Comparative Psychology Commons^™

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

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 …

Science, Values And Animal Welfare: Exploring The ‘Inextricable Connection’, D. Fraser

Animal Welfare Collection

In conceptualizing animal welfare, it is useful to distinguish among three types of concepts. 'Type l' are single, measurable attributes. 'Type 2' are single attributes that cannot be measured directly but can be estimated by correctly combining various contributing attributes. 'Type 3' are concepts involving multiple attributes which are grouped together because they serve some common function, and whose relative importance cannot be established in an entirely objective way. Individuals who treat animal welfare as a type 1 concept may propose single, objective measures of welfare, such as longevity or levels of stress-related hormones; however, this approach rests on judgements, …

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

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 …

Play Signals As Punctuation: The Structure Of Social Play In Canids, Marc Bekoff

Ethology Collection

Actions called play signals have evolved in many species in which social play has been observed. Despite there being only few empirical demonstrations, it generally is accepted that play signals are important in the initiation ("I want to play") and maintenance ("I still want to play") of ongoing social play. In this study I consider whether a specific and highly stereotyped signal, the bow, is used to maintain social play in adult and infant domestic dogs, infant wolves, and infant coyotes.

To answer this question the temporal placement of bows relative to actions that are also used in other contexts …

Vigilance, Flock Size, And Flock Geometry: Information Gathering By Western Evening Grosbeaks (Aves, Fringillidae), Marc Bekoff

Ethology Collection

Vigilance (scanning) and other behavior patterns were studied in free-ranging Evening Grosbeaks (Coccothraustes vespertinus) at feeders to assess how flock size and flock geometry influenced the behavior of individual birds. The present results indicate that the way in which individual grosbeaks are positioned with respect to one another effects many aspects of their behavior, especially when a flock contains four or more birds. Birds in a linear array who have difficulty seeing one another, when compared to individuals organized in a circle who can easily see one another, are (1) more vigilant, (2) change their head and body positions more …

Calling By Domestic Piglets: Reliable Signals Of Need?, Daniel M. Weary, David Fraser

Communication Skills Collection

Two manipulations were performed on domestic piglets to determine whether differences in calling during periods of separation from the mother can indicate differences in need. In both cases, the aim was to manipulate the piglet's need for the sow's attention. In the first manipulation a 'thriving' piglet (i.e. the piglet with the heaviest weight and most rapid weight gain) and a 'non-thriving' one (lightest and slowest weight gain) were selected from each of 15 litters. The two piglets were removed from the sow and litter and recorded for 13 min in separate isolated enclosures. For the second manipulation, two piglets …

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

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 …

The Relationship Between Creep Feeding Behavior Of Piglets And Adaptation To Weaning: Effect Of Diet Quality, David Fraser, J. J.R. Feddes, E. A. Pajor

Feeding Behavior Collection

Individual variation in creep feed intake and its relation to adaptation to weaning were studied in piglets weaned at 4 wk of age. The animals received either a "low-complexity" creep-starter diet based on corn, barley and soybean meal (12 litters), or a "high-complexity", medicated, commercial diet without soybean meal (12 litters). Diets were fed as creep feed during the 2 wk before weaning, and as the sole diet during the 2 wk after weaning. Creep feeding behavior of piglets was monitored by video recording. Pigs fed the high-complexity diet consumed more creep feed (P < 0.05), tended to gain more during the week before weaning (P < 0.10), and converted feed more efficiently and gained more weight in the 2 wk after weaning (P < 0.01). Use of creep feed varied greatly among individual littermates. Multiple regression analysis showed that on the high-complexity diet, pigs that used creep feed more than their littermates tended to be those with low gains in weeks 1-3 after birth (P < 0.001), and tended to gain more weight during the week before and during the 2 wk after weaning (P < 0.01). The trends were consistent but weaker with the low-complexity diet. However, predictive power was low, with creep feeding accounting for only 4% of individual variation in post-weaning gain on the high-complexity diet and 1% on the low. Regardless of diet quality, therefore, creep feeding remained highly variable and only weakly related to weight gains during the 2 wk after weaning.

Individual Differences In The Cognitive Abilities Of Chimpanzees, Sarah T. Boysen

Psychology Collection

No abstract provided.

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 …

Counting In Chimpanzees: Nonhuman Principles And Emergent Properties Of Number, Sarah T. Boysen

Numeracy Collection

No abstract provided.

