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.     

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).     

Human interventions in a behavioural experiment for Asian Elephants (Elephas maximus)

Animal Cognition - Experiments are widely used to investigate the behaviour and cognition of animals. While the automation of experiments to avoid potential experimenter bias is sometimes possible,...     

"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.     

Performance of rats on a discrimination operant alley task discriminated

An automated discriminated operant alley apparatus is described. Data from four rat strains indicate that the light-dark choice is learned by both pigmented and albino rats. The task requires a minimum of experimenter time and allows initial acquisition to be recorded without the interference of a shaping procedure.     

Acquisition of a same-different discrimination task by pigeons (Columba livia)

Four homing pigeons were trained to discriminate two figures simultaneously presented on an LCD screen. The figure was either a rectangle (A) or a square (B), and four combinations of the two figures, AA, AB, BA, BB, appeared in a pseudo-randomized order. The pigeons' task was to peck one of these figures based upon whether the two figures were identical or not. One pigeon successfully learned this discrimination, with proportions of correct responses above 90% in two consecutive sessions. Of the other birds, two performed above chance level but had difficulty meeting a learning criterion of above 80% in two consecutive sessions. All birds achieved this criterion when the combinations of figures presented were reduced to two. Results suggested that learning the present same-different discrimination is within the capacity of pigeons to a certain extent, although there exists considerable individual variation in the pigeons' skills to acquire complex discrimination.     

An experimental investigation of the effect of worry on responses to a discrimination learning task

The current study examined the impact of both the tendency to worry (trait worry) and the process of worry (state worry) on subsequent behavioral responding in a schedule discrimination learning task. High and low trait worriers were randomly assigned to a state worry or relaxation incubation condition and completed a test of executive functioning and a dual contingency learning task that utilized neutral discriminative cues over the course of 2 contingency phases. Although state and trait worry did not impact executive functioning, the state worry condition was associated with diminished sensitivity to learning task contingencies over the course of the first contingency learning trials in comparison to the relaxation condition. This relationship was unique to the state worry condition above and beyond shared variance with subjective anxiety level. Results suggest that state worry may lead to a decrement in selective behavioral responding to neutral discriminative cues in the environment. The findings suggest that the process of worry may lead to less adaptive responding to neutral cues and interfere with adaptive behaviors, which may thereby contribute to and maintain anxiety.     

Working and reference memory of pigs (Sus scrofa domesticus) in a holeboard spatial discrimination task: the influence of environmental enrichment

Interest in cognitive research in pigs is increasing, but little is known about the impact of environmental conditions on pigs’ cognitive capabilities. The present study investigated the effect of environmental enrichment on cognitive performance of pigs in a holeboard spatial task, in which they had to discriminate four baited buckets out of 16. Pigs (n = 32) were either housed in stimulus-poor, barren pens, or in larger pens enriched with rooting substrates. Pigs were subjected to 30 holeboard trials. Both working memory (WM), that is, the ratio (baited visits/total number of (re)visits to baited buckets), and reference memory (RM), that is, the ratio ((re)visits to baited buckets/total number of visits to all buckets), improved over trials. WM scores were higher in pigs from enriched pens than in pigs from barren pens. Housing did not affect RM scores. Personality type of the pigs, as assessed early in life using a backtest, did not affect WM or RM. In conclusion, housing conditions of pigs did not affect reference memory, but environmental enrichment improved working memory of pigs in a spatial discrimination task. Based on the findings of this study, we suggest that cognitive functioning of pigs may be impaired under commonly used housing conditions.     

Performance in a computerized self-control task by rhesus macaques (Macaca mulatta): The combined influence of effort and delay

The variables of delay and effort have been found to influence self-control predictably and in similar fashion when tested independently, but it is unclear how they influence self-control interactively. In the present study, I tested these two variables simultaneously to gain better understanding of their combined influence on self-control. A computerized task was employed in which monkey participants could sequence 1 or more digital images before “cashing-out,” after which they would receive their accumulated rewards. Delay was manipulated by adjusting the speed of the cursor used to select images. Cognitive effort was manipulated by presenting image sets that appeared in either a constant or a randomized configuration. For most monkeys, an interaction was found between the effects of delay and effort on the number of images selected before cashing-out. The results suggest that, when combined, these two variables have a complex influence on self-control.     

