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Articles 91 - 120 of 129
Full-Text Articles in Other Animal Sciences
Size Matters: Impact Of Item Size And Quantity On Array Choice By Chimpanzees (Pan Troglodytes), Sarah T. Boysen, Gary G. Berntson, Kimberly L. Mukobi
Size Matters: Impact Of Item Size And Quantity On Array Choice By Chimpanzees (Pan Troglodytes), Sarah T. Boysen, Gary G. Berntson, Kimberly L. Mukobi
Sentience Collection
The authors previously reported that chimpanzees (Pan troglodytes) showed a striking bias to select the larger of 2 candy arrays, despite a reversed reward contingency in which the animals received the smaller, nonselected array as a reward, except when Arabic numerals were used as stimuli. A perceptual or incentive-based interference occurred that was overcome by symbolic stimuli. The authors of the present study examined the impact of element size in choice arrays, using 1 to 5 large and small candies. Five test-sophisticated chimpanzees selected an array from the 2 presented during each trial. Their responses were not optimal, as animals …
Animal Suffering: An Invertebrate Perspective, Jennifer A. Mather
Animal Suffering: An Invertebrate Perspective, Jennifer A. Mather
Sentience Collection
Consideration of the welfare of other animals often is anthropocentric, focusing usually on mammals similar to humans. This article argues the necessity of evaluating the extension of such consideration more widely to invertebrates. Although unlike humans, some groups such as cephalopod molluscs probably have the potential for pain and suffering. In addition, a morality of care, rather than one of rights, and the damage humans do to themselves by cruel treatment of animals both argue for the extension of consideration to all animal species. This consideration predicts extension of basic care of cephalopods from simple housing and feeding into areas …
Possible Levels Of Animal Consciousness With Reference To Grey Parrots (Psittacus Erithacus), Irene M. Pepperberg, Spencer K. Lynn
Possible Levels Of Animal Consciousness With Reference To Grey Parrots (Psittacus Erithacus), Irene M. Pepperberg, Spencer K. Lynn
Sentience Collection
Researchers often study nonhuman abilities by assuming their subjects form representations about perceived stimuli and then process such information; why then would consciousness be required, and, if required, at what level? Arguments about nonhuman consciousness range from claims of levels comparable to humans to refutation of any need to study such phenomena. We suggest that (a) species exhibit different levels attuned to their ecological niches, and (b) animals, within their maximum possible level, exhibit different extents of awareness appropriate to particular situations, much like humans (presumably conscious) who often act without conscious awareness of factors controlling their behavior. We propose …
Spontaneous Discrimination Of Natural Stimuli By Chimpanzees (Pan Troglodytes), David A. Brown, Sarah T. Boysen
Spontaneous Discrimination Of Natural Stimuli By Chimpanzees (Pan Troglodytes), David A. Brown, Sarah T. Boysen
Sentience Collection
Six chimpanzees (Pan troglodytes) were presented with pairs of color photographic images of 5 different categories of animals (cat, chimp, gorilla, tiger, fish). The subjects responded to each pair using symbols for "same" and "different." Both within- and between-category discriminations were tested, and all chimpanzees classified the image pairs in accordance with the 5 experimenter-defined categories under conditions of nondifferential reinforcement. Although previous studies have demonstrated identification or discrimination of natural categories by nonhuman animals, subjects were typically differentially reinforced for their responses. The present findings demonstrate that chimpanzees can classify natural objects spontaneously and that such classifications may be …
Animal Emotions: Exploring Passionate Natures, Marc Bekoff
Animal Emotions: Exploring Passionate Natures, Marc Bekoff
Sentience Collection
No abstract provided.
