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Garcia-Pelegrin E, Miller R, Plotnik JM, Schnell AK. A special issue in honor of the contributions of Professor Nicola S. Clayton FRS. Learn Behav 2025:10.3758/s13420-025-00666-3. [PMID: 39966279 DOI: 10.3758/s13420-025-00666-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/10/2025] [Indexed: 02/20/2025]
Abstract
It has been an honor to edit this special issue of Learning & Behavior to recognize the exceptional contributions of Prof. Nicky S. Clayton FRS to the fields of comparative cognition and developmental and experimental psychology. Prof. Clayton has also provided supervision, mentorship, and support for many students, researchers, and colleagues throughout her career, including over 52 PhD candidates and postdoctoral researchers, helping to pave the way for a generation of future scientists in academia and industry. Indeed, all four of the co-editors on this special issue worked with Prof. Clayton in her Cambridge University Comparative Cognition Lab as PhD candidates and/or postdoctoral researchers (from 2011 to 2022), and we happily continue to collaborate together. Prof. Clayton was awarded the 2024 Comparative Cognition Society (CCS) Research Award and delivered the Master Lecture at the 31st International Conference on Comparative Cognition (CO3, April 2024). Dr. Rachael Miller and Prof. Joshua Plotnik (co-editors) co-organized a symposium at the CO3 conference dedicated to Prof. Clayton. The invited symposium speakers were Prof. Mike Beran (Georgia State University), Prof. Jon Crystal (Indiana University), Dr. Christelle Jozet-Alves (Université de Caen Normandie), and Prof. Thomas Bugnyar (University of Vienna). Dr Elias Garcia-Pelegrin (co-editor) served as Master of Ceremony for an evening CO3 banquet, which included a video compilation of "thank you" messages from many of Prof. Clayton's colleagues, students, and friends.
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Schnell AK. Octopus toss-up: Is debris throwing driven by intent? Learn Behav 2024; 52:285-286. [PMID: 37962807 DOI: 10.3758/s13420-023-00611-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/31/2023] [Indexed: 11/15/2023]
Abstract
In a noteworthy observation, Godfrey-Smith and colleagues report the first evidence of debris throwing in wild octopuses, including instances where they target conspecifics. Proposing parallels with behaviours observed in select social mammals, this discovery prompts inquiries into the extent of their similarity and the potential role of cognition.
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Ajuwon V, Monteiro T, Schnell AK, Clayton NS. To know or not to know? Curiosity and the value of prospective information in animals. Learn Behav 2024:10.3758/s13420-024-00647-y. [PMID: 39414697 DOI: 10.3758/s13420-024-00647-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/10/2024] [Indexed: 10/18/2024]
Abstract
Humans and other animals often seek instrumental information to strategically improve their decisions in the present. Our curiosity also leads us to acquire non-instrumental information that is not immediately useful but can be encoded in memory and stored for use in the future by means of episodic recall. Despite its adaptive benefits and central role in human cognition, questions remain about the cognitive mechanisms and evolutionary origins that underpin curiosity. Here, we comparatively review recent empirical studies that some authors have suggested reflects curiosity in nonhuman animals. We focus on findings from laboratory tasks in which individuals can choose to gain advanced information about uncertain future outcomes, even though the information cannot be used to increase future rewards and is often costly. We explore the prevalence of preferences in these tasks across animals, discuss the theoretical advances that they have promoted, and outline some limitations in contemporary research. We also discuss several features of human curiosity that can guide future empirical research aimed at characterising and understanding curiosity in animals. Though the prevalence of curiosity in animals is actively debated, we surmise that investigating behavioural candidates for curiosity-motivated behaviour in a broader range of species and contexts, should help promote theoretical advances in our understanding of cognitive principles and evolutionary pressures that support curiosity-driven behaviour.
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Garcia-Pelegrin E, Schnell AK, Wilkins C, Clayton NS. Beyond the Tricks: The Science and Comparative Cognition of Magic. Annu Rev Psychol 2024; 75:269-293. [PMID: 38236652 DOI: 10.1146/annurev-psych-012723-100945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
Magic is an art form that has fascinated humans for centuries. Recently, the techniques used by magicians to make their audience experience the impossible have attracted the attention of psychologists, who, in just a couple of decades, have produced a large amount of research regarding how these effects operate, focusing on the blind spots in perception and roadblocks in cognition that magic techniques exploit. Most recently, this investigation has given a pathway to a new line of research that uses magic effects to explore the cognitive abilities of nonhuman animals. This new branch of the scientific study of magic has already yielded new evidence illustrating the power of magic effects as a psychological tool for nonhuman animals. This review aims to give a thorough overview of the research on both the human and nonhuman perception of magic effects by critically illustrating the most prominent works of both fields of inquiry.
