Animals' representation of enclosed spaces: Evidence for use of a similar frame of reference following different disorientation procedures in the domestic chick (gallus gallus).

A wide range of vertebrate species has been proved to be capable, following passive disorientation, to reorient into enclosures of different shapes using the metrical distribution of surfaces as surfaces and the geometric sense of left and right. Two procedures can be used to get a subject to loose its orientation: The subject itself can be rotated with the eyes closed or in the dark (viewer-movement procedure) or the external enclosure can be rotated while the subject stays still in a fixed position with the eyes closed or in the dark (i.e., without the possibility to notice any change outside; space-movement procedure). Although the 2 procedures are equivalent in that both cause a change in the spatial relationships between the viewer and the external layout, it has been suggested on the basis of research in human infants that they may involve the use of different frames of reference to reestablish one's bearing and relocate the target. However, no comparison between viewer- and space-movement procedures has been carried out in nonhuman species. Here, the authors show that newborn domestic chicks (Gallus gallus) can reorient effectively irrespective of the specific disorienting procedure applied. The results are discussed in comparative and developmental perspectives. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rudimental numerical competence in 5-day-old domestic chicks (Gallus gallus): Identification of ordinal position.

Numerical competencies were investigated for the 1st time in very young nonhuman animals. Chicks (Gallus gallus) learned to identify the 3rd, 4th, or 6th positions in a series of 10 identical positions (Experiment 1). Use of spatial information (i.e., distances) was ruled out in Experiment 2 (chicks generalized the reinforced response to an array of stimuli rotated by 90° as compared with training) and Experiment 3 (chicks generalized their response to a series in which distances between the single positions had been manipulated). Chicks found the correct position even when both identity and distance of each position changed from trial to trial (Experiment 4). Overall, young chicks seemed to use ordinality when required to identify a target by its numerical serial position. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Preference for symmetry is experience dependent in newborn chicks (Gallus gallus).

Spontaneous pecking preferences toward symmetric or asymmetric stimuli were tested in newborn chicks (Gallus gallus). A preference for asymmetric patterns was found in na?ve chicks (either 24 or 48 hours old), although a preference for symmetry appeared at retest after chicks had experienced standard rearing conditions (Experiments 1 and 2). Only food-experienced chicks preferred symmetric patterns; food-deprived and hand-fed chicks did not show any preference (Experiment 3). A key factor that allowed for the emergence of a preference for symmetry may relate to the improving of pecking sensorimotor skills occurring during active food manipulation. Possible explanations are discussed for the late emergence of the preference for symmetry and for the preference for asymmetry found in na?ve chicks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Affiliation and aggression as related to gender in domestic chicks (Gallus gallus).

Social discrimination in male and female domestic chicks (Gallus gallus) was investigated by using (1) latencies of approach response, (2) simultaneous free choice, and (3) intersubject aggressive-pecking tests. In approach-response tests, females showed shorter latencies when tested with cagemates than when tested with strangers, whereas males showed shorter latencies when tested with strangers than when tested with cagemates. In simultaneous-choice tests, females spent more time near a cagemate, whereas males spent more time near a strange chick. In aggressive-pecking tests, both sexes pecked more at strangers than at cagemates; aggressive pecking at strangers, however, was higher in males than in females. It is argued that gender effects in social discrimination can be accounted for in terms of stronger social attachment in females and aggressive responses in males. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The acquisition of stimulus control over released pecking by hatchling chicks (Gallus gallus).

Analyzed the spatial and dynamic stimulus characteristics of the pecking arrow display that control simple release and/or learned release of pecking by 254 hatchling chicks in 5 experiments. Findings show (1) a pronounced preference by Ss to peck at red rather than green illuminated lamps, (2) significantly greater pecking by Ss to lamps attached to, and on the floor beneath, the pecking arrow during the display, and (3) little evidence that placement of a stimulus on the arrow, on the floor beneath the arrow, or in both locations differentially affected frequency of pecking to matching stimulus colors. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Incentive contrast in domestic dogs (Canis familiaris).

