Lucia Regolin | Università degli Studi di Padova (original) (raw)
Papers by Lucia Regolin
Symmetry
Declarative memory is an explicit, long-term memory system, used in generalization and categoriza... more Declarative memory is an explicit, long-term memory system, used in generalization and categorization processes and to make inferences and to predict probable outcomes in novel situations. Animals have been proven to possess a similar declarative-like memory system. Here, we investigated declarative-like memory representations in young chicks, assessing the roles of the two hemispheres in memory recollection. Chicks were exposed for three consecutive days to two different arenas (blue/yellow), where they were presented with two panels, each depicting a different stimulus (cross/square). Only one of the two stimuli was rewarded, i.e., it hid a food reward. The position (left/right) of the rewarded stimulus remained constant within the same arena, but it differed between the two arenas (e.g., reward always on the left in the blue context and on the right in the yellow one). At test, both panels depicted the rewarded stimulus, thus chicks had to remember food position depending on the ...
Biochemical and Biophysical Research Communications
Non-symbolic numerical abilities are widespread among vertebrates due to their important adaptive... more Non-symbolic numerical abilities are widespread among vertebrates due to their important adaptive value. Moreover, these abilities were considered peculiar of vertebrate species as numerical competence is regarded as cognitively sophisticated. However, recent evidence convincingly showed that this is not the case: invertebrates, with their limited number of neurons, proved able to successfully discriminate different quantities (e.g., of prey), to use the ordinal property of numbers, to solve arithmetic operations as addition and subtraction and even to master the concept of zero numerosity. To date, though, the debate is still open on the presence and the nature of a «sense of number» in invertebrates. Whether this is peculiar for discrete countable quantities (numerosities) or whether this is part of a more general magnitude system dealing with both discrete and continuous quantities, as hypothesized for humans and other vertebrates. Here we reviewed the main studies on numerical abilities of invertebrates, discussing in particular the recent findings supporting the hypothesis of a general mechanism that allows for processing of both discrete (i.e., number) and continuous dimensions (e.g., space).
Annals of the New York Academy of Sciences
Different species show an intriguing similarity in representing numerosity in space, starting fro... more Different species show an intriguing similarity in representing numerosity in space, starting from left to right. This bias has been attributed to a right hemisphere dominance in processing spatial information. Here, to disentangle the role of each hemisphere in dealing with spatial versus ordinal–numerical information, we tested domestic chicks during monocular versus binocular vision. In the avian brain, the contralateral hemisphere mainly processes the visual input from each eye. Four‐day‐old chicks learned to peck at the fourth element in a sagittal series of 10 identical elements. At testing, chicks faced a left‐to‐right–oriented series where the interelement distance was manipulated so that the third element was where the fourth had been at training; this compelled chicks to use either spatial or ordinal cues. Chicks tested binocularly selected both the fourth left and (to a lesser extent) right elements. Chicks tested monocularly chose the third and fourth elements on the seeing side equally. Interhemispheric cooperation resulted in the use of ordinal–numerical information, while each single hemisphere could rely on spatial or ordinal–numerical cue. Both hemispheres can process spatial and ordinal–numerical information, but their interaction results in the supremacy of processing the ordinal–numerical cue.
Animal Cognition
In a constantly changing environment, it is advantageous for animals to encode a location (such a... more In a constantly changing environment, it is advantageous for animals to encode a location (such as a food source) relying on more than one single cue. A certain position might, in fact, be signalled by the presence of information acquired through different sensory modalities which may be integrated into cohesive memories. Here, we aimed to investigate multi-sensory learning capabilities and multi-modal information integration in Lasius niger ants. Individual ants were placed in a Y-maze where odour information always led to a food reward; moreover, arm and wall colour were also predictive but only when co-occurring with odour in a specific combination. At test, the odour cue was made uninformative (it was present in both arms). Ants were still able to correctly locate the reward by integrating odour with the right colour and side combination. In a second experiment, we tested whether multi-modal cue integration can take place in a single trial. To this end, ants were exposed to a rewarded odour in a single-arm maze and could experience the Y-maze (with all available cues) only once. At test (which was identical to that of Experiment 1), ants showed a slight preference for the correct colour-side combination, although not significantly different from chance level. Our results showed the capability of black garden ants to code apparently redundant contextual information and to create and rely on conditional relationships between the information available. We argue that future studies should deepen the inquiry on the timing and progression of multi-modal cue learning.
