Comparative Psychology Research Articles

Personality dimensions in the common octopus (Octopus vulgaris)

Abstract Understanding the origin, universality, and maintenance of among-individual variation in behaviour is a current focus of behavioural ecology and comparative psychology. Research on animal personality emphasising the central role of the individual contributes to conservation efforts and animal welfare by tailoring guidelines and interventions at the individual level. Cephalopods are understudied in this respect, despite being the only invertebrate group currently included in international directives for the protection of animals used for scientific purposes. Here, we assessed among-individual variation in behavioural responses (i.e., animal personality) of 21 common octopuses (Octopus vulgaris) temporarily kept in captivity. We performed a battery of tests across three different experimental contexts, namely a Startle test, a Foraging test, and a Disturbance test, each repeated for four consecutive days, adapting established protocols from other cephalopods. Behavioural variables were moderately repeatable. Results of a principal component analysis revealed a three-component structure, with components we labelled Alertness, Exploration, and Boldness. The components were also moderately repeatable. The components Exploration and Boldness predicted each other across experimental contexts, suggesting a behavioural syndrome. Overall, findings indicate marked individual differences in common octopuses, and provide evidence of personality dimensions in a widely used animal model in neurophysiology and cognition. Our findings thus contribute to the study of the evolution of personality structure from a comparative perspective, and may help individual-level welfare refinement.

The Mexican Native Primates from the Comparative Psychology Point of View: State of the Art and Perspectives

Primates have been studied extensively to understand their behavior and the mechanisms that allow information processing. However, when we closely analyze the species studied and the different projects and topics carried out with them, we found that some species have been highly studied, while others have only a few studies. These differences create a significant underrepresentation of some primate species that could be especially problematic when we use the available information to track the evolution and the diversification of behavior and the mechanisms for information processing. With this in mind, this review aims to show the state-of-the-art of different topics studied in Mexican primates and identify topics that could be studied in the future. The review also aims to demonstrate why working with native species is a path that many low- and middle-income countries like Mexico can follow to develop research programs in their homelands.

A Conceptualist Reading of the Continuity Argument

In this paper I analyze the non-conceptualist continuity argument to show that it implies an implausible conception of perceptual experience in animals that are supposed to lack concepts. In order to do this, I show the limitations and implicit premises in the traditional formulations of the argument, and the additional premises needed to use it as an objection against conceptualism. Then, I review studies in cognitive neuroscience, ethology, comparative psychology, developmental psychology, and philosophical considerations to show that the argument implies a conception of animal experience that is at odds with our scientific theories and even with the motivations for adopting non-conceptualism. I conclude that, if we wish to defend the continuity between adult human’s and other animal’s experiences, we should do it by attributing concepts to the latter.

Why might animals remember? A functional framework for episodic memory research in comparative psychology.

One of Clayton's major contributions to our understanding of animal minds has been her work on episodic-like memory. A central reason for the success of this work was its focus on ecological validity: rather than looking for episodic memory for arbitrary stimuli in artificial contexts, focussing on contexts in which episodic memory would serve a biological function such as food caching. This review aims to deepen this insight by surveying the numerous functions that have been proposed for episodic memory, articulating a philosophically grounded framework for understanding what exactly functions are, and drawing on these to make suggestions for future directions in the comparative cognitive psychology of episodic memory. Our review suggests four key insights. First, episodic memory may have more than one function and may have different functions in different species. Second, cross-disciplinary work is key to developing a functional account of episodic memory. Third, there is scope for further theoretical elaboration of proposals relating episodic memory to food caching and, in particular, future-oriented cognition. Finally, learning-related functions suggested by AI (artificial intelligence)-based models are a fruitful avenue for future behavioural research.

Why we should study animal consciousness.

The New York Declaration on Animal Consciousness (Andrews et al., 2024) highlights increasing empirical evidence supporting the existence of sentience in many animal species. The views in the declaration rest on an increasingly popular theoretical approach that comparative psychologists could use to guide research on non-human consciousness.

Affective foundations in AI-human interactions: Insights from evolutionary continuity and interspecies communications

The imminent arrival of Artificial General Intelligence (AGI) compels a reevaluation of AI-human interactions, particularly through affective communication. This research synthesizes insights from evolutionary biology, comparative psychology, and AI development, advocating for a paradigm shift beyond conventional human-like cognitive processes. It emphasizes the universal nature of affective pathways, as evidenced across various species. We introduce three affective interaction models — the Affective Threshold Model, the Dynamic Set-Point Model, and the Affective Schema Model — all of which stem from an in-depth analysis of interspecies communications. These models present a roadmap to craft AI interfaces attuned to human affective experiences, elucidating avenues of trust, intuition, and reciprocal recognition between machines and their human counterparts. By further crystallizing the concept of the “Large Affect Model”, we project a horizon where AI not only deciphers but also empathizes with human partners, paving the way for a revolutionary cooperative paradigm between AI and humanity.