Dogs (Canis familiaris) trained to receive a preferred food (dry beef liver) from an experimenter learned to maintain a longer gaze on the experimenter than dogs receiving a less preferred food (dog pellets). Dogs downshifted from dry liver to pellets rejected food more frequently than nonshifted controls. Gaze duration also decreased in downshifted dogs below the level of a group always reinforced with pellets. In addition, downshifted dogs tended to move away from the experimenter, adopting a lying down posture. This phenomenon, called successive negative contrast, has been described in analogous experiments with a variety of mammalian species, but has failed to occur in similar experiments with nonmammalian vertebrates. Unlike similar previous observations, the present data were obtained in an environment involving interspecific communication. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Searching for the center: Spatial cognition in the domestic chick (Gallus gallus).

Chicks learned to find food hidden under sawdust by ground-scratching in the central position of the floor of a closed arena. When tested in an arena of identical shape but a larger area, chicks searched at 2 different locations, one corresponding to the correct distance (i.e., center) in the smaller (training) arena and the other to the actual center of the test arena. When tested in an arena of the same shape but a smaller area, chicks searched in the center of it. These results suggest that chicks are able to encode information on the absolute and relative distance of the food from the walls of the arena. After training in the presence of a landmark located at the center of the arena, animals searched at the center even after the removal of the landmark. Marked changes in the height of the walls of the arena produced some displacement in searching behavior, suggesting that chicks used the angular size of the walls to estimate distances. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Defining the rhythmicity of memory-enhancing acoustic stimuli in the young domestic chick (Gallus gallus).

Research has demonstrated that exposure to a rhythmic auditory stimulus can promote retention of a simple memory task in an avian species. In the current study, day-old domestic chicks (Gallus gallus) were trained on a weakly reinforced discriminative avoidance task for which retention is typically lost 30 min posttraining. Exposure to rhythmic stimuli 5 min posttraining prevented memory loss, but only when sequences were highly metrical and contained sufficient repetition. These data provide further support for the claim that rhythmicity is a key feature of memory-enhancing auditory stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Landmark-based search memory in the domestic dog (Canis familiaris).

Recent studies have suggested that any animal that relies on landmark-based search memory encodes and uses metric properties of space to navigate. So far, however, metric information provided by landmarks has been predominantly investigated in avian species. In the present study, I investigated whether the domestic dog (Canis familiaris), a mammalian species, encodes the distance and direction from landmarks. Dogs were trained to find a ball hidden next to an array of two distinct landmarks that remained at a constant location in a room from trial to trial. After training, the dogs were occasionally tested on unrewarded conditions where the array was either left in its usual position or shifted laterally, perpendicularly, or diagonally relative to the rear wall of the room. Although the dogs significantly shifted their search as a function of the displacement of the landmarks, they did not search at the predicted coordinates of the goal relative to the shift of the landmarks, suggesting that the global cues available in the testing room were also encoded and used by dogs to locate the position of the goal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Control of spatial orientation in terrestrial toads (Rhinella arenarum).

Three experiments were conducted to determine problem-solving strategies used by toads, Rhinella arenarum (= Bufo arenarum), in spatial learning situations, using water as reward. Experiment 1 showed that toads can acquire a spatial orientation based on a body-centered turn -an internal self-reference cue. Experiment 2 showed that toads can use a fixed landmark (visual cue) as guidance to solve a spatial problem. Experiment 3 determined whether maze learning was based on “body-centered turn” or “guidance”. In this case, animals were trained with a fixed visual cue in relation to a body-centered turn (i.e., simultaneously with the internal self-reference cue) and then tested with the visual cue dissociated from positional cues. Toads trained with the combination of a visual cue and a body-centered turn preferred the latter (turn response) when the two sources of information were set in conflict on probe trials. Toads showed behavioral patterns similar to those described in rodents trained under similar condition, thus, suggesting an early evolutionary origin for these problem-solving strategies. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Of mice (Mus musculus) and toddlers (Homo sapiens): Evidence for species-general spatial reorientation.