Scientific Reports
A large body of literature shows that non-human animals master numerical discriminations, but a l... more A large body of literature shows that non-human animals master numerical discriminations, but a limit has been reported in a variety of species in the comparison 3vs.4. Little is known regarding the possibility of using "cognitive strategies" to enable this discrimination. The aims of this study were to investigate: whether domestic chicks discriminated 3vs.4, and if changes in stimuli presentation could improve chicks' numerical performance. Newly hatched chicks were reared with seven identical objects. On day 4, they underwent 20 consecutive testing trials to assess their capability to discriminate 3vs.4. The objects were presented, one-by-one, to the chicks and hidden behind one of two identical panels. As expected, the chicks did not discriminate (Experiment 1). When objects were presented and hidden in groups comprising one or two objects (2 + 1)vs.(2 + 2), the chicks succeeded (Experiment 2). The grouping strategy did not help in the case of a harder discrimination of (3 + 1)vs.(3 + 2) (Experiment 3), unless chicks were allowed to rest for two hours between testing sessions (Experiment 4). Our results suggest that in some cases, the limits reported for numerical performance in animals do not depend on cognitive limitations but on attentional or motivational factors, which can be overcome employing simple procedural adjustments. Numerical evaluation is one of the core abilities of the animal mind 1,2. From the very first days of life, human and non-human animals can discriminate between groups on the basis of numerosity 3-7. Such non-verbal numerical skills are based on two cognitive systems: one that represents small numerosities (the Object File System, OFS) and one that can also represent large numerical magnitudes (the Analogue Magnitude System, AMS). The OFS is an object-based attentional mechanism that precisely tracks individual objects by representing each of them as a distinct file in the working memory 8-11. Spatio-temporal information 12-14 and property/kind changes 13,15-20 are used by the OFS to individuate and discern different objects. Hence, such a system is not specific to number representation, though numbers are implicitly represented. This system's signature is a set-size limit on the number (usually 3-4 for each set) of object-files that can be simultaneously attended to and held in the working memory 21. Differences in the upper limit, 3 in the case of children and chicks 22,23 and 4 in the case of adult monkeys 24,25 , have been attributed to maturational factors 1. The AMS can compute larger numerosities; its signature feature is to be ratio-dependent according to Weber's law: as the ratio between the numbers to be discriminated becomes smaller, response times increase and accuracy decreases; e.g., to discriminate 1/2 would be easier than to discriminate 2/3 26. The minimum discernible ratio diminishes over development in humans from 1/3 for newborns to 1/2 at six months, 2/3 for nine months, and 3/4 for preschool children 5,6,27. In non-verbal numerical cognition, 3vs.4 is a critical comparison. Some species succeed in this discrimination, such as: monkeys (Macaca mulatta), which discriminate 1vs.2; 2vs.3; 3vs.4, 3vs.5 but not 4vs.5; 3vs.6) 28 ; mosquito fish (Gambusia hoolbrooki) 29 ; domestic dogs (Canis lupus familiaris) 30 ; Asian elephants (Elephas maximus) 31 ; North Island robins (Petroica longipes) 32 ; and orangutans (Pongo pygmaeus) 33. However, a failure in discriminating 3vs.4 has been reported in: infants 34 ; salamanders (Plethodon cinereus) 35 ; and frogs (Bombina orientalis) 36. Lack of discrimination between 3vs.4 could be explained by a difficult (too small) ratio to be discriminated by the AMS or by a too large absolute number of elements in each set to be computed by the OFS. In previous studies, newly hatched domestic chicks, reared with identical objects, when presented with sets of 2vs.3; 1vs.4; 1vs.5; 2vs.4 objects that disappeared one-by-one behind separate panels, spontaneously inspected the panel occluding the larger set 37-39 .