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Schnell AK, Farndale Wright NR, Clayton NS. The Inner Lives of Cephalopods. Integr Comp Biol 2023; 63:1298-1306. [PMID: 37757469 PMCID: PMC10755188 DOI: 10.1093/icb/icad122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 08/31/2023] [Accepted: 09/07/2023] [Indexed: 09/29/2023] Open
Abstract
The minds of cephalopods have captivated scientists for millennia, yet the extent that we can understand their subjective experiences remains contested. In this article, we consider the sum of our scientific progress towards understanding the inner lives of cephalopods. Here, we outline the behavioral responses to specific experimental paradigms that are helping us to reveal their subjective experiences. We consider evidence from three broad research categories, which help to illuminate whether soft-bodied cephalopods (octopus, cuttlefish, and squid) have an awareness of self, awareness of others, and an awareness of time. Where there are current gaps in the literature, we outline cephalopod behaviors that warrant experimental investigation. We argue that investigations, especially framed through the lens of comparative psychology, have the potential to extend our understanding of the inner lives of this extraordinary class of animals.
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Abstract
Cephalopod molluscs are renowned for their unique central nervous system - a donut-shaped brain organised around the oesophagus. This brain supports sophisticated learning and memory abilities. Between the 1950s and 1980s, these cognitive abilities were extensively studied in octopus (Figure 1A) - a now leading model for the study of memory and its neural substrates (approximately 200 papers during this period). The focus on octopus learning and memory was mainly due to their curious nature and the fact that they adapt to laboratory-controlled conditions, making them easy to test and maintain in captivity. Research on cephalopod cognition began to widen in the late 20th century, when scientists started focusing on other coleoid cephalopods (i.e., cuttlefish and squid) (Figure 1B,C), and not just on associative learning and memory per se, but other more complex aspects of cognition such as episodic-like memory (the ability to remember the what, where, and when of a past event), source memory (the retrieval of contextual details from a memory), and self-control (the ability to inhibit an action in the present to gain a more valuable future reward). Attention broadened further over the last two decades to focus on the shelled cephalopods - the nautiloids (Figure 1D). The nautiloids have relatively primitive brains compared to their soft-bodied cousins (octopus, cuttlefish, and squid) but research shows that they are still able to comparatively succeed in some cognitive tasks. In this primer, we will provide a general description of the types of memory studied in cephalopods, and discuss learning and memory experiments that address the main challenges cephalopods face during their daily lives: navigation, timing, and food selection. Determining the type of information cephalopods learn and remember and whether they use such information to overcome ecological challenges will highlight why these invertebrates evolved large and sophisticated brains.
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Gaffney LP, Lavery JM, Schiestl M, Trevarthen A, Schukraft J, Miller R, Schnell AK, Fischer B. A theoretical approach to improving interspecies welfare comparisons. FRONTIERS IN ANIMAL SCIENCE 2023. [DOI: 10.3389/fanim.2022.1062458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The number of animals bred, raised, and slaughtered each year is on the rise, resulting in increasing impacts to welfare. Farmed animals are also becoming more diverse, ranging from pigs to bees. The diversity and number of species farmed invite questions about how best to allocate currently limited resources towards safeguarding and improving welfare. This is of the utmost concern to animal welfare funders and effective altruism advocates, who are responsible for targeting the areas most likely to cause harm. For example, is tail docking worse for pigs than beak trimming is for chickens in terms of their pain, suffering, and general experience? Or are the welfare impacts equal? Answering these questions requires making an interspecies welfare comparison; a judgment about how good or bad different species fare relative to one another. Here, we outline and discuss an empirical methodology that aims to improve our ability to make interspecies welfare comparisons by investigating welfare range, which refers to how good or bad animals can fare. Beginning with a theory of welfare, we operationalize that theory by identifying metrics that are defensible proxies for measuring welfare, including cognitive, affective, behavioral, and neuro-biological measures. Differential weights are assigned to those proxies that reflect their evidential value for the determinants of welfare, such as the Delphi structured deliberation method with a panel of experts. The evidence should then be reviewed and its quality scored to ascertain whether particular taxa may possess the proxies in question to construct a taxon-level welfare range profile. Finally, using a Monte Carlo simulation, an overall estimate of comparative welfare range relative to a hypothetical index species can be generated. Interspecies welfare comparisons will help facilitate empirically informed decision-making to streamline the allocation of resources and ultimately better prioritize and improve animal welfare.
