Relative quantity judgment by Asian elephants (Elephas maximus)

This study investigated whether Asian elephants can make relative quantity judgment (RQJ), a dichotomous judgment of unequal quantities ordered in magnitude. In Experiment 1, elephants were simultaneously shown two baskets with differing quantities of bait (up to 6 items). In Experiment 2, elephants were sequentially presented with baits, which could not be seen by elephants in their total quantities. The task of elephants was to choose the larger quantity in both experiments. Results showed that the elephants chose the larger quantity with significantly greater frequency. Interestingly, the elephants did not exhibit disparity or magnitude effects, in which performance declines with a smaller difference between quantities in a two-choice task, or the total quantity increases, respectively. These findings appear to be inconsistent with the previous reports of RQJ in other animals, suggesting that elephants may be using a different mechanism to compare and represent quantities than previously suggested for other species.     

Social learning in captive African elephants (Loxodonta africana africana)

Social learning is a more efficient method of information acquisition and application than trial and error learning and is prevalent across a variety of animal taxa. Social learning is assumed to be important for elephants, but evidence in support of that claim is mostly anecdotal. Using a herd of six adult female African bush elephants (Loxodonta africana africana) at the San Diego Zoo’s Safari Park, we evaluated whether viewing a conspecific’s interactions facilitated learning of a novel task. The tasks used feeding apparatus that could be solved in one of two distinct ways. Contrary to our hypothesis, the method the demonstrating animal used did not predict the method used by the observer. However, we did find evidence of social learning: After watching the model, subjects spent a greater percentage of their time interacting with the apparatus than they did in unmodeled trials. These results suggest that the demonstrations of a model may increase the motivation of elephants to explore novel foraging tasks.     

Simultaneous visual discrimination in Asian elephants

Two experiments explored the behavior of 20 Asian elephants (Elephas aximus) in simultaneous visual discrimination tasks. In Experiment 1, 7 Burmese logging elephants acquired a white+/black- discrimination, reaching criterion in a mean of 2.6 sessions and 117 discrete trials, whereas 4 elephants acquired a black+/white- discrimination in 5.3 sessions and 293 trials. One elephant failed to reach criterion in the white+/black- task in 9 sessions and 549 trials, and 2 elephants failed to reach criterion in the black+/white- task in 9 sessions and 452 trials. In Experiment 2, 3 elephants learned a large/small transposition problem, reaching criterion within a mean of 1.7 sessions and 58 trials. Four elephants failed to reach criterion in 4.8 sessions and 193 trials. Data from both the black/white and large/small discriminations showed a surprising age effect, suggesting that elephants beyond the age of 20 to 30 years either may be unable to acquire these visual discriminations or may require an inordinate number of trials to do so. Overall, our results cannot be readily reconciled with the widespread view that elephants possess exceptional intelligence.     

Interpretation of human pointing by African elephants: generalisation and rationality

Factors influencing the abilities of different animals to use cooperative social cues from humans are still unclear, in spite of long-standing interest in the topic. One of the few species that have been found successful at using human pointing is the African elephant (Loxodonta africana); despite few opportunities for learning about pointing, elephants follow a pointing gesture in an object-choice task, even when the pointing signal and experimenter’s body position are in conflict, and when the gesture itself is visually subtle. Here, we show that the success of captive African elephants at using human pointing is not restricted to situations where the pointing signal is sustained until the time of choice: elephants followed human pointing even when the pointing gesture was withdrawn before they had responded to it. Furthermore, elephants rapidly generalised their response to a type of social cue they were unlikely to have seen before: pointing with the foot. However, unlike young children, they showed no sign of evaluating the ‘rationality’ of this novel pointing gesture according to its visual context: that is, whether the experimenter’s hands were occupied or not.     

"Right-trunkers" and "left-trunkers": side preferences of trunk movements in wild Asian elephants (Elephas maximus)

In this article, the side preferences of feeding-related trunk movements of free-ranging Asian elephants (Elephas maximus) were investigated for the first time. It is hypothesized that a functional asymmetry of the trunk is necessary to perform skillful feeding movements more efficiently. This might be connected with a corresponding hemispheric specialization. Video recordings of 41 wild elephants provided frequencies and durations of the following trunk-movement categories: object contact, retrieval, and reaching. In each category, individual side preferences were found. The strength of side preferences varied between the trunk-movement categories and the sexes. Mean durations of retrieval and reaching correlated negatively with the strength of side biases. Comparing the side preferences in the unpaired trunk with analogous phenomena in other unpaired grasping organs and in primate handedness. the authors discuss possible explanations for the evolution of asymmetries in unpaired grasping organs.     

