ArticlePublisher preview available

Food quantity discrimination in puppies (Canis lupus familiaris)

DOI:10.1007/s10071-020-01378-z
Authors:
Maria Elena Miletto Petrazzini at University of Padova
Maria Elena Miletto Petrazzini
Fabio Mantese
Fabio Mantese
Fabio Mantese
  • This person is not on ResearchGate, or hasn't claimed this research yet.
Emanuela Prato-Previde at University of Milan
Emanuela Prato-Previde
Read publisher preview
Download citation
To read the full-text of this research, you can request a copy directly from the authors.

Abstract and Figures

There is considerable evidence that animals are able to discriminate between quantities. Despite the fact that quantitative skills have been extensively studied in adult individuals, research on their development in early life is restricted to a limited number of species. We, therefore, investigated whether 2-month-old puppies could spontaneously discriminate between different quantities of food items. We used a simultaneous two-choice task in which puppies were presented with three numerical combinations of pieces of food (1 vs. 8, 1 vs. 6 and 1 vs. 4), and they were allowed to select only one option. The subjects chose the larger of the two quantities in the 1 vs. 8 and the 1 vs. 6 combinations but not in the 1 vs. 4 combination. Furthermore, the last quantity the puppies looked at before making their choice and the time spent looking at the larger/smaller amounts of food were predictive of the choices they made. Since adult dogs are capable of discriminating between more difficult numerical contrasts when tested with similar tasks, our findings suggest that the capacity to discriminate between quantities is already present at an early age, but that it is limited to very easy discriminations.
Figures - available from: Animal Cognition
This content is subject to copyright. Terms and conditions apply.
  • A preview of this full-text is provided by Springer Nature.
  • Learn more
Preview content only
Content available from Animal Cognition
This content is subject to copyright. Terms and conditions apply.
Vol.:(0123456789)
1 3
Animal Cognition (2020) 23:703–710
https://doi.org/10.1007/s10071-020-01378-z
ORIGINAL PAPER
Food quantity discrimination inpuppies (Canis lupus familiaris)
MariaElenaMilettoPetrazzini1· FabioMantese2· EmanuelaPrato‑Previde3
Received: 16 November 2019 / Revised: 24 March 2020 / Accepted: 30 March 2020 / Published online: 6 April 2020
© Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract
There is considerable evidence that animals are able to discriminate between quantities. Despite the fact that quantitative
skills have been extensively studied in adult individuals, research on their development in early life is restricted to a limited
number of species. We, therefore, investigated whether 2-month-old puppies could spontaneously discriminate between
different quantities of food items. We used a simultaneous two-choice task in which puppies were presented with three
numerical combinations of pieces of food (1 vs. 8, 1 vs. 6 and 1 vs. 4), and they were allowed to select only one option. The
subjects chose the larger of the two quantities in the 1 vs. 8 and the 1 vs. 6 combinations but not in the 1 vs. 4 combination.
Furthermore, the last quantity the puppies looked at before making their choice and the time spent looking at the larger/
smaller amounts of food were predictive of the choices they made. Since adult dogs are capable of discriminating between
more difficult numerical contrasts when tested with similar tasks, our findings suggest that the capacity to discriminate
between quantities is already present at an early age, but that it is limited to very easy discriminations.
Keywords Quantity discrimination· Dog· Puppies· Food choice task· Development
Introduction
Being able to correctly estimate whether one quantity is
larger or smaller than another confers advantages in sev-
eral ecological contexts and allows animals to cope with
problems in their natural environments. For instance, such a
competence is useful in regulating intergroup conflicts based
on the number of individuals in an opponent group, selecting
the best mating strategy according to the number of potential
mating partners, and reducing predation risk by joining a
larger group of social companions. Because of their high
adaptive value, it is not surprising that quantitative abilities
have been widely described both in vertebrate and in inverte-
brate species (Agrillo and Bisazza 2018; Geary etal. 2014).
The benefits associated with quantitative abilities are
probably most obvious in a foraging context in which
animals try to maximise the amount of energy which they
acquire (Stephens and Krebs 1986) by selecting larger food
sources. A wealth of studies has exploited the natural pref-
erence for larger amounts of food to investigate the quan-
titative abilities of several species. One commonly used
paradigm is the spontaneous choice task, in which animals
are offered two quantities of food items and are allowed to
choose only one option. Species as different as elephants
(Perdue etal. 2012), olive baboons (Barnard etal. 2013),
cats (Bánszegi etal. 2016), crows (Bogale etal. 2014), tor-
toises (Gazzola etal. 2018), and guppies (Lucon-Xiccato
etal. 2015) proved able to select sets that contained larger
quantities of food. However, their performances were ratio-
dependent, and their accuracy decreased as the ratio between
the quantities being compared increased (e.g., discriminating
between 3 vs. 12 items with a 0.25 ratio was easier than dis-
criminating between 3 vs. 5 items with a 0.6 ratio) (Ferrigno
and Cantlon 2017).
