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Matsushima T, Izumi T, Vallortigara G. The domestic chick as an animal model of autism spectrum disorder: building adaptive social perceptions through prenatally formed predispositions. Front Neurosci 2024; 18:1279947. [PMID: 38356650 PMCID: PMC10864568 DOI: 10.3389/fnins.2024.1279947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Accepted: 01/10/2024] [Indexed: 02/16/2024] Open
Abstract
Equipped with an early social predisposition immediately post-birth, humans typically form associations with mothers and other family members through exposure learning, canalized by a prenatally formed predisposition of visual preference to biological motion, face configuration, and other cues of animacy. If impaired, reduced preferences can lead to social interaction impairments such as autism spectrum disorder (ASD) via misguided canalization. Despite being taxonomically distant, domestic chicks could also follow a homologous developmental trajectory toward adaptive socialization through imprinting, which is guided via predisposed preferences similar to those of humans, thereby suggesting that chicks are a valid animal model of ASD. In addition to the phenotypic similarities in predisposition with human newborns, accumulating evidence on the responsible molecular mechanisms suggests the construct validity of the chick model. Considering the recent progress in the evo-devo studies in vertebrates, we reviewed the advantages and limitations of the chick model of developmental mental diseases in humans.
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Affiliation(s)
- Toshiya Matsushima
- Department of Biology, Faculty of Science, Hokkaido University, Sapporo, Japan
- Faculty of Pharmaceutical Science, Health Science University of Hokkaido, Tobetsu, Japan
- Centre for Mind/Brain Sciences, University of Trento, Rovereto, Italy
| | - Takeshi Izumi
- Faculty of Pharmaceutical Science, Health Science University of Hokkaido, Tobetsu, Japan
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2
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De Roni P, Geraci A, Simion F, Regolin L. Sensitivity to the role of an animated agent from observed interactions in newborn chicks ( Gallus gallus). ROYAL SOCIETY OPEN SCIENCE 2023; 10:210020. [PMID: 37885990 PMCID: PMC10598414 DOI: 10.1098/rsos.210020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 10/02/2023] [Indexed: 10/28/2023]
Abstract
Few month old human infants are able to detect the social roles of artificial agents and consistently choose the object behaving as 'approacher' rather than 'repulser'. This preference has been considered evidence of a pre-linguistic and pre-cultural origin of the social mind. Similar preferences have not been described in other species, though comparative data could help clarify the nature of this phenomenon and its evolutionary origin. In this study, we investigated sensitivity to the social role of an artificial agent in domestic chicks. Birds offer an excellent model to study the evolutionary roots of cognitive abilities, since they separated from mammals over 300 Ma. Moreover, the investigation of newly hatched chicks allows control for previous experience. After being exposed to computer-presented animations depicting an interaction among two agents, chicks underwent a free choice test among those same objects. While no initial evidence of a clear preference emerged from the planned analysis, chicks in the experimental condition showed a preference for the 'approacher' when controlling for side bias, mirroring human infants behaviour. This suggests the existence of an early ability to discriminate agents from their interactions, independent from any social experience.
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Affiliation(s)
- P. De Roni
- Department of Developmental Psychology and Socialisation, University of Padova, 35131 Padua, Italy
| | - A. Geraci
- Department of Social and Educational Sciences of the Mediterranean Area, University for Foreigners of Reggio Calabria, 89125 Reggio Calabria, Italy
| | - F. Simion
- Department of Developmental Psychology and Socialisation, University of Padova, 35131 Padua, Italy
| | - L. Regolin
- Department of General Psychology, University of Padova, 35131 Padua, Italy
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3
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Mota-Rojas D, Marcet-Rius M, Domínguez-Oliva A, Buenhombre J, Daza-Cardona EA, Lezama-García K, Olmos-Hernández A, Verduzco-Mendoza A, Bienboire-Frosini C. Parental behavior and newborn attachment in birds: life history traits and endocrine responses. Front Psychol 2023; 14:1183554. [PMID: 37599744 PMCID: PMC10434784 DOI: 10.3389/fpsyg.2023.1183554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 07/14/2023] [Indexed: 08/22/2023] Open
Abstract
In birds, parental care and attachment period differ widely depending on the species (altricial or precocial), developmental strategies, and life history traits. In most bird species, parental care can be provided by both female and male individuals and includes specific stages such as nesting, laying, and hatching. During said periods, a series of neuroendocrine responses are triggered to motivate parental care and attachment. These behaviors are vital for offspring survival, development, social bonding, intergenerational learning, reproductive success, and ultimately, the overall fitness and evolution of bird populations in a variety of environments. Thus, this review aims to describe and analyze the behavioral and endocrine systems of parental care and newborn attachment in birds during each stage of the post-hatching period.