Can language models handle recursively nested grammatical structures? A case study on comparing models and humans

Abstract How should we compare the capabilities of language models (LMs) and humans? In this paper, I draw inspiration from comparative psychology to highlight challenges in these comparisons. I focus on a case study: processing of recursively nested grammatical structures. Prior work suggests that LMs cannot process these structures as reliably as humans can. However, the humans were provided with instructions and substantial training, while the LMs were evaluated zero-shot. I therefore match the evaluation more closely. Providing large LMs with a simple prompt—with substantially less content than the human training—allows the LMs to consistently outperform the human results, even in more deeply nested conditions than were tested with humans. Furthermore, the effects of prompting are robust to the particular structures and vocabulary used in the prompt. Finally, reanalyzing the existing human data suggests that the humans may not perform above chance at the difficult structures initially. Thus, large LMs may indeed process recursively nested grammatical structures as reliably as humans, when evaluated comparably. This case study highlights how discrepancies in the evaluation methods can confound comparisons of language models and humans. I conclude by reflecting on the broader challenge of comparing human and model capabilities, and highlight an important difference between evaluating cognitive models and foundation models.

The Anthropocentric Bias in Animal Cognition

In the classical philosophical tradition, animals had the special function of serving as “objects of comparison” concerning humans. In that sense, philosophy adopted a peculiar comparative perspective focused on the categoric difference that separates humans from other creatures: an exceptionalist perspective. The Humanities developed an anthropocentric canon for the study of animals and privileged the search for differences over similarities of these with humans. On the other hand, the great boost that animal studies received under the influence of Darwin's work promoted a different comparative perspective in the natural sciences. However, especially in comparative psychology, ingent efforts were devoted to avoid the errors that anthropomorphism would entail: attributing human properties to other creatures and privileging similarities over differences. It assumed that anthropomorphic bias entails a more fundamental type of error than anthropocentric bias. Now, this asymmetric diagnosis has beenunmasked with different arguments. In the context of both disciplinary traditions, it is timely to reexamine the most persistent and negative manifestations of anthropocentric bias as a comparative bias for the study of animal cognition. In this work I will identify the following: the homogenization of animals into a single general category; psychological speciesism and the “de-mentalization” of animals; the survival of a hierarchical conception of cognitive abilities; the selective application - only to animals - of Morgan's Canon or anthropodenial and its complement, the assumption of idealized mental capacities in the human case or anthropofabulation; asymmetrical or distorsive methodological strategies for the study of animals versus humans which affects the comparative interpretations; and different manifestations of semantic anthropocentrism.

A Bridge between Animal Psychology and Sexual Selection: Possible Effects of Habituation and Neural Adaptation on Mate Choice Signals

A Bridge between Animal Psychology and Sexual Selection: Possible Effects of Habituation and Neural Adaptation on Mate Choice Signals

Problems of Analogies and Neuroimaging in the Study of Animal Psychology

Possibilities of understanding of animal psychology are considered. In results of performed analysis hypothesis about possibility of approximate understanding of animal with the brain psychology (not in full) is formulated. It is shown that understanding the sensations of animals based on similarity of excited brain regions in them and in humans, i.e. extrapolations, and visualization data is very problematic. For the purposes of understanding the psychology of animals, the author proposed and established using complex hierarchical approach based on multilevel simulation with experimental methods.

Editorial.

The Journal of Comparative Psychology (JCP) is the flagship APA journal dedicated to understanding psychological processes from a comparative perspective. Traditionally, "comparative" has meant comparison across species. However, "comparative" means more than just assessing as many species as possible or relating species to each other. I also think of the importance of a "comparative psychology" perspective in two other ways that should be reflected in the journal's publications. I would like to outline a few important points about how I view the mission of JCP, and how my term as chief editor will address some of the major issues that exist for the journal and for the field of comparative psychology more broadly. Preregistration, replication, and the review process are highlighted. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Willard Stanton Small (1870-1943): The man who made the maze.

Willard Stanton Small (1870-1943) was among the earliest scientists to perform psychological research with rats and conducted the first experiment with a rat in a maze. This article represents the first biography devoted to Small and provides highlights from his childhood, undergraduate and graduate work, personal life, and professional career. Special attention is given to the events that led to the first rat maze experiment, which Small performed as a graduate student at Clark University. A detailed analysis of Small's published report of the maze experiment is also provided. His employment history after graduate school is discussed and includes teaching and administrative roles at multiple academic institutions, in addition to his role as a field investigator for the U.S. Bureau of Education. It is shown that Small's work impacted not only comparative psychology, but also U.S. public health, school hygiene, and education. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

On parrots, delay of gratification, executive function, and how sometimes we do the best we can.