Primate Numerical Competence: Contributions Toward Understanding Nonhuman Cognition, Sarah T. Boysen, Karen I. Hallberg
Primate Numerical Competence: Contributions Toward Understanding Nonhuman Cognition, Sarah T. Boysen, Karen I. Hallberg
Sentience Collection
Nonhuman primates represent the most significant extant species for comparative studies of cognition, including such complex phenomena as numerical competence, among others. Studies of numerical skills in monkeys and apes have a long, though somewhat sparse history, although questions for current empirical studies remain of great interest to several fields, including comparative, developmental, and cognitive psychology; anthropology; ethology; and philosophy, to name a few. In addition to demonstrated similarities in complex information processing, empirical studies of a variety of potential cognitive limitations or constraints have provided insights into similarities and differences across the primate order, and continue to offer theoretical …
Agonistic Behaviour And Biogenic Amines In Shore Crabs Carcinus Maenas, Lynne U. Sneddon, Alan C. Taylor, Felicity A. Huntingford, David G. Watson
Agonistic Behaviour And Biogenic Amines In Shore Crabs Carcinus Maenas, Lynne U. Sneddon, Alan C. Taylor, Felicity A. Huntingford, David G. Watson
Sentience Collection
To investigate the role of certain neurohormones in agonistic behaviour, fights were staged between pairs of size-matched male shore crabs Carcinus maenas, and blood samples were taken immediately after the contests had been resolved. Samples were also taken from these crabs at rest (before and after fighting) and after walking on a treadmill. A control group of crabs also had samples taken on each experimental day. Concentrations of tyramine, dopamine, octopamine, serotonin (5-HT) and norepinephrine were determined in each blood sample using a gas chromatography/mass spectrometry (GC-MS) system. Norepinephrine was not detectable in any of the samples, but the standards …
A Preliminary Investigation Of The Construct Of Psychopathic Personality (Psychopathy) In Chimpanzees (Pan Troglodytes), Scott O. Lilienfeld, Jonathan Gershon, Marshall Duke, Lori Marino, Frans B. M. De Waal
A Preliminary Investigation Of The Construct Of Psychopathic Personality (Psychopathy) In Chimpanzees (Pan Troglodytes), Scott O. Lilienfeld, Jonathan Gershon, Marshall Duke, Lori Marino, Frans B. M. De Waal
Sentience Collection
Although the construct of psychopathy has received considerable attention in humans, its relevance to other animals is largely unknown. We developed a measure of psychopathy for use in chimpanzees (Pan troglodytes), the Chimpanzee Psychopathy Measure (CPM), and asked 6 raters to complete this index on 34 chimpanzees. The CPM (a) demonstrated satisfactory interrater reliability and internal consistency; (b) exhibited marginally significant sex differences (males > females); (c) correlated positively with measures of extraversion, agreeableness, and observational ratings of agonism, sexual activity, daring behaviors, teasing, silent bluff displays, and temper tantrums, and negatively with observational ratings of generosity; and (d) demonstrated incremental …
Scale-Model Comprehension By Chimpanzees (Pan Troglodytes), Valerie A. Kuhlmeier, Sarah T. Boysen, Kimberly L. Mukobi
Scale-Model Comprehension By Chimpanzees (Pan Troglodytes), Valerie A. Kuhlmeier, Sarah T. Boysen, Kimberly L. Mukobi
Sentience Collection
The ability of chimpanzees (Pan troglodytes) to recognize the correspondence between a scale model and its real-world referent was examined. In Experiments 1 and 2, an adult female and a young adult male watched as an experimenter hid a miniature model food in 1 of 4 sites in a scale model. Then, the chimpanzees were given the opportunity to find the real food item that had been hidden in the analogous location in the real room. The female performed significantly above chance, whereas the male performed at chance level. Experiments 3 and 4 tested 5 adult and 2 adolescent chimpanzees …
Overcoming Response Bias Using Symbolic Representations Of Number By Chimpanzees (Pan Troglodytes), Sarah T. Boysen, Kimberly L. Mukobi, Gary G. Berntson
Overcoming Response Bias Using Symbolic Representations Of Number By Chimpanzees (Pan Troglodytes), Sarah T. Boysen, Kimberly L. Mukobi, Gary G. Berntson
Sentience Collection