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Affiliation(s)
- Daniel Mota-Rojas
- Neurophysiology, Behavior and Animal Welfare Assessment, DPAA, Universidad Autónoma Metropolitana, Mexico City, Mexico
| | - Míriam Marcet-Rius
- Department of Animal Behaviour and Welfare, Research Institute in Semiochemistry and Applied Ethology, Apt, France
| | - Adriana Domínguez-Oliva
- Neurophysiology, Behavior and Animal Welfare Assessment, DPAA, Universidad Autónoma Metropolitana, Mexico City, Mexico
| | - Jhon Buenhombre
- Faculty of Veterinary Medicine, Antonio Nariño University, Bogotá, Colombia
| | | | - Karina Lezama-García
- Neurophysiology, Behavior and Animal Welfare Assessment, DPAA, Universidad Autónoma Metropolitana, Mexico City, Mexico
| | - Adriana Olmos-Hernández
- Division of Biotechnology—Bioterio and Experimental Surgery, Instituto Nacional de Rehabilitación-Luis Guillermo Ibarra Ibarra, Mexico City, Mexico
| | - Antonio Verduzco-Mendoza
- Division of Biotechnology—Bioterio and Experimental Surgery, Instituto Nacional de Rehabilitación-Luis Guillermo Ibarra Ibarra, Mexico City, Mexico
| | - Cécile Bienboire-Frosini
- Department of Molecular Biology and Chemical Communication, Research Institute in Semiochemistry and Applied Ethology, Apt, France
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4
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Chiba Y, Tsuchida K, Maekawa F, Nakamori T, Inaoka H, Ohki-Hamazaki H. Presence of sibling during the learning phase of imprinting affects escape behavior from a new object in chicks. Neurosci Res 2023; 190:60-66. [PMID: 36516887 DOI: 10.1016/j.neures.2022.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 12/03/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022]
Abstract
Imprinting is a crucial learning behavior by the hatchlings of precocious birds. In nature, hatchlings in a group environment imprint on a hen, but the effect of siblings on the imprinting process remains largely unknown. To investigate this issue, we examined how the social context modulated visual imprinting in domestic chicks. One-day-old postnatal chicks in isolation (RS chicks) or with siblings (RD chicks), were first exposed to an imprinting stimulus, and subsequently the responses to the imprinting stimulus as well as a new stimulus were examined and compared. The experiment constituted three types of siblings: a 20-min pre-trained tutor, a 60-min pre-trained tutor, and a naïve chick. A multiple comparison test revealed that the preference score (PS) to the new stimulus of RD chicks trained with a 60-min pre-trained tutor was significantly lower than that of RS chicks. Multiple linear regression analysis revealed that the length of the tutor's pre-training significantly correlated negatively with the PS to the new stimulus, but this variable did not correlate with the PS to the imprinting stimulus. These results revealed that the presence of highly imprinted siblings could enhance the escape response to the new stimulus. We discussed the possible involvement of the chick's medial amygdala in the social aspect of imprinting.
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Affiliation(s)
- Yurino Chiba
- College of Liberal Arts and Sciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan
| | - Kei Tsuchida
- College of Liberal Arts and Sciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan
| | - Fumihiko Maekawa
- Health and Environmental Risk Research Division, National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506, Japan
| | - Tomoharu Nakamori
- College of Liberal Arts and Sciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan
| | - Hidenori Inaoka
- Basic Medical Sciences, School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan
| | - Hiroko Ohki-Hamazaki
- College of Liberal Arts and Sciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan.
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Processing Individually Distinctive Schematic-Faces Supports Proto-Arithmetical Counting in the Young Domestic Chicken. Animals (Basel) 2022; 12:ani12182322. [PMID: 36139181 PMCID: PMC9494947 DOI: 10.3390/ani12182322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/26/2022] [Accepted: 08/31/2022] [Indexed: 12/03/2022] Open
Abstract
Simple Summary Baby chicks, like infants and other animals, are unable to distinguish 3 vs. 4 identical objects. Because infants and chicks discriminate among larger sets (e.g., 4 vs. 12; 6 vs. 9), the 3 vs. 4 limitation has been considered the key-signature of the counting cognitive system that processes small numerosities. Here, we explored if the experience with different bird-like faces as objects—which naturally trigger chicks’ attention—could make the 3 vs. 4 task easier. Chicks reared with seven different faces, characterized by two “eyes” and a “beak” as features, succeeded in the 1 + 1 + 1 vs. 1 + 1 + 1 + 1 operation (Exp. 1); while birds, reared and tested with seven identical copies of a same face, failed (Exp. 2). Processing different individuals, and not experience with copies of one single individual per se, increased proto-arithmetic performance. Surprisingly, chicks, after being reared with seven identical faces, succeeded in the proto-arithmetic task when presented with seven completely novel faces (Exp. 3). On the contrary, similar experience with seven identical and featureless faces did not allow discrimination of novel faces (Exp. 4). Experience of one face probably helps to focus on the facial features which are later used to individually process new faces. In turn, individual processing enhances proto-arithmetical calculation. Abstract A key signature of small-number processing is the difficulty in discriminating between three and four objects, as reported in infants and animals. Five-day-old chicks overcome this limit if individually distinctive features characterize each object. In this study, we have investigated whether processing individually different face-like objects can also support discrimination between three and four objects. Chicks were reared with seven face-like stimuli and tested in the proto-arithmetic comparison 1 + 1 + 1 vs. 1 + 1 + 1 + 1. Birds reared and tested with all different faces discriminated and approached the larger group (Exp. 1), whereas new birds reared and tested with seven identical copies of one same face failed (Exp. 2). The presence at test of individually different faces allowed discrimination even when chicks were reared with copies of one face (Exp. 3). To clarify the role of the previous experience of at least one specific arrangement of facial features, in Experiment 4, featureless faces were employed during rearing. During testing, chicks were unable to discriminate between three and four individually distinct faces. Results highlight the importance of having experienced at least one “face” in prompting individual processing and proto-arithmetical calculation later during testing. We speculate that mechanisms effective at the non-symbolic level may positively affect numerical performance.