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Schnell AK, Boeckle M, Clayton NS. Waiting for a better possibility: delay of gratification in corvids and its relationship to other cognitive capacities. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210348. [PMID: 36314150 PMCID: PMC9620750 DOI: 10.1098/rstb.2021.0348] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Self-control, the ability to resist temptation and wait for better but delayed possibilities, is an important cognitive skill that underpins decision-making and planning. The capacity to exert self-control has been linked to intelligence in humans, chimpanzees and most recently cuttlefish. Here, we presented 10 Eurasian jays, Garrulus glandarius, with a delayed maintenance task, which measured the ability to choose a preferred outcome as well as the ability to sustain the delay prior to that outcome. Jays were able to wait for better possibilities, but maximum wait times varied across the subjects. We also presented them with five cognitive tasks that assessed spatial memory, spatial relationships and learning capacity. These tasks are commonly used as measures of general intelligence within an ecological context. Individual performance was correlated across the cognitive tasks, which suggests that there was a general intelligence factor underlying their performance. Performance in these tasks was correlated significantly with the jays' capacity to wait for better possibilities. This study demonstrates that self-control and intelligence are correlated in jays. The fact that this correlation exists in diverse species suggests that self-control is a fundamental feature of cognition. Our results are discussed in the context of convergent evolution. This article is part of the theme issue ‘Thinking about possibilities: mechanisms, ontogeny, functions and phylogeny’.
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Schnell AK, Clayton NS, Hanlon RT, Jozet-Alves C. Episodic-like memory is preserved with age in cuttlefish. Proc Biol Sci 2021; 288:20211052. [PMID: 34403629 PMCID: PMC8370807 DOI: 10.1098/rspb.2021.1052] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Episodic memory, remembering past experiences based on unique what–where–when components, declines during ageing in humans, as does episodic-like memory in non-human mammals. By contrast, semantic memory, remembering learnt knowledge without recalling unique what–where–when features, remains relatively intact with advancing age. The age-related decline in episodic memory likely stems from the deteriorating function of the hippocampus in the brain. Whether episodic memory can deteriorate with age in species that lack a hippocampus is unknown. Cuttlefish are molluscs that lack a hippocampus. We test both semantic-like and episodic-like memory in sub-adults and aged-adults nearing senescence (n = 6 per cohort). In the semantic-like memory task, cuttlefish had to learn that the location of a food resource was dependent on the time of day. Performance, measured as proportion of correct trials, was comparable across age groups. In the episodic-like memory task, cuttlefish had to solve a foraging task by retrieving what–where–when information about a past event with unique spatio-temporal features. In this task, performance was comparable across age groups; however, aged-adults reached the success criterion (8/10 correct choices in consecutive trials) significantly faster than sub-adults. Contrary to other animals, episodic-like memory is preserved in aged cuttlefish, suggesting that memory deterioration is delayed in this species.
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Schnell AK, Loconsole M, Garcia-Pelegrin E, Wilkins C, Clayton NS. Jays are sensitive to cognitive illusions. ROYAL SOCIETY OPEN SCIENCE 2021; 8:202358. [PMID: 34457330 PMCID: PMC8371373 DOI: 10.1098/rsos.202358] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 07/23/2021] [Indexed: 06/13/2023]
Abstract
Jays hide food caches, steal them from conspecifics and use tactics to minimize cache theft. Jays are sensitive to the content of their own caches, retrieving items depending on their preferences and the perishability of the cached item. Whether jays impose the same content sensitivity when they steal caches is less clear. We adapted the 'cups-and-balls' magic routine, creating a cognitive illusion to test whether jays are sensitive to the (i) content of hidden items and (ii) type of displacement. Subjects were presented with two conditions in which hidden food was consistent with their expectations; and two conditions in which food was manipulated to violate their expectations by switching their second preferred food for their preferred food (up-value) or vice versa (de-value). Subjects readily accepted food when it was consistent with their expectations but were more likely to re-inspect the baited cup and alternative cup when their expectations were violated. In the de-value condition, jays exhibited longer latencies to consume the food and often rejected it. Dominant subjects were more likely to reject the food, suggesting that social factors influence their responses to cognitive illusions. Using cognitive illusions offers innovative avenues for investigating the psychological constraints in diverse animal minds.
