| 1. |
- Bshary, Redouan, et al.
(författare)
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Fish ecology and cognition : insights from studies on wild and wild-caught teleost fishes
- 2022
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Ingår i: Current Opinion in Behavioral Sciences. - : Elsevier BV. - 2352-1546. ; 46
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Tidskriftsartikel (refereegranskat)abstract
- Over the last decades, we witnessed a growing interest in animal cognition, in general, and in fish cognition, in particular. Here, we provide various study examples that employ an ecological approach to study cognition through field observations, field manipulations and laboratory tests on wild teleost fishes. In this review, we focus on cases with implications for understanding endotherm vertebrate cognition, that is, cases that show fishes possess supposedly ‘complex’ cognitive processes originally thought to warrant a more complex brain. Furthermore, in contrast to the classic interpretation of high/low performance as high/low cognitive abilities, incorporating an individual-level ecological approach reveals that low performance in a cognitive task may be caused by a mismatch between the experimental paradigm and the individual’s experience. The future avenue for wild fish cognition is to grasp better how individual, population and species differences in performance stem from differences in their ecological conditions.
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| 2. |
- De Dreu, Carsten K. W., et al.
(författare)
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Intergroup conflict : Origins, dynamics and consequences across taxa
- 2022
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Ingår i: Philosophical Transactions of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8436 .- 1471-2970. ; 377:1851, s. 332-342
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Although uniquely destructive and wasteful, intergroup conflict and warfare are not confined to humans. They are seen across a range of group-living species, from social insects, fishes and birds to mammals, including nonhuman primates. With its unique collection of theory, research and review contributions from biology, anthropology and economics, this theme issue provides novel insights into intergroup conflict across taxa. Here, we introduce and organize this theme issue on the origins and consequences of intergroup conflict. We provide a coherent framework by modelling intergroup conflicts as multi-level games of strategy in which individuals within groups cooperate to compete with (individuals in) other groups for scarce resources, such as territory, food, mating opportunities, power and influence. Within this framework, we identify cross-species mechanisms and consequences of (participating in) intergroup conflict. We conclude by highlighting crosscutting innovations in the study of intergroup conflict set forth by individual contributions. These include, among others, insights on how within-group heterogeneities and leadership relate to group conflict, how intergroup conflict shapes social organization and how climate change and environmental degradation transition intergroup relations from peaceful coexistence to violent conflict.
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| 3. |
- Demairé, Camille, et al.
(författare)
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Reduced access to cleaner fish negatively impacts the physiological state of two resident reef fishes
- 2020
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Ingår i: Marine Biology. - : Springer Science and Business Media LLC. - 0025-3162 .- 1432-1793. ; 167:4
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Tidskriftsartikel (refereegranskat)abstract
- Many client coral reef fishes have their ectoparasites removed by the cleaner wrasse Labroides dimidiatus in mutualistic interactions. Clients regularly receiving cleaning services reportedly benefit from increased growth and cognitive performance, but the underlying physiological changes that covary with such benefits are unknown. Here, we tested whether reduced access to cleaning services affects physiological state in two species of damselfish, Amblyglyphidodon curacao and Acanthochromis polyacanthus. We performed an in situ removal experiment on the Great Barrier Reef, Australia, whereby 47% of cleaners on a natural reef were removed. Since cleaners occupy defined territories (called cleaning stations), this removal created areas where small, resident clients, including A. polyacanthus and A. amblyglyphidodon, had no access to cleaning services. One month following cleaner removal, we measured body condition and collected blood samples from both damselfish species from territories with and without access to cleaners. Blood was used for estimating haematocrit levels, hormonal analyses, and immune cell counts. We tested for correlations among all these parameters to explore potential trade-offs in terms of growth, aerobic capacity, immune activation, and/or reproduction as a result of the loss of cleaning benefits. In both species, we found that fish without access to cleaners had lower haematocrit, testosterone levels, and lymphocyte counts than fish with access. There were no significant changes in fish body condition, leukocytes, granulocytes, or plasma cortisol levels between fish with access to cleaners or not. However, testosterone levels correlated negatively with the proportion of granulocytes in the blood of fish with access to cleaners. Our results suggest that even a relatively short-term reduction in access to cleaning services can have negative physiological outcomes for clients. Thus, the presence of cleaners on coral reefs appears to have important benefits for coral reef fish community health.