We previously reported that chimpanzees were unable to optimally select the smaller of two candy arrays in order to receive a larger reward. When Arabic numerals were substituted for the candy arrays, animals who had had prior training with numerical symbols showed an immediate and significant improvement in performance and were able to select reliably the smaller numeric representation in order to obtain a larger reward. Poor performance with candy arrays was interpreted as reflecting a response bias toward the intrinsic incentive and/or perceptual features of the larger array. In contrast, the Arabic numerals represent numerosity symbolically and appear to …
Development Of Piagetian Object Permanence In A Grey Parrot (Psittacus Erithacus), Irene M. Pepperberg, Mark R. Willner, Lauren B. Gravitz
Development Of Piagetian Object Permanence In A Grey Parrot (Psittacus Erithacus), Irene M. Pepperberg, Mark R. Willner, Lauren B. Gravitz
Sentience Collection
The authors evaluated the ontogenetic performance of a grey parrot (Psittacus erithacus) on object permanence tasks designed for human infants. Testing began when the bird was 8 weeks old, prior to fledging and weaning. Because adult grey parrots understand complex invisible displacements (I. M. Pepperberg & F. A. Kozak, 1986), the authors continued weekly testing until the current subject completed all of I. C. Uzgiris and J. Hunt's (1975) Scale 1 tasks. Stage 6 object permanence with respect to these tasks emerged at 22 weeks, after the bird had fledged but before it was completely weaned. Although the parrot progressed …
Language-Naive Chimpanzees (Pan Troglodytes) Judge Relations Between Relations In A Conceptual Matching-To-Sample Task, Roger K.R. Thompson, David L. Oden, Sarah T. Boysen
Language-Naive Chimpanzees (Pan Troglodytes) Judge Relations Between Relations In A Conceptual Matching-To-Sample Task, Roger K.R. Thompson, David L. Oden, Sarah T. Boysen
Sentience Collection
Three chimpanzees with a history of conditional and numeric token training spontaneously matched relations between relations under conditions of nondifferential reinforcement. Heretofore, this conceptual ability was demonstrated only in language-trained chimpanzees. The performance levels of the language-naive animals in this study, however, were equivalent to those of a 4th animal—Sarah—whose history included language training and analogical problem solving. There was no evidence that associative factors mediated successful performance in any of the animals. Prior claims of a profound disparity between language-trained and language-naive chimpanzees apparently can be attributed to prior experience with arbitrary tokens consistently associated with abstract relations and …
Quantity-Based Interference And Symbolic Representations In Chimpanzees (Pan Troglodytes), S. T. Boysen, G. G. Berntson, M. B. Hannan, J. T. Cacioppo
Quantity-Based Interference And Symbolic Representations In Chimpanzees (Pan Troglodytes), S. T. Boysen, G. G. Berntson, M. B. Hannan, J. T. Cacioppo
Sentience Collection
Five chimpanzees with training in counting and numerical skills selected between 2 arrays of different amounts of candy or 2 Arabic numerals. A reversed reinforcement contingency was in effect, in which the selected array was removed and the subject received the nonselected candies (or the number of candies represented by the nonselected Arabic numeral). Animals were unable to maximize reward by selecting the smaller array when candies were used as array elements. When Arabic numerals were substituted for the candy arrays, all animals showed an immediate shift to a more optimal response strategy of selecting the smaller numeral, thereby receiving …
Mechanisms Of American English Vowel Production In A Grey Parrot (Psittacus Erithacus), Denice K. Warren, Dianne K. Patterson, Irene M. Pepperberg
Mechanisms Of American English Vowel Production In A Grey Parrot (Psittacus Erithacus), Denice K. Warren, Dianne K. Patterson, Irene M. Pepperberg
Sentience Collection
Parrots are known for their capacity to reproduce the sounds of human speech, but few studies have investigated their mechanisms for producing such vocalizations. Using three methods of noninvasive video imaging (Super VHS video, infrared, X-ray radiography), we examined correlations between several elements of a Grey Parrot's (Psittacus erithacus) vocal-tract configuration and the bird's production of two vowels, /i/ ("eat") and /a/ ("rock"). This parrot uses mechanisms that both resemble and differ from those used by: (a) humans to produce English speech; and (b) some avian species to produce conspecific vocalizations. This Grey Parrot, for example, uses its vocal apparatus …
Mirror Use By African Grey Parrots (Psittacus Erithacus), Irene M. Pepperberg, Sean E. Garcia, Eric C. Jackson, Sharon Marconi
Mirror Use By African Grey Parrots (Psittacus Erithacus), Irene M. Pepperberg, Sean E. Garcia, Eric C. Jackson, Sharon Marconi
Sentience Collection
No abstract provided.