Wild female African elephants (Loxodonta africana) exhibit personality traits of leadership and social integration

Animal personalities have been demonstrated for almost 200 species, with stable dimensions of responses (aggressive to fearful; shy to bold) across contexts and with a heritable basis to these traits. As a long-lived and highly social species, elephants (Loxodonta africana) were expected to demonstrate complex dimensions to individual characteristics or personalities, which would be obvious to human observers and validated by behavioral observations. We used principal-components analysis of ratings on 26 behavioral adjectives applied to one social unit, coded as the EB family, which has been observed for 38 years. Eleven adult females were rated by four observers and found to have individually variable traits on four dimensions described by principal-components analysis. The first component was associated with effective and confident family leadership. Component 2 was age-related, and defined by playfulness, exploration and high levels of activity, suggesting both an experience and an age-related element to its structure. Component 3 represented gentleness and at its other extreme, aggression, and Component 4 was related to constancy (predictability and popularity), with both of these latter components reflecting social integration. Leadership among elephant females represents the successful negotiation among individual interests, and our components were related to a capacity to affect the behavior of others in the absence of aggressive dominance. The family matriarch, Echo, was high on elements associated with leadership. The importance of the matriarch in this family's success suggests that elements of personality may underlie interfamilial variation in long-term survival and reproduction. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Humans as professional interactants with elephants in a global commons

All current versions of ethics for human interaction with animals are based on theories originally developed for relationships between humans or for human understanding of the environment. The perceived analogies between relationships among humans those theories were designed for and the relationships between human and animals have led to specifically revised and adapted theories for ethical interaction between humans and animals. In this essay I propose two further analogies that I develop into one core argument to cover specific issues in human–animal relationships not yet adequately addressed. First I adapt the ethical theory designed for use between human professionals and their clients for analogous use in the power relationship between humans and animals; second I similarly adapt the ethical theory designed for interactions between humans and the global environment. I use elephants as example of an animal species and they stand as proxy for all similar animal species. The overall argument justifies moral duties for humanity to protect both species and the global biosphere as home for all living organisms.     

The properties of geophysical fields and their effects on elephants and other animals

Geophysical properties of acoustic, seismic, electric, and magnetic waveforms create opportunities and constraints for animals' communication and sensory monitoring of the environment. The geometric spreading of waves differs; at some frequencies, transmission is most efficient and has minimal noise. The spreading properties of seismic waves favor long-distance propagation for communication and environmental monitoring, and would benefit elephants (Elephas maximus and Loxodonta africana), such as in locating subsurface water. Extending C. E. O'Connell-Rodwell, B. T. Amason, and L. A. Hart (2000), a man jumping at 1.11 km propagated seismic waves at 10-40 Hz. Given the noise of lightning and the Schumann resonances, near field magnetic and electric transmission by animals would be most efficient around 1000 Hz.     

Elephant resource-use traditions

African elephants (Loxodonta africana) use unusual and restricted habitats such as swampy clearings, montane outcrops and dry rivers for a variety of social and ecological reasons. Within these habitats, elephants focus on very specific areas for resource exploitation, resulting in deep caves, large forest clearings and sand pits as well as long-established and highly demarcated routes for moving between resources. We review evidence for specific habitat exploitation in elephants and suggest that this represents socially learned cultural behaviour. Although elephants show high fidelity to precise locations over the very long term, these location preferences are explained neither by resource quality nor by accessibility. Acquiring techniques for exploiting specific resource sites requires observing conspecifics and practice and is evidence for social learning. Elephants possess sophisticated cognitive capacities used to track relationships and resources over their long lifespans, and they have an extended period of juvenile dependency as a result of the need to acquire this considerable social and ecological knowledge. Thus, elephant fidelity to particular sites results in traditional behaviour over generations, with the potential to weaken relationships between resource quality and site preferences. Illustrating the evidence for such powerful traditions in a species such as elephants contributes to understanding animal cognition in natural contexts.     