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| 4. |
- Romano, A., et al.
(författare)
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Reputation and socio-ecology in humans
- 2021
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Ingår i: Philosophical Transactions of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8436 .- 1471-2970. ; 376:1838
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Forskningsöversikt (refereegranskat)abstract
- Reputation is a fundamental feature of human sociality as it sustains cooperative relationships among unrelated individuals. Research from various disciplines provides insights on how individuals form impressions of others, condition their behaviours based on the reputation of their interacting partners and spread or learn such reputations. However, past research has often neglected the socio-ecological conditions that can shape reputation systems and their effect on cooperation. Here, we outline how social environments, cultural values and institutions come to play a crucial role in how people navigate reputation systems. Moreover, we illustrate how these socio-ecological dimensions affect the interdependence underlying social interactions (e.g. potential recipients of reputational benefits, degree of dependence) and the extent to which reputation systems promote cooperation. To do so, we review the interdisciplinary literature that illustrates how reputation systems are shaped by the variation of prominent ecological features. Finally, we discuss the implications of a socio-ecological approach to the study of reputation and outline potential avenues for future research.
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| 5. |
- Ros, Albert F. H., et al.
(författare)
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The impact of long-term reduced access to cleaner fish on health indicators of resident client fish
- 2020
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Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 223:24
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Tidskriftsartikel (refereegranskat)abstract
- In many mutualisms, benefits in the form of food are exchanged for services such as transport or protection. In the marine cleaning mutualism, a variety of 'client' reef fishes offer 'cleaner' fish Labroides dimidiatus access to food in the form of their ectoparasites, where parasite removal supposedly protects the clients. Yet, the health benefits individual clients obtain in the long term from repeated ectoparasite removal remain relatively unknown. Here, we tested whether long-term reduced access to cleaning services alters indicators of health status such as body condition, immunity and the steroids cortisol and testosterone in four client damselfish species Pomacentrus amboinensis, Amblyglyphidodon curacao, Acanthochromis polyacanthus and Dischistodus perspicillatus. To do so, we took advantage of a long-term experimental project in which several small reefs around Lizard Island (Great Barrier Reef, Australia) have been maintained cleaner-free since the year 2000, while control reefs had their cleaner presence continuously monitored. We found that the four damselfish species from reef sites without cleaners for 13 years had lower body condition than fish from reefs with cleaners. However, immunity measurements and cortisol and testosterone levels did not differ between experimental groups. Our findings suggest that clients use the energetic benefits derived from long-term access to cleaning services to selectively increase body condition, rather than altering hormonal or immune system functions.
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| 6. |
- Triki, Zegni, et al.
(författare)
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A proposal to enhance data quality and FAIRness
- 2022
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Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 128:9, s. 647-651
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Forskningsöversikt (refereegranskat)abstract
- In recent years, we witnessed an increasing number of funding agencies, scientific journals and scientists agreeing that society and science benefit from open access to research data. Benefits derive mainly from increased access to knowledge for all and improved transparency and credibility in academia. However, despite the advances in open science and open data, three significant aspects still need considerable policing: data quality, the accompanying summaries with basic information of the data files (i.e. metadata) and computational codes used to generate the research outcomes. Only by having these three components together, we can achieve efficient data sharing and reuse, and hence higher transparency. Here, we present two complementary approaches that potentially can help with shared data quality: (i) data file(s) sharing should be guided step-by-step in public archives with mandatory metadata, and (ii) journals creating assistant data editor positions at editorial boards with a leading role in data quality and computational reproducibility. Forty-four editors-in-chief in the field of behaviour, ecology and evolution shared their opinion with us regarding these two approaches. Although most of the views were divided, the majority estimated that their current editorial board members do not have the necessary skills to assess the quality of shared data. Since data are the core of research studies, we should consider not only data presence but also quality as a requirement for publication.
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| 7. |
- Triki, Zegni, et al.
(författare)
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Artificial mosaic brain evolution of relative telencephalon size improves cognitive performance in the guppy (Poecilia reticulata)
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The telencephalon is a brain region believed to have played an essential role during cognitive evolution in vertebrates. However, till now, all the evidence on the evolutionary association between telencephalon size and cognition stems from comparative studies. To investigate the potential evolutionary association between cognitive abilities and telencephalon size experimentally, we used male guppies artificially selected for large and small telencephalon relative to the rest of the brain. We tested a functionally important aspect of executive cognitive ability, inhibitory control, in a detour task and found that males with larger telencephalon outperformed males with smaller telencephalon. Theyshowed faster improvement in performance during detour training and weremore successful in reaching the food reward without touching the transparent barrier. Together, our findings provide the first experimental evidence showing that evolutionary enlargements of relative telencephalon size confer cognitive benefits, supporting an important role for mosaic brain evolution during cognitive evolution.