Indicating Acts During Counting By A Chimpanzee (Pan Troglodytes), Sarah T. Boysen, Gary G. Berntson, Traci A. Shreyer, Michelle B. Hannan
Indicating Acts During Counting By A Chimpanzee (Pan Troglodytes), Sarah T. Boysen, Gary G. Berntson, Traci A. Shreyer, Michelle B. Hannan
Sentience Collection
A chimpanzee (Pan troglodytes) experienced in counting arrays of 0-7 items and trained for comprehension of number symbols, spontaneously displayed a variety of indicating acts (e.g., pointing, touching, and rearranging items) during counting. Twenty-five sessions were videotaped, and all trials were evaluated for the relations among number of items presented, number of indicating acts displayed, and the Arabic number selected to represent the array. Significant correlations included the relations between number of items and the cardinal number selected by the animal, between the number of items and indicating acts displayed by the chimpanzee, and between the number of indicating acts …
Comprehension Of Cause-Effect Relations In A Tool-Using Task By Chimpanzees (Pan Troglodytes), Luca Limongelli, Sarah T. Boysen, Elisabetta Visalberghi
Comprehension Of Cause-Effect Relations In A Tool-Using Task By Chimpanzees (Pan Troglodytes), Luca Limongelli, Sarah T. Boysen, Elisabetta Visalberghi
Sentience Collection
Five chimpanzees (Pan troglodytes) were tested to assess their understanding of causality in a tool task. The task consisted of a transparent tube with a trap-hole drilled in its middle. A reward was randomly placed on either side of the hole. Depending on which side the chimpanzee inserted the stick into, the candy was either pushed out of the tube or into the trap. In Experiment 1, the success rate of 2 chimpanzees rose highly above chance, but that of the other subjects did not. Results show that the 2 successful chimpanzees selected the correct side for insertion beforehand. Experiment …
Responses To Quantity: Perceptual Versus Cognitive Mechanisms In Chimpanzees (Pan Troglodytes), Sarah T. Boysen, Gary G. Berntson
Responses To Quantity: Perceptual Versus Cognitive Mechanisms In Chimpanzees (Pan Troglodytes), Sarah T. Boysen, Gary G. Berntson
Sentience Collection
Two chimpanzees were trained to select among 2 different amounts of candy (1-6 items). The task was designed so that selection of either array by the active (selector) chimpanzee resulted in that array being given to the passive (observer) animal, with the remaining (nonselected) array going to the selector. Neither animal was able to select consistently the smaller array, which would reap the larger reward. Rather, both animals preferentially selected the larger array, thereby receiving the smaller number of reinforcers. When Arabic numerals were substituted for the food arrays, however, the selector animal evidenced more optimal performance, immediately selecting the …
Vocal Learning In Grey Parrots (Psittacus Erithacus): Effects Of Social Interaction, Reference, And Context, Irene M. Pepperberg
Vocal Learning In Grey Parrots (Psittacus Erithacus): Effects Of Social Interaction, Reference, And Context, Irene M. Pepperberg
Sentience Collection
For many passerines, the extent,timing, and even presence of allospecific vocal learning can be influenced by the form of input that is received. Little data exist, however, on vocal learning in parrots (Psittacidae). I have previously proposed that such vocal learning proceeds most readily when input is (1) referential, (2) contextually applicable, and (3) interactive. The referential aspect demonstrates the meaning of the code to be taught, the contextual aspect demonstrates the use that can be made of the information contained in the code, and the interactive aspect provides explicit training that is constantly adjusted to the level of the …
Numerical Competence In An African Gray Parrot (Psittacus Erithacus), Irene M. Pepperberg
Numerical Competence In An African Gray Parrot (Psittacus Erithacus), Irene M. Pepperberg
Sentience Collection
An African gray parrot (Psittacus erithacus), Alex, trained to label vocally collections of 1-6 simultaneously presented homogeneous objects, correctly identified, without further training, quantities of targeted subsets in heterogeneous collections. For each test trial Alex was shown different collections of 4 groups of items that varied in 2 colors and 2 object categories (e.g., blue and red keys and trucks) and was asked to label the number of items uniquely defined by the conjunction of 1 color and 1 object category (e.g., "How many blue key?"). The collections were designed to provide maximal confounds (or distractions) and thus replicate the …