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Garcia-Pelegrin E, Schnell AK, Wilkins C, Clayton NS. Exploring the perceptual inabilities of Eurasian jays ( Garrulus glandarius) using magic effects. Proc Natl Acad Sci U S A 2021; 118:e2026106118. [PMID: 34074798 PMCID: PMC8214664 DOI: 10.1073/pnas.2026106118] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In recent years, scientists have begun to use magic effects to investigate the blind spots in our attention and perception [G. Kuhn, Experiencing the Impossible: The Science of Magic (2019); S. Macknik, S. Martinez-Conde, S. Blakeslee, Sleights of Mind: What the Neuroscience of Magic Reveals about Our Everyday Deceptions (2010)]. Recently, we suggested that similar techniques could be transferred to nonhuman animal observers and that such an endeavor would provide insight into the inherent commonalities and discrepancies in attention and perception in human and nonhuman animals [E. Garcia-Pelegrin, A. K. Schnell, C. Wilkins, N. S. Clayton, Science 369, 1424-1426 (2020)]. Here, we performed three different magic effects (palming, French drop, and fast pass) to a sample of six Eurasian jays (Garrulus glandarius). These magic effects were specifically chosen as they utilize different cues and expectations that mislead the spectator into thinking one object has or has not been transferred from one hand to the other. Results from palming and French drop experiments suggest that Eurasian jays have different expectations from humans when observing some of these effects. Specifically, Eurasian jays were not deceived by effects that required them to expect an object to move between hands when observing human hand manipulations. However, similar to humans, Eurasian jays were misled by magic effects that utilize fast movements as a deceptive action. This study investigates how another taxon perceives the magician's techniques of deception that commonly deceive humans.
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Rouxel Y, Crawford R, Cleasby IR, Kibel P, Owen E, Volke V, Schnell AK, Oppel S. Buoys with looming eyes deter seaducks and could potentially reduce seabird bycatch in gillnets. ROYAL SOCIETY OPEN SCIENCE 2021; 8:210225. [PMID: 33981446 PMCID: PMC8103233 DOI: 10.1098/rsos.210225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 04/12/2021] [Indexed: 06/12/2023]
Abstract
Bycatch of seabirds in gillnet fisheries is a global conservation issue with an estimated 400 000 seabirds killed each year. To date, no underwater deterrents trialled have consistently reduced seabird bycatch across operational fisheries. Using a combination of insights from land-based strategies, seabirds' diving behaviours and their cognitive abilities, we developed a floating device exploring the effect of large eyespots and looming movement to prevent vulnerable seabirds from diving into gillnets. Here, we tested whether this novel above-water device called 'Looming eyes buoy' (LEB) would consistently deter vulnerable seaducks from a focal area. We counted the number of birds present in areas with and without LEBs in a controlled experimental setting. We show that long-tailed duck Clangula hyemalis abundance declined by approximately 20-30% within a 50 m radius of the LEB and that the presence of LEBs was the most important variable explaining this decline. We found no evidence for a memory effect on long-tailed ducks but found some habituation to the LEB within the time frame of the project (62 days). While further research is needed, our preliminary trials indicate that above-water visual devices could potentially contribute to reduce seabird bycatch if appropriately deployed in coordination with other management measures.
