Observational Spatial Memory Research Articles

Investigating the relationship between physical cognitive tasks and a social cognitive task in a wild bird

Despite considerable research into the structure of cognition in non-human animal species, there is still much debate as to whether animal cognition is organised as a series of discrete domains or an overarching general cognitive factor. In humans, the existence of general intelligence is widely accepted, but less work has been undertaken in animal psychometrics to address this question. The relatively few studies on non-primate animal species that do investigate the structure of cognition rarely include tasks assessing social cognition and focus instead on physical cognitive tasks. In this study, we tested 36 wild Western Australian magpies (Gymnorhina tibicen dorsalis) on a battery of three physical (associative learning, spatial memory, and numerical assessment) and one social (observational spatial memory) cognitive task, to investigate if cognition in this species fits a general cognitive factor model, or instead one of separate physical and social cognitive domains. A principal component analysis (PCA) identified two principal components with eigenvalues exceeding 1; a first component onto which all three physical tasks loaded strongly and positively, and a second component onto which only the social task (observational spatial memory) loaded strongly and positively. These findings provide tentative evidence for separate physical and social cognitive domains in this species, and highlight the importance of including tasks assessing both social and physical cognition in cognitive test batteries.

Observational spatial memory in wolves and dogs.

Social learning is highly adaptive in transmitting essential information between individuals in many species. While several mechanisms have been observed, less is known about how much animals can remember. However, results on observational spatial memory among caching species, i.e. a form of social learning allowing individuals to remember and pilfer food caches made by others, suggest that this ability correlates with their social organization. Both wolves and their domesticated form, dogs, are social species known to make food caches, and previous studies have shown that they both can use observational spatial memory abilities to find hidden food. In order to test how much socially transmitted information wolves and dogs can remember, we tested both species in a task requiring them to find 4, 6 or 8 caches after they observed a human hiding food items, or after a control condition where they could not observe the hiding. We found that both wolves and dogs retrieved more caches and were more efficient for the first few caches if they observed the hiding than in the control condition, suggesting that they did not simply rely on scent to find the rewards. Interestingly, wolves outperformed dogs irrespective of whether the caching could be observed or not. We suggest that this result is due to a difference in motivation/persistence between wolves and dogs rather than observational spatial memory.

Evidence against observational spatial memory for cache locations of conspecifics in marsh tits Poecile palustris

Many species in the family Paridae, such as marsh tits Poecile palustris, are large-scale scatter hoarders of food that make cryptic caches and disperse these in large year-round territories. The perhaps most well-known species in the family, the great tit Parus major, does not store food itself but is skilled in stealing caches from the other species. We have previously demonstrated that great tits are able to memorise positions of caches they have observed marsh tits make and later return and steal the food. As great tits are explorative in nature and unusually good learners, it is possible that such “memorisation of caches from a distance” is a unique ability of theirs. The other possibility is that this ability is general in the parid family. Here, we tested marsh tits in the same experimental set-up as where we previously have tested great tits. We allowed caged marsh tits to observe a caching conspecific in a specially designed indoor arena. After a retention interval of 1 or 24 h, we allowed the observer to enter the arena and search for the caches. The marsh tits showed no evidence of such observational memorization ability, and we believe that such ability is more useful for a non-hoarding species. Why should a marsh tit that memorises hundreds of their own caches in the field bother with the difficult task of memorising other individuals’ caches? We argue that the close-up memorisation procedure that marsh tits use at their own caches may be a different type of observational learning than memorisation of caches made by others. For example, the latter must be done from a distance and hence may require the ability to adopt an allocentric perspective, i.e. the ability to visualise the cache from the hoarder’s perspective.Significance statementMembers of the Paridae family are known to possess foraging techniques that are cognitively advanced. Previously, we have demonstrated that a non-hoarding parid species, the great tit P. major, is able to memorise positions of caches that they have observed marsh tits P. palustris make. However, it is unknown whether this cognitively advanced foraging strategy is unique to great tits or if it occurs also in other parids. Here, we demonstrated that “pilfering by observational memorization strategy” is not a general strategy in parids. We believe that such ability is important for a non-hoarding species such as the great tit and, most likely, birds owning many caches do not need this foraging strategy.

Pilfering Eurasian jays use visual and acoustic information to locate caches.

