Modularity as a fish (Xenotoca eiseni) views it: conjoining geometric and nongeometric information for spatial reorientation

Core knowledge of object, number, and geometry: a comparative and neural approach

Studies on the ontogenetic origins of human knowledge provide evidence for a small set of separable systems of core knowledge dealing with the representation of inanimate and animate objects, number, and geometry. Because core knowledge systems are evolutionarily ancient, they can be investigated from a comparative perspective, making use of various animal models. In this review, I discuss evidence showing precocious abilities in nonhuman species to represent (a) objects that move partly or fully out of view and their basic mechanical properties such as solidity, (b) the cardinal and ordinal/sequential aspects of numerical cognition and rudimentary arithmetic with small numerosities, and (c) the geometrical relationships among extended surfaces in the surrounding layout. Controlled rearing studies suggest that the abilities associated with core knowledge systems of objects, number, and geometry are observed in animals in the absence (or with very reduced) experience, supporting a nativistic foundation of such cognitive mechanisms. Animal models also promise a fresh approach to the issue of the neurobiological and genetic mechanisms underlying the expression of core knowledge systems.

Potentiation and overshadowing between landmarks and environmental geometric cues

Rats were required in three experiments to find one of two submerged platforms that were situated in the same pair of diagonally opposite corners of a rectangular grey swimming pool. The experimental groups were trained with landmarks, comprising A4 cards attached to the walls, located in the corners containing the platforms. For the control groups, the landmarks were situated in the corners containing the platforms for half of the trials, and in the other corners for the remaining trials. Learning about the positions of the platforms with reference to the shape of the pool was overshadowed in the experimental groups when the landmarks were white, and enhanced when the landmarks were black. A fourth experiment assessed whether geometric cues influenced the control acquired by the landmarks. As in the previous experiments, the presence of the geometric cues overshadowed learning about the landmarks when they were white, but enhanced learning when the landmarks were black.

Kindergarten children's sensitivity to geometry in maps

Geometrical concepts are critical to a host of human cognitive achievements, from maps to measurement to mathematics, and both the development of these concepts, and their variation by gender, have long been studied. Most studies of geometrical reasoning, however, present children with materials containing both geometric and non-geometric information, and with tasks that are open to multiple solution strategies. Here we present kindergarten children with a task requiring a focus on geometry: navigation in a small-scale space by a purely geometric map. Children spontaneously extracted and used relationships of both distance and angle in the maps, without prior demonstration, instruction, or feedback, but they failed to use the sense information that distinguishes an array from its mirror image. Children of both genders showed a common profile of performance, with boys showing no advantage on this task. These findings provide evidence that some map-reading abilities arise prior to formal instruction, are common to both genders, and are used spontaneously to guide children's spatial behavior.

View-based strategy for reorientation by geometry

Human and non-human animals can use geometric information (metric information and left-right discrimination sense) to reorient themselves in an environment. The hypothesis that in so doing they rely on allocentric (map-like) representations has received wide consensus. However, theoretical models suggest that egocentric representations may represent efficient strategies for visuo-spatial navigation. Here, we provide, for the first time, evidence that a view-based strategy is effectively used by animals to reorient themselves in an array of landmarks. Domestic chicks were trained to locate a food-reward in a rectangular array of either four indistinguishable or distinctive pipes. In the key experimental series, the pipes had four openings, only one of which allowed the chicks to access the reward. The direction of the open access relative to the array was either maintained stable or it was changed throughout training. The relative position of the pipes in the array was maintained stable in both training conditions. Chicks reoriented according to configural geometry as long as the open access pointed in the same direction during training but failed when the positions of the openings was changed throughout training. When the correct pipe was characterized by a distinctive featural cue, chicks learnt to locate the reward irrespective of the stability of the direction to openings, indicating that place-navigation was dissociated from non-spatial learning. These findings provide evidence that view-based strategies to reorient by geometry could be used by animals.