Putting the elephant back in the herd: elephant relative quantity judgments match those of other species

The ability to discriminate between quantities has been observed in many species. Typically, when an animal is given a choice between two sets of food, accurate performance (i.e., choosing the larger amount) decreases as the ratio between two quantities increases. A recent study reported that elephants did not exhibit ratio effects, suggesting that elephants may process quantitative information in a qualitatively different way from all other nonhuman species that have been tested (Irie-Sugimoto et al. in Anim Cogn 12:193-199, 2009). However, the results of this study were confounded by several methodological issues. We tested two African elephants (Loxodonta africana) to more thoroughly investigate relative quantity judgment in this species. In contrast to the previous study, we found evidence of ratio effects for visible and nonvisible sequentially presented sets of food. Thus, elephants appear to represent and compare quantities in much the same way as other species, including humans when they are prevented from counting. Performance supports an accumulator model in which quantities are represented as analog magnitudes. Furthermore, we found no effect of absolute magnitude on performance, providing support against an object-file model explanation of quantity judgment.     

Do Asian elephants (Elephas maximus) apply causal reasoning to tool-use tasks?

Two experiments addressed contradictory claims about causal reasoning in elephants. In Experiment 1, 4 Asian elephants (Elephas maximus) were pretrained to remove a lid from the top of a bucket and retrieve a food reward. Subsequently, in the first 5 critical trials, when the lid was placed alongside the bucket and no longer obstructed access to the reward, each elephant continued to remove the lid before retrieving the reward. Experiment 2, which involved 11 additional elephants and variations of the original design, yielded similarly counterintuitive observations. Although the results are open to alternative interpretations, they appear more consistent with associative learning than with causal reasoning. Future applications of Fabrean methodologies (J. H. Fabre, 1915) to animal cognition are proposed.     

Evidence of means–end behavior in Asian elephants (<Emphasis Type="Italic">Elephas maximus</Emphasis>)

The present study explores to what extent Asian elephants show “means–end” behavior. We used captive Asian elephants (N = 2) to conduct four variations of the Piagetian “support” problem, which involves a goal object that is out of reach, but rests on a support within reach. In the first condition, elephants were simultaneously presented with two identical trays serving as the “support”, with the bait on one tray and the other tray left empty. In the next two conditions, the bait was placed on one tray, while additional bait was placed beside the other tray. In the last condition, both trays contained bait, but one of the trays had a small gap which prevented the elephants from reaching the reward. Subjects were required to choose and pull either tray with their trunk and to obtain the bait (i.e. goal). Results showed that one elephant performed all of the support problems significantly above chance after several sessions, suggesting that the elephant was capable of understanding that pulling the tray was the “means” for achieving the “end” of obtaining the bait. This study showed that elephants show means–end behavior when subjected to a Piagetian “support” task, and indicates that such goal-directed behavior occurs in species other than primates.     

Visual laterality in belugas (Delphinapterus leucas) and Pacific white-sided dolphins (Lagenorhynchus obliquidens) when viewing familiar and unfamiliar humans

Lateralization of cognitive processes and motor functions has been demonstrated in a number of species, including humans, elephants, and cetaceans. For example, bottlenose dolphins (Tursiops truncatus) have exhibited preferential eye use during a variety of cognitive tasks. The present study investigated the possibility of visual lateralization in 12 belugas (Delphinapterus leucas) and six Pacific white-sided dolphins (Lagenorhynchus obliquidens) located at two separate marine mammal facilities. During free swim periods, the belugas and Pacific white-sided dolphins were presented a familiar human, an unfamiliar human, or no human during 10–15 min sessions. Session videos were coded for gaze duration, eye presentation at approach, and eye preference while viewing each stimulus. Although we did not find any clear group level lateralization, we found individual left eye lateralized preferences related to social stimuli for most belugas and some Pacific white-sided dolphins. Differences in gaze durations were also observed. The majority of individual belugas had longer gaze durations for unfamiliar rather than familiar stimuli. These results suggest that lateralization occurs during visual processing of human stimuli in belugas and Pacific white-sided dolphins and that these species can distinguish between familiar and unfamiliar humans.     

Elephant psychology: What we know and what we would like to know

Although elephants are well-known and one of the most popular species among people, their behavior and cognitive abilities have not been studied very extensively. But recently, more and more researchers are becoming interested in studying their cognition, particularly their general intelligence, including causal reasoning and mirror self recognition, memory, and numerical cognition. Although genetically elephants are more closely related to the small-brained aardvarks and manatees than to primates, they hold enormous potential in their cognitive skills. Also, studying their cognition is important from the point of view of animal welfare in captivity.     