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Witjes VL, Bruckmaier RM, Gebhardt-Henrich SG, Toscano MJ. Effects of on-farm hatching on short term stress indicators, weight gain, and cognitive ability in layer chicks. Appl Anim Behav Sci 2022. [DOI: 10.1016/j.applanim.2022.105692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Aoki N, Mori C, Fujita T, Serizawa S, Yamaguchi S, Matsushima T, Homma KJ. Imprintability of Newly Hatched Domestic Chicks on an Artificial Object: A Novel High Time-Resolution Apparatus Based on a Running Disc. Front Physiol 2022; 13:822638. [PMID: 35370801 PMCID: PMC8965712 DOI: 10.3389/fphys.2022.822638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 02/18/2022] [Indexed: 11/19/2022] Open
Abstract
In filial imprinting, newly hatched chicks repeatedly approach a conspicuous object nearby and memorize it, even though it is an artificial object instead of their mother hen. Imprinting on an artificial object in a laboratory setting has a clear sensitive period from post hatch days 1–3 in the case of domestic chicks. However, the establishment of imprintability are difficult to investigate because of the limitations of the behavioral apparatus. In this study, we developed a novel behavioral apparatus, based on a running disc, to investigate the learning processes of imprinting in newly hatched domestic chicks. In the apparatus, the chick repeatedly approaches the imprinting object on the disc. The apparatus sends a transistor-transistor-logic signal every 1/10 turn of the disc to a personal computer through a data acquisition system following the chick’s approach to the imprinting object on the monitor. The imprinting training and tests were designed to define the three learning processes in imprinting. The first process is the one in which chicks spontaneously approach the moving object. The second is an acquired process in which chicks approach an object even when it is static. In the third process, chicks discriminate between the differently colored imprinting object and the control object in the preference test. Using the apparatus, the difference in the chicks’ behavior during or after the sensitive period was examined. During the sensitive period, the chicks at post hatch hour 12 and 18 developed the first imprinting training process. The chicks at post hatch hour 24 maintained learning until the second process. The chicks at post hatch hour 30 reached the discrimination process in the test. After the sensitive period, the chicks reared in darkness until post hatch day 4 exhibited poor first learning process in the training. Thus, this apparatus will be useful for the detection of behavioral changes during neuronal development and learning processes.
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Affiliation(s)
- Naoya Aoki
- Department of Molecular Biology, Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo, Japan
| | - Chihiro Mori
- Department of Molecular Biology, Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo, Japan
| | - Toshiyuki Fujita
- Department of Biological Sciences, Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo, Japan
| | - Shouta Serizawa
- Department of Molecular Biology, Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo, Japan
| | - Shinji Yamaguchi
- Department of Biological Sciences, Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo, Japan
| | - Toshiya Matsushima
- Department of Biology, Faculty of Science, Hokkaido University, Hokkaido, Japan
| | - Koichi J. Homma
- Department of Molecular Biology, Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo, Japan
- *Correspondence: Koichi J. Homma,
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8
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Versace E, Ragusa M, Pallante V, Wang S. Attraction for familiar conspecifics in young chicks (Gallus gallus): An interbreed study. Behav Processes 2021; 193:104498. [PMID: 34499985 DOI: 10.1016/j.beproc.2021.104498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 09/01/2021] [Accepted: 09/03/2021] [Indexed: 10/20/2022]
Abstract
From the beginning of life, discriminating between familiar and unfamiliar individuals and staying in contact with conspecifics are important to establish social relationships. To better understand these early social behaviours, we studied the different responses to familiar/unfamiliar individuals in 4-day-old domestic chicks (Gallus gallus) in three genetically isolated breeds: Padovana, Polverara and Robusta maculata. Chicks discriminated between familiar and unfamiliar individuals, staying closer to familiar individuals. Social reinstatement and fear responses were measured as the average distance between subjects, the latency of the first step and exploration of the arena differed between breeds. More socially motivated chicks, that stayed in closer proximity, were less afraid of starting to move and explored the environment more extensively. Interbreed differences in social reinstatement indicate that social attraction shows genetic variability from the early stages of life.
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Affiliation(s)
- Elisabetta Versace
- School of Biological and Behavioural Sciences, Department of Biological and Experimental Psychology, Queen Mary University of London, 327 Mile End Road, E1 4NS, London, UK; Center for Mind/Brain Sciences, University of Trento, Italy.