Communications Biology
A form of deductive reasoning, transitive inference, is thought to allow animals to infer relatio... more A form of deductive reasoning, transitive inference, is thought to allow animals to infer relationships between members of a social group without having to remember all the interactions that occur. Such an ability means that animals can avoid direct confrontations which could be costly. Here we show that chicks perform a transitive inference task differently according to sex and rank. In female chicks, low-ranking birds performed better than did the highest ranked. Male chicks, however, showed an inverted U-shape of ability across rank, with the middle ranked chicks best able to perform the task. These results are explained according to the roles the sexes take within the group. This research directly links the abilities of transitive inference learning and social hierarchy formation and prompts further investigation into the role of both sex and rank within the dynamics of group living.
Biochemical and Biophysical Research Communications
Scientific Reports
Day-old domestic chicks approach the larger of two groups of identical objects, but in a 3 vs 4 c... more Day-old domestic chicks approach the larger of two groups of identical objects, but in a 3 vs 4 comparison, their performance is random. Here we investigated whether adding individually distinctive features to each object would facilitate such discrimination. Chicks reared with 7 objects were presented with the operation 1 + 1 + 1 vs 1 + 1 + 1 + 1. When objects were all identical, chicks performed randomly, as expected (Experiment 1). In the remaining experiments, objects differed from one another due to additional features. Chicks succeeded when those features were differently oriented segments (Experiment 2) but failed when the features were arranged to depict individually different face-like displays (Experiment 3). Discrimination was restored if the face-like stimuli were presented upside-down, disrupting global processing (Experiment 4). Our results support the claim that numerical discrimination in 3 vs 4 comparison benefits from the presence of distinctive features that enhan...
Scientific Reports
Statistical learning is a key mechanism for detecting regularities from a variety of sensory inpu... more Statistical learning is a key mechanism for detecting regularities from a variety of sensory inputs. Precocial newborn domestic chicks provide an excellent model for (1) exploring unsupervised forms of statistical learning in a comparative perspective, and (2) elucidating the ecological function of statistical learning using imprinting procedures. Here we investigated the role of the sex of the chicks in modulating the direction of preference (for familiarity or novelty) in a visual statistical learning task already employed with chicks and human infants. Using both automated tracking and direct human coding, we confirmed chicks’ capacity to recognize the presence of a statistically defined structure underlying a continuous stream of shapes. Using a different chicken strain than previous studies, we were also able to highlight sex differences in chicks’ propensity to approach the familiar or novel sequence. This could also explain a previous failure to reveal statistical learning in...
Journal of comparative psychology (Washington, D.C. : 1983), 2018
Animals can perceive the numerosity of sets of visual elements. Qualitative and quantitative simi... more Animals can perceive the numerosity of sets of visual elements. Qualitative and quantitative similarities in different species suggest the existence of a shared system (approximate number system). Biases associated with sensory properties are informative about the underlying mechanisms. In humans, regular spacing increases perceived numerosity (regular-random numerosity illusion). This has led to a model that predicts numerosity based on occupancy (a measure that decreases when elements are close together). We used a procedure in which observers selected one of two stimuli and were given feedback with respect to whether the choice was correct. One configuration had 20 elements and the other 40, randomly placed inside a circular region. Participants had to discover the rule based on feedback. Because density and clustering covaried with numerosity, different dimensions could be used. After reaching a criterion, test trials presented two types of configurations with 30 elements. One t...
Current biology : CB, Dec 5, 2016
The ability to extract probabilistic information from visual inputs has been reported in human ad... more The ability to extract probabilistic information from visual inputs has been reported in human adults and infants (reviewed in [1,2]), and in adults of non-human species, though only under supervised (conditioning) procedures [3]. Here, we report spontaneous sensitivity to the probabilistic structure underlying sequences of visual stimuli in newly hatched domestic chicks using filial imprinting, suggesting that statistical learning may be fully operating at the onset of life in precocial avian species.