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| 8. |
- Triki, Zegni, et al.
(författare)
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Artificial mosaic brain evolution of relative telencephalon size improves inhibitory control abilities in the guppy (Poecilia reticulata)
- 2022
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Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 76:1, s. 128-138
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Tidskriftsartikel (refereegranskat)abstract
- Mosaic brain evolution, the change in the size of separate brain regions in response to selection on cognitive performance, is an important idea in the field of cognitive evolution. However, untill now, most of the data on how separate brain regions respond to selection and their cognitive consequences stem from comparative studies. To experimentally investigate the influence of mosaic brain evolution on cognitive ability, we used male guppies artificially selected for large and small telencephalons relative to the rest of the brain. Here, we tested an important aspect of executive cognitive ability using a detour task. We found that males with larger telencephalons outperformed males with smaller telencephalons. Fish with larger telencephalons showed faster improvement in performance during detour training and were more successful in reaching the food reward without touching the transparent barrier (i.e., through correct detouring) during the test phase. Together, our findings provide the first experimental evidence showing that evolutionary enlargement of relative telencephalon size confers cognitive benefits, supporting an important role for mosaic brain evolution during cognitive evolution.
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| 9. |
- Triki, Zegni, et al.
(författare)
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Brain morphology correlates of learning and cognitive flexibility in a fish species (Poecilia reticulata)
- 2022
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 289:1978
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Tidskriftsartikel (refereegranskat)abstract
- Determining how variation in brain morphology affects cognitive abilities is important to understand inter-individual variation in cognition and, ultimately, cognitive evolution. Yet, despite many decades of research in this area, there is surprisingly little experimental data available from assays that quantify cognitive abilities and brain morphology in the same individuals. Here, we tested female guppies (Poecilia reticulata) in two tasks, colour discrimination and reversal learning, to evaluate their learning abilities and cognitive flexibility. We then estimated the size of five brain regions (telencephalon, optic tectum, hypothalamus, cerebellum and dorsal medulla), in addition to relative brain size. We found that optic tectum relative size, in relation to the rest of the brain, correlated positively with discrimination learning performance, while relative telencephalon size correlated positively with reversal learning performance. The other brain measures were not associated with performance in either task. By evaluating how fast learning occurs and how fast an animal adjusts its learning rules to changing conditions, we find support for that different brain regions have distinct functional correlations at the individual level. Importantly, telencephalon size emerges as an important neural correlate of higher executive functions such as cognitive flexibility. This is rare evidence supporting the theory that more neural tissue in key brain regions confers cognitive benefits.
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| 10. |
- Triki, Zegni, et al.
(författare)
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Brain morphology predicts social intelligence in wild cleaner fish
- 2020
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- The causes and consequences of social intelligence are challenging to establish. A study on wild cleaner fish reports that large forebrains enable individuals to score higher in a social competence test, suggesting forebrain size is important for complex social decision-making. It is generally agreed that variation in social and/or environmental complexity yields variation in selective pressures on brain anatomy, where more complex brains should yield increased intelligence. While these insights are based on many evolutionary studies, it remains unclear how ecology impacts brain plasticity and subsequently cognitive performance within a species. Here, we show that in wild cleaner fish (Labroides dimidiatus), forebrain size of high-performing individuals tested in an ephemeral reward task covaried positively with cleaner density, while cerebellum size covaried negatively with cleaner density. This unexpected relationship may be explained if we consider that performance in this task reflects the decision rules that individuals use in nature rather than learning abilities: cleaners with relatively larger forebrains used decision-rules that appeared to be locally optimal. Thus, social competence seems to be a suitable proxy of intelligence to understand individual differences under natural conditions.
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| 11. |
- Triki, Zegni, 1984-, et al.