| | - Morgana Ragusa
- Center for Mind/Brain Sciences, University of Trento, Italy
| | - Virginia Pallante
- Center for Mind/Brain Sciences, University of Trento, Italy; Netherlands Institute for the Study of Crime and Law Enforcement, Amsterdam, the Netherlands
| | - Shuge Wang
- School of Biological and Behavioural Sciences, Department of Biological and Experimental Psychology, Queen Mary University of London, 327 Mile End Road, E1 4NS, London, UK
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9
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Young chicks quickly lose their spontaneous preference to aggregate with females. Behav Ecol Sociobiol 2021. [DOI: 10.1007/s00265-021-03012-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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10
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Lemaire BS, Rucco D, Josserand M, Vallortigara G, Versace E. Stability and individual variability of social attachment in imprinting. Sci Rep 2021; 11:7914. [PMID: 33846440 PMCID: PMC8041793 DOI: 10.1038/s41598-021-86989-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 03/22/2021] [Indexed: 02/01/2023] Open
Abstract
Filial imprinting has become a model for understanding memory, learning and social behaviour in neonate animals. This mechanism allows the youngs of precocial bird species to learn the characteristics of conspicuous visual stimuli and display affiliative response to them. Although longer exposures to an object produce stronger preferences for it afterwards, this relation is not linear. Sometimes, chicks even prefer to approach novel rather than familiar objects. To date, little is known about how filial preferences develop across time. This study aimed to investigate filial preferences for familiar and novel imprinting objects over time. After hatching, chicks were individually placed in an arena where stimuli were displayed on two opposite screens. Using an automated setup, the duration of exposure and the type of stimuli were manipulated while the time spent at the imprinting stimulus was monitored across 6 days. We showed that prolonged exposure (3 days vs 1 day) to a stimulus produced robust filial imprinting preferences. Interestingly, with a shorter exposure (1 day), animals re-evaluated their filial preferences in functions of their spontaneous preferences and past experiences. Our study suggests that predispositions influence learning when the imprinting memories are not fully consolidated, driving animal preferences toward more predisposed stimuli.
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Affiliation(s)
- Bastien S. Lemaire
- grid.11696.390000 0004 1937 0351Center for Mind and Brain Sciences, University of Trento, Trento, Italy
| | - Daniele Rucco
- grid.11696.390000 0004 1937 0351Center for Mind and Brain Sciences, University of Trento, Trento, Italy ,grid.7563.70000 0001 2174 1754Department of Psychology, University of Milano-Bicocca, Milan, Italy
| | - Mathilde Josserand
- grid.11696.390000 0004 1937 0351Center for Mind and Brain Sciences, University of Trento, Trento, Italy ,grid.25697.3f0000 0001 2172 4233Laboratory Dynamique du Language, University of Lyon 2, Lyon, France
| | - Giorgio Vallortigara
- grid.11696.390000 0004 1937 0351Center for Mind and Brain Sciences, University of Trento, Trento, Italy
| | - Elisabetta Versace
- grid.11696.390000 0004 1937 0351Center for Mind and Brain Sciences, University of Trento, Trento, Italy ,grid.4868.20000 0001 2171 1133School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
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11
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Rosa-Salva O, Mayer U, Versace E, Hébert M, Lemaire BS, Vallortigara G. Sensitive periods for social development: Interactions between predisposed and learned mechanisms. Cognition 2021; 213:104552. [PMID: 33402251 DOI: 10.1016/j.cognition.2020.104552] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 12/08/2020] [Accepted: 12/12/2020] [Indexed: 12/13/2022]
Abstract
We analysed research that makes use of precocial species as animal models to describe the interaction of predisposed mechanisms and environmental factors in early learning, in particular for the development of social cognition. We also highlight the role of sensitive periods in this interaction, focusing on domestic chicks as one of the main animal models for this field. In the first section of the review, we focus on the emergence of early predispositions to attend to social partners. These attentional biases appear before any learning experience about social stimuli. However, non-specific experiences occurring during sensitive periods of the early post-natal life determine the emergence of these predisposed mechanisms for the detection of social partners. Social predispositions have an important role for the development learning-based social cognitive functions, showing the interdependence of predisposed and learned mechanisms in shaping social development. In the second part of the review we concentrate on the reciprocal interactions between filial imprinting and spontaneous (not learned) social predispositions. Reciprocal influences between these two sets of mechanisms ensure that, in the natural environment, filial imprinting will target appropriate social objects. Neural and physiological mechanisms regulating the sensitive periods for the emergence of social predispositions and for filial imprinting learning are also described.
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Affiliation(s)
- Orsola Rosa-Salva
- Center for Mind/Brain Sciences, University of Trento, Piazza Manifattura 1, 38068 Rovereto, TN, Italy
| | - Uwe Mayer
- Center for Mind/Brain Sciences, University of Trento, Piazza Manifattura 1, 38068 Rovereto, TN, Italy
| | - Elisabetta Versace
- Center for Mind/Brain Sciences, University of Trento, Piazza Manifattura 1, 38068 Rovereto, TN, Italy; Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, 327 Mile End Road, London E1 4NS, United Kingdom
| | - Marie Hébert
- Center for Mind/Brain Sciences, University of Trento, Piazza Manifattura 1, 38068 Rovereto, TN, Italy
| | - Bastien S Lemaire
- Center for Mind/Brain Sciences, University of Trento, Piazza Manifattura 1, 38068 Rovereto, TN, Italy
| | - Giorgio Vallortigara
- Center for Mind/Brain Sciences, University of Trento, Piazza Manifattura 1, 38068 Rovereto, TN, Italy.