Scientific reports, Jul 28, 2016
A large body of literature shows that non-human animals master a variety of numerical tasks, but ... more A large body of literature shows that non-human animals master a variety of numerical tasks, but studies involving proportional discrimination are sparse and primarily done with mature animals. Here we trained 4-day-old domestic chicks (Gallus gallus) to respond to stimuli depicting multiple examples of the proportion 4:1 when compared with the proportion 2:1. Stimuli were composed of green and red dot arrays; for the rewarded 4:1 proportion, 4 green dots for every red dot (e.g. ratios: 32:8, 12:3, and 44:11). The birds continued to discriminate when presented with new ratios at test (such as 20:5), characterized by new numbers of dots and new spatial configurations (Experiment 1). This indicates that chicks can extract the common proportional value shared by different ratios and apply it to new ones. In Experiment 2, chicks identified a specific proportion (2:1) from either a smaller (4:1) or a larger one (1:1), demonstrating an ability to represent the specific, and not relative, ...
Http Dx Doi Org 10 1080 17470910903529795, Feb 1, 2010
The ability of animals to perform transitive inference is associated with social group formation ... more The ability of animals to perform transitive inference is associated with social group formation and dominance hierarchies. Brain lateralization is also linked to the selective pressures associated with social life. We investigated whether transitive inference is better performed by lateralized than non-lateralized brains. In the domestic chick (Gallus gallus) exposure of eggs to light before hatching leads to the development of lateralization of some visual functions. Thus, it is possible to obtain chicks with strong (light-incubated, Li-chicks) or weak (dark-incubated, Di-chicks) lateralization. Di- and Li-chicks were trained to discriminate stimulus pairs, in order to build a hierarchy (A > B > C > D > E). Chicks were subsequently tested on stimulus pairs never seen together before (AE and BD). Li-chicks performed the discrimination BD better than did Di-chicks, suggesting that exposure to light in the egg leads to an increased ability to carry out representational learning. Moreover, lateralized chicks using their left eye only (right hemisphere) during test showed a better performance than did right eye only (left hemisphere) chicks on the BD task. Females also tended to perform better than males. Results demonstrate that chicks with lateralized brain hemispheres show greater inference, and this is under right hemisphere control: the brain hemisphere that is dominant in social interactions.
Proceedings of Fechner Day, 2010
Giornale italiano di psicologia, 2001
... Non appena riusciremo a comprendere maggiormente le prospetti-ve di altre specie credo che a ... more ... Non appena riusciremo a comprendere maggiormente le prospetti-ve di altre specie credo che a prestazioni eccezionali quali la memoria spaziale degli uccelli che fanno incetta di cibo e la capacità di ruotare immagini mentali dei piccioni (la cui ... 71 EVANS CS, EVANS L. (1999 ...
Cognitive science, 2017
Núñez and Fias raised concerns on whether our results demonstrate a linear number-space mapping. ... more Núñez and Fias raised concerns on whether our results demonstrate a linear number-space mapping. Patro and Nuerk urge caution on the use of animal models to understand the origin (cultural vs. biological) of the orientation of spatial-numerical association. Here, we discuss why both objections are unfounded.
Pre-verbal infants and non-human animals associate small numbers with the left space and large nu... more Pre-verbal infants and non-human animals associate small numbers with the left space and large numbers with the right space. Birds and primates, trained to identify a given position in a sagittal series of identical positions, whenever required to respond on a left/right oriented series, referred the given position starting from the left end. Here, we extended this evidence by selectively investigating the role of either cerebral hemisphere, using the temporary monocular occlusion technique. In birds, lacking the corpus callosum, visual input is fed mainly to the contralateral hemisphere. We trained 4-day-old chicks to identify the 4th element in a sagittal series of 10 identical elements. At test, the series was identical but left/right oriented. Test was conducted in right monocular, left monocular or binocular condition of vision. Right monocular chicks pecked at the 4th right element; left monocular and binocular chicks pecked at the 4th left element. Data on monocular chicks demonstrate that both hemispheres deal with an ordinal (sequential) task. Data on binocular chicks indicate that the left bias is linked to a right hemisphere dominance, that allocates the attention toward the left hemispace. This constitutes a first step towards understanding the neural basis of number space mapping.