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 …

Colostrum Intake By Newborn Piglets, David Fraser, Jeffrey Rushen

Feeding Behavior Collection

Colostrum intake by newborn piglets was studied by weighing piglets every 10 min for their first 1-4 h with the sow, and their cumulative weight increases were used as estimates of colostrum intake. In seven litters, four piglets were monitored for 4 h beginning about 2 h after the birth of the first piglet in order to determine if colostrum is available continuously or released in discrete ejections. There was little synchrony between litter-mates in their intake in the first hour, but by the second hour of monitoring (starting about 3 h after farrowing began), much of the colostrum was …

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 …

Counting As The Chimpanzee Views It, Sarah T. Boysen

Numeracy Collection

No abstract provided.

Consumption Of Solid Food By Suckling Pigs: Individual Variation And Relation To Weight Gain, Edmond A. Pajor, David Fraser, Donald L. Kramer

Feeding Behavior Collection

Individual daily consumption of supplementary solid food ('creep feed') was measured from Day 10 to weaning at Day 28 for 39 piglets in four litters, and its relationship to body weight and weight gain up to Day 42 was investigated. Individual consumption was measured by combining the weight of the feed removed from the dispensers (monitored electronically) and a video image of piglet activity at the feeder. Creep feed consumption varied greatly, both between and within litters. On average, pigs began feeding on Day 12 (range Day 10-28), intake was relatively low (usually < 5 g day ^‒1) until Day 20 but increased …

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 …

Effect Of Straw On The Behaviour Of Growing Pigs, David Fraser, P. A. Phillips, B. K. Thompson, T. Tennessen

Social Behavior Collection

The effects of straw on the behaviour of young growing pigs were studied in two experiments. In Experiment 1, group of three pigs, aged about 7 weeks, were housed in raised decks with or without straw bedding. Time-lapse video recording showed no major differences between treatments in the amount or daily pattern of overall activity and feeding. Detailed observations showed that bedding reduced the incidence of rooting and chewing on pen-mates, but had little effect on other social activities such as mounting and aggressive biting. Experiment 2 compared groups of eight growing pigs aged about 10 weeks, housed in floor …

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

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 …

Nutritive And Nonnutritive Sucking And The Temporal Organization Of The Suckling Behavior Of Domestic Piglets, Jeffrey Rushen, David Fraser

Feeding Behavior Collection

Detailed video recordings of the suckling behavior of one piglet from each of four litters were analyzed to determine how the components of piglet suckling behavior are organized in relation to the time of milk ejection and the temporal pattern of grunting by the sow. Early in the suckling episode, most piglets massaged the udder with their snouts, and then changed gradually to sucking the teats with slow mouth movements (1-2/sec). The piglets then had a distinct phase of sucking with rapid mouth movements (4-5/sec) which began suddenly and lasted about 5 to 15 sec. The weight gains of piglets …

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 …

Non-Breeder Asymmetry In Florida Scrub Jays, Jonathan P. Balcombe

Ethology Collection

The data of Woolfenden and Fitzpatrick (1984) show a statistically significant asymmetry in the sex ratio of non-breeders when one of the breeders is not the non-breeder's parent. 1 propose that the asymmetry is attributable to a combination of two factors acting on non-breeders: the value of inheriting a territory, and incest avoidance. Although natal territories are only occasionally inherited by non-breeders, and then apparently only by males, the rate of inheritance is significantly higher for parent/step-parent breeders (n = 6) than when both breeders are the non-breeder's parents (n = 1). An alternative hypothesis, that step-parents determine the non-breeder …

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

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 …

Mineral-Deficient Diets And The Pig’S Attraction To Blood: Implications For Tail-Biting, David Fraser

Abnormal Behavior Collection

In two experiments, individually penned growing pigs were exposed daily to two "tail models” (lengths of cotton cord about the size of a pig's tail), one of which had been impregnated with pigs' blood. When fed a balanced "control" diet, the pigs chewed significantly more on the blood-covered model than on the plain one, but with Iarge individual differences between animals. Four weeks of receiving a diet lacking all mineral supplements (iodized salt, dicalcium phosphate, limestone, iron, zinc, manganese, copper, and selenium) caused a pronounced increase in chewing the blood-covered model, and 4 wk of recovery on the control diet …

Attraction To Blood As A Factor In Tail-Biting By Pigs, David Fraser

Abnormal Behavior Collection

Canvas models, about the size of a pig's tail, were impregnated with pigs' blood or left plain, and were presented to pigs for 12 days in a 2-choice preference test. The pigs showed large, consistent, individual differences in response: some pigs chewed the models continuously while others chewed only slightly; some chewed much more on the blood-covered model, while others showed no preference. On average, the pigs chewed considerably more on the blood-covered model than on the plain one. In a second experiment, pigs presented with a choice test involving a blood-covered and a plain model showed a significant increase …