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Kasperek K, Zięba G, Pluta A, Ziemiańska A, Rozempolska-Rucińska I. Breed-related differences in the preference for inanimate objects between chicks of laying hens. Appl Anim Behav Sci 2020. [DOI: 10.1016/j.applanim.2020.105104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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13
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Santolin C, Rosa-Salva O, Lemaire BS, Regolin L, Vallortigara G. Statistical learning in domestic chicks is modulated by strain and sex. Sci Rep 2020; 10:15140. [PMID: 32934260 PMCID: PMC7492455 DOI: 10.1038/s41598-020-72090-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 08/20/2020] [Indexed: 11/08/2022] Open
Abstract
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 chicks which sex was however not determined. Our study confirms chicks' ability to track visual statistics. The pivotal role of sex in determining familiarity or novelty preferences in this species and the interaction with the animals' strain highlight the importance to contextualize comparative research within the ecology of each species.
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Affiliation(s)
- Chiara Santolin
- Center for Brain and Cognition, Universitat Pompeu Fabra, Barcelona, Spain.
| | - Orsola Rosa-Salva
- Centre for Mind/Brain Sciences, University of Trento, Rovereto, Italy
| | - Bastien S Lemaire
- Centre for Mind/Brain Sciences, University of Trento, Rovereto, Italy
| | - Lucia Regolin
- Department of General Psychology, University of Padova, Padua, Italy
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Maylott SE, Paukner A, Ahn YA, Simpson EA. Human and monkey infant attention to dynamic social and nonsocial stimuli. Dev Psychobiol 2020; 62:841-857. [PMID: 32424813 PMCID: PMC7944642 DOI: 10.1002/dev.21979] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 03/23/2020] [Accepted: 03/31/2020] [Indexed: 12/14/2022]
Abstract
The present study explored behavioral norms for infant social attention in typically developing human and nonhuman primate infants. We examined the normative development of attention to dynamic social and nonsocial stimuli longitudinally in macaques (Macaca mulatta) at 1, 3, and 5 months of age (N = 75) and humans at 2, 4, 6, 8, and 13 months of age (N = 69) using eye tracking. All infants viewed concurrently played silent videos-one social video and one nonsocial video. Both macaque and human infants were faster to look to the social than the nonsocial stimulus, and both species grew faster to orient to the social stimulus with age. Further, macaque infants' social attention increased linearly from 1 to 5 months. In contrast, human infants displayed a nonlinear pattern of social interest, with initially greater attention to the social stimulus, followed by a period of greater interest in the nonsocial stimulus, and then a rise in social interest from 6 to 13 months. Overall, human infants looked longer than macaque infants, suggesting humans have more sustained attention in the first year of life. These findings highlight potential species similarities and differences, and reflect a first step in establishing baseline patterns of early social attention development.
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Affiliation(s)
- Sarah E. Maylott
- Department of Psychology, University of Miami, Coral Gables, Florida, USA
| | - Annika Paukner
- Department of Psychology, Nottingham Trent University, Nottingham, England
| | - Yeojin A. Ahn
- Department of Psychology, University of Miami, Coral Gables, Florida, USA
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15
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Versace E, Ragusa M, Vallortigara G. A transient time window for early predispositions in newborn chicks. Sci Rep 2019; 9:18767. [PMID: 31822755 PMCID: PMC6904448 DOI: 10.1038/s41598-019-55255-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 11/21/2019] [Indexed: 02/07/2023] Open
Abstract
Neonates of different species are born with a set of predispositions that influence their early orienting responses toward the first stimuli encountered in their life. Human neonates and domestic chicks exhibit several similarities in the predisposition for attending to objects that move with speed changes, face-like stimuli and biological motion. Although early predispositions are connected to physiological development, little is known on the temporal course of early predispositions (whether they are stable or change in time) and on the associated genetic variability. To address these issues, we tested the preference for objects that change in speed vs. linear motion in three chicken breeds (Padovana, Polverara and Robusta maculata) within one day after hatching and three days after hatching. We found that the predisposition to preferentially attend to changes in speed is shared by different breeds on the first day of life and that it disappears by day three. These results indicate the existence of a short and transient time window of early predispositions that does not depend on visual experience.
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Affiliation(s)
- Elisabetta Versace
- Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, London, UK. .,Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy.
| | - Morgana Ragusa
- Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy
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16
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Miura M, Nishi D, Matsushima T. Combined predisposed preferences for colour and biological motion make robust development of social attachment through imprinting. Anim Cogn 2019; 23:169-188. [PMID: 31712936 DOI: 10.1007/s10071-019-01327-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 10/19/2019] [Accepted: 10/31/2019] [Indexed: 01/02/2023]
Abstract
To study how predisposed preferences shape the formation of social attachment through imprinting, newly hatched domestic chicks (Gallus gallus domesticus) were simultaneously exposed to two animations composed of comparable light points in different colours (red and yellow), one for a walking motion and another for a linear motion. When a walking animation in red was combined with a linear one in yellow, chicks formed a learned preference for the former that represented biological motion (BM). When the motion-colour association was swapped, chicks failed to form a preference for a walking in yellow, indicating a bias to a specific association of motion and colour. Accordingly, experiments using realistic walking chicken videos revealed a preference for a red video over a yellow one, when the whole body or the head was coloured. On the other hand, when the BM preference had been pre-induced using an artefact moving rigidly (non-BM), a clear preference for a yellow walking animation emerged after training by the swapped association. Even if the first-seen moving object was a nonbiological artefact such as the toy, the visual experience would induce a predisposed BM preference, making chicks selectively memorize the object with natural features. Imprinting causes a rapid inflow of thyroid hormone in the telencephalon leading to the induction of the BM preference, which would make the robust formation of social attachment selectively to the BM-associated object such as the mother hen.