To date, longitudinal data on numerical competence are
only available in humans. There is clear evidence that our
species is endowed with a “numbers sense”, namely the abil-
ity to discriminate between sets of different number of items
(Dehaene 1997), which is supported by the “approximate
number system” (ANS) (Halberda and Feigenson 2008).
The ANS allows humans to discriminate between quantities
* Maria Elena Miletto Petrazzini
mariaelena.milettopetrazzini@gmail.com
1 School ofBiological andChemical Sciences, Queen Mary
University ofLondon, London, UK
2 Department ofAnimal andHuman Biology, University
ofTurin, Turin, Italy
3 Department ofPathophysiology andTransplantation,
University ofMilan, Milan, Italy
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... Since the chicks' response time and accuracy is ratio dependent when they process both large (e.g. 10 vs. 20) and small numbers (e.g. 2 vs. 3) it suggests they rely only on the AMS (Rugani et al. 2013(Rugani et al. , 2014. To our knowledge the only mammalian study on the ontogeny of quantity discrimination, apart from children, was done in puppies of the domestic dog (Canis lupus familiaris), where puppies' choices were found to be also ratio dependent, but where they discriminated ratios only below 0.25 (Miletto Petrazzini et al. 2020). In contrast, adult dogs spontaneously differentiate between a ratio of 0.6 (Miletto Petrazzini and Wynne 2016;Ward and Smuts 2007) and they can be trained to discriminate between objects with an area ratio of 0.8 (Rivas-Blanco et al. 2020). ...
... Eight of these were the same as those tested with adult cats (Bánszegi et al. 2016): 1 vs. 4 (ratio: 0.25), 1 vs. 3 (ratio: 0.33), 2 vs. 5 (ratio: 0.4), 1 vs. 2 (ratio: 0.5), 2 vs. 4 (ratio: 0.5), 3 vs. 5 (ratio: 0.6), 2 vs. 3 (ratio: 0.67), 3 vs. 4 (ratio: 0.75). Since a recent study on puppies reported the lack of differentiation between 1 vs. 4 pieces of food (Miletto Petrazzini et al. 2020), we added 1 vs. 6 (ratio: 0.17) and 1 vs. 9 (ratio: 0.11) to give the kittens a considerably easier tasks. We also added 2 vs. 6 (ratio: 0.33) and 4 vs. 6 (ratio: 0.67) comparisons to test whether the kittens would differentiate between larger numbers too. ...
... Despite the fundamental role that quantitative abilities play in an animal's life still little is known about the development of this. It has been studied only in a limited number of species and, to our knowledge, in only one non-human mammal, the domestic dog (Miletto Petrazzini et al. 2020). In the present study we investigated the spontaneous quantity discrimination of pre-weaning age kittens in two different experiments. ...
Quantity discrimination by kittens of the domestic cat (Felis silvestris catus)
Article
Full-text available
Quantitative abilities are well described in many species and in diverse life situations, including in the adult domestic cat. However, such abilities have been much less studied during ontogeny. In the present study we examined spontaneous quantity discrimination by pre-weaning age kittens in two-way food choice experiments. In Experiment 1, 26 kittens performed 12 trials with different ratios between the number of same-size food items. In Experiment 2, 24 other kittens performed eight trials with different ratios between the size of two food items. We found, in general, that the kittens discriminated between the different amounts of food and spontaneously chose the larger one, but that their choice was influenced by the ratio of difference. The kittens in Experiment 1 chose the larger number of same-size food items if the ratio was smaller than 0.4 and in Experiment 2 they chose the larger pieces of food if the ratio between the items was smaller than 0.5. Because the kittens’ choice was not influenced by the absolute number of food items or the numerical difference between them in Experiment 1, it suggests that their cognitive performance relied on an analog magnitude system rather than on an object file system during the quantity discrimination tasks. We discuss our results considering the ecological and social background of cats and compare it with the performance of previously studied species.