(författare)
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Experimental expansion of relative telencephalon size improves the main executive function abilities in guppy
- 2023
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Ingår i: PNAS Nexus. - 2752-6542. ; 2:6
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Tidskriftsartikel (refereegranskat)abstract
- Executive functions are a set of cognitive control processes required for optimizing goal-directed behavior. Despite more than two centuries of research on executive functions, mostly in humans and nonhuman primates, there is still a knowledge gap in what constitutes the mechanistic basis of evolutionary variation in executive function abilities. Here, we show experimentally that size changes in a forebrain structure (i.e. telencephalon) underlie individual variation in executive function capacities in a fish. For this, we used male guppies (Poecilia reticulata) issued from artificial selection lines with substantial differences in telencephalon size relative to the rest of the brain. We tested fish from the up- and down-selected lines not only in three tasks for the main core executive functions: cognitive flexibility, inhibitory control, and working memory, but also in a basic conditioning test that does not require executive functions. Individuals with relatively larger telencephalons outperformed individuals with smaller telencephalons in all three executive function assays but not in the conditioning assay. Based on our findings, we propose that the telencephalon is the executive brain in teleost fish. Together, it suggests that selective enlargement of key brain structures with distinct functions, like the fish telencephalon, is a potent evolutionary pathway toward evolutionary enhancement of advanced cognitive abilities in vertebrates.
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| 12. |
- Triki, Zegni, et al.
(författare)
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Marine Cleaning Mutualism Defies Standard Logic of Supply and Demand
- 2022
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Ingår i: American Naturalist. - : University of Chicago Press. - 0003-0147 .- 1537-5323. ; 199:4, s. 455-467
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Tidskriftsartikel (refereegranskat)abstract
- Supply and demand affect the values of goods exchanged in cooperative trades. Studies of humans and other species typically describe the standard scenario that an increase in demand leads to a higher price. Here, we challenge the generality of that logic with empirical data and a theoretical model. In our study system, “client” fishes visit cleaner wrasse (Labroides dimidiatus) to have ectoparasites removed, but cleaners prefer client mucus, which constitutes “cheating.” We removed 31 of 65 preselected cleaners from a large isolated reef patch. We compared cleaner-client interactions at the reef and a control reef before removal and 4 weeks after removal. Cleaner fish from the experimental treatment site interacted more frequently with large clients (typically visitors with access to alternative cleaning stations), but we did not observe any changes in service quality measures. A game-theoretic analysis revealed that interaction duration and service quality might increase, decrease, or remain unchanged depending on the precise relationships between key parameters, such as the marginal benefits of cheating as a function of satiation or the likelihood of clients responding to cheating as a function of market conditions. The analyses show that the principle of diminishing return may affect exchanges in ways not predicted by supply-to-demand ratios.
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| 13. |
- Triki, Zegni, et al.
(författare)
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Oxytocin has 'tend-and-defend' functionality in group conflict across social vertebrates
- 2022
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Ingår i: Philosophical Transactions of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8436 .- 1471-2970. ; 377:1851
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Forskningsöversikt (refereegranskat)abstract
- Across vertebrate species, intergroup conflict confronts individuals with a tension between group interests best served by participation in conflict and personal interest best served by not participating. Here, we identify the neurohormone oxytocin as pivotal to the neurobiological regulation of this tension in distinctly different group-living vertebrates, including fishes, birds, rodents, non-human primates and humans. In the context of intergroup conflict, a review of emerging work on pro-sociality suggests that oxytocin and its fish and birds homologues, isotocin and mesotocin, respectively, can elicit participation in group conflict and aggression. This is because it amplifies (i) concern for the interests of genetically related or culturally similar 'in-group' others and (ii) willingness to defend against outside intruders and enemy conspecifics. Across a range of social vertebrates, oxytocin can induce aggressive behaviour to 'tend-and-defend' the in-group during intergroup contests.This article is part of the theme issue 'Intergroup conflict across taxa'.
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| 14. |
- Triki, Zegni, et al.