There is ongoing debate in spatial cognition about the mechanisms by which organisms are able to reorient, or reestablish a position, in the world after losing their bearing. The traditional view is that there is an encapsulated reorientation module that can only process environmental geometry such as distances or angles (Cheng, 1986). Recently, this view has been challenged on the grounds that the reorientation mechanism is only able to accept geometric information and may instead depend on a more general ability to use relative cues. J. Huttenlocher and S. F. Lourenco (2007) demonstrated that toddlers are successfully able to reorient with continuous cues but show remarkable deficits using categorical cues that are similar in perceptual complexity for reorientation. Here, the authors show the same pattern of results with mice (Mus musculus). These findings provide evidence that there is a homologous reorientation mechanism between mice and humans. Thus, future researchers can examine the genetic basis of this important cognitive ability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Variations in Intensity and Frequency Moderate the Facilitative Effects of a Complex Rhythm Stimulus on Long-Term Memory Consolidation in the Day-Old Chick (Callus gallus).

The authors have previously shown that exposure to 1 min of a complex, but not an isochronous, rhythm stimulus facilitates long-term memory consolidation in chicks (Gallus gallus) trained on a passive-avoidance task (S. R. Toukhsati & N. S. Rickard, 2001). The acoustic parameters of this stimulus were explored further in the current study. Retention was found to be best facilitated when the complex rhythm stimulus was presented at intensities between 5 and 15 dBA above background laboratory noise levels and at a frequency of 1 kHz. Removal of an accent from the stimulus did not moderate the effect. These findings provide confirmation that memory in an avian species can be facilitated by exposure to a complex rhythm stimulus and suggest that pattern repetition may be an important feature of this effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial memory of domestic dogs (Canis familiaris) for hidden objects in a detour task.

Spatial memory of domestic dogs (Canis familiaris) for hidden objects was investigated via a visible displacement problem of object permanence with a detour paradigm. Experiment 1 showed that dogs were able to spontaneously locate a disappearing object in a detour situation. In Experiments 2 and 3, dead reckoning and allocentric spatial information were put in conflict. Results revealed that dogs simultaneously encoded both sources of information when they had to bypass an obstacle to locate a hidden object. Experiment 3 also revealed that, over the course of testing, dogs gradually learned to rely predominantly on allocentric cues when the detour involved several reorientations. The current study reveals that spatial memory of dogs for hidden objects in a detour task was guided by flexibility in processing spatial information. Dogs could simultaneously encode dead reckoning and allocentric information to locate a disappearing object and used them hierarchically according to the complexity of the detour they encountered in the environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning of absolute and relative distance and direction from discrete visual landmarks by pigeons (Columba livia).

In an open-field search task, pigeons (Columba livia) were trained to search for a goal located at the midpoint of the hypothetical line connecting two discrete visual landmarks positioned 60 cm apart. In Experiment 1, global orienting cues were absent. After reaching training criteria, pigeons were tested with novel interlandmark distances. Search location and error on test trials suggested pigeons learned relative distance. In Experiment 2, a global orienting cue was present. After reaching training criteria, pigeons were again tested with novel interlandmark distances. Results suggested pigeons learned relative and absolute distances. In Experiment 3, pigeons searched at the midpoint of rotated arrays in both the presence and absence of an orienting cue indicating learning of relative direction. In Experiment 4, pigeons searched in the appropriate goal direction when presented with a single landmark in the presence of the orienting cue but not in its absence indicating learning of absolute direction. Results implicate a stable frame of reference as critical to spatial coding strategies and suggest pigeons are able to code location based on absolute and relative distance and direction from discrete visual landmarks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chimpanzees (Pan troglodytes) remember the location of a hidden food item after altering their orientation to a spatial array.

Two chimpanzees (Pan troglodytes) had a direct view of an experimenter placing a food item beneath one of several cups within a horizontal spatial array. The chimpanzees then were required to move around the spatial array, shifting their orientation to the array by 180°. Both chimpanzees remembered the location of the food item. In the next experiment, a visual barrier was placed between the chimpanzees and the spatial array after the food item had been hidden to prevent visual tracking of the location of the object during the chimpanzees' movement. One chimpanzee remembered the location of the hidden item in this variation. These results demonstrate another capacity for spatial memory in this species that complements data indicating chimpanzee spatial memory for invisible displacements, array rotations, and array transpositions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The relative importance of global and local landmarks in navigation by Columbian ground squirrels (Spermophilus columbianus).