Frontiers in human neuroscience, 2016
Symmetry
Declarative memory is an explicit, long-term memory system, used in generalization and categoriza... more Declarative memory is an explicit, long-term memory system, used in generalization and categorization processes and to make inferences and to predict probable outcomes in novel situations. Animals have been proven to possess a similar declarative-like memory system. Here, we investigated declarative-like memory representations in young chicks, assessing the roles of the two hemispheres in memory recollection. Chicks were exposed for three consecutive days to two different arenas (blue/yellow), where they were presented with two panels, each depicting a different stimulus (cross/square). Only one of the two stimuli was rewarded, i.e., it hid a food reward. The position (left/right) of the rewarded stimulus remained constant within the same arena, but it differed between the two arenas (e.g., reward always on the left in the blue context and on the right in the yellow one). At test, both panels depicted the rewarded stimulus, thus chicks had to remember food position depending on the ...
Biochemical and Biophysical Research Communications
Non-symbolic numerical abilities are widespread among vertebrates due to their important adaptive... more Non-symbolic numerical abilities are widespread among vertebrates due to their important adaptive value. Moreover, these abilities were considered peculiar of vertebrate species as numerical competence is regarded as cognitively sophisticated. However, recent evidence convincingly showed that this is not the case: invertebrates, with their limited number of neurons, proved able to successfully discriminate different quantities (e.g., of prey), to use the ordinal property of numbers, to solve arithmetic operations as addition and subtraction and even to master the concept of zero numerosity. To date, though, the debate is still open on the presence and the nature of a «sense of number» in invertebrates. Whether this is peculiar for discrete countable quantities (numerosities) or whether this is part of a more general magnitude system dealing with both discrete and continuous quantities, as hypothesized for humans and other vertebrates. Here we reviewed the main studies on numerical abilities of invertebrates, discussing in particular the recent findings supporting the hypothesis of a general mechanism that allows for processing of both discrete (i.e., number) and continuous dimensions (e.g., space).
Annals of the New York Academy of Sciences
Different species show an intriguing similarity in representing numerosity in space, starting fro... more Different species show an intriguing similarity in representing numerosity in space, starting from left to right. This bias has been attributed to a right hemisphere dominance in processing spatial information. Here, to disentangle the role of each hemisphere in dealing with spatial versus ordinal–numerical information, we tested domestic chicks during monocular versus binocular vision. In the avian brain, the contralateral hemisphere mainly processes the visual input from each eye. Four‐day‐old chicks learned to peck at the fourth element in a sagittal series of 10 identical elements. At testing, chicks faced a left‐to‐right–oriented series where the interelement distance was manipulated so that the third element was where the fourth had been at training; this compelled chicks to use either spatial or ordinal cues. Chicks tested binocularly selected both the fourth left and (to a lesser extent) right elements. Chicks tested monocularly chose the third and fourth elements on the seeing side equally. Interhemispheric cooperation resulted in the use of ordinal–numerical information, while each single hemisphere could rely on spatial or ordinal–numerical cue. Both hemispheres can process spatial and ordinal–numerical information, but their interaction results in the supremacy of processing the ordinal–numerical cue.
Animal Cognition
In a constantly changing environment, it is advantageous for animals to encode a location (such a... more In a constantly changing environment, it is advantageous for animals to encode a location (such as a food source) relying on more than one single cue. A certain position might, in fact, be signalled by the presence of information acquired through different sensory modalities which may be integrated into cohesive memories. Here, we aimed to investigate multi-sensory learning capabilities and multi-modal information integration in Lasius niger ants. Individual ants were placed in a Y-maze where odour information always led to a food reward; moreover, arm and wall colour were also predictive but only when co-occurring with odour in a specific combination. At test, the odour cue was made uninformative (it was present in both arms). Ants were still able to correctly locate the reward by integrating odour with the right colour and side combination. In a second experiment, we tested whether multi-modal cue integration can take place in a single trial. To this end, ants were exposed to a rewarded odour in a single-arm maze and could experience the Y-maze (with all available cues) only once. At test (which was identical to that of Experiment 1), ants showed a slight preference for the correct colour-side combination, although not significantly different from chance level. Our results showed the capability of black garden ants to code apparently redundant contextual information and to create and rely on conditional relationships between the information available. We argue that future studies should deepen the inquiry on the timing and progression of multi-modal cue learning.