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Schnell AK, Boeckle M, Rivera M, Clayton NS, Hanlon RT. Cuttlefish exert self-control in a delay of gratification task. Proc Biol Sci 2021; 288:20203161. [PMID: 33653135 DOI: 10.1098/rspb.2020.3161] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The ability to exert self-control varies within and across taxa. Some species can exert self-control for several seconds whereas others, such as large-brained vertebrates, can tolerate delays of up to several minutes. Advanced self-control has been linked to better performance in cognitive tasks and has been hypothesized to evolve in response to specific socio-ecological pressures. These pressures are difficult to uncouple because previously studied species face similar socio-ecological challenges. Here, we investigate self-control and learning performance in cuttlefish, an invertebrate that is thought to have evolved under partially different pressures to previously studied vertebrates. To test self-control, cuttlefish were presented with a delay maintenance task, which measures an individual's ability to forgo immediate gratification and sustain a delay for a better but delayed reward. Cuttlefish maintained delay durations for up to 50-130 s. To test learning performance, we used a reversal-learning task, whereby cuttlefish were required to learn to associate the reward with one of two stimuli and then subsequently learn to associate the reward with the alternative stimulus. Cuttlefish that delayed gratification for longer had better learning performance. Our results demonstrate that cuttlefish can tolerate delays to obtain food of higher quality comparable to that of some large-brained vertebrates.
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Schnell AK, Clayton NS. Cephalopods: Ambassadors for rethinking cognition. Biochem Biophys Res Commun 2021; 564:27-36. [PMID: 33390247 DOI: 10.1016/j.bbrc.2020.12.062] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 12/14/2020] [Accepted: 12/17/2020] [Indexed: 11/28/2022]
Abstract
Traditional approaches in comparative cognition have a long history of focusing on a narrow range of vertebrate species. However, in recent years the range of model species has expanded. Despite this development, invertebrate taxa are still largely neglected in comparative cognition, which limits our ability to locate the origins of cognitive traits. The time has come to rethink cognition and develop a more comprehensive understanding of cognitive evolution by expanding comparative analyses to include a diverse range of invertebrate taxa. In this review, we contend that cephalopods are suitable ambassadors for rethinking cognition. Cephalopods have large complex brains, exhibit sophisticated behavioral traits, and increasing evidence suggests that they possess complex cognitive abilities once thought to be unique to large-brained vertebrates. Comparing cephalopods with vertebrates, whose cognition has evolved independently, provides prominent opportunities to circumvent current limitations in comparative cognition that have arisen from traditional vertebrate comparisons. Increased efforts in investigating the cognitive abilities of cephalopods have also led to important welfare-related improvements. These large-brained molluscs are paving the way for a more inclusive approach to investigating cognitive evolution that we hope will extend to other invertebrate taxa.
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Birch J, Schnell AK, Clayton NS. Dimensions of Animal Consciousness. Trends Cogn Sci 2020; 24:789-801. [PMID: 32830051 PMCID: PMC7116194 DOI: 10.1016/j.tics.2020.07.007] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 07/21/2020] [Accepted: 07/23/2020] [Indexed: 01/29/2023]
Abstract
How does consciousness vary across the animal kingdom? Are some animals 'more conscious' than others? This article presents a multidimensional framework for understanding interspecies variation in states of consciousness. The framework distinguishes five key dimensions of variation: perceptual richness, evaluative richness, integration at a time, integration across time, and self-consciousness. For each dimension, existing experiments that bear on it are reviewed and future experiments are suggested. By assessing a given species against each dimension, we can construct a consciousness profile for that species. On this framework, there is no single scale along which species can be ranked as more or less conscious. Rather, each species has its own distinctive consciousness profile.
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Schnell AK, Amodio P, Boeckle M, Clayton NS. How intelligent is a cephalopod? Lessons from comparative cognition. Biol Rev Camb Philos Soc 2020; 96:162-178. [DOI: 10.1111/brv.12651] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 08/22/2020] [Accepted: 08/25/2020] [Indexed: 11/30/2022]
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Abstract
Cephalopods have captivated the minds of scientists for thousands of years, dating back to approximately 330 BC when Aristotle became fascinated by their ability to rapidly change colour. This remarkable ability, however, is not the only aspect of cephalopod behaviour that has garnered attention from the scientific community. The soft-bodied cephalopods (henceforth cephalopods), namely octopus, cuttlefish, and squid, are widely considered to be the most cognitively advanced group of invertebrates. They possess highly developed perceptual, memory, and spatial learning abilities and are also capable of intriguing feats of behaviour that appear to indicate complex cognition.
