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Plotnik JM, Jacobson SL. A “thinking animal” in conflict: studying wild elephant cognition in the shadow of anthropogenic change. Curr Opin Behav Sci 2022. [DOI: 10.1016/j.cobeha.2022.101148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Snyder RJ, Barrett LP, Emory RA, Perdue BM. Performance of Asian elephants (Elephas maximus) on a quantity discrimination task is similar to that of African savanna elephants (Loxodonta africana). Anim Cogn 2021; 24:1121-1131. [PMID: 33811595 DOI: 10.1007/s10071-021-01504-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 01/24/2021] [Accepted: 03/08/2021] [Indexed: 02/04/2023]
Abstract
Using an object-choice task, we measured the relative quantity discrimination ability of Asian elephants. Two zoo-housed elephants were given auditory cues of food being dropped into two containers (Nonvisible condition), and in one condition they could also see the food on top of the containers (Visible condition). Elephants received sets of varying ratios and magnitudes. We found that the elephants chose the greater quantity of food significantly above chance in both the Visible and Nonvisible conditions. Additionally, we found the elephants' ability to discriminate between quantities decreased as the ratio, and not the absolute difference, between the quantities increased, which is predicted by the accumulator model. We also compare our findings to those from a study using the same methods with African savanna elephants and found that the two species performed at similar levels, but given our small sample size it is difficult to make strong species-level conclusions. In discussing our results, we consider differences between the two species' wild environments as well as the types of sensory cues provided in human care, and we provide recommendations for extensions of this work.
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Affiliation(s)
- Rebecca J Snyder
- Oklahoma City Zoo, 2000 Remington Way, Oklahoma City, OK, 73111, USA.
| | - Lisa P Barrett
- Oklahoma City Zoo, 2000 Remington Way, Oklahoma City, OK, 73111, USA
| | - Rachel A Emory
- Oklahoma City Zoo, 2000 Remington Way, Oklahoma City, OK, 73111, USA
| | - Bonnie M Perdue
- Agnes Scott College, 141 E. College Avenue, Decatur, GA, 30030, USA
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Rivas-Blanco D, Pohl IM, Dale R, Heberlein MTE, Range F. Wolves and Dogs May Rely on Non-numerical Cues in Quantity Discrimination Tasks When Given the Choice. Front Psychol 2020; 11:573317. [PMID: 33041945 PMCID: PMC7518719 DOI: 10.3389/fpsyg.2020.573317] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 08/25/2020] [Indexed: 12/03/2022] Open
Abstract
A wide array of species throughout the animal kingdom has shown the ability to distinguish between quantities. Aside from being important for optimal foraging decisions, this ability seems to also be of great relevance in group-living animals as it allows them to inform their decisions regarding engagement in between-group conflicts based on the size of competing groups. However, it is often unclear whether these animals rely on numerical information alone to make these decisions or whether they employ other cues that may covary with the differences in quantity. In this study, we used a touch screen paradigm to investigate the quantity discrimination abilities of two closely related group-living species, wolves and dogs, using a simultaneous visual presentation paradigm. Both species were able to successfully distinguish between stimuli of different quantities up to 32 items and ratios up to 0.80, and their results were in accordance with Weber’s law (which predicts worse performances at higher ratios). However, our controls showed that both wolves and dogs may have used continuous, non-numerical cues, such as size and shape of the stimuli, in conjunction with the numerical information to solve this task. In line with this possibility, dogs’ performance greatly exceeded that which they had shown in other numerical competence paradigms. We discuss the implications these results may have on these species’ underlying biases and numerical capabilities, as well as how our paradigm may have affected the animals’ ability to solve the task.