Scientific Reports
A large body of literature shows that non-human animals master numerical discriminations, but a l... more A large body of literature shows that non-human animals master numerical discriminations, but a limit has been reported in a variety of species in the comparison 3vs.4. Little is known regarding the possibility of using "cognitive strategies" to enable this discrimination. The aims of this study were to investigate: whether domestic chicks discriminated 3vs.4, and if changes in stimuli presentation could improve chicks' numerical performance. Newly hatched chicks were reared with seven identical objects. On day 4, they underwent 20 consecutive testing trials to assess their capability to discriminate 3vs.4. The objects were presented, one-by-one, to the chicks and hidden behind one of two identical panels. As expected, the chicks did not discriminate (Experiment 1). When objects were presented and hidden in groups comprising one or two objects (2 + 1)vs.(2 + 2), the chicks succeeded (Experiment 2). The grouping strategy did not help in the case of a harder discrimination of (3 + 1)vs.(3 + 2) (Experiment 3), unless chicks were allowed to rest for two hours between testing sessions (Experiment 4). Our results suggest that in some cases, the limits reported for numerical performance in animals do not depend on cognitive limitations but on attentional or motivational factors, which can be overcome employing simple procedural adjustments. Numerical evaluation is one of the core abilities of the animal mind 1,2. From the very first days of life, human and non-human animals can discriminate between groups on the basis of numerosity 3-7. Such non-verbal numerical skills are based on two cognitive systems: one that represents small numerosities (the Object File System, OFS) and one that can also represent large numerical magnitudes (the Analogue Magnitude System, AMS). The OFS is an object-based attentional mechanism that precisely tracks individual objects by representing each of them as a distinct file in the working memory 8-11. Spatio-temporal information 12-14 and property/kind changes 13,15-20 are used by the OFS to individuate and discern different objects. Hence, such a system is not specific to number representation, though numbers are implicitly represented. This system's signature is a set-size limit on the number (usually 3-4 for each set) of object-files that can be simultaneously attended to and held in the working memory 21. Differences in the upper limit, 3 in the case of children and chicks 22,23 and 4 in the case of adult monkeys 24,25 , have been attributed to maturational factors 1. The AMS can compute larger numerosities; its signature feature is to be ratio-dependent according to Weber's law: as the ratio between the numbers to be discriminated becomes smaller, response times increase and accuracy decreases; e.g., to discriminate 1/2 would be easier than to discriminate 2/3 26. The minimum discernible ratio diminishes over development in humans from 1/3 for newborns to 1/2 at six months, 2/3 for nine months, and 3/4 for preschool children 5,6,27. In non-verbal numerical cognition, 3vs.4 is a critical comparison. Some species succeed in this discrimination, such as: monkeys (Macaca mulatta), which discriminate 1vs.2; 2vs.3; 3vs.4, 3vs.5 but not 4vs.5; 3vs.6) 28 ; mosquito fish (Gambusia hoolbrooki) 29 ; domestic dogs (Canis lupus familiaris) 30 ; Asian elephants (Elephas maximus) 31 ; North Island robins (Petroica longipes) 32 ; and orangutans (Pongo pygmaeus) 33. However, a failure in discriminating 3vs.4 has been reported in: infants 34 ; salamanders (Plethodon cinereus) 35 ; and frogs (Bombina orientalis) 36. Lack of discrimination between 3vs.4 could be explained by a difficult (too small) ratio to be discriminated by the AMS or by a too large absolute number of elements in each set to be computed by the OFS. In previous studies, newly hatched domestic chicks, reared with identical objects, when presented with sets of 2vs.3; 1vs.4; 1vs.5; 2vs.4 objects that disappeared one-by-one behind separate panels, spontaneously inspected the panel occluding the larger set 37-39 .