View
... In turn, spontaneous choices can be recorded either presenting each individual only once with the choice (e.g., Banerjee and Bhadra, 2019;Lõoke et al., 2020) or presenting animals repeatedly with the same choice (e.g., Ward and Smuts, 2007;Beran et al., 2008;Wynne, 2016, 2017). There are several studies concerning quantity/numerical discrimination in dogs (Canis lupus familiaris) and factors affecting it, for example ratio between quantities being compared (Ward and Smuts, 2007;Baker et al., 2011;Miletto Petrazzini and Wynne, 2017;Lõoke et al., 2020), human behaviour toward the quantities (Prato Previde et al., 2008;Marshall-Pescini et al., 2011, 2012, Horowitz et al., 2013Barnard et al., 2019), dog's age (Miletto Petrazzini et al., 2020), visibility of the quantities at choice and sensory system involved (Ward and Smuts, 2007;Baker et al., 2011;Horowitz et al., 2013, Miletto Petrazzini andWynne, 2016;Jackson et al., 2021). ...
... Six of the dogs completing the test had to be excluded due to a 100% spatial bias (i.e., to choosing the same side for all 18 trials, Table 1). When excluding individuals on the basis of a spatial bias in quantity discrimination studies in naïve dogs faced with repeated choices, the 100% criterion we applied is the most widely used one (Ward and Smuts, 2007;Marshall-Pescini et al., 2012;Miletto Petrazzini and Wynne, 2016;Barnard et al., 2019;Miletto Petrazzini et al., 2020). Thus, statistical analyses were run on a total of 72 subjects (40 males, 32 females, mean age 72.9 months, minimum 9 months, maximum 192 months). ...
... In this regard, it is important to note that, to our knowledge, this is the first study which focused both on the first choice and on the overall performance in a quantity discrimination test using the repeated choice paradigm in dogs (with the partial exception of Miletto Petrazzini et al., 2020), even if in other species and contexts (e.g., Kupán et al., 2011;Sovrano et al., 2015;Potier et al., 2019) performing an analysis on the first choice, together with analyses on other general performance variables, is common in experiments entailing the possibility for the animals to express their preference multiple times. ...
How spontaneous is spontaneous quantity discrimination in companion dogs?
Article
Although quantity discrimination and the factors affecting it have been widely studied in the domestic dog using a variety of paradigms, little attention has been given to the possible effects of the used paradigm itself. In the present study, we employed a paradigm in which naïve companion dogs were repeatedly presented with a free choice between two quantities of food (2vs.4, more difficult comparison, and 1 vs.8, simpler comparison). Dogs did not undergo any previous training and could freely choose to feed from either plate. After the choice was made, the second plate was withdrawn without letting the dog to eat its content. We hypothesized that a preference for the larger quantity of food may emerge as a consequence of experiencing the experimental procedure, and may not be expressed by the dogs on their first choice (hypothesis 1). If so, rewards experienced in the first trial may affect behaviour on subsequent trials (hypothesis 2). Data were analysed using generalized linear mixed models. Both hypothesis 1 (general performance P<0.0001, i.e., above chance level; first choice P=0.06, i.e., chance level) and 2 (P=0.001) were confirmed by the experimental results. The difficulty of the numerical comparison and the neuter status of the dogs had a significant effect on the overall performance, but not on the first choice nor on the likelihood of redirecting after the first trial. The results suggest that domestic dogs are highly sensitive to the results of their experience and adjust their behaviour accordingly, even after one single event. Future studies may help to disentangle the role of the food seen vs. eaten by the dog and the possible role of unintentional human feedback after the first choice.
View
... In particular, the number of studies investigating dogs' quantitative abilities have been increasing in recent years 14 . Several studies have shown that dogs are capable of discriminating larger from smaller quantities and their ability is in agreement with the Weber's law [41][42][43][44][45][46][47] . Dogs are able to discriminate up to a ratio of 0.67 spontaneously 47 , and up to 0.80 if trained to do so 45 . ...
... It is worth noting that the time spent looking at the unconnected items before dogs' choice was positively correlated with their final choices. The positive correlation between looking behaviour and dogs' choices has been recently reported also by Miletto Petrazzini et al. 46 in another food choice task. The fact that dogs looked at the unconnected stimulus and then selected this array indirectly resembles a phenomenon known in cognitive science as "quiet eye", defined as the final fixation or tracking gaze at a task-relevant location immediately prior to movement 62 . ...