Control of anterodorsal thalamic head direction cells by environmental boundaries: comparison with conflicting distal landmarks

Experiments were conducted to determine whether environmental boundaries exert preferential control over the tuning of head direction (HD) cells. In each experiment, HD cells were recorded in the rat anterodorsal thalamus while they foraged for randomly scattered food in trapezoid- and rectangle-shaped environments. After an initial recording session, each environment was rotated 90°, and changes in the preferred firing directions of HD cells were monitored. Rats were disoriented before each test session to prevent the use of self-movement cues to maintain orientation from one session to the next. In Experiment 1, we demonstrate that HD cell tuning consistently shifted in register with the trapezoid shaped enclosure, but was more variable in the rectangle shaped environment. In Experiments 2 and 3, we show that the strong control by the trapezoid persists in the presence of one clearly visible distal landmark, but not when three or more distal landmarks, including view of the recording room, are present. Together, the results indicate that distinct environmental boundaries exert strong stimulus control over HD cell orientation. However, this geometric control can be overridden with a sufficient number of salient distal landmarks. These results stand in contrast to the view that information from geometric cues usually takes precedence over information from landmark cues.

Two systems of spatial representation underlying navigation

We review evidence for two distinct cognitive processes by which humans and animals represent the navigable environment. One process uses the shape of the extended 3D surface layout to specify the navigator's position and orientation. A second process uses objects and patterns as beacons to specify the locations of significant objects. Although much of the evidence for these processes comes from neurophysiological studies of navigating animals and neuroimaging studies of human adults, behavioral studies of navigating children shed light both on the nature of these systems and on their interactions.

Habituation of medaka (Oryzias latipes) demonstrated by open-field testing

Habituation to novel environments is frequently studied to analyze cognitive phenotypes in animals, and an open-field test is generally conducted to investigate the changes that occur in animals during habituation. The test has not been used in behavioral studies of medaka (Oryzias latipes), which is recently being used in behavioral research. Therefore, we examined the open-field behavior of medaka on the basis of temporal changes in 2 conventional indexes of locomotion and position. The findings of our study clearly showed that medaka changed its behavior through multiple temporal phases as it became more familiar with new surroundings; this finding is consistent with those of other ethological studies in animals. During repeated open-field testing on 2 consecutive days, we observed that horizontal locomotion on the second day was less than that on the first day, which suggested that habituation is retained in fish for days. This temporal habituation was critically affected by water factors or visual cues of the tank, thereby suggesting that fish have spatial memory of their surroundings. Thus, the data from this study will afford useful fundamental information for behavioral phenotyping of medaka and for elucidating cognitive phenotypes in animals.

Selective involvement of the goldfish lateral pallium in spatial memory

The involvement of the main pallial subdivisions of the teleost telencephalic pallium in spatial cognition was evaluated in a series of three experiments. The first two compared the effects of lesions selective to the lateral (LP), medial (MP) and dorsal (DP) telencephalic pallium of goldfish, on the retention and the reversal learning of a spatial constancy task which requires the use of allocentric or relational strategies. The results showed that LP lesions produced a selective impairment on the capability of goldfish to solve the spatial task previously learned and on the reversal learning of the same procedure, whereas MP and DP lesions did not produce observable deficits. The third experiment evaluated, by means of the AgNOR stain, learning-dependent changes of the neuronal transcription activity in the pallium of goldfish trained in the spatial constancy task or in a cue version of the same procedure, which only differed on their spatial cognition demands. The results revealed that training in the spatial task produced an increment in the transcriptive activity which was selective to the neurons of the ventral lateral pallium, as indicated by increases in the size of the nucleolar organizing region (NOR), the nucleolar organelles associated with the synthesis of ribosomal proteins. In contrast, training in the cue version did not produced observable changes. These data, revealing a striking functional similarity between the lateral telencephalic pallium of the teleost fish and the amniote hippocampus, provide additional evidence regarding the homology of both structures.

Features enhance the encoding of geometry

Successful navigation within an environment requires that the traveler establish the correct heading--a process referred to as orienting. Many studies have now shown that humans and non-human animals can use the geometric properties of an enclosure to orient. In the present study, two groups of Clark's nutcrackers (Nucifraga columbiana) were trained, in a reference memory task, to find food hidden in one of four containers arranged to form a rectangular array. One group had unique objects placed next to each of the containers, whereas the second group had identical objects placed next to each of the containers. Here, I show for the first time that for the Clark's nutcracker, the distinctive properties of these objects enhanced the encoding of the array's geometry compared to the learning of geometric properties from an array of identical objects, which remained at chance after substantial amounts of training. Subsequent transformation tests showed that an object not associated with reward, but sharing the same geometric properties as the correct object, may have had inhibitory qualities. Furthermore, by systematically removing objects from the array, I show that although nutcrackers encoded the geometry of the array, they did not encode a complete featural representation of the objects within the array.

