Visible Displacement Tasks Research Articles

Now You See It, Now You Don’t

The cognitive ability of dogs can be assessed using tasks from the human developmental literature. A task that appears to have ecological relevance is the object-permanence task, in which performance hinges on understanding that an object continues to exist once it can no longer be seen. Although dogs are good at visible displacement tasks, in which an object disappears into a container, they can also understand an invisible displacement, in which the container holding the object is moved. Furthermore, we have found that dogs are able to show considerable memory for the invisibly displaced object. We have also found evidence for object permanence in dogs using the violation-of-expectancy procedure, in which subjects look longer at a stimulus that violates expectations (a screen that appears to pass through an object that has been placed behind the screen) than one that does not. Similarly, we have found that dogs look longer at an object that appears to have changed color or size after being placed behind a screen compared to an object that has not changed. Object-permanence tasks provide an ecologically relevant means of evaluating the cognitive development of dogs.

The use of a displacement device negatively affects the performance of dogs (Canis familiaris) in visible object displacement tasks.

Visible and invisible displacement tasks have been used widely for comparative studies of animals' understanding of object permanence, with evidence accumulating that some species can solve invisible displacement tasks and, thus, reach Piagetian stage 6 of object permanence. In contrast, dogs appear to rely on associative cues, such as the location of the displacement device, during invisible displacement tasks. It remains unclear, however, whether dogs, and other species that failed in invisible displacement tasks, do so because of their inability to form a mental representation of the target object, or simply because of the involvement of a more salient but potentially misleading associative cue, the displacement device. Here we show that the use of a displacement device impairs the performance of dogs also in visible displacement tasks: their search accuracy was significantly lower when a visible displacement was performed with a displacement device, and only two of initially 42 dogs passed the sham-baiting control conditions. The negative influence of the displacement device in visible displacement tasks may be explained by strong associative cues overriding explicit information about the target object's location, reminiscent of an overshadowing effect, and/or object individuation errors as the target object is placed within the displacement device and moves along a spatiotemporally identical trajectory. Our data suggest that a comprehensive appraisal of a species' performance in object permanence tasks should include visible displacement tasks with the same displacement device used in invisible displacements, which typically has not been done in the past.

Object permanence in domestic dogs (Canis lupus familiaris) and gray wolves (Canis lupus).

Recent evidence suggests that phylogenetic constraints exerted on dogs by the process of domestication have altered the ability of dogs to represent the physical world and the displacement of objects. In this study, invisible (Experiment 1) and visible (Experiment 2) displacement problems were administered to determine whether domestic dogs' and gray wolves' cognitive capacities to infer the position of a hidden object differ. The results revealed that adult dogs and wolves performed similarly in searching for disappearing objects: Both species succeeded the visible displacement tasks but failed the invisible displacement problems. We conclude that physical cognition for finding hidden objects in domestic dogs and gray wolves is alike and unrelated to the process of domestication.

What do dolphins (Tursiops truncatus) understand about hidden objects?

Object permanence, the ability to mentally represent and reason about objects that have disappeared from view, is a fundamental cognitive skill that has been extensively studied in human infants and terrestrial animals, but not in marine animals. A series of four experiments examined this ability in bottlenose dolphins (Tursiops truncatus). After being trained on a "find the object" game, dolphins were tested on visible and invisible displacement tasks, and transpositions. In Experiments 1 and 2, dolphins succeeded at visible displacements, but not at invisible displacements or transpositions. Experiment 3 showed that they were able to pass an invisible displacement task in which a person's hand rather than a container was used as the displacement device. However, follow-up controls suggested they did so by learning local rules rather than via a true representation of the movement of hidden objects. Experiment 4 demonstrated that the dolphins did not rely on such local rules to pass visible displacement tasks. Thus, like many terrestrial animals, dolphins are able to succeed on visible displacement tasks, but seem unable to succeed on tasks requiring the tracking of hidden objects.