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Affiliation(s)
- Dániel Rivas-Blanco
- Domestication Lab, Department of Interdisciplinary Life Sciences, Konrad Lorenz Institute of Ethology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Ina-Maria Pohl
- Clever Dog Lab, Comparative Cognition, Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna, University of Vienna, Vienna, Austria
| | - Rachel Dale
- Domestication Lab, Department of Interdisciplinary Life Sciences, Konrad Lorenz Institute of Ethology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Marianne Theres Elisabeth Heberlein
- Domestication Lab, Department of Interdisciplinary Life Sciences, Konrad Lorenz Institute of Ethology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Friederike Range
- Domestication Lab, Department of Interdisciplinary Life Sciences, Konrad Lorenz Institute of Ethology, University of Veterinary Medicine Vienna, Vienna, Austria.,Clever Dog Lab, Comparative Cognition, Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna, University of Vienna, Vienna, Austria.,Wolf Science Center, Ernstbrunn, Austria
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DeLong CM, Barbato S, O’Leary T, Wilcox KT. Small and large number discrimination in goldfish (Carassius auratus) with extensive training. Behav Processes 2017; 141:172-183. [DOI: 10.1016/j.beproc.2016.11.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 11/21/2016] [Accepted: 11/23/2016] [Indexed: 11/26/2022]
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Trained Quantity Abilities in Horses (Equus caballus): A Preliminary Investigation. Behav Sci (Basel) 2014; 4:213-225. [PMID: 25379278 PMCID: PMC4219264 DOI: 10.3390/bs4030213] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 07/11/2014] [Accepted: 07/15/2014] [Indexed: 11/29/2022] Open
Abstract
Once believed to be a human prerogative, the capacity to discriminate between quantities now has also been reported in several vertebrates. To date, only two studies investigated numerical abilities in horses (Equus caballus) but reported contrasting data. To assess whether horses can be trained to discriminate between quantities, I have set up a new experimental protocol using operant conditioning. One adult female was trained to discriminate between 1 and 4 (Test 1) in three different conditions: non-controlled continuous variables (numerical and continuous quantities that co-vary with number are simultaneously available), 50% controlled continuous variables (intermediate condition), and 100% controlled continuous variables (only numerical information available). The subject learned the discrimination in all conditions, showing the capacity to process numerical information. When presented with a higher numerical ratio (2 vs. 4, Test 2), the subject still discriminated between the quantities but its performance was statistically significant only in the non-controlled condition, suggesting that the subject used multiple cues in presence of a more difficult discrimination. On the whole, the results here reported encourage the use of this experimental protocol as a valid tool to investigate the capacity to process numerical and continuous quantities in horses in future research.
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Agrillo C, Bisazza A. Spontaneous versus trained numerical abilities. A comparison between the two main tools to study numerical competence in non-human animals. J Neurosci Methods 2014; 234:82-91. [PMID: 24793399 DOI: 10.1016/j.jneumeth.2014.04.027] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 04/23/2014] [Accepted: 04/24/2014] [Indexed: 01/29/2023]
Abstract
A large body of experimental evidence shows that animals as diverse as mammals, birds, and fish are capable of processing numerical information. Considerable differences have been reported in some cases among species and a wide debate currently surrounds the issue of whether all vertebrates share the same numerical systems or not. Part of the problem is due to the fact that these studies often use different methods, a circumstance that potentially introduces confounding factors in a comparative analysis. In most studies, two main methodological approaches have been used: spontaneous choice tests and training procedures. The former approach consists of presenting to the subjects two groups of biologically-relevant stimuli (e.g., food items or social companions) differing in numerosity with the assumption that if they are able to discriminate between the two quantities, they are expected to spontaneously select the larger/smaller quantity. In the latter approach, subjects undergo extensive training in which some neutral stimuli (e.g., a quantity of dots) are associated with a reward and the capacity to learn a numerical rule is taken as evidence of numerical abilities. We review the literature on this topic, highlighting the relevance, and potential weaknesses in controlling confounding factors obtained with either approach.
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Affiliation(s)
| | - Angelo Bisazza
- Department of General Psychology, University of Padova, Italy
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Jones SM, Pearson J, DeWind NK, Paulsen D, Tenekedjieva AM, Brannon EM. Lemurs and macaques show similar numerical sensitivity. Anim Cogn 2014; 17:503-15. [PMID: 24068469 PMCID: PMC3966981 DOI: 10.1007/s10071-013-0682-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 09/07/2013] [Accepted: 09/09/2013] [Indexed: 01/29/2023]
Abstract
We investigated the precision of the approximate number system (ANS) in three lemur species (Lemur catta, Eulemur mongoz, and Eulemur macaco flavifrons), one Old World monkey species (Macaca mulatta) and humans (Homo sapiens). In Experiment 1, four individuals of each nonhuman primate species were trained to select the numerically larger of two visual arrays on a touchscreen. We estimated numerical acuity by modeling Weber fractions (w) and found quantitatively equivalent performance among all four nonhuman primate species. In Experiment 2, we tested adult humans in a similar procedure, and they outperformed the four nonhuman species but showed qualitatively similar performance. These results indicate that the ANS is conserved over the primate order.
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Affiliation(s)
- Sarah M Jones
- Department of Psychology and Neuroscience, Duke University, Durham, NC, USA,
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Samhita L, Gross HJ. The "Clever Hans Phenomenon" revisited. Commun Integr Biol 2013; 6:e27122. [PMID: 24563716 PMCID: PMC3921203 DOI: 10.4161/cib.27122] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 11/06/2013] [Indexed: 11/19/2022] Open
Abstract
In the first decade of the 20th century, a horse named Hans drew worldwide attention in Berlin as the first and most famous "speaking" and thinking animal. Hans solved calculations by tapping numbers or letters with his hoof in order to answer questions. Later on, it turned out that the horse was able to give the correct answer by reading the microscopic signals in the face of the questioning person. This observation caused a revolution and as a consequence, experimenters avoided strictly any face-to-face contact in studies about cognitive abilities of animals-a fundamental lesson that is still not applied rigorously.