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Schnell AK, Jozet-Alves C, Hall KC, Radday L, Hanlon RT. Fighting and mating success in giant Australian cuttlefish is influenced by behavioural lateralization. Proc Biol Sci 2020; 286:20182507. [PMID: 30862306 DOI: 10.1098/rspb.2018.2507] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Behavioural lateralization is widespread. Yet, a fundamental question remains, how can lateralization be evolutionary stable when individuals lateralized in one direction often significantly outnumber individuals lateralized in the opposite direction? A recently developed game theory model predicts that fitness consequences which occur during intraspecific interactions may be driving population-level lateralization as an evolutionary stable strategy. This model predicts that: (i) minority-type individuals exist because they are more likely to adopt unpredictable fighting behaviours during competitive interactions (e.g. fighting); and (ii) majority-type individuals exist because there is a fitness advantage in having their biases synchronized with other conspecifics during interactions that require coordination (e.g. mating). We tested these predictions by investigating biases in giant Australian cuttlefish during fighting and mating interactions. During fighting, most male cuttlefish favoured the left eye and these males showed higher contest escalation; but minority-type individuals with a right-eye bias achieved higher fighting success. During mating interactions, most male cuttlefish favoured the left eye to inspect females. Furthermore, most male cuttlefish approached the female's right side during a mating attempt and these males achieved higher mating success. Our data support the hypothesis that population-level biases are an evolutionary consequence of the fitness advantages involved in intraspecific interactions.
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Billard P, Schnell AK, Clayton NS, Jozet-Alves C. Cuttlefish show flexible and future-dependent foraging cognition. Biol Lett 2020; 16:20190743. [PMID: 32019464 PMCID: PMC7058941 DOI: 10.1098/rsbl.2019.0743] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 01/09/2020] [Indexed: 12/24/2022] Open
Abstract
Some animals optimize their foraging activity by learning and memorizing food availability, in terms of quantity and quality, and adapt their feeding behaviour accordingly. Here, we investigated whether cuttlefish flexibly adapt their foraging behaviour according to the availability of their preferred prey. In Experiment 1, cuttlefish switched from a selective to an opportunistic foraging strategy (or vice versa) when the availability of their preferred prey at night was predictable versus unpredictable. In Experiment 2, cuttlefish exhibited day-to-day foraging flexibility, in response to experiencing changes in the proximate future (i.e. preferred prey available on alternate nights). In Experiment 1, the number of crabs eaten during the day decreased when shrimp (i.e. preferred food) were predictably available at night, while the consumption of crabs during the day was maintained when shrimp availability was unpredictable. Cuttlefish quickly shifted from one strategy to the other, when experimental conditions were reversed. In Experiment 2, cuttlefish only reduced their consumption of crabs during the daytime when shrimps were predictably available the following night. Their daytime foraging behaviour appeared dependent on shrimps' future availability. Overall, cuttlefish can adopt dynamic and flexible foraging behaviours including selective, opportunistic and future-dependent strategies, in response to changing foraging conditions.
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Schnell AK, Bellanger C, Vallortigara G, Jozet-Alves C. Visual asymmetries in cuttlefish during brightness matching for camouflage. Curr Biol 2019; 28:R925-R926. [PMID: 30205059 DOI: 10.1016/j.cub.2018.07.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Many animals use camouflage to avoid detection by predators. Camouflage can take several forms, one of which includes brightness matching, a form of crypsis, which occurs when an individual resembles the brightness of their surrounding habitat. Most animals have evolved skin patterning that is fixed and specific to their environment, typically limiting their camouflage abilities to a particular habitat [1]. By contrast, crypsis in cuttlefish is dynamic because they can change their body patterns rapidly (270-730 milliseconds) in response to the visual environment through neural control of pigmented organs known as chromatophores [2,3]. Cuttlefish respond to conflicting visual cues, that is, to different visual information on their left and right sides, with mixed body patterns [4]. This response may be modulated by perceptual asymmetries in visual processing, since cuttlefish exhibit biases when processing visual information, termed visual lateralization [5]. Visual lateralization occurs when information in one visual field is prioritized over the other visual field during a specific behavior, but this phenomenon and its potential effect on camouflage behavior have never before been investigated. We report here that juvenile cuttlefish have a right eye preference for brightness matching, as the substrate perceived in their right visual field was prioritized.