Bonobos, chimpanzees, gorillas, and orang utans use feature and spatial cues in two spatial memory tasks

Animals commonly use feature and spatial strategies when remembering places of interest such as food sources or hiding places. We conducted three experiments with great apes to investigate strategy preferences and factors that may shape them. In the first experiment, we trained 17 apes to remember 12 different food locations on the floor of their sleeping room. The 12 food locations were associated with one feature cue, so that feature and spatial cues were confounded. In a single test session, we brought the cues into conflict and found that apes, irrespective of species, showed a preference for a feature strategy. In the second experiment, we used a similar procedure and trained 25 apes to remember one food location on a platform in front of them. On average, apes preferred to use a feature strategy but some individuals relied on a spatial strategy. In the final experiment, we investigated whether training might influence strategy preferences. We tested 21 apes in the platform set-up and found that apes used both, feature and spatial strategies irrespective of training. We conclude that apes can use feature and spatial strategies to remember the location of hidden food items, but that task demands (e.g. different numbers of search locations) can influence strategy preferences. We found no evidence, however, for the role of training in shaping these preferences.

Encoding geometric and non-geometric information: a study with evolved agents

Vertebrate species use geometric information and non-geometric or featural cues to orient. Under some circumstances, when both geometric and non-geometric information are available, the geometric information overwhelms non-geometric cues (geometric primacy). In other cases, we observe the inverse tendency or the successful integration of both cues. In past years, modular explanations have been proposed for the geometric primacy: geometric and non-geometric information are processed separately, with the geometry module playing a dominant role. The modularity issue is related to the recent debate on the encoding of geometric information: is it innate or does it depend on environmental experience? In order to get insight into the mechanisms that cause the wide variety of behaviors observed in nature, we used Artificial Life experiments. We demonstrated that agents trained mainly with a single class of information oriented efficiently when they were exposed to one class of information (geometric or non-geometric). When they were tested in environments that contained both classes of information, they displayed a primacy for the information that they had experienced more during their training phase. Encoding and processing geometric and non-geometric information was run in a single cognitive neuro-representation. These findings represent a theoretical proof that the exposure frequency to different spatial information during a learning/adaptive history could produce agents with no modular neuro-cognitive systems that are able to process different types of spatial information and display various orientation behaviors (geometric primacy, non-geometric primacy, no primacy at all).

Doing Socrates experiment right: controlled rearing studies of geometrical knowledge in animals

The issue of whether encoding of geometric information for navigational purposes crucially depends on environmental experience or whether it is innately predisposed in the brain has been recently addressed in controlled rearing studies. Non-human animals can make use of the geometric shape of an environment for spatial reorientation and in some circumstances reliance on purely geometric information (metric properties and sense) can overcome use of local featural information. Animals reared in home cages of different geometric shapes proved to be equally capable of learning and performing navigational tasks based on geometric information. The findings suggest that effective use of geometric information for spatial reorientation does not require experience in environments with right angles and metrically distinct surfaces.

Sex differences in spatial cognition in an invertebrate: the cuttlefish

Evidence of sex differences in spatial cognition have been reported in a wide range of vertebrate species. Several evolutionary hypotheses have been proposed to explain these differences. The one best supported is the range size hypothesis that links spatial ability to range size. Our study aimed to determine whether male cuttlefish (Sepia officinalis; cephalopod mollusc) range over a larger area than females and whether this difference is associated with a cognitive dimorphism in orientation abilities. First, we assessed the distance travelled by sexually immature and mature cuttlefish of both sexes when placed in an open field (test 1). Second, cuttlefish were trained to solve a spatial task in a T-maze, and the spatial strategy preferentially used (right/left turn or visual cues) was determined (test 2). Our results showed that sexually mature males travelled a longer distance in test 1, and were more likely to use visual cues to orient in test 2, compared with the other three groups. This paper demonstrates for the first time a cognitive dimorphism between sexes in an invertebrate. The data conform to the predictions of the range size hypothesis. Comparative studies with other invertebrate species might lead to a better understanding of the evolution of cognitive dimorphism.