Communications Biology
A form of deductive reasoning, transitive inference, is thought to allow animals to infer relatio... more A form of deductive reasoning, transitive inference, is thought to allow animals to infer relationships between members of a social group without having to remember all the interactions that occur. Such an ability means that animals can avoid direct confrontations which could be costly. Here we show that chicks perform a transitive inference task differently according to sex and rank. In female chicks, low-ranking birds performed better than did the highest ranked. Male chicks, however, showed an inverted U-shape of ability across rank, with the middle ranked chicks best able to perform the task. These results are explained according to the roles the sexes take within the group. This research directly links the abilities of transitive inference learning and social hierarchy formation and prompts further investigation into the role of both sex and rank within the dynamics of group living.
Biochemical and Biophysical Research Communications
Scientific Reports
Day-old domestic chicks approach the larger of two groups of identical objects, but in a 3 vs 4 c... more Day-old domestic chicks approach the larger of two groups of identical objects, but in a 3 vs 4 comparison, their performance is random. Here we investigated whether adding individually distinctive features to each object would facilitate such discrimination. Chicks reared with 7 objects were presented with the operation 1 + 1 + 1 vs 1 + 1 + 1 + 1. When objects were all identical, chicks performed randomly, as expected (Experiment 1). In the remaining experiments, objects differed from one another due to additional features. Chicks succeeded when those features were differently oriented segments (Experiment 2) but failed when the features were arranged to depict individually different face-like displays (Experiment 3). Discrimination was restored if the face-like stimuli were presented upside-down, disrupting global processing (Experiment 4). Our results support the claim that numerical discrimination in 3 vs 4 comparison benefits from the presence of distinctive features that enhan...
Scientific Reports
Statistical learning is a key mechanism for detecting regularities from a variety of sensory inpu... more Statistical learning is a key mechanism for detecting regularities from a variety of sensory inputs. Precocial newborn domestic chicks provide an excellent model for (1) exploring unsupervised forms of statistical learning in a comparative perspective, and (2) elucidating the ecological function of statistical learning using imprinting procedures. Here we investigated the role of the sex of the chicks in modulating the direction of preference (for familiarity or novelty) in a visual statistical learning task already employed with chicks and human infants. Using both automated tracking and direct human coding, we confirmed chicks’ capacity to recognize the presence of a statistically defined structure underlying a continuous stream of shapes. Using a different chicken strain than previous studies, we were also able to highlight sex differences in chicks’ propensity to approach the familiar or novel sequence. This could also explain a previous failure to reveal statistical learning in...
Journal of comparative psychology (Washington, D.C. : 1983), 2018
Animals can perceive the numerosity of sets of visual elements. Qualitative and quantitative simi... more Animals can perceive the numerosity of sets of visual elements. Qualitative and quantitative similarities in different species suggest the existence of a shared system (approximate number system). Biases associated with sensory properties are informative about the underlying mechanisms. In humans, regular spacing increases perceived numerosity (regular-random numerosity illusion). This has led to a model that predicts numerosity based on occupancy (a measure that decreases when elements are close together). We used a procedure in which observers selected one of two stimuli and were given feedback with respect to whether the choice was correct. One configuration had 20 elements and the other 40, randomly placed inside a circular region. Participants had to discover the rule based on feedback. Because density and clustering covaried with numerosity, different dimensions could be used. After reaching a criterion, test trials presented two types of configurations with 30 elements. One t...
Current biology : CB, Dec 5, 2016
The ability to extract probabilistic information from visual inputs has been reported in human ad... more The ability to extract probabilistic information from visual inputs has been reported in human adults and infants (reviewed in [1,2]), and in adults of non-human species, though only under supervised (conditioning) procedures [3]. Here, we report spontaneous sensitivity to the probabilistic structure underlying sequences of visual stimuli in newly hatched domestic chicks using filial imprinting, suggesting that statistical learning may be fully operating at the onset of life in precocial avian species.