Pilfering corvids use observational spatial memory to accurately locate caches that they have seen another individual make. Accordingly, many corvid cache-protection strategies limit the transfer of visual information to potential thieves. Eurasian jays (Garrulus glandarius) employ strategies that reduce the amount of visual and auditory information that is available to competitors. Here, we test whether or not the jays recall and use both visual and auditory information when pilfering other birds' caches. When jays had no visual or acoustic information about cache locations, the proportion of available caches that they found did not differ from the proportion expected if jays were searching at random. By contrast, after observing and listening to a conspecific caching in gravel or sand, jays located a greater proportion of caches, searched more frequently in the correct substrate type and searched in fewer empty locations to find the first cache than expected. After only listening to caching in gravel and sand, jays also found a larger proportion of caches and searched in the substrate type where they had heard caching take place more frequently than expected. These experiments demonstrate that Eurasian jays possess observational spatial memory and indicate that pilfering jays may gain information about cache location merely by listening to caching. This is the first evidence that a corvid may use recalled acoustic information to locate and pilfer caches.

Exclusion in corvids: The performance of food-caching Eurasian jays (Garrulus glandarius).

Choice by exclusion involves selecting a rewarded stimulus by rejecting alternatives that are unlikely to be rewarded. It has been proposed that in corvids, exclusion is an adaptive specialization for caching that, together with object permanence and observational spatial memory, enhances a bird's ability to keep track of the contents of caches. Thus, caching species are predicted to perform well in tasks requiring exclusion. We tested this prediction by assessing the performance of Eurasian jays (Garrulus glandarius), a highly specialized cacher, in a two-way object choice task in which food was hidden in 1 of 2 cups. Consistent with the corvids' capacity for observational spatial memory, jays were highly accurate when shown the location of the food reward. However, the jays failed to exclude the empty cup when shown its contents. This failure to select the baited cup when shown the empty cup was possibly due to jays attending to the experimenter's movements and erroneously selecting the empty cup by responding to these local enhancement cues. To date, no corvids have been tested in an auditory two-way object choice task. Testing exclusion in the auditory domain requires that a bird use the noise produced when the baited cup is shaken to locate the reward. Although jays chose the baited cup more frequently than predicted by chance, their performance did not differ from trials controlling for the use of conflicting cues provided by the experimenter. Overall, our results provide little support for the hypothesis that caching has shaped exclusion abilities in corvids.

Indian mynahs, Acridotheres tristis, learn about dangerous places by observing the fate of others

Studies of learning have consistently shown that animals form strong associations between aversive events, such as a predatory attack, and the environments in which those events are experienced. Place learning through direct exposure to threat puts the individual at a risk that may be avoided, however, by remembering the location in which encounters between conspecifics and dangerous events are observed. Despite much theoretical work predicting that individuals should rely less on private information and more on public information as the risk of individual assessment increases, there have been no tests of observational spatial memory for potentially dangerous places. We investigated whether Indian mynahs learn about an area in which they observe another individual experience an aversive event, namely capture by a human. Experimental observers watched a human chase, catch and remove a conspecific from a feeding site in which observers were accustomed to feeding. A control group watched a human perform the same capture gestures, but with no mynah present. Analysis of observer behaviour at the feeding site both before and after observational training revealed that experimental observers locomoted more after training than before, relative to control observers, suggesting that mynahs acquired a fear response after watching a predatory attack on a conspecific. It appears that, in addition to learning about the location in which aversive events are experienced directly, animals learn about an environment in which they observe others encounter dangerous events.

The social life of corvids

The social life of corvids

Observational visuospatial encoding of the cache locations of others by western scrub-jays (Aphelocoma californica)

Western scrub-jays (Aphelocoma californica) hide food and rely on spatial memory to recover their caches at a later date. They also rely on observational spatial memory to steal caches made by other individuals. Successful pilfering may require an understanding of allocentric space because the observer will often be in a different position from the demonstrator when the caching event occurs. We compared cache recovery accuracy of pairs of observers that watched a demonstrator cache food. The pattern of recovery searches showed that observers were more accurate when they had observed the caching event from the same viewing direction as the demonstrator than when they had watched from the opposite direction. Search accuracy was not affected by whether or not the tray-specific local cues provided left–right landmark information (i.e. heterogeneous vs. homogeneous local cues), or whether or not the caching tray location was rotated. Taken together, these results suggest that observers have excellent spatial memory and that they have little difficulty with mental rotation.