... This result might have interesting methodological implications. Recording the stimulus reached by the subjects sometimes is problematic in binary choices as it introduces spatial biases not directly related to animals' capacity to make relative quantity judgments, such as the spontaneous tendency to turn consistently on one side of the environment (e.g., right) regardless to the position of the most favourable group 46,63,64 . The observation of looking time, without releasing the dogs, may be a reliable measure of dogs' discriminative abilities in food choice tasks. ...
Dogs (canis familiaris) underestimate the quantity of connected items: first demonstration of susceptibility to the connectedness illusion in non-human animals
Article
Full-text available
  • Dec 2021
In humans, numerical estimation is affected by perceptual biases, such as those originating from the spatial arrangement of elements. Different animal species can also make relative quantity judgements. This includes dogs, who have been proposed as a good model for comparative neuroscience. However, dogs do not show the same perceptual biases observed in humans. Thus, the exact perceptual/cognitive mechanisms underlying quantity estimations in dogs and their degree of similarity with humans are still a matter of debate. Here we explored whether dogs are susceptible to the connectedness illusion, an illusion based on the tendency to underestimate the quantity of interconnected items. Dogs were first trained to choose the larger of two food arrays. Then, they were presented with two arrays containing the same quantity of food, of which one had items interconnected by lines. Dogs significantly selected the array with unconnected items, suggesting that, like in humans, connectedness determines underestimation biases, possibly disrupting the perceptual system’s ability to segment the display into discrete objects. The similarity in dogs’ and humans’ susceptibility to the connectedness, but not to other numerical illusions, suggests that different mechanisms are involved in the estimation of quantity of stimuli with different characteristics.
View
... After data collection, three dogs had to be excluded from the final analysis due to a spatial bias, i.e., the dogs responded by choosing the same side in all trials (one male dog showed a left bias; two female dogs showed a right bias). We employed a 100% criterion for determining the spatial bias in line with previous studies on companion dogs (Ward & Smuts, 2007;Marshall-Pescini et al., 2012;Miletto Petrazzini et al., 2020;Normando et al., 2022). As a result, the statistical analysis was run on a total sample of 48 dogs. ...
... This procedure aimed at exploring whether a direct association between the chosen quantity and the reward eaten was necessary for the dogs to discriminate. Interestingly, we found that dogs could solve both the 1 vs 8, and the 2 vs 4 comparisons, and they also showed the well-known magnitude effect (Feigenson et al., 2002;Ward & Smuts, 2007;Rugani et al., 2014;Miletto Petrazzini et al., 2020) for which they were better in discriminating the set with the smaller ratio (i.e., 1 vs 8 having a ratio of 0.125) with respect to that with a higher one (i.e., 2 vs 4, having a 0.5 ratio). The same effect had been reported by Normando et al. (2022), suggesting that dogs rely on similar mechanisms for numerical discrimination regardless the reward experience, i.e., irrespective of them obtaining different amount (differential condition) or always the same amount (non-differential condition) of food as a consequence of their choice. ...
Eyes over stomach: companion dogs choose the larger quantity by sight, irrespective of the actual reward eaten
Article
  • Mar 2023
Domestic dogs tested in a free-choice task between two sets of food prefer that of a larger quantity. A recent study pointed out the critical role of the first trial. Dogs succeeded only after being allowed at least once to eat the selected food. Here we explore the importance of the actual experience of consuming the selected reward on dogs’ capability to redirect their choice to solve numerical discriminations. Dogs tested in the 2 vs 4 and 1 vs 8 comparisons could never consume the quantity selected but always obtained a single dogs’ treat. Despite never experiencing a difference in the eaten quantity, dogs discriminated between the two sets, preferring the larger. Whereas they behaved at chance at first choice, they successfully redirected their preference toward the larger set already on their second trial. We discuss our results in terms of motivational biases toward the larger quantity that can bear relevant ecological value.
View
... One aspect of quantity discrimination is the evaluation of the number of items in a group, the numerosity. Although quantitative abilities of many species have been studied [1][2][3], research into the ontogeny of the ability to assess numerosity has been restricted so far to humans [4,5], fish (Poecilia reticulata) and domestic chicks (Gallus gallus) [6,7]. Typically, in species other than chicks, which are a precocial species, the ability to assess numerosity changes with age until individuals reach adulthood. ...
... Indeed, zebrafish consistently selected 3 social companions over 2 only from the fourth week of life. These results are consistent with findings in humans, guppies, tadpoles and dogs where, although possessing some number sense at birth, numerical acuity increases across development [1,7,8,52,53]. Hence, zebrafish possess some quantitative skills at an early age, but they are not mature enough to discriminate comparisons of increased difficulty. ...