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Affiliation(s)
- Momoko Miura
- Department of Biology, Faculty of Science, Hokkaido University, N10-W8, Kita-ku, Sapporo, Hokkaido, 060-0810, Japan
| | - Daisuke Nishi
- Department of Biology, Faculty of Science, Hokkaido University, N10-W8, Kita-ku, Sapporo, Hokkaido, 060-0810, Japan
| | - Toshiya Matsushima
- Department of Biology, Faculty of Science, Hokkaido University, N10-W8, Kita-ku, Sapporo, Hokkaido, 060-0810, Japan.
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17
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Rosa-Salva O, Mayer U, Vallortigara G. Unlearned visual preferences for the head region in domestic chicks. PLoS One 2019; 14:e0222079. [PMID: 31479480 PMCID: PMC6719852 DOI: 10.1371/journal.pone.0222079] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 08/21/2019] [Indexed: 02/07/2023] Open
Abstract
Unlearned tendencies to approach animate creatures are of great adaptive value, especially for nidifugous social birds that need to react to the presence of potential social companions shortly after hatching. Domestic chicks’ preferences for taxidermized hens provided the first evidence of social predispositions. However, the nature of the stimuli eliciting this predisposition is not completely understood. Here we explore the unlearned preferences of visually naïve domestic chicks for taxidermized animals. Visually naive chicks were tested for their approach preferences between a target stimulus (an intact stuffed animal whose head region was clearly visible) and a control stimulus. After confirming the predisposition for the intact stuffed fowl hen (Exp. 1), we found an analogous preference for a taxidermized, young domestic chick over a severely scrambled version of the same stimulus, whose body structure was completely disrupted, extending to same-age individuals the results that had been obtained with taxidermized hens (Exp. 2). We also directly tested preferences for specimens whose head region is visible compared to ones whose head region was occluded. To clarify whether chicks are sensitive to species-specific information, we employed specimens of female mallard ducks and of a mammalian predator, the polecat. Chicks showed a preference for the duck stimulus whose wings have been covered over a similar stimulus whose head region has been covered, providing direct evidence that the visibility of the head region of taxidermized models drive chicks’ behaviour in this test, and that the attraction for the head region indeed extends to females of other bird species (Exp. 3). However, no similar preference was obtained with the polecat stimuli (Exp. 4). We thus confirmed the presence of unlearned visual preferences for the head region in newly-hatched chicks, though other factors can limit the species-generality of the phenomenon.
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Affiliation(s)
- Orsola Rosa-Salva
- Center for Mind/Brain Sciences, University of Trento, Rovereto (TN), Italy
| | - Uwe Mayer
- Center for Mind/Brain Sciences, University of Trento, Rovereto (TN), Italy
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18
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Loveland JL, Stewart MG, Vallortigara G. Effects of oxytocin‐family peptides and substance P on locomotor activity and filial preferences in visually naïve chicks. Eur J Neurosci 2019; 50:3674-3687. [DOI: 10.1111/ejn.14520] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 07/07/2019] [Accepted: 07/15/2019] [Indexed: 11/30/2022]
Affiliation(s)
- Jasmine L. Loveland
- Center for Mind/Brain Sciences (CIMeC) University of Trento Rovereto Italy
- Behavioural Genetics and Evolutionary Ecology Research Group Max Planck Institute for Ornithology Seewiesen Germany
| | - Michael G. Stewart
- Department of Life, Health and Chemical Sciences The Open University Milton Keynes UK
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19
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Hewlett SE, Nordquist RE. Effects of Maternal Care During Rearing in White Leghorn and Brown Nick Layer Hens on Cognition, Sociality and Fear. Animals (Basel) 2019; 9:ani9070454. [PMID: 31323729 PMCID: PMC6680883 DOI: 10.3390/ani9070454] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 07/15/2019] [Indexed: 12/31/2022] Open
Abstract
Both genetic background and maternal care can have a strong influence on cognitive and emotional development. To investigate these effects and their possible interaction, White Leghorn (LH) and Brown Nick (BN) chicks, two hybrid lines of layer hen commonly used commercially, were housed either with or without a mother hen in their first five weeks of life. From three weeks of age, the chicks were tested in a series of experiments to deduce the effects of breed and maternal care on their fear response, foraging and social motivation, and cognitive abilities. The LH were found to explore more and showed more attempts to reinstate social contact than BN. The BN were less active in all tests and less motivated than LH by social contact or by foraging opportunity. No hybrid differences were found in cognitive performance in the holeboard task. In general, the presence of a mother hen had unexpectedly little effect on behavior in both LH and BN chicks. It is hypothesized that hens from commercially used genetic backgrounds may have been inadvertently selected to be less responsive to maternal care than ancestral or non-commercial breeds. The consistent and strong behavioral differences between genetic strains highlights the importance of breed-specific welfare management processes.
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Affiliation(s)
- Susie E Hewlett
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia
| | - Rebecca E Nordquist
- Behavior and Welfare in Farm Animals Research Group, Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, 3584CL Utrecht, The Netherlands.