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Amodio P, Boeckle M, Schnell AK, Ostojic L, Fiorito G, Clayton NS. Shell Loss in Cephalopods: Trigger for, or By-Product of, the Evolution of Intelligence? A Reply to Mollo et al. Trends Ecol Evol 2019; 34:690-692. [PMID: 31174876 DOI: 10.1016/j.tree.2019.05.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 05/15/2019] [Indexed: 11/27/2022]
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Amodio P, Boeckle M, Schnell AK, Ostojíc L, Fiorito G, Clayton NS. Grow Smart and Die Young: Why Did Cephalopods Evolve Intelligence? Trends Ecol Evol 2018; 34:45-56. [PMID: 30446408 DOI: 10.1016/j.tree.2018.10.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/16/2018] [Accepted: 10/18/2018] [Indexed: 11/16/2022]
Abstract
Intelligence in large-brained vertebrates might have evolved through independent, yet similar processes based on comparable socioecological pressures and slow life histories. This convergent evolutionary route, however, cannot explain why cephalopods developed large brains and flexible behavioural repertoires: cephalopods have fast life histories and live in simple social environments. Here, we suggest that the loss of the external shell in cephalopods (i) caused a dramatic increase in predatory pressure, which in turn prevented the emergence of slow life histories, and (ii) allowed the exploitation of novel challenging niches, thus favouring the emergence of intelligence. By highlighting convergent and divergent aspects between cephalopods and large-brained vertebrates we illustrate how the evolution of intelligence might not be constrained to a single evolutionary route.
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Allen JJ, Akkaynak D, Schnell AK, Hanlon RT. Dramatic Fighting by Male Cuttlefish for a Female Mate. Am Nat 2017; 190:144-151. [PMID: 28617634 DOI: 10.1086/692009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Male cuttlefish compete for females with a repertoire of visually dramatic behaviors. Laboratory experiments have explored this system in Sepia officinalis, but corroborative field data have eluded collection attempts by many researchers. While scuba diving in Turkey, we fortuitously filmed an intense sequence of consort/intruder behaviors in which the consort lost and then regained his female mate from the intruder. These agonistic bouts escalated in stages, leading to fast dramatic expression of the elaborate intense zebra display and culminating in biting and inking as the intruder male attempted a forced copulation of the female. When analyzed in the context of game theory, the patterns of fighting behavior were more consistent with mutual assessment than self-assessment of fighting ability. Additional observations of these behaviors in nature are needed to conclusively determine which models best represent conflict resolution, but our field observations agree with laboratory findings and provide a valuable perspective.
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Schnell AK, Hanlon RT, Benkada A, Jozet-Alves C. Lateralization of Eye Use in Cuttlefish: Opposite Direction for Anti-Predatory and Predatory Behaviors. Front Physiol 2016; 7:620. [PMID: 28018245 PMCID: PMC5149545 DOI: 10.3389/fphys.2016.00620] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 11/28/2016] [Indexed: 12/02/2022] Open
Abstract
Vertebrates with laterally placed eyes typically exhibit preferential eye use for ecological activities such as scanning for predators or prey. Processing visual information predominately through the left or right visual field has been associated with specialized function of the left and right brain. Lateralized vertebrates often share a general pattern of lateralized brain function at the population level, whereby the left hemisphere controls routine behaviors and the right hemisphere controls emergency responses. Recent studies have shown evidence of preferential eye use in some invertebrates, but whether the visual fields are predominately associated with specific ecological activities remains untested. We used the European common cuttlefish, Sepia officinalis, to investigate whether the visual field they use is the same, or different, during anti-predatory, and predatory behavior. To test for lateralization of anti-predatory behavior, individual cuttlefish were placed in a new environment with opaque walls, thereby obliging them to choose which eye to orient away from the opaque wall to scan for potential predators (i.e., vigilant scanning). To test for lateralization of predatory behavior, individual cuttlefish were placed in the apex of an isosceles triangular arena and presented with two shrimp in opposite vertexes, thus requiring the cuttlefish to choose between attacking a prey item to the left or to the right of them. Cuttlefish were significantly more likely to favor the left visual field to scan for potential predators and the right visual field for prey attack. Moreover, individual cuttlefish that were leftward directed for vigilant scanning were predominately rightward directed for prey attack. Lateralized individuals also showed faster decision-making when presented with prey simultaneously. Cuttlefish appear to have opposite directions of lateralization for anti-predatory and predatory behavior, suggesting that there is functional specialization of each optic lobe (i.e., brain structures implicated in visual processing). These results are discussed in relation to the role of lateralized brain function and the evolution of population level lateralization.
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