Canis familiaris)

Behavioural Processes, Volume 81, Issue 1, May 2009, Pages 44–49

Abstract

Domestic dogs are very successful at following human cues like gazing or pointing to find hidden food in an object choice task. They solve this kind of situation at their first attempts and from early stages of their development and perform better than wolves. Most of the authors proposed that these abilities are a domestication product, and independent from learning processes. There are few systematic studies on the effects of learning on dogs’ communicative skills. We aim to evaluate the effect of extinction and reversal learning procedures on the use of the pointing gesture in an object choice task. The results showed that dogs stopped following the pointing cue in the extinction and that they learned to choose the not pointed container in the reversal learning. Results suggest that instrumental learning plays an important role in interspecific communication mechanisms between humans and dogs. In both experiments for half of the subjects the pointer was the owner and for the rest was a stranger. A differential effect was found: extinction was slower but reversal learning was faster when the owner gave the cue. This data indicates that the relationship of the dog with the person who emits the cue influences performance.