Whither geometry? Troubles of the geometric module

In rectangular arenas, rats often confuse diagonally opposite corners, even when distinctive cues differentiate them. This led to the postulation that rats rely preferentially on the geometry of space, encoded in a dedicated geometric module. Recent research casts doubt on this idea. Distinctive featural cues such as entire walls of a distinct color can hinder or aid the learning of geometry. In one situation in which using geometry would help greatly, rats had trouble learning the task. An associative model has been developed to capture these different learning processes, and view-based matching has been proposed as an alternative to the explicit coding of geometric cues. Considerations about how cues interact in learning are crucial in a recent theory of human spatial cognition.

Growing in circles: rearing environment alters spatial navigation in fish

Animals of many species use the geometric shape of an enclosed rectangular environment to reorient, even in the presence of a more informative featural cue. Manipulating the rearing environment affects performance on spatial tasks, but its effect on the use of geometric versus featural navigational cues is unknown. Our study varied the geometric information available in the rearing environment (circular vs. rectangular rearing tanks) of convict cichlids (Archocentrus nigrofasciatus) and tested their use of navigational cues. All the fish used geometric information to navigate when no features were present. When features were present, the fish used geometric and featural information separately. If cues were in conflict, fish raised in a circular tank showed significantly less use of geometric information than fish raised in a rectangular tank. Thus, the ability to use geometry to navigate does not require exposure to angular geometric cues during rearing, though rearing environment affects the dominance of featural and geometric cues.

Recognition of partly occluded objects by fish

The ability to visually complete partly occluded objects (so-called "amodal completion") has been documented in mammals and birds. Here, we report the first evidence of such a perceptual ability in a fish species. Fish (Xenotoca eiseni) were trained to discriminate between a complete and an amputated disk. Thereafter, the fish performed test trials in which hexagonal polygons were either exactly juxtaposed or only placed close to the missing sectors of the disk in order to produce or not produce the impression (to a human observer) of an occlusion of the missing sectors of the disk by the polygon. In another experiment, fish were first trained to discriminate between hexagonal polygons that were either exactly juxtaposed or only placed close to the missing sectors of a disk, and then tested for choice between a complete and an amputated disk. In both experiments, fish behaved as if they were experiencing visual completion of the partly occluded stimuli. These findings suggest that the ability to visually complete partly occluded objects may be widespread among vertebrates, possibly inherited in mammals, birds and fish from early vertebrate ancestors.

Asymmetrical participation of the left and right hippocampus for representing environmental geometry in homing pigeons

Control, right and left HF lesioned homing pigeons (Columba livia) were trained to locate a goal in one corner of a rectangular enclosure with a distinctive feature cue. Probe tests revealed that all groups were able to encode in parallel geometric (enclosure shape) and feature information, and in the absence of one of them, they could us the other to locate the goal. However, left HF lesioned pigeons learned the task at a faster rate, and when the geometric and feature information were set in conflict, they relied more on the feature cue compared to control and right HF lesioned pigeons. It was also found that pigeons, independent of group, trained to a goal adjacent to the feature cue learned the task in fewer sessions and relied more on feature information compared to pigeons trained to a goal opposite the feature cue. The latter group relied more on geometric information. The results support the hypothesis that the left HF plays a more important role in the representation of a goal location with respect to environmental shape/geometry. We further propose that the observed functional asymmetry can be explained by the lateralized properties of the pigeon tectofugal visual system.

Spatial encoding in mountain chickadees: features overshadow geometry

Encoding the global geometric shape of an enclosed environment is a principal means of orientation in human and non-human animals. Animals spontaneously encode the geometry of an enclosure even when featural information is available. Although features can be used, they typically do not overshadow geometry. However, all previously tested organisms have been reared in human-made environments with salient geometrical cues. Here, we show that wild-caught mountain chickadees (Poecile gambeli) do not spontaneously encode the geometry of an enclosure when salient features are present near the goal. However, chickadees trained without salient features encode geometric information, but this encoding is overshadowed by features.