Vocal Perception: Brain Event-Related Potentials In A Chimpanzee, Gary G. Berntson, Sarah T. Boysen, Michael W. Torello
Vocal Perception: Brain Event-Related Potentials In A Chimpanzee, Gary G. Berntson, Sarah T. Boysen, Michael W. Torello
Sentience Collection
We describe the first brain event-related potential (ERP) study of cognitive processes in the chimpanzee. In an extension of our studies on the ontogeny of vocal perception, ERP measures were obtained during the presentation of simple nonsignal stimuli as well as conspecific and human vocalizations. We initially confirmed findings from humans and monkeys of the appearance of a long-latency positivity in the ERP waveform to a rare stimulus in an oddball paradigm. This ERP component is reminiscent of the P3a reported in humans under similar (passive) experimental conditions. We further demonstrated that both conspecific and human vocal stimuli having affective …
Comprehension Of Role Reversal In Chimpanzees: Evidence Of Empathy?, Daniel J. Povinelli, Kurt E. Nelson, Sarah T. Boysen
Comprehension Of Role Reversal In Chimpanzees: Evidence Of Empathy?, Daniel J. Povinelli, Kurt E. Nelson, Sarah T. Boysen
Sentience Collection
Four chimpanzees, Pan troglodytes, were individually trained to cooperate with a human partner on a task that allowed both participants to obtain food rewards. In each chimpanzee-human dyad, one of the participants (the informant) could see which pair of food trays on a four-choice apparatus was baited, but had no means of obtaining it. The other participant (the operator) could pull one of four handles to bring a pair of the trays within reach of both participants, but could not see which choice was correct. Two of the chimpanzees were initially trained as informants and adopted spontaneous gestures to indicate …
Vocal Recognition In Mexican Free-Tailed Bats: Do Pups Recognize Mothers?, Jonathan Balcombe, Gary F. Mccracken
Vocal Recognition In Mexican Free-Tailed Bats: Do Pups Recognize Mothers?, Jonathan Balcombe, Gary F. Mccracken
Sentience Collection
Mother Mexican free-tailed bats, Tadarida brasiliensis mexicana, produce 'directive' calls while searching for pups inside cave maternity roosts. These calls consist of highly repetitive pulses of sound uttered in rapid sequence. Calls are sufficiently intense that they are perceptible above the substantial background noise within roosts at distances of at least 1m. Calls are stereotyped within individuals, and statistically discriminable between individuals. These characteristics are expected for vocalizations that function for mother-pup reunions, and are shared with directive calls described previously in other bats. Mother T. b. mexicana directive calls are statistically no less discriminable than are the isolation calls …
Kin Recognition In Vertebrates: What Do We Really Know About Adaptive Value?, Andrew R. Blaustein, Marc Bekoff, John A. Byers, Thomas J. Daniels
Kin Recognition In Vertebrates: What Do We Really Know About Adaptive Value?, Andrew R. Blaustein, Marc Bekoff, John A. Byers, Thomas J. Daniels
Sentience Collection
The ability of an animal to discriminate between kin and non-kin (kin recognition) has been the subject of numerous recent investigations. Grafen (Anim. Behav., 1990, 39, 42-54) recently reported that the evidence in support of kin recognition is weak and the data illustrating a preference for kin to associate in the laboratory may be more consistently explained as species recognition. It is suggested here, however, that in many cases it may be impossible to distinguish between species recognition and kin recognition, but in some cases, kin recognition seems apparent. It is also emphasized that very little is known about the …
Inferences About Guessing And Knowing By Chimpanzees (Pan Troglodytes), Daniel J. Povinelli, Kurt E. Nelson, Sarah T. Boysen
Inferences About Guessing And Knowing By Chimpanzees (Pan Troglodytes), Daniel J. Povinelli, Kurt E. Nelson, Sarah T. Boysen
Sentience Collection
The visual perspective-taking ability of 4 chimpanzees (Pan troglodytes) was investigated. The subjects chose between information about the location of hidden food provided by 2 experimenters who randomly alternated between two roles (the guesser and the knower). The knower baited 1 of 4 obscured cups so that the subjects could watch the process but could not see which of the cups contained the reward. The guesser waited outside the room until the food was hidden. Finally, the knower pointed to the correct cup while the guesser pointed to an incorrect one. The chimpanzees quickly learned to respond to the knower. …