Potential performance theory (PPT): a general theory of task performance applied to morality

People can use a variety of different strategies to perform tasks and these strategies all have two characteristics in common. First, they can be evaluated in comparison with either an absolute or a relative standard. Second, they can be used at varying levels of consistency. In the present article, the authors develop a general theory of task performance called potential performance theory (PPT) that distinguishes between observed scores and true scores that are corrected for inconsistency (i.e., potential scores). In addition, they argue that any kind of improvement to task performance, whatever it may be, works by influencing either task strategies, which comprise all nonrandom components that are relevant to the task, or the consistency with which strategies are used. In the current study, PPT is used to demonstrate how task strategies and the consistencies with which they are used impact actual performance in the domain of morality. These conclusions are extended to other domains of task performance.     

Gamma is a Measure of the Accuracy of Predicting Performance on One Item Relative to Another Item,not of the Absolute Performance on an Individual Item Comments on Schraw (1995)

The recent paper by Schraw ( Measures of feeling-of-knowing accuracy: a new look at an old problem , Applied Cognitive Psychology, 1995, 9, 321—332) is flawed by several inaccuracies and by Schraw's failure to distinguish between two fundamentally different aspects of the accuracy of metacognitive predictions: (1) calibration (aka absolute accuracy, defined in terms of whether the predicted value assigned to a single item is followed by the occurrence of that value on the criterion test), and (2) resolution (aka relative accuracy, defined in terms of whether the predicted performance on one item relative to another item is followed by the occurrence of that ordering of the two items on the criterion test). Because of these (and other) problems, his recommendations seem misleading and counterproductive.     

Dogs (Canis lupus familiaris) fail to show understanding of means-end connections in a string-pulling task

Domestic dogs (Canis lupus familiaris) were tested in four experiments for their understanding of means-end connections. In each of the experiments, the dogs attempted to retrieve a food treat that could be seen behind a barrier and which was connected, via string, to a within-reach wooden block. In the experiments, either one or two strings were present, but the treat was attached only to one string. Successful retrieval of the treat required the animals to pull the appropriate string (either by pawing or by grasping the wooden block in their jaws) until the treat emerged from under the barrier. The results showed that the dogs were successful if the treat was in a perpendicular line to the barrier, i.e. straight ahead, but not when the string was at an angle: in the latter condition, the typical response was a proximity error in that the dogs pawed or mouthed at a location closest in line to the treat. When two strings that crossed were present, the dogs tended to pull on the wrong string. The combined results from the experiments show that, although dogs can learn to pull on a string to obtain food, they do not spontaneously understand means-end connections involving strings.     

Performance on the Hamilton search task,and the influence of lateralization,in captive orange-winged Amazon parrots (Amazona amazonica)

Psittacines are generally considered to possess cognitive abilities comparable to those of primates. Most psittacine research has evaluated performance on standardized complex cognition tasks, but studies of basic cognitive processes are limited. We tested orange-winged Amazon parrots (Amazona amazonica) on a spatial foraging assessment, the Hamilton search task. This task is a standardized test used in human and non-human primate studies. It has multiple phases, which require trial and error learning, learning set breaking, and spatial memory. We investigated search strategies used to complete the task, cognitive flexibility, and long-term memory for the task. We also assessed the effects of individual strength of motor lateralization (foot preference) and sex on task performance. Almost all (92 %) of the parrots acquired the task. All had significant foot preferences, with 69 % preferring their left foot, and showed side preferences contralateral to their preferred limb during location selection. The parrots were able to alter their search strategies when reward contingencies changed, demonstrating cognitive flexibility. They were also able to remember the task over a 6-month period. Lateralization had a significant influence on learning set acquisition but no effect on cognitive flexibility. There were no sex differences. To our knowledge, this is the first cognitive study using this particular species and one of the few studies of cognitive abilities in any Neotropical parrot species.     

A pharmacological analysis of an associative learning task: 5-HT(1) to 5-HT(7) receptor subtypes function on a pavlovian/instrumental autoshaped memory

Recent studies using both invertebrates and mammals have revealed that endogenous serotonin (5-hydroxytryptamine [5-HT]) modulates plasticity processes, including learning and memory. However, little is currently known about the mechanisms, loci, or time window of the actions of 5-HT. The aim of this review is to discuss some recent results on the effects of systemic administration of selective agonists and antagonists of 5-HT on associative learning in a Pavlovian/instrumental autoshaping (P/I-A) task in rats. The results indicate that pharmacological manipulation of 5-HT1-7 receptors or 5-HT reuptake sites might modulate memory consolidation, which is consistent with the emerging notion that 5-HT plays a key role in memory formation.     