Potentiation, overshadowing, and blocking of spatial learning based on the shape of the environment

Rats were trained in Experiment 1 to find a submerged platform in 1 corner of either a rectangular or a kite-shaped pool. When the walls creating this corner were a different color than the opposite walls, then learning about the shape of the pool was potentiated in the kite but not in the rectangle. Experiments 2-4 revealed that learning about the rectangle can be overshadowed and blocked when information about the wall color indicates the location of the platform. The results mimic findings that have been obtained with Pavlovian conditioning, and they challenge the claim that learning about the shape of the environment takes places in a dedicated geometric module.

Spatial cognition based on geometry and landmarks in the domestic chick (Gallus gallus)

Recent evidence suggest that encoding of spatial information based on extended surfaces may differ from encoding based on discrete arrays of local elements. Here we investigated the use of these different frames of reference in domestic chicks. Chicks were trained to search for food hidden under sawdust in the center of the floor of a square-shaped landmark array, with its center in coincidence with the center of a square-shaped enclosure. Displacement of the array to a corner caused a shift of searching behavior toward the array, the search activity spanning between the center of the arena and the center of the array. After changing distances between landmarks, chicks still searched in the central area. Asymmetries were apparent in chicks tested in monocular conditions, with left-eyed chicks being more affected by the overall enclosure and right-eyed chicks by local landmarks. These results suggest that chicks can use both distances from extended surfaces and local information provided by the landmarks of the array to orient in space. However, chicks do not seem to perceive the array as a whole configuration, rather they tend to rely only on single landmarks to locate the goal.

Adult but not aged C57BL/6 male mice are capable of using geometry for orientation

Geometry, e.g., the shape of the environment, can be used by numerous animal species to orientate, but data concerning the mouse are lacking. We addressed the question of whether mice are capable of using geometry for navigating. To test whether aging could affect searching strategies, we compared adult (3- to 5-mo old) and aged (20- to 21-mo old) C57BL/6 male mice. We established a water maze task in which spatial information is provided by one landmark proximal to the target (featural information) and by the rectangular shape of the maze (geometric information). By means of probe trials in which we manipulated the presence of these two kinds of information, we show that adult mice can use both geometry and landmark to orientate. By contrast, aged mice do not use geometry and rely exclusively on the landmark to locate the platform. This study provides the first evidence that mice are capable of using geometric information for orientation and that this ability declines in aged animals.

Small-scale spatial cognition in pigeons

Roberts and Van Veldhuizen's [Roberts, W.A., Van Veldhuizen, N., 1985. Spatial memory in pigeons on the radial maze. J. Exp. Psychol.: Anim. Behav. Proc. 11, 241-260] study on pigeons in the radial maze sparked research on landmark use by pigeons in lab-based tasks as well as variants of the radial-maze task. Pigeons perform well on open-field versions of the radial maze, with feeders scattered on the laboratory floor. Pigeons can also be trained to search precisely for buried food. The search can be based on multiple landmarks, but is sometimes controlled by just one or two landmarks, with the preferred landmarks varying across individuals. Findings are similar in landmark-based searching on a computer monitor and on a lab floor, despite many differences between the two kinds of tasks. A number of general learning principles are found in landmark-based searching, such as cue competition, generalization and peak shift, and selective attention. Pigeons also learn the geometry of the environment in which they are searching. Neurophysiological studies have implicated the hippocampal formation (HF) in avian spatial cognition, with the right hippocampus hypothesized to play a more important role in the spatial recognition of goal locations. Most recently, single-cell recording from the pigeon's hippocampal formation has revealed cells with different properties from the classic 'place' cells of rats, as well as differences in the two sides of the hippocampus.

Spatial learning based on the shape of the environment is influenced by properties of the objects forming the shape

In 3 experiments rats had to find a submerged platform that was located in a corner of a kite-shaped pool. The color of the walls creating this corner provided an additional cue for finding the platform in the shape + color condition but not the shape-only condition. During tests in a pool with walls of a uniform color but no platform, more time was spent in the corner where the platform was originally located after training in the shape + color than in the shape-only condition. The results challenge theories that assume either that learning about the shape of the environment takes place in a dedicated module or that cues compete for the control they acquire over behavior.