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20
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Golüke S, Bischof HJ, Engelmann J, Caspers BA, Mayer U. Social odour activates the hippocampal formation in zebra finches (Taeniopygia guttata). Behav Brain Res 2019; 364:41-49. [DOI: 10.1016/j.bbr.2019.02.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 02/04/2019] [Accepted: 02/05/2019] [Indexed: 02/06/2023]
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21
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Rosa-Salva O, Hernik M, Broseghini A, Vallortigara G. Visually-naïve chicks prefer agents that move as if constrained by a bilateral body-plan. Cognition 2019; 173:106-114. [PMID: 29367016 DOI: 10.1016/j.cognition.2018.01.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 01/09/2018] [Accepted: 01/10/2018] [Indexed: 01/01/2023]
Abstract
From the first hours of life, the prompt detection of animate agents allows identification of biologically relevant entities. The motion of most animate agents is constrained by their bilaterally-symmetrical body-plan, and consequently tends to be aligned with the main body-axis. Thus parallelism between the main axis of a moving object and its motion trajectory can signal the presence of animate agents. Here we demonstrated that visually-naïve newborn chicks (Gallus gallus domesticus) are attracted to objects displaying such parallelism, and thus show preference for the same type of motion patterns that elicit perception of animacy in humans. This is the first demonstration of a newborn non-human animal's social preference for a visual cue related to the constraints imposed on behaviour by bilaterian morphology. Chicks also showed preference for rotational movements - a potential manifestation of self-propulsion. Results are discussed in relation to the mechanisms of animacy and agency detection in newborn organisms.
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Affiliation(s)
- O Rosa-Salva
- Center for Mind/Brain Sciences, University of Trento, Corso Bettini 31, 38068 Rovereto (TN), Italy.
| | - M Hernik
- Cognitive Development Center, Department of Cognitive Science, Central European University, Oktober 6 utca 7, Budapest 1051, Hungary
| | - A Broseghini
- Center for Mind/Brain Sciences, University of Trento, Corso Bettini 31, 38068 Rovereto (TN), Italy
| | - G Vallortigara
- Center for Mind/Brain Sciences, University of Trento, Corso Bettini 31, 38068 Rovereto (TN), Italy
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22
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Sgadò P, Rosa-Salva O, Versace E, Vallortigara G. Embryonic Exposure to Valproic Acid Impairs Social Predispositions of Newly-Hatched Chicks. Sci Rep 2018; 8:5919. [PMID: 29650996 PMCID: PMC5897402 DOI: 10.1038/s41598-018-24202-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 03/28/2018] [Indexed: 12/13/2022] Open
Abstract
Biological predispositions to attend to visual cues, such as those associated with face-like stimuli or with biological motion, guide social behavior from the first moments of life and have been documented in human neonates, infant monkeys and domestic chicks. Impairments of social predispositions have been recently reported in neonates at high familial risk of Autism Spectrum Disorder (ASD). Using embryonic exposure to valproic acid (VPA), an anticonvulsant associated to increased risk of developing ASD, we modeled ASD behavioral deficits in domestic chicks. We then assessed their spontaneous social predispositions by comparing approach responses to a stimulus containing a face configuration, a stuffed hen, vs. a scrambled version of it. We found that this social predisposition was abolished in VPA-treated chicks, whereas experience-dependent mechanisms associated with filial imprinting were not affected. Our results suggest a specific effect of VPA on the development of biologically-predisposed social orienting mechanisms, opening new perspectives to investigate the neurobiological mechanisms involved in early ASD symptoms.
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Affiliation(s)
- Paola Sgadò
- Center for Mind/Brain Sciences, University of Trento, Piazza della Manifattura 1, Rovereto, Italy.
| | - Orsola Rosa-Salva
- Center for Mind/Brain Sciences, University of Trento, Piazza della Manifattura 1, Rovereto, Italy
| | - Elisabetta Versace
- Center for Mind/Brain Sciences, University of Trento, Piazza della Manifattura 1, Rovereto, Italy.,Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Giorgio Vallortigara
- Center for Mind/Brain Sciences, University of Trento, Piazza della Manifattura 1, Rovereto, Italy
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23
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24
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Brecht KF, Wagener L, Ostojić L, Clayton NS, Nieder A. Comparing the face inversion effect in crows and humans. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:1017-1027. [PMID: 28905251 PMCID: PMC5696503 DOI: 10.1007/s00359-017-1211-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 08/23/2017] [Accepted: 08/26/2017] [Indexed: 12/03/2022]
Abstract
Humans show impaired recognition of faces that are presented upside down, a phenomenon termed face inversion effect, which is thought to reflect the special relevance of faces for humans. Here, we investigated whether a phylogenetically distantly related avian species, the carrion crow, with similar socio-cognitive abilities to human and non-human primates, exhibits a face inversion effect. In a delayed matching-to-sample task, two crows had to differentiate profiles of crow faces as well as matched controls, presented both upright and inverted. Because crows can discriminate humans based on their faces, we also assessed the face inversion effect using human faces. Both crows performed better with crow faces than with human faces and performed worse when responding to inverted pictures in general compared to upright pictures. However, neither of the crows showed a face inversion effect. For comparative reasons, the tests were repeated with human subjects. As expected, humans showed a face-specific inversion effect. Therefore, we did not find any evidence that crows-like humans-process faces as a special visual stimulus. Instead, individual recognition in crows may be based on cues other than a conspecific's facial profile, such as their body, or on processing of local features rather than holistic processing.