In order to survive, small burrowing mammals need to remember the locations of escape burrows. Therefore, it is important to know what types of landmarks are used to aid navigation in the wild. The author tested the ability of free-ranging Columbian ground squirrels (Spermophilus columbianus) to locate escape burrows when local (e.g., vegetation pattern, local relief), global (e.g., forest edge, mountain outline), or both types of landmarks were obstructed. Results suggest that squirrels need both local and global landmarks of the environment for successful navigation, and that the upper portion of the horizon is especially important for orientation. Moreover, the lack of information from one type of landmark (local or global) cannot be completely compensated by the other type. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Different ways of encoding geometric information by goldfish (Carassius auratus).

On the basis of results of a probe trial in 2 different experiments, K. Cheng (2005) has proposed a common mechanism for orientation in fish trained in both a maplike or relational procedure and a directly cued procedure. However, K. Cheng's model is inconsistent with previous results of goldfish (Carassius auratus) trained in these 2 tasks. Given that K. Cheng's proposal assumes that fish choose the goal by using a matching strategy in which they try to match as many properties as possible, including geometric and featural properties, future research is necessary to clarify what properties of the environmental space are codified and used for navigation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Use of cue configuration geometry for spatial orientation in human infants (Homo sapiens).

Research with both rats and human infants has found that after inertial disorientation, the geometry of an enclosed environment is used in preference over distinctive featural information during goal localization. Infants (Homo sapiens, 18–24 months) were presented with a toy search task involving inertial disorientation in 1 of 2 conditions. In the identical condition, 4 identical hiding boxes in a rectangular formation were set within a circular enclosure. In the distinctive condition, 4 distinctive hiding boxes were used. Infants searched the goal box and its rotational equivalent significantly more than would be expected by chance in the identical condition, showing that they were sensitive to the geometric configuration of the array of boxes. Unlike the results of studies using a rectangular enclosure, however, in the distinctive condition, infants searched at the correct location significantly more than at other locations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial learning in a T-maze by the crayfish Orconectes rusticus.

The T-maze has commonly been used to investigate the mechanisms underlying spatial learning in vertebrates and has yielded much information about how animals use response and place cues to orient toward a goal. We designed a T-maze to study the spatial learning abilities of crayfish (Orconectes rusticus), using tactile stimuli as a place cue and escape from warm water for reinforcement. An initial experiment found that most animals did not display a side-turning bias when first placed in the maze, and hence animals were randomly assigned to escape from the left or the right arm, one of which contained a smooth floor and the other a rough floor. We found that, over repeated trials, the latency to escape and the number of turns made prior to escaping significantly decreased indicating that crayfish learned to escape from the maze more rapidly and efficiently. Learning occurred over the course of six trials on a single day, and over 5 days of testing, providing evidence for spatial memory lasting 24 hr. In probe trials, in which experienced animals started the maze in an arm opposite to that used during training trials, crayfish did not display a preference for either response-based learning or place-based learning. Instead they engaged in renewed exploration of the entire maze. These findings suggest that, in addition to remembering the location of the exit, crayfish also remembered the overall configuration of the maze. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Rats (Rattus norvegicus) in a water maze learn both an egocentric trajectory and landmarks.

In two experiments we investigated the extent to which rats (Rattus norvegicus) use an egocentric trajectory and landmarks to locate a goal. In Experiment 1 we trained groups to locate the hidden platform in a water maze with either 1 of 3 or 3 of 3 predictive landmarks, and with either a random or fixed egocentric trajectory. A choice test revealed that regardless of the landmark configuration, rats relied on a directional, egocentric trajectory, when it was available, to locate the platform. In Experiment 2 we found that adding four predictive landmarks following training with a constant egocentric trajectory did not alter rats' initial attention to the trajectory. We conclude that the presence of nonpredictive landmarks in a predictive array did not affect the use of landmarks. With a blocking design, rats used initially an egocentric path, then landmarks. These results add to the notion that animals use available spatial cues sequentially. (PsycINFO Database Record (c) 2010 APA, all rights reserved)