Characterizing ontogeny of quantity discrimination in zebrafish
Article
Full-text available
  • Feb 2022
A sense of non-symbolic numerical magnitudes is widespread in the animal kingdom and has been documented in adult zebrafish. Here, we investigated the ontogeny of this ability using a group size preference (GSP) task in juvenile zebrafish. Fish showed GSP from 21 days post-fertilization and reliably chose the larger group when presented with discriminations of between 1 versus 3, 2 versus 5 and 2 versus 3 conspecifics but not 2 versus 4 conspecifics. When the ratio between the number of conspecifics in each group was maintained at 1 : 2, fish could discriminate between 1 versus 2 individuals and 3 versus 6, but again, not when given a choice between 2 versus 4 individuals. These findings are in agreement with studies in other species, suggesting the systems involved in quantity representation do not operate separately from other cognitive mechanisms. Rather they suggest quantity processing in fishes may be the result of an interplay between attentional, cognitive and memory-related mechanisms as in humans and other animals. Our results emphasize the potential of the use of zebrafish to explore the genetic and neural processes underlying the ontogeny and function of number cognition.
View
... An even simpler strategy would be to always choose the same side. Side biases are relatively common in animal choice experiments (Andrade et al., 2001;Miletto Petrazzini, Pecunioso, et al., 2020), including dog studies (Gácsi et al., 2009;Miletto Petrazzini, Mantese, et al., 2020). In our study, this would be a reasonable strategy because it would result in a reward on average every other trial. ...
ManyDogs 1: A Multi-Lab Replication Study of Dogs’ Pointing Comprehension
Article
Full-text available
  • Aug 2023
To promote collaboration across canine science, address replicability issues, and advance open science practices within animal cognition, we have launched the ManyDogs consortium, modeled on similar ManyX projects in other fields. We aimed to create a collaborative network that (a) uses large, diverse samples to investigate and replicate findings, (b) promotes open science practices of pre-registering hypotheses, methods, and analysis plans, (c) investigates the influence of differences across populations and breeds, and (d) examines how different research methods and testing environments influence the robustness of results. Our first study combines a phenomenon that appears to be highly reliable—dogs’ ability to follow human pointing—with a question that remains controversial: do dogs interpret pointing as a social communicative gesture or as a simple associative cue? We collected data (N = 455) from 20 research sites on two conditions of a 2-alternative object choice task: (1) Ostensive (pointing to a baited cup after making eye-contact and saying the dog’s name); (2) Non-ostensive (pointing without eye-contact, after a throat-clearing auditory control cue). Comparing performance between conditions, while both were significantly above chance, there was no significant difference in dogs’ responses. This result was consistent across sites. Further, we found that dogs followed contralateral, momentary pointing at lower rates than has been reported in prior research, suggesting that there are limits to the robustness of point-following behavior: not all pointing styles are equally likely to elicit a response. Together, these findings underscore the important role of procedural details in study design and the broader need for replication studies in canine science.
View
... Likewise, most insights into quantity discrimination in dogs rose from visual numerical discrimination Wynne 2016, 2017;Prato-Previde et al. 2008). These studies showed that dogs, including puppies (Petrazzini et al. 2020), tend to select significantly more often the visually presented large food quantity than the small food quantity in a choice task Wynne 2016, 2017) or the visually presented larger amount of non-food items on two magnetic boards (Macpherson and Roberts 2013), particularly for quantities of lower ratio (i.e. a large difference between the two quantities). This result conforms with Weber's law (Fechner 1860), where two comparable quantities (i.e. when the small quantity divided by the large quantity produces a large value) are harder to discriminate than two different quantities (i.e. when the small quantity divided by the large quantity produces a small value). ...
An investigation on the olfactory capabilities of domestic dogs (Canis lupus familiaris)
Article
Full-text available
The extraordinary olfactory capabilities in detection and rescue dogs are well-known. However, the olfactory performance varies by breed and search environment (Jezierski et al. in Forensic Sci Int 237:112–118, 2014), as well as by the quantity of training (Horowitz et al. in Learn Motivation 44(4):207–217, 2013). While detection of an olfactory cue inherently demands a judgment regarding the presence or absence of a cue at a given location, olfactory discrimination requires an assessment of quantity, a task demanding more attention and, hence, decreasing reliability as an informational source (Horowitz et al. 2013). This study aims at gaining more clarity on detection and discrimination of olfactory cues in untrained dogs and in a variety of dog breeds. Using a two-alternative forced choice (2AFC) paradigm, we assessed olfactory detection scores by presenting a varied quantity of food reward under one or the other hidden cup, and discrimination scores by presenting two varied quantities of food reward under both hidden cups. We found relatively reliable detection performances across all breeds and limited discrimination abilities, modulated by breed. We discuss our findings in relation to the cognitive demands imposed by the tasks and the cephalic index of the dog breeds.