Evolution of the brain and intelligence

Intelligence has evolved many times independently among vertebrates. Primates, elephants and cetaceans are assumed to be more intelligent than 'lower' mammals, the great apes and humans more than monkeys, and humans more than the great apes. Brain properties assumed to be relevant for intelligence are the (absolute or relative) size of the brain, cortex, prefrontal cortex and degree of encephalization. However, factors that correlate better with intelligence are the number of cortical neurons and conduction velocity, as the basis for information-processing capacity. Humans have more cortical neurons than other mammals, although only marginally more than whales and elephants. The outstanding intelligence of humans appears to result from a combination and enhancement of properties found in non-human primates, such as theory of mind, imitation and language, rather than from 'unique' properties.     

Convergence of calls as animals form social bonds, active compensation for noisy communication channels, and the evolution of vocal learning in mammals

The classic evidence for vocal production learning involves imitation of novel, often anthropogenic sounds. Among mammals, this has been reported for dolphins, elephants, harbor seals, and humans. A broader taxonomic distribution has been reported for vocal convergence, where the acoustic properties of calls from different individuals converge when they are housed together in captivity or form social bonds in the wild. Vocal convergence has been demonstrated for animals as diverse as songbirds, parakeets, hummingbirds, bats, elephants, cetaceans, and primates. For most species, call convergence is thought to reflect a group-distinctive identifier, with shared calls reflecting and strengthening social bonds. A ubiquitous function for vocal production learning that is starting to receive attention involves modifying signals to improve communication in a noisy channel. Pooling data on vocal imitation, vocal convergence, and compensation for noise suggests a wider taxonomic distribution of vocal production learning among mammals than has been generally appreciated. The wide taxonomic distribution of this evidence for vocal production learning suggests that perhaps more of the neural underpinnings for vocal production learning are in place in mammals than is usually recognized.     

Syllogistic reasoning and belief-bias inhibition in school children: evidence from a negative priming paradigm

Research on deductive reasoning in adolescents and adults has shown that errors in deductive logic are not necessarily due to a lack of logical ability but can stem from an executive failure to inhibit biases. Few studies have examined this dissociation in children. Here, we used a negative priming paradigm with 64 children (8-10 years old) to test the role of cognitive inhibition in syllogisms with belief-bias effects. On trials where negative priming was predicted, results were as follows: For the first syllogism (A), the strategy 'unbelievable-equals-invalid' had to be inhibited. The logic of the syllogism led to affirming a conclusion inconsistent with one's knowledge of the world, such as 'All elephants are light.' For the second syllogism (B), one's real-world knowledge and the syllogism's logic were congruent but the latter required affirming exactly what had been inhibited for A (i.e. that elephants are heavy). A negative priming effect on the A-B sequence was reflected in a significant drop in reasoning performance on B. This supports the idea that during cognitive development, inhibitory control is required for success on syllogisms where beliefs and logic interfere.     

DO ELEPHANTS EVER FORGET?1

Three adult female elephants (Elephas maximus) were tested on a light-dark discrimination problem with an 8-yr intertrial interval. The first subject took only 6 min to reach criterion and made only two errors, suggesting remarkable retention. The other two subjects were found to have visual anomalies that would have gone undetected without this research.     

The cognitive dynamics of negated sentence verification

We explored the influence of negation on cognitive dynamics, measured using mouse-movement trajectories, to test the classic notion that negation acts as an operator on linguistic processing. In three experiments, participants verified the truth or falsity of simple statements, and we tracked the computer-mouse trajectories of their responses. Sentences expressing these facts sometimes contained a negation. Such negated statements could be true (e.g., "elephants are not small") or false (e.g., "elephants are not large"). In the first experiment, as predicted by the classic notion of negation, we found that negation caused more discreteness in the mouse trajectory of a response. The second experiment induced a simple context for these statements, yet negation still increased discreteness in trajectories. A third experiment enhanced the pragmatic context of sentences, and the discreteness was substantially diminished, with one primary measure no longer significantly showing increased discreteness at all. Traditional linguistic theories predict rapid shifts in cognitive dynamics occur due to the nature of negation: It is an operator that reverses the truth or falsity of an interpretation. We argue that these results support both propositional and contextual accounts of negation present in the literature, suggesting that contextual factors are crucial for determining the kind of cognitive dynamics displayed. We conclude by drawing broader lessons about theories of cognition from the case of negation.