(författare)
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Relative Brain Size and Cognitive Equivalence in Fishes
- 2022
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Ingår i: Brain, behavior, and evolution. - : S. Karger AG. - 0006-8977 .- 1421-9743. ; 96:3, s. 124-136
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Tidskriftsartikel (refereegranskat)abstract
- Scientists have long struggled to establish how larger brains translate into higher cognitive performance across species. While absolute brain size often yields high predictive power of performance, its positive correlation with body size warrants some level of correction. It is expected that larger brains are needed to control larger bodies without any changes in cognitive performance. Potentially, the mean value of intraspecific brain-body slopes provides the best available estimate for an interspecific correction factor. For example, in primates, including humans, an increase in body size translates into an increase in brain size without changes in cognitive performance. Here, we provide the first evaluation of this hypothesis for another clade, teleost fishes. First, we obtained a mean intraspecific brain-body regression slope of 0.46 (albeit with a relatively large range of 0.26-0.79) from a dataset of 51 species, with at least 10 wild adult specimens per species. This mean intraspecific slope value (0.46) is similar to that of the encephalisation quotient reported for teleosts (0.5), which can be used to predict mean cognitive performance in fishes. Importantly, such a mean value (0.46) is much higher than in endothermic vertebrate species (<= 0.3). Second, we used wild-caught adult cleaner fish Labroides dimidiatus as a case study to test whether variation in individual cognitive performance can be explained by body size. We first obtained the brain-body regression slope for this species from two different datasets, which gave slope values of 0.58 (MRI scan data) and 0.47 (dissection data). Then, we used another dataset involving 69 adult cleaners different from those tested for their brain-body slope. We found that cognitive performance from four different tasks that estimated their learning, numerical, and inhibitory control abilities was not significantly associated with body size. These results suggest that the intraspecific brain-body slope captures cognitive equivalence for this species. That is, individuals that are on the brain-body regression line are cognitively equal. While rather preliminary, our results suggest that fish and mammalian brain organisations are fundamentally different, resulting in different intra- and interspecific slopes of cognitive equivalence.
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| 15. |
- Triki, Zegni, et al.
(författare)
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Sex differences in the cognitive abilities of a sex-changing fish species Labroides dimidiatus
- 2021
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Ingår i: Royal Society Open Science. - : The Royal Society. - 2054-5703. ; 8:7
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Tidskriftsartikel (refereegranskat)abstract
- Males and females of the same species are known to differ at least in some cognitive domains, but such differences are not systematic across species. As a consequence, it remains unclear whether reported differences generally reflect adaptive adjustments to diverging selective pressures, or whether differences are mere side products of physiological differences necessary for reproduction. Here, we show that sex differences in cognition occur even in a sex-changing species, a protogynous hermaphroditic species where all males have previously been females. We tested male and female cleaner fish Labroides dimidiatus in four cognitive tasks to evaluate their learning and inhibitory control abilities first in an abstract presentation of the tasks, then in more ecologically relevant contexts. The results showed that males were better learners than females in the two learning tasks (i.e. reversal learning as an abstract task and a food quantity assessment task as an ecologically relevant task). Conversely, females showed enhanced abilities compared with males in the abstract inhibitory control task (i.e. detour task); but both sexes performed equally in the ecologically relevant inhibitory control task (i.e. 'audience effect' task). Hence, sex-changing species may offer unique opportunities to study proximate and/or ultimate causes underlying sex differences in cognitive abilities.
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| 16. |
- van Schaik, Carel P., et al.
(författare)
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A Farewell to the Encephalization Quotient : A New Brain Size Measure for Comparative Primate Cognition
- 2021
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Ingår i: Brain, behavior, and evolution. - : S. Karger AG. - 0006-8977 .- 1421-9743. ; 96:1, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Both absolute and relative brain sizes vary greatly among and within the major vertebrate lineages. Scientists have long debated how larger brains in primates and hominins translate into greater cognitive performance, and in particular how to control for the relationship between the noncognitive functions of the brain and body size. One solution to this problem is to establish the slope of cognitive equivalence, i.e., the line connecting organisms with an identical bauplan but different body sizes. The original approach to estimate this slope through intraspecific regressions was abandoned after it became clear that it generated slopes that were too low by an unknown margin due to estimation error. Here, we revisit this method. We control for the error problem by focusing on highly dimorphic primate species with large sample sizes and fitting a line through the mean values for adult females and males. We obtain the best estimate for the slope of circa 0.27, a value much lower than those constructed using all mammal species and close to the value expected based on the genetic correlation between brain size and body size. We also find that the estimate of cognitive brain size based on cognitive equivalence fits empirical cognitive studies better than the encephalization quotient, which should therefore be avoided in future studies on primates and presumably mammals and birds in general. The use of residuals from the line of cognitive equivalence may change conclusions concerning the cognitive abilities of extant and extinct primate species, including hominins.
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