Engaging executive functions provides an individual with the means to engage in cognitive control by adjusting to the environment and processing information in a way that leads to optimal outcomes. There are some claims that explicit training on certain executive functioning abilities provides benefits beyond the training tasks, but other studies indicate that this may not be true or may be limited based on age and other factors. This same mixed pattern has been reported with nonhuman species, where training or even experience in one specific area, like inhibition, sometimes leads to positive transfer in new but similar tasks that presumably also require executive functions. Pepperberg and Hartsfield (2024) sought to determine whether experience in previous tasks that required different executive functions impacted how well three African grey parrots: Griffin, Pepper, and Franco could perform in a new assessment of delayed gratification. Griffin showed a clear and consistent capacity to wait through a delay for a quantitatively better reward. This suggested that the previous experience with the tokens aided improvement in the quantitative delay of gratification task with food items as the options to choose between. The other two parrots, Pepper and Franco, never completed the intended sequence of phases in their study. Unfortunately, the testing conditions dictated by COVID restrictions were such that these two subjects appeared to exhibit stress in doing the task, and so no further testing was conducted with them. This article is an example of what can happen when two intelligent species (people and parrots) are put in difficult circumstances (a global pandemic unlike anything any of us has ever been through), and yet both species attempted to continue to engage in science. The effects of COVID-19 will remain an integral factor in comparative psychology for some time to come, and I suspect there are many other half-completed experiments that suffered because of the pandemic. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

A longitudinal comparison of maternal behaviour in German urban humans (Homo sapiens) and captive chimpanzees (Pan troglodytes)

Comparative perspectives are crucial in the study of human development, yet longitudinal comparisons of humans and other primates are still relatively uncommon. Here, we combined theoretical frameworks from cross-cultural and comparative psychology, to study maternal style in 10 mother–infant pairs of German urban humans (Homo sapiens) and 10 mother–infant pairs of captive chimpanzees (Pan troglodytes), during the first year of infants’ development. We conducted focal observations of different behaviours (i.e. nursing, carrying, body contact, touching, grooming, restraining, approaching, leaving, rejection, aggression, mutual gaze, object stimulation), during natural interactions. Analyses revealed a more distal maternal style in WEIRD humans than in captive chimpanzees, with different behaviours being generally more common in one of the two species throughout development. For other behaviours (i.e. nursing), developmental trajectories differed between WEIRD humans and captive chimpanzees, although differences generally decreased through infants’ development. Overall, our study confirms functional approaches as a valid tool for comparative longitudinal studies.

My parenting enjoyed the blessing from animal psychology

My parenting enjoyed the blessing from animal psychology

Opinion: Which animals have personality?

Human personality generally refers to coherent individuating patterns in affect, behavior, and cognition. We can only observe and measure behavior, from which we then infer personality and other psychological processes (affect, cognition, etc.). We emphasize that the study of personality always explains or summarizes patterns not only in behavior but also in these other psychological processes inferred from behavior. We thus argue that personality should be attributed only to nonhuman animals with behaviors from which we can infer a sufficiently rich set of psychological processes. The mere inference of a biological trait that explains behavioral variability, on our view, is not sufficient to count as a personality construct and should be given a different term. Methodologically, inferring personality in nonhuman animals entails challenges in characterizing ecologically valid behaviors, doing so across rich and varied environments, and collecting enough data. We suggest that studies should gradually accumulate such corpora of data on a species through well-curated shared databases. A mixture of approaches should include both top-down fit with extant human personality theories (such as the Big Five) as well as bottom-up discovery of species-specific personality dimensions. Adopting the above framework will help us to build a comparative psychology and will provide the most informative models also for understanding human personality, its evolution, and its disorders.

Humane Rather than Human Endpoints for Comparative Psychology

Humane Rather than Human Endpoints for Comparative Psychology

Morgan's Quaker gun and the species of belief

AbstractIn this article, I explore how researchers’ metaphysical commitments can be conducive—or unconducive—to progress in animal cognition research. The methodological dictum known as Morgan's Canon exhorts comparative psychologists to countenance the least mentalistic fair interpretation of animal actions. This exhortation has frequently been misread as a blanket condemnation of mentalistic interpretations of animal behaviors that could be interpreted behavioristically. But Morgan meant to demand only that researchers refrain from accepting default interpretations of (apparent) actions until other fair interpretations have been duly considered. The Canon backfired largely because of Morgan's background metaphysical commitment to a univocal, hierarchical, and anthropocentric account of cognitive architecture. I make the case that, going forward, comparative psychologists would do well to pair judicious use of Morgan's Canon with an openness to the existence of non‐humanlike animal minds comprising phenomena belonging to distinct cognitive and folk psychological ontologies. And I argue that this case gives us pragmatic reason to reconcile deep—e.g., psychofunctionalist—and superficial—e.g., dispositionalist—approaches to the metaphysics of belief.

The Inner Lives of Cephalopods.

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.

Theopsych: A Psychological Science Primer for Theologians

Theopsych: A Psychological Science Primer for Theologians