Lateralized fish perform better than nonlateralized fish in spatial reorientation tasks

Lines of fish (Girardinus falcatus) obtained through selective breeding showing different degree and direction of behavioural lateralization in a variety of tasks were tested for their ability for spatial reorientation. In the first experiment, fish were required to reorient themselves after passive disorientation in a rectangular tank in the presence of a salient feature (a blue wall). Lateralized fish proved to be better than nonlateralized fish at using the geometric cues provided by the shape of the tank in order to disambiguate between corners with similar featural information. In the second experiment fish were tested in a square-shaped tank (in order to eliminate any geometric cues) in the presence of salient features (panels) located at the corners. Lateralized fish proved better than nonlateralized fish in using featural cues to reorient themselves. These findings suggest that lateralization may confer advantages in spatial reorientation based on the use of geometric and nongeometric cues.

Reorientation by geometric and landmark information in environments of different size

It has been found that disoriented children could use geometric information in combination with landmark information to reorient themselves in large but not in small experimental spaces. We tested domestic chicks in the same task and found that they were able to conjoin geometric and nongeometric (landmark) information to reorient themselves in both the large and the small space used. Moreover, chicks reoriented immediately when displaced from a large to a small experimental space and vice versa, suggesting that they used the relative metrics of the environment. However, when tested with a transformation (affine transformation) that alters the geometric relations between the target and the shape of the environment, chicks tended to make more errors based on geometric information when tested in the small than in the large space. These findings suggest that the reliance of the use of geometric information on the spatial scale of the environment is not restricted to the human species.

Is there a geometric module for spatial orientation? Squaring theory and evidence

There is evidence, beginning with Cheng (1986), that mobile animals may use the geometry of surrounding areas to reorient following disorientation. Gallistel (1990) proposed that geometry is used to compute the major or minor axes of space and suggested that such information might form an encapsulated cognitive module. Research reviewed here, conducted on a wide variety of species since the initial discovery of the use of geometry and the formulation of the modularity claim, has supported some aspects of the approach, while casting doubt on others. Three possible processing models are presented that vary in the way in which (and the extent to which) they instantiate the modularity claim. The extant data do not permit us to discriminate among them. We propose a modified concept of modularity for which an empirical program of research is more tractable.

Egocentric search for disappearing objects in domestic dogs: evidence for a geometric hypothesis of direction

In several species, the ability to locate a disappearing object is an adaptive component of predatory and social behaviour. In domestic dogs, spatial memory for hidden objects is primarily based on an egocentric frame of reference. We investigated the geometric components of egocentric spatial information used by domestic dogs to locate an object they saw move and disappear. In experiment 1, the distance and the direction between the position of the animal and the hiding location were put in conflict. Results showed that the dogs primarily used the directional information between their own spatial coordinates and the target position. In experiment 2, the accuracy of the dogs in finding a hidden object by using directional information was estimated by manipulating the angular deviation between adjacent hiding locations and the position of the animal. Four angular deviations were tested: 5, 7.5, 10 and 15 degrees . Results showed that the performance of the dogs decreased as a function of the angular deviations but it clearly remained well above chance, revealing that the representation of the dogs for direction is precise. In the discussion, we examine how and why domestic dogs determine the direction in which they saw an object disappear.

Failure of a landmark to restrict spatial learning based on the shape of the environment

Rats were required to find a submerged platform in the corner of a swimming pool with a distinctive shape. A landmark near the platform did not interfere with the control acquired by the pool's shape over searching for the platform. This outcome was observed with an overshadowing and a blocking design. A comparison of the ease with which the landmark and the pool's shape gained control over searching for the platform indicates that the failure of overshadowing and blocking was not a consequence of the landmark being less salient than the shape of the pool. The results are not readily explained by theories of associative learning, but they are consistent with the claim that learning about the shape of the environment takes place in a dedicated module, which excludes information about the significance of individual landmarks.