Scientific reports, Jul 28, 2016
A large body of literature shows that non-human animals master a variety of numerical tasks, but ... more A large body of literature shows that non-human animals master a variety of numerical tasks, but studies involving proportional discrimination are sparse and primarily done with mature animals. Here we trained 4-day-old domestic chicks (Gallus gallus) to respond to stimuli depicting multiple examples of the proportion 4:1 when compared with the proportion 2:1. Stimuli were composed of green and red dot arrays; for the rewarded 4:1 proportion, 4 green dots for every red dot (e.g. ratios: 32:8, 12:3, and 44:11). The birds continued to discriminate when presented with new ratios at test (such as 20:5), characterized by new numbers of dots and new spatial configurations (Experiment 1). This indicates that chicks can extract the common proportional value shared by different ratios and apply it to new ones. In Experiment 2, chicks identified a specific proportion (2:1) from either a smaller (4:1) or a larger one (1:1), demonstrating an ability to represent the specific, and not relative, ...
Http Dx Doi Org 10 1080 17470910903529795, Feb 1, 2010
The ability of animals to perform transitive inference is associated with social group formation ... more The ability of animals to perform transitive inference is associated with social group formation and dominance hierarchies. Brain lateralization is also linked to the selective pressures associated with social life. We investigated whether transitive inference is better performed by lateralized than non-lateralized brains. In the domestic chick (Gallus gallus) exposure of eggs to light before hatching leads to the development of lateralization of some visual functions. Thus, it is possible to obtain chicks with strong (light-incubated, Li-chicks) or weak (dark-incubated, Di-chicks) lateralization. Di- and Li-chicks were trained to discriminate stimulus pairs, in order to build a hierarchy (A > B > C > D > E). Chicks were subsequently tested on stimulus pairs never seen together before (AE and BD). Li-chicks performed the discrimination BD better than did Di-chicks, suggesting that exposure to light in the egg leads to an increased ability to carry out representational learning. Moreover, lateralized chicks using their left eye only (right hemisphere) during test showed a better performance than did right eye only (left hemisphere) chicks on the BD task. Females also tended to perform better than males. Results demonstrate that chicks with lateralized brain hemispheres show greater inference, and this is under right hemisphere control: the brain hemisphere that is dominant in social interactions.
Proceedings of Fechner Day, 2010
Giornale italiano di psicologia, 2001
... Non appena riusciremo a comprendere maggiormente le prospetti-ve di altre specie credo che a ... more ... Non appena riusciremo a comprendere maggiormente le prospetti-ve di altre specie credo che a prestazioni eccezionali quali la memoria spaziale degli uccelli che fanno incetta di cibo e la capacità di ruotare immagini mentali dei piccioni (la cui ... 71 EVANS CS, EVANS L. (1999 ...
Cognitive science, 2017
Núñez and Fias raised concerns on whether our results demonstrate a linear number-space mapping. ... more Núñez and Fias raised concerns on whether our results demonstrate a linear number-space mapping. Patro and Nuerk urge caution on the use of animal models to understand the origin (cultural vs. biological) of the orientation of spatial-numerical association. Here, we discuss why both objections are unfounded.
Pre-verbal infants and non-human animals associate small numbers with the left space and large nu... more Pre-verbal infants and non-human animals associate small numbers with the left space and large numbers with the right space. Birds and primates, trained to identify a given position in a sagittal series of identical positions, whenever required to respond on a left/right oriented series, referred the given position starting from the left end. Here, we extended this evidence by selectively investigating the role of either cerebral hemisphere, using the temporary monocular occlusion technique. In birds, lacking the corpus callosum, visual input is fed mainly to the contralateral hemisphere. We trained 4-day-old chicks to identify the 4th element in a sagittal series of 10 identical elements. At test, the series was identical but left/right oriented. Test was conducted in right monocular, left monocular or binocular condition of vision. Right monocular chicks pecked at the 4th right element; left monocular and binocular chicks pecked at the 4th left element. Data on monocular chicks demonstrate that both hemispheres deal with an ordinal (sequential) task. Data on binocular chicks indicate that the left bias is linked to a right hemisphere dominance, that allocates the attention toward the left hemispace. This constitutes a first step towards understanding the neural basis of number space mapping.
Frontiers in human neuroscience, 2016