Cache protection strategies by western scrub-jays, Aphelocoma californica: implications for social cognition

Food-caching western scrub-jays cache items themselves, and use observational spatial memory to steal the caches of others. Our aim in this study was to investigate the strategies used by scrub-jays to reduce cache theft by conspecifics. In three experiments, scrub-jays were allowed to cache wax worms in two different locations. In experiment 1, the birds preferred to hide items in distant sites when watched by another jay, but used near and distant sites equally when the observer's view was obscured by a screen. As conspecifics rely on observational spatial memory to steal other jays' caches, this use of distance might reduce the visual information available to the potential thief and thus decrease pilfering accuracy. Where possible, however, placing caches out of sight may be more effective. In experiment 2, storers cached predominantly in distant, out-of-view, sites. However, items placed in view of the observer were moved multiple times, possibly confusing the observer as to their location. In experiment 3, when in-view and out-of-view sites were equidistant to the observer, storers cached mainly in out-of-view sites when observed, but cached equally in both sites when not observed. In all three experiments, some items were cached in nonpreferred sites (near, in view). During recovery sessions, when the storer was not observed, these items were selectively recached in new sites unbeknown to the observer. It may be advantageous not to hide all the caches in one place, because unpredictability might provide the best insurance against pilfering.

Observational learning and the raiding of food caches in ravens, Corvus corax: is it ‘tactical’ deception?

Group-foraging ravens scatter-hoard when they are competing for food and, to some extent, also raid the caches made by others. We investigated the effects of observational spatial memory on individual caching and raiding tactics. With captive ravens, we found visual observation was essential for locating and raiding the caches of conspecifics. Both captive and free-ranging ravens, food cachers as well as potential cache raiders, responded to each other's presence. Cachers withdrew from conspecifics and most often placed their caches behind structures, obstructing the view of potential observers. Raiders watched inconspicuously and kept at a distance to cachers close to their cache sites. In response to the presence of potential raiders or because of their initial movements towards caches, the cachers frequently interrupted caching, changed cache sites, or recovered their food items. These results suggest that ravens, regardless of whether they act as cachers or raiders, are capable of withholding information about their intentions and, hence, manipulate the other bird's attention either to prevent or to achieve social-learning opportunities. Such interactions may qualify as ‘tactical’ deception and may have created a considerable pressure selecting for social cognition in ravens. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.

Observational spatial memory in Clark's nutcrackers and Mexican jays

Recent work has demonstrated that pinyon jays, Gymnorhinus cyanocephalus, can remember the locations at which they have seen conspecifics cache food. Pinyon jays are both highly dependent on cached food and live in large social groups. To examine the importance of food caching and social living for observational spatial memory, Clark's nutcrackers, Nucifraga columbiana, and Mexican jays, Aphelocoma ultramarina, were tested on the same spatial memory tasks as used with pinyon jays. Clark's nutcrackers are highly adapted for caching food and live alone or in family groups, and Mexican jays are non-specialized cachers that live in highly structured groups. In these experiments, Clark's nutcrackers performed poorly at relocating caches they had seen conspecifics create. Observer nutcrackers were significantly more accurate than expected by chance at one but not two days after cache creation. Caching nutcrackers were more accurate at recovering caches than were observers. In contrast, Mexican jay observers performed at above-chance levels on both intervals after cache creation and were as accurate during cache recovery as were caching Mexican jays. These results suggest that observational spatial memory could be common among corvids and that its degree of development may be influenced by group living.

Social Caching and Observational Spatial Memory in Pinyon Jays

In the wild, pinyon jays (Gymnorhinus cyanocephalus) live in large, integrated flocks and cache tens of thousands of seeds per year. This study explored social aspects of caching and recovering by pinyon jays. In Experiment 1, birds cached in a large experimental room under three conditions: alone, paired with a dominant, and paired with a subordinate. In all cases, birds recovered caches alone seven days later. Individuals ate more seeds before caching when alone than when paired and started caching sooner when subordinate than when dominant. Pinyon jays accurately returned to sites containing their own caches but not to sites containing caches made by partner birds. However, they went to areas containing partner caches sooner than would be expected, indicating memory for the general areas containing caches made by other pinyon jays. In Experiments 2 and 3 birds were placed closer to each other and allowed to recover one or two days after caching. In Experiment 2, both free-flying and caged observers found caches with accuracies above chance. Cachers made significantly fewer errors than observers. During Experiment 3, caged observers saw the cachers recover some seeds one day after they were cached. On the next day cachers and observers were separately allowed to visit all cache sites. Both cachers and observers performed accurately and did not differ in accuracy. Neither group discriminated between extant and depleted caches. Observational spatial memory in pinyon jays may allow economical cache robbery by wild pinyon jays under some circumstances, particularly shortly after caches are created.