Vocal Recognition Of Pups By Mother Mexican Free-Tailed Bats, Tadarida Brasiliensis Mexicana, Jonathan P. Balcombe
Vocal Recognition Of Pups By Mother Mexican Free-Tailed Bats, Tadarida Brasiliensis Mexicana, Jonathan P. Balcombe
Sentience Collection
The ability of Mexican free-tailed bat mothers and pups to recognize vocalizations of their presumptive kin (pup isolation calls and mother echolocation calls, respectively) was tested using playbacks of recorded calls. Captive individuals were presented with calls of two bats, one presumptive kin and the other a stranger, from opposite sides of a circular wire arena. Response was determined by amount of time spent on each side of the arena, time spent in contact with a cloth bat model in front of each speaker, and number of separate contacts with each model. For the latter two measures, mothers showed a …
Specificity Of The Cardiac Response To Conspecific Vocalizations In Chimpanzees, Gary G. Berntson, Sarah T. Boysen
Specificity Of The Cardiac Response To Conspecific Vocalizations In Chimpanzees, Gary G. Berntson, Sarah T. Boysen
Sentience Collection
Heart rate measures were used to examine the functional response of young chimpanzees and orangutans to acoustic stimuli, including white noise and chimpanzee vocalizations (threat, stress, and alarm). The initial response of the animals to all stimuli was characterized by a prominent cardiac deceleration and an increase in heart period variability. The deceleratory responses persisted with repeated presentations of the noise, stress, and alarm stimuli. In contrast, the response of chimpanzees to the conspecific threat stimulus reverted over trials to a notable cardiac acceleration. This acceleratory response was not attributable to potential patterns of evoked somatic responses. The features of …
Numerical Competence In A Chimpanzee (Pan Troglodytes), Sarah T. Boysen, Gary G. Berntson
Numerical Competence In A Chimpanzee (Pan Troglodytes), Sarah T. Boysen, Gary G. Berntson
Sentience Collection
A chimpanzee (Pan troglodytes), trained to count foods and objects by using Arabic numbers, demonstrated the ability to sum arrays of 0-4 food items placed in 2 of 3 possible sites. To address representational use of numbers, we next baited sites with Arabic numbers as stimuli. In both cases performance was significantly above chance from the first sessions, which suggests that without explicit training in combining arrays, the animal was able to select the correct arithmetic sum for arrays of foods or Arabic numbers under novel test conditions. These findings demonstrate that counting strategies and the representational use of numbers …
Conspecific Recognition In The Chimpanzee (Pan Troglodytes): Cardiac Responses To Significant Others, Sarah T. Boysen, Gary G. Berntson
Conspecific Recognition In The Chimpanzee (Pan Troglodytes): Cardiac Responses To Significant Others, Sarah T. Boysen, Gary G. Berntson
Sentience Collection
The ability of a chimpanzee (Pan troglodytes) to recognize photographs of conspecifics was evaluated with heart-rate measures. Heart rate was recorded before, during, and after viewing photographs of an aggressive chimpanzee, a friendly companion animal, and an unfamiliar chimpanzee. The subject displayed a differential pattern of heart-rate response to the stimulus animals, without prior experience with the photographs. Responses to the aggressive animal were acceleratory, which suggests a defensive response. Respiratory sinus arrhythmia suggested that this response was associated with sympathetic activation. In contrast, responses to the familiar animal were minimal, whereas cardiac deceleration was observed in response to the …
Comprehension Of "Absence" By An African Grey Parrot: Learning With Respect To Questions Of Same/Different, Irene M. Pepperberg
Comprehension Of "Absence" By An African Grey Parrot: Learning With Respect To Questions Of Same/Different, Irene M. Pepperberg
Sentience Collection
An African Grey parrot, Alex, learned to report on the absence or presence of similarity and difference between two objects. Alex was shown pairs of objects that were (a) totally dissimilar, (b) identical, or (c) similar or different with respect to one of three attributes (color, shape, or material). In the first two cases, he responded to the respective queries of "What's same?" or "What's different?" with the vocalization "none," and in the third case he responded with the appropriate category label ("color," "shape," or "mah-mah" [matter]). His accuracy was 80.9% to 83.9% for pairs of familiar objects not used …