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Affiliation(s)
- Katharina F Brecht
- Department of Psychology, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK.
- Animal Physiology, Institute of Neurobiology, University of Tübingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany.
| | - Lysann Wagener
- Animal Physiology, Institute of Neurobiology, University of Tübingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany
| | - Ljerka Ostojić
- Department of Psychology, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK
| | - Nicola S Clayton
- Department of Psychology, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK
| | - Andreas Nieder
- Animal Physiology, Institute of Neurobiology, University of Tübingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany
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25
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Lorenzi E, Mayer U, Rosa-Salva O, Vallortigara G. Dynamic features of animate motion activate septal and preoptic areas in visually naïve chicks ( Gallus gallus ). Neuroscience 2017; 354:54-68. [DOI: 10.1016/j.neuroscience.2017.04.022] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 03/25/2017] [Accepted: 04/17/2017] [Indexed: 02/03/2023]
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26
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Versace E, Spierings MJ, Caffini M, Ten Cate C, Vallortigara G. Spontaneous generalization of abstract multimodal patterns in young domestic chicks. Anim Cogn 2017; 20:521-529. [PMID: 28260155 DOI: 10.1007/s10071-017-1079-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 01/02/2017] [Accepted: 02/27/2017] [Indexed: 10/20/2022]
Abstract
From the early stages of life, learning the regularities associated with specific objects is crucial for making sense of experiences. Through filial imprinting, young precocial birds quickly learn the features of their social partners by mere exposure. It is not clear though to what extent chicks can extract abstract patterns of the visual and acoustic stimuli present in the imprinting object, and how they combine them. To investigate this issue, we exposed chicks (Gallus gallus) to three days of visual and acoustic imprinting, using either patterns with two identical items or patterns with two different items, presented visually, acoustically or in both modalities. Next, chicks were given a choice between the familiar and the unfamiliar pattern, present in either the multimodal, visual or acoustic modality. The responses to the novel stimuli were affected by their imprinting experience, and the effect was stronger for chicks imprinted with multimodal patterns than for the other groups. Interestingly, males and females adopted a different strategy, with males more attracted by unfamiliar patterns and females more attracted by familiar patterns. Our data show that chicks can generalize abstract patterns by mere exposure through filial imprinting and that multimodal stimulation is more effective than unimodal stimulation for pattern learning.
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Affiliation(s)
- Elisabetta Versace
- Center for Mind/Brain Sciences, University of Trento, Piazza della Manifattura 1, 38068, Rovereto, Italy.
| | - Michelle J Spierings
- Behavioural Biology, Institute of Biology Leiden, Leiden University, Leiden, 2300 RA, The Netherlands.,Leiden Institute for Brain and Cognition, Leiden University, Leiden, 2300 RC, The Netherlands
| | - Matteo Caffini
- Center for Mind/Brain Sciences, University of Trento, Piazza della Manifattura 1, 38068, Rovereto, Italy
| | - Carel Ten Cate
- Behavioural Biology, Institute of Biology Leiden, Leiden University, Leiden, 2300 RA, The Netherlands.,Leiden Institute for Brain and Cognition, Leiden University, Leiden, 2300 RC, The Netherlands
| | - Giorgio Vallortigara
- Center for Mind/Brain Sciences, University of Trento, Piazza della Manifattura 1, 38068, Rovereto, Italy
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27
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Versace E, Schill J, Nencini AM, Vallortigara G. Naïve Chicks Prefer Hollow Objects. PLoS One 2016; 11:e0166425. [PMID: 27851773 PMCID: PMC5112871 DOI: 10.1371/journal.pone.0166425] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Accepted: 10/30/2016] [Indexed: 01/22/2023] Open
Abstract
Biological predispositions influence approach and avoid responses from the time of birth or hatching. Neonates of species that require parental care (e.g. human babies and chicks of the domestic fowl) are attracted by stimuli associated with animate social partners, such as face-like configurations, biological motion and self-propulsion. The property of being filled is used as a cue of animacy by 8-month-old human infants but it is not known whether this reflects the effect of previous experience. We used chicks of the domestic fowl (Gallus gallus) to investigate whether the property of being filled vs. hollow elicits spontaneous or learned preferences. To this aim we tested preferences of naïve and imprinted chicks for hollow and closed cylinders. Contrary to our expectations, we documented an unlearned attraction for hollow stimuli. The preference for hollow stimuli decreased when chicks were imprinted on filled stimuli but did not increase when chicks were imprinted on hollow stimuli, suggesting that hollowness is not crucial to determine affiliative responses for imprinting objects. When chicks were imprinted on occluded stimuli that could be either filled or hollow, the preference for hollow stimuli emerged again, showing that imprinting does not disrupt the spontaneous preference for hollow objects. Further experiments revealed that hollow objects were mainly attractive by means of depth cues such as darker innards, more than as places to hide or as objects with high contrast. Our findings point to predisposed preferences for hollow objects, and suggest that early predispositions might be driven by factors different from animacy cues.
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Affiliation(s)
- Elisabetta Versace
- Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy
- * E-mail:
| | - Jana Schill
- Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy
- Universität Osnabrück, Osnabrück, Germany
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