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Affiliation(s)
- Laasya Samhita
- Department of Microbiology and Cell Biology; Indian Institute of Science; Bangalore, India
| | - Hans J Gross
- BEEgroup and Chair of Biochemistry; Biocenter; Julius-Maximilians-University; Würzburg, Germany
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Henselek Y, Fischer J, Schloegl C. Does the stimulus type influence horses' performance in a quantity discrimination task? Front Psychol 2012. [PMID: 23181043 PMCID: PMC3499915 DOI: 10.3389/fpsyg.2012.00504] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The ability to understand the relation between quantities has been documented in a wide range of species. Such quantity discrimination competences are commonly demonstrated by a choice of the larger quantity or numerosity in a two-choice task. However, despite their overall success, many subjects commit a surprisingly large number of errors even in simple discriminations such as 1 vs. 3. Recently, it had been suggested that this is a result of the testing procedure. When monkeys could choose between different quantities of edible rewards, they showed low-level success. If, however, they chose between inedible items and were rewarded with edible items, their performance increased. The same held true if they chose between edible items but were rewarded with other edible items (Schmitt and Fischer, 2011). This led to the suggestion that the monkeys may not have been able to mentally separate between choice- and reward-stimuli in the initial test situation. To investigate if this response pattern can also be found in non-primate species, we replicated the experiment with 12 Icelandic horses kept at a private horse-riding school. Horses are known to discriminate between quantities up to three, but are very distantly related to primates. Unexpectedly, we found only weak evidence for quantity discrimination skills and no effect of the type of stimuli. Only some subjects reliably selected the larger quantity in some, but not all quantity pairs. These findings are not only in contrast to the previously conducted study on monkeys, but also to other studies on horses. From this, we conclude that quantity discrimination competence may only be of minor importance for horses and highlight the influence of experimental conditions on the outcome of cognitive tests.
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Affiliation(s)
- Yuki Henselek
- Cognitive Ethology Laboratory, German Primate Center Göttingen, Germany
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Baker JM, Morath J, Rodzon KS, Jordan KE. A shared system of representation governing quantity discrimination in canids. Front Psychol 2012; 3:387. [PMID: 23060847 PMCID: PMC3465982 DOI: 10.3389/fpsyg.2012.00387] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Accepted: 09/17/2012] [Indexed: 11/13/2022] Open
Abstract
One way to investigate the evolution of cognition is to compare the abilities of phylogenetically related species. The domestic dog (Canis lupus familiaris), for example, still shares cognitive abilities with the coyote (Canis latrans). Both of these canids possess the ability to make psychophysical "less/more" discriminations of food based on quantity. Like many other species including humans, this ability is mediated by Weber's Law: discrimination of continuous quantities is dependent on the ratio between the two quantities. As two simultaneously presented quantities of food become more similar, choice of the large or small option becomes random in both dogs and coyotes. It remains unknown, however, whether these closely related species within the same family - one domesticated, and one wild - make such quantitative comparisons with comparable accuracy. Has domestication honed or diminished this quantitative ability? Might different selective and ecological pressures facing coyotes drive them to be more or less able to accurately represent and discriminate food quantity than domesticated dogs? This study is an effort to elucidate this question concerning the evolution of non-verbal quantitative cognition. Here, we tested the quantitative discrimination ability of 16 domesticated dogs. Each animal was given nine trials in which two different quantities of food were simultaneously displayed to them. The domesticated dogs' performance on this task was then compared directly to the data from 16 coyotes' performance on this same task reported by Baker et al. (2011). The quantitative discrimination abilities between the two species were strikingly similar. Domesticated dogs demonstrated similar quantitative sensitivity as coyotes, suggesting that domestication may not have significantly altered the psychophysical discrimination abilities of canids. Instead, this study provides further evidence for similar non-verbal quantitative abilities across multiple species.
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Affiliation(s)
- Joseph M Baker
- Multisensory Cognition Lab, Department of Psychology, Utah State University Logan, UT, USA
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Putting the elephant back in the herd: elephant relative quantity judgments match those of other species. Anim Cogn 2012; 15:955-61. [DOI: 10.1007/s10071-012-0521-y] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 05/17/2012] [Accepted: 05/28/2012] [Indexed: 10/28/2022]
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Agrillo C, Miletto Petrazzini ME. The importance of replication in comparative psychology: the lesson of elephant quantity judgments. Front Psychol 2012; 3:181. [PMID: 22675317 PMCID: PMC3365653 DOI: 10.3389/fpsyg.2012.00181] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 05/17/2012] [Indexed: 11/13/2022] Open
Affiliation(s)
- Christian Agrillo
- Department of General Psychology, University of Padova Padova, Italy
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