Shape Parameters Explain Data From Spatial Transformations: Comment on Pearce et al. (2004) and Tommasi & Polli (2004)

In 2 recent studies on rats (J. M. Pearce, M. A. Good, P. M. Jones, & A. McGregor, see record 2004-12429-006) and chicks (L. Tommasi & C. Polli, see record 2004-15642-007), the animals were trained to search in 1 corner of a rectilinear space. When tested in transformed spaces of different shapes, the animals still showed systematic choices. Both articles rejected the global matching of shape in favor of local matching processes. The present authors show that although matching by shape congruence is unlikely, matching by the shape parameter of the 1st principal axis can explain all the data. Other shape parameters, such as symmetry axes, may do even better. Animals are likely to use some global matching to constrain and guide the use of local cues; such use keeps local matching processes from exploding in complexity.

Goldfish (Carassius auratus) matching geometric and featural cues: A reinterpretation of some of the data of Vargas, López, Salas, and Thinus-Blanc (2004)

Vargas, López, Salas, and Thinus-Blanc showed that goldfish (Carassius auratus) can use both geometric and featural cues in relocating a target corner in a rectangular enclosure. When featural cues (arrangement of striped walls) were put in conflict with geometric cues, results differed according to target location during training. Vargas, López, et al. explained the results of their cue conflict in terms of 2 different strategies: mapping and cue guidance. I provide an alternative, more parsimonious interpretation in which the same strategy of attempting to match as many cues as possible applies to both cases.

Reorienting in Images of a Three-Dimensional Environment

Adult humans searched for a hidden goal in images depicting 3-dimensional rooms. Images contained either featural cues, geometric cues, or both, which could be used to determine the correct location of the goal. In Experiment 1, participants learned to use featural and geometric information equally well. However, men and women showed significant differences in their use of distant featural cues and the spontaneous encoding of geometric information when trained with features present. Transformation tests showed that participants could use either the color or the shape of the features independently to locate the goal. Experiment 2 showed that participants could use either configural or surface geometry when searching for the goal. However, their weighing of these geometric cues was dependent on initial training experience.

What Do Rats Learn About the Geometry of Object Arrays? Tests With Exploratory Behavior

Six experiments using habituation of exploratory behavior tested whether disoriented rats foraging in a large arena encode the shapes of arrays of objects. Rats did not respond to changes in position of a single object, but they responded to a change in object color and to a change in position of 1 object in a square array, as in previous research (e.g., C. Thinus-Blanc et al., 1987). Rats also responded to an expansion of a square array, suggesting that they encoded sets of interobject distances rather than overall shape. In Experiments 4-6, rats did not respond to changes in sense of a triangular array that maintained interobject distances and angles. Shapes of object arrays are encoded differently from shapes of enclosures.

Animals' use of landmarks and metric information to reorient: effects of the size of the experimental space

Disoriented children could use geometric information in combination with landmark information to reorient themselves in large but not in small experimental spaces. We tested fish in the same task and found that they were able to conjoin geometric and non-geometric (landmark) information to reorient themselves in both the large and the small space used. Moreover, fish proved able to reorient immediately when dislocated from a large to a small experimental space and vice versa, suggesting that they encoded the relative rather than the absolute metrics of the environment. However, fish tended to make relatively more errors based on geometric information when transfer occurred from a small to a large space, and to make relatively more errors based on landmark information when transfer occurred from a large to a small space. The hypothesis is discussed that organisms are prepared to use only distant featural information as landmarks.

Preference for spatial cues in a non-storing songbird species

Male mammals typically outperform their conspecific females on spatial tasks. A sex difference in cues used to solve the task could underlie this performance difference as spatial ability is reliant on appropriate cue use. Although comparative studies of memory in food-storing and non-storing birds have examined species differences in cue preference, few studies have investigated differences in cue use within a species. In this study, we used a one-trial associative food-finding task to test for sex differences in cue use in the great tit, Parus major. Birds were trained to locate a food reward hidden in a well covered by a coloured cloth. To determine whether the colour of the cloth or the location of the well was learned during training, the birds were presented with three wells in the test phase: one in the original location, but covered by a cloth of a novel colour, a second in a new location covered with the original cloth and a third in a new location covered by a differently coloured cloth. Both sexes preferentially visited the well in the training location rather than either alternative. As great tits prefer colour cues over spatial cues in one-trial associative conditioning tasks, cue preference appears to be related to the task type rather than being species dependent.