Hand preference and its flexibility according to the position of the object: a study in cercopithecines examining spontaneous behaviour and an experimental task (the Bishop QHP task)

The extant literature on manual laterality in non-human primates is inconclusive, plagued by inconsistent or contradictory findings and by disturbing methodological issues (e.g. uncontrolled influential factors, comparability issues). The present study examined hand preference and its flexibility in 15 red-capped mangabeys (C. t. torquatus) and 13 Campbell's monkeys (C. c. campbelli), two species that differ in their degree of arboreality. We investigated the influence of the spatial position of the object on hand preference for reaching. We considered spontaneous behaviour (reaching for food during daily feeding) and an experimental task: the QHP task. The QHP is a task that is used in humans. This is a simple reaching task that involves high spatial constraints on hand use. In our study, the subject had to reach for items that were placed on a semi-circle in front of it on five positions, including in the centre position, in the ipsilateral space and in the contralateral space. We assessed hand preference for reaching in front (baseline condition), and we examined how this preference changed when reaching in lateral positions. For reaching in front, about half of the subjects were lateralized and no group-level bias occurred, for both spontaneous and experimental conditions. When considering reaching in the lateral positions, we observed that the position of the object influenced hand use: individuals used the hand that was closest to the object. The results are discussed in relation to previous findings in humans and in non-human primates and regarding theories on handedness and flexibility of hand preference.     

How the great apes (Pan troglodytes, Pongo pygmaeus, Pan paniscus, and Gorilla gorilla) perform on the reversed contingency task: the effects of food quantity and food visibility

S. T. Boysen and G. G. Berntson (1995) found that chimpanzees performed poorly on a reversed contingency task in which they had to point to the smaller of 2 food quantities to acquire the larger quantity. The authors compared the performance of 4 great ape species (Pan troglodytes, Pongo pygmaeus, Pan paniscus, and Gorilla gorilla) on the reversed contingency task while manipulating food quantity (0-4 or 1-4) and food visibility (visible pairs or covered pairs). Results showed no systematic species differences but large individual differences. Some individuals of each species were able to solve the reversed contingency task. Both quantity and visibility of the food items had a significant effect on performance. Subjects performed better when the disparity between quantities was smaller and the quantities were not directly visible.     

Ontogenetic effects on gazing behaviour: a case study of kennel dogs (Labrador Retrievers) in the impossible task paradigm

Life experiences and living conditions can influence the problem-solving strategies and the communicative abilities of dogs with humans. The goals of this study were to determine any behavioural differences between Labrador Retrievers living in a kennel and those living in a house as pets and to assess whether kennel dogs show preferences in social behaviours for their caretaker relative to a stranger when they are faced with an unsolvable task. Nine Labrador Retrievers living in a kennel from birth and ten Labrador Retrievers living in a family as pets were tested. The experimental procedure consisted of three “solvable” tasks in which the dogs could easily retrieve food from a container followed by an “unsolvable” task in which the container was hermetically locked. Dogs of both groups spent the same amount of time interacting with the experimental apparatus. Kennel dogs gazed towards people for less time and with higher latency than pet dogs; however, there were no significant preferences in gazing towards the stranger versus the caretaker in both groups. These findings demonstrated that kennel dogs are less prone to use human-directed gazing behaviour when they are faced with an unsolvable problem, taking the humans into account to solve a task less than do the pet dogs.     

How the great apes (Pan troglodytes, Pongo pygmaeus, Pan paniscus, Gorilla gorilla) perform on the reversed reward contingency task II: transfer to new quantities, long-term retention, and the impact of quantity ratios

We tested 6 chimpanzees (Pan troglodytes), 3 orangutans (Pongo pygmaeus), 4 bonobos (Pan paniscus), and 2 gorillas (Gorilla gorilla) in the reversed reward contingency task. Individuals were presented with pairs of quantities ranging between 0 and 6 food items. Prior to testing, some experienced apes had solved this task using 2 quantities while others were totally na?ve. Experienced apes transferred their ability to multiple-novel pairs after 6 to 19 months had elapsed since their initial testing. Two out of 6 na?ve apes (1 chimpanzee, 1 bonobo) solved the task--a proportion comparable to that of a previous study using 2 pairs of quantities. Their acquisition speed was also comparable to the successful subjects from that study. The ratio between quantities explained a large portion of the variance but affected na?ve and experienced individuals differently. For smaller ratios, na?ve individuals were well below 50% correct and experienced ones were well above 50%, yet both groups tended to converge toward 50% for larger ratios. Thus, some apes require no procedural modifications to overcome their strong bias for selecting the larger of 2 quantities.