View
... 51 Likewise, most insights into quantity discrimination in dogs rose from visual numerical discrimination 52 Wynne, 2016, 2017;Prato-Previde et al., 2008). These studies showed that dogs, 53 including puppies (Petrazzini et al., 2020), tend to select significantly more often the visually presented 54 large food quantity than the small food quantity in a choice task Wynne, 2016, 2017) 55 or the visually presented larger amount of non-food items on two magnetic boards (Macpherson and 56 Roberts, 2013), particularly for quanities of lower ratio (i.e. a large difference between the two quantities). 57 This result conforms with Weber's law (Fechner, 1860), where two comparable quantities (i.e. when 58 the small quantity divided by the large quantity produces a large value) are harder to discriminate 59 than two different quantities (i.e. when the small quantity divided by the large quantity produces a 60 small value). ...
Olfactory detection and discrimination in domestic dogs (Canis lupus familiaris)
Preprint
Full-text available
  • Feb 2022
The extraordinary olfactory capabilities in detection and rescue dogs are well-known. However, the olfactory performance varies by breed and search environment (Jezierski et al., 2014), as well as by the quantity of training (Horowitz et al., 2013). While detection of an olfactory cue inherently demands a judgment regarding the presence or absence of a cue at a given location, olfactory discrimination requires an assessment of quantity, a task demanding more attention and, hence, decreasing reliability as an informational source (Horowitz et al., 2013). This study aims at gaining more clarity on detection and discrimination of olfactory cues in untrained dogs and in a variety of dog breeds. Using a two-alternative forced choice (2AFC) paradigm, we assessed olfactory detection scores by presenting a varied quantity of food reward under one or the other hidden cup, and discrimination scores by presenting two varied quantities of food reward under both hidden cups. We found relatively reliable detection performances across all breeds and limited discrimination abilities, modulated by breed. We discuss our findings in relation to the cognitive demands imposed by the tasks and the cephalic index of the dog breeds.
View
Dog Olfactory Cognition
Chapter
  • Oct 2023
Davila and colleagues cover methods and review findings regarding dog olfactory cognition. The chapter begins by introducing the topic of dog cognition. Specific aspects of dog olfactory cognition are explored. The authors review methods and procedures that investigate different aspects of olfaction and memory, including episodic memory, working memory, and long-term memory. Next, olfactory category and concept learning in dogs is reviewed followed by a discussion of the nature of olfactory representations in dogs, as well as studies that involve an olfactory search image. Finally, the last section reviews olfactory quantity judgments. The authors conclude by emphasizing the importance of dog cognition and suggesting a converging operation approach for future research.
View
Review of Olfactory Detection and Discrimination in Domestic Dogs (Canis lupus familiaris)
Preprint
Full-text available
  • Mar 2022
The manuscript is a review of an article about detection and discrimination abilities in dogs that are delineated by breed and also by cephalic index. The original authors used classic psychophysics (Weber's Just Noticeable Difference or JND), approximate number system (ANS), and Gestalt laws in psychology to measure and compare canine olfactory abilities. In the review, it is recommended that future studies use the Signal Detection Theory (SDT)'s concepts of noise and bias. Examples are used to illustrate recommendations. Additionally, collaboration with effective trainers of canine scent detection and discrimination dogs (as was done by Schoon in Holland) is recommended in order to better quantify and differentiate the type and quantities scents utilized to test dogs, as well as the circumstances under which the scents are presented.
View
Perception, cognition and decision training: The quiet eye in action
Book
Full-text available
  • Jun 2007
Athletes must be able to make split-second decisions under the pressures of competition, but often this vital learning is left to chance. With Perception, Cognition, and Decision Training: The Quiet Eye in Action, readers gain access to the research foundations behind an innovative decision-training system that has been used successfully for years in training athletes. Certain to become the definitive guide to decision making in sport, this text presents three innovations solidly based in research. The first is the vision- in-action method of recording what athletes actually see when they perform. The second is the quiet eye phenomenon that has attracted considerable media attention. The third innovation is decision training to identify not only how athletes make performance decisions but also how to facilitate visual perception and action to enhance performance. Author Joan Vickers—who discovered the quiet eye and developed the vision-in-action method—takes the next step by integrating all three innovations into a system for helping athletes improve. Together, these advances provide scientific evidence of the effectiveness of perception– action coupling in athletes’ training.