When pigeons in motion lose sight of their food: behaviour on visible displacement tasks revisited

In traditional visible displacement tasks, animals view an object as it is moved out of their sight, but either the object moves behind an occluder or an occluder moves in front of it. Here we present a more ecologically realistic visible displacement task for pigeons ( Columba livia (Gmelin, 1789)) in which it was the animal that occluded the object, a food dish in this case, by virtue of its own motion. In a branched maze, pigeons had visual access to food, which they would lose from view as they moved through the maze. A within-subject design was used whereby the task was presented first in descending order of difficulty (i.e., decreasing memory load owing to the opening of (i) gaps and (ii) windows in the walls of the maze), and followed 10 months later by an ascending order. When the food was visible at all times through windows and gaps, pigeons would make turns in the maze that would bring them closer to the food (i.e., they chose the shortest route above chance levels). In general, they failed to do so when the food was lost from view, but there was one exception at the end of the study (the second time that there were gaps but no windows): there was a significant tendency for the last two turns that brought the bird out of the maze to be the shortest route to the food. The pigeons may have learned to take advantage of opportunities to lighten their memory load.

Piagetian object permanence and its development in Eurasian jays (Garrulus glandarius)

Object permanence in Eurasian jays (Garrulus glandarius) was investigated using a complete version of the Uzgiris and Hunt scale 1. Nine hand-raised jays were studied, divided into two groups according to their different developmental stages (experiment 1, older jays: 2-3 months old, n = 4; experiment 2, younger jays: 15 days old, n = 5). In the first experiment, we investigated whether older jays could achieve piagetian stage 6 of object permanence. Tasks were administered in a fixed sequence (1-15) according to the protocols used in other avian species. The aim of the second experiment was to check whether testing very young jays before their development of "neophobia" could influence the achievement times of piagetian stages. Furthermore, in this experiment tasks were administered randomly to investigate whether the jays' achievement of stage 6 follows a fixed sequence related to the development of specific cognitive abilities. All jays tested in experiments 1 and 2 fully achieved piagetian stage 6 and no "A not B" errors were observed. Performance on visible displacement tasks was better than performance on invisible ones. The results of experiment 2 show that "neophobia" affected the response of jays in terms of achievement times; the older jays in experiment 1 took longer to pass all the tasks when compared with the younger, less neophobic, jays in experiment 2. With regard to the achieving order, jays followed a fixed sequence of acquisition in experiment 2, even if tasks were administered randomly, with the exception of one subject. The results of these experiments support the idea that piagetian stages of cognitive development exist in avian species and that they progress through relatively fixed sequences.

Finding hidden food: Behavior on visible displacement tasks by mynahs (Gracula religiosa) and pigeons (Columba livia).

Finding hidden food: Behavior on visible displacement tasks by mynahs (Gracula religiosa) and pigeons (Columba livia).

Finding hidden food: Behavior on visible displacement tasks by mynahs (Gracula religiosa) and pigeons (Columba livia).

Finding hidden food: Behavior on visible displacement tasks by mynahs (Gracula religiosa) and pigeons (Columba livia).

Development of object permanence in the New Zealand parakeet (Cyanoramphus auriceps)

Eleven young kakarikis (Cyanoramphus auriceps) were tested on 15 object-permanence tasks in a standardized scale that has been used to assess the development of human infants, some nonhuman primates, and other mammals. The birds successfully completed all tasks in this scale, and many aspects of their testing were similar to human results, such as evidencing the A-not-B error. However, the birds differed slightly but significantly from human subjects in that some of the “invisible displacements” of the later tasks were performed before the earlier visible displacement tasks. These results may relate to common ecological activities of this species. Six of the birds were parent-raised; 5 were hand-raised. The hand-raised birds achieved criteria more quickly than did the parent-raised birds possibly because the former were more accustomed to the investigator and less distractible in the test situation.

Search Behavior on Multi-Choice Hiding Tasks: Evidence for an Objective Conception of Space in Infancy

Nineto 10-month old infants were presented with a series of visible displacement hiding trials at a first location (A), and, subsequently, at a second location (B). Infants had to choose among 3, 5, or 6 salient alternative search locations on each trial. Infants seldom searched perseveratively during B-hiding trials, regardless of the number of alternative search locations presented. Instead, infant search attempts tended to cluster around the currently correct location during Aand B-hiding trials on all apparatuses. These findings suggest that infants do not err on visible displacement tasks because they (a) link objects with previous action-locations, (b) rely upon egocentric spatial reference systems, or (c) confuse different hiding locations as a result of a specific form of retrieval competition from the previous hiding location. The results are discussed as evidence for a memory explanation of infant search behavior which contends that infants comprehend the objective nature of spatial relationships, but are less effective information processors than older individuals.