View
The More the Merrier:Dogs can Assess Quantities in Food-Choice Tasks
Article
Full-text available
Animals in their natural environment often face situa-tions where it may be advantageous for them to be able to make decisions based on numerical or quantity discrimination. Canids like pet dogs, wolves and coy-otes have been known to have a preliminary sense of number. We tested 303 unique free-ranging dogs for seven food-choice tasks, skewed in terms of stimulus: olfactory, visual and reward obtained. The dogs pri-marily used olfactory cues in the decision-making process, rather than visual cues, to discriminate between different quantities in a context-dependent manner.
View
Effects of breed group and development on dogs’ willingness to follow a human misleading advice
Article
Full-text available
The aim of this work was to investigate the effect of dog breed groups, i.e., primitive, hunting/herding and Mastiff like (Study 1) and development, i.e., 4-month-old puppies vs adults (Study 2) on a quantity discrimination task. The task consisted of three conditions: C1—dogs were asked to choose between a large and a small amount of food; C2—the same choice was presented and dogs could choose after having witnessed the experimenter favouring the small quantity. C3—similar to C2 but the plates had two equally small food quantities. Study 1 revealed that dogs in the hunting/herding group were significantly more likely than Mastiff-like group to choose the small quantity indicated by the person over the large one, although all dog groups chose the large quantity over the small when they had a free choice. These results are consistent with the hypothesis that hunting/herding breeds have been selected for working in cooperation with humans and thus may be more sensitive to human social communicative cues than other breeds. In Study 2, results showed that 4-month-old puppies performed at chance level in C1, whereas in C2 both adults and puppies conformed to the experimenter’s choice. In C3, adults followed the experimenter significantly more than puppies, although puppies still followed the experimenter above chance. Overall, domestic dogs seem to rely heavily on social communicative cues from humans, even when the information contradicts their own perception. This tendency to respond to human social cues is present, although at a lesser extent already at 4 months.
View
Discrimination of group numerousness under predation risk in anuran tadpoles
Article
Full-text available
For social animals, group size discrimination may play a major role in setting the trade-off between the costs and benefits of membership. Several anuran tadpoles show different degrees of social aggregation when exposed to the risk of predation. Despite the importance of aggregative behaviour as an anti-predatory response, the mechanism underlying tadpole choice of the group to join to has not been sufficiently investigated. To establish whether visual cues provide sufficient information to enable tadpoles to choose between aggregations differing in size, we explored the abilities of the larvae of two anuran species (green toad Bufotes balearicus and edible frog Pelophylax esculentus) to discriminate among four numerical combinations of conspecific tadpoles (1 vs. 4, 3 vs. 4, 4 vs. 6 and 4 vs. 8), either in the presence or absence of predatory cues. Our results suggest that in anuran larvae the capacity to discriminate between quantities is limited to small numbers (1 vs. 4 for B. balearicus and both 1 vs. 4 and 3 vs. 4 for P. esculentus). Predator-exposed toad tadpoles stayed longer close to the larger group, supporting aggregation as a major anti-predator behaviour in bufonids, while frog tadpoles showed a preference for the smaller groups, though in predator-free trials only, probably associated with lower intra-specific competition.
View
Continuous and discrete quantity discrimination in tortoises
Article
Full-text available
  • Dec 2018
The ability to estimate quantity, which is crucially important in several aspects of animal behaviour (e.g. foraging), has been extensively investigated in most taxa, with the exception of reptiles. The few studies available, in lizards, report lack of spontaneous discrimination of quantity, which may suggest that reptiles could represent an exception in numerical abilities among vertebrates. We investigated the spontaneous ability of Hermann's tortoises (Testudo hermanni) to select the larger quantity of food items. Tortoises were able to choose the larger food item when exposed to two options differing in size, but equal in numerousness (0.25, 0.50, 0.67 and 0.75 ratio) and when presented with two groups differing in numerousness, but equal in size (1 versus 4, 2 versus 4, 2 versus 3 and 3 versus 4 items). The tortoises succeeded in both size and numerousness discrimination, and their performance appeared to depend on the ratio of items to be discriminated (thus following Weber's Law). These findings in chelonians provide evidence of an ancient system for the extrapolation of numerical magnitudes from given sets of elements, shared among vertebrates.
View
Understanding the origin of number sense: A review of fish studies
Article
Full-text available
The ability to use quantitative information is thought to be adaptive in a wide range of ecological contexts. For nearly a century, the numerical abilities of mammals and birds have been extensively studied using a variety of approaches. However, in the last two decades, there has been increasing interest in investigating the numerical abilities of teleosts (i.e. a large group of ray-finned fish), mainly due to the practical advantages of using fish species as models in laboratory research. Here, we review the current state of the art in this field. In the first part, we highlight some potential ecological functions of numerical abilities in fish and summarize the existing literature that demonstrates numerical abilities in different fish species. In many cases, surprising similarities have been reported among the numerical performance of mammals, birds and fish, raising the question as to whether vertebrates' numerical systems have been inherited from a common ancestor. In the second part, we will focus on what we still need to investigate, specifically the research fields in which the use of fish would be particularly beneficial, such as the genetic bases of numerical abilities, the development of these abilities and the evolutionary foundation of vertebrate number sense. This article is part of a discussion meeting issue ‘The origins of numerical abilities’.
View
View
BORIS: A free, versatile open-source event-logging software for video/audio coding and live observations
Article
Full-text available
Quantitative aspects of the study of animal and human behaviour are increasingly relevant to test hypotheses and find empirical support for them. At the same time, photo and video cameras can store a large number of video recordings and are often used to monitor the subjects remotely. Researchers frequently face the need to code considerable quantities of video recordings with relatively flexible software, often constrained by species‐specific options or exact settings. BORIS is a free, open‐source and multiplatform standalone program that allows a user‐specific coding environment to be set for a computer‐based review of previously recorded videos or live observations. Being open to user‐specific settings, the program allows a project‐based ethogram to be defined that can then be shared with collaborators, or can be imported or modified. Projects created in BORIS can include a list of observations, and each observation may include one or two videos (e.g. simultaneous screening of visual stimuli and the subject being tested; recordings from different sides of an aquarium). Once the user has set an ethogram, including state or point events or both, coding can be performed using previously assigned keys on the computer keyboard. BORIS allows definition of an unlimited number of events (states/point events) and subjects. Once the coding process is completed, the program can extract a time‐budget or single or grouped observations automatically and present an at‐a‐glance summary of the main behavioural features. The observation data and time‐budget analysis can be exported in many common formats ( TSV , CSV , ODF , XLS , SQL and JSON ). The observed events can be plotted and exported in various graphic formats ( SVG , PNG , JPG , TIFF , EPS and PDF ).
View
Quantity discrimination in canids: Dogs ( Canis familiaris ) and wolves ( Canis lupus ) compared
Article
Accumulating evidence indicates that animals are able to discriminate between quantities. Recent studies have shown that dogs' and coyotes' ability to discriminate between quantities of food items decreases with increasing numerical ratio. Conversely, wolves' performance is not affected by numerical ratio. Cross-species comparisons are difficult because of differences in the methodologies employed, and hence it is still unclear whether domestication altered quantitative abilities in canids. Here we used the same procedure to compare pet dogs and wolves in a spontaneous food choice task. Subjects were presented with two quantities of food items and allowed to choose only one option. Four numerical contrasts of increasing difficulty (range 1-4) were used to assess the influence of numerical ratio on the performance of the two species. Dogs' accuracy was affected by numerical ratio, while no ratio effect was observed in wolves. These results align with previous findings and reinforce the idea of different quantitative competences in dogs and wolves. Although we cannot exclude that other variables might have played a role in shaping quantitative abilities in these two species, our results might suggest that the interspecific differences here reported may have arisen as a result of domestication.
View
Evolutionary Constraints on the Emergence of Human Mathematical Concepts
Chapter
  • Jan 2017
Nonhuman animals and humans share many kinds of insights about the physical world. One of those is the ability to reason logically about the number of items in a set of physical objects. Current research suggests that nonverbal numerical reasoning about physical objects is the first type of numerical cognition that emerges in human development and it influences the development of children's formal numerical concepts such as verbal counting and arithmetic. Comparative research between humans and nonhuman primates can help us gain an understanding of the evolutionary origins of primitive mathematical concepts in humans, and characterize the basic algorithms that support the emergence of mathematical reasoning over human development. In this chapter we describe current knowledge from comparative cognition and neuroscience about the genetic/maturational, environmental, and evolutionary factors that underlie early mathematical concept development in humans.
View