Fish personality: meta-theoretical issues, personality dimensions, and applications to neuroscience and psychopathology

Abstract

While the field of personality neuroscience has extensively focused on humans and, in a few cases, primates and rodents, a wide range of research on fish personality has emerged in the last decades. This research is focused mainly on the ecological and evolutionary causes of individual differences and also aimed less extensively at proximal mechanisms (e.g., neurochemistry or genetics). We argue that, if consistent and intentional work is made to solve some of the meta-theoretical issues of personality research both on fish and mammals, fish personality research can lead to important advances in personality neuroscience as a whole. The five dimensions of personality in fish (shyness-boldness, exploration-avoidance, activity, aggressiveness, and sociability) need to be translated into models that explicitly recognize the impacts of personality in psychopathology, synergizing research on fish as model organisms in experimental psychopathology, personality neuroscience, and ecological-ethological approaches to the evolutionary underpinnings of personality to produce a powerful framework to understand individual differences.

Non-human contributions to personality neuroscience: From fish through primates – a concluding editorial overview

“…Indeed, it can be argued that the variation in the precise form, and structure, of traits with homology based on common function and neural conservation is where inter-species comparisons can be particularly instructive. For example, fish may have a 5-dimensional trait structure but this is hard to map to the human Big 5 and may be easier to fit with the motivational systems of RST (Luchiari & Maximino, 2023 , see §3.2). At the more detailed level, fish appear to be similar to humans in showing cognitive bias in the appraisal of stimuli and similar stress-related reactions and resilience (or otherwise) to them (Buenhombre et al, 2024 , §3.3).…”

“…Luchiari and Maximino ( 2023 ) provide an overview and critique of what is known about fish personality. Their discussion includes “metatheoretical issues, personality dimensions, and applications to neuroscience and psychopathology.” These two applications are considered further in sections 4 and 5.…”

“…However, they note that some caution is needed in seeing these as the basis of individual differences since most work in this area assesses differences between distinct populations (see also the rat work described in section 2), with little analysis of within-individual correlations. Critically, in at least one case (Lee & Bereijikian, 2007 ), “a specific stability of correlations between behavioral variables at the population level did not hold at the individual level” (Luchiari & Maximino, 2023 , p. 2). They emphasize (p. 3) that “simply referring to the term used for a specific dimension is not enough, and grasping the full meaning of that dimension/trait is only possible by considering the context and methods of each study.” We would see this labeling problem as identical to the problem with scale labels versus actual item content with questionnaires and so particularly important (for both ends) when attempting translation.…”

“…With 5 fish dimensions, it is also tempting to ask how far these can map to the domains of the human Big 5 (Costa & McCrae, 1985 , 1995 ; McCrae & Costa, 2008 ). However, Luchiari and Maximino ( 2023 , p. 8) say: “…to the best of our knowledge, no attempts have been made to map fish data and the Big Five model; it could be argued that shyness-boldness could conceptually map to Neuroticism, exploration-avoidance could conceptually map to Agreeableness, activity to Conscientiousness, aggressiveness to Extraversion, and sociability to Openness/ Intellect. But it could be similarly argued that sociability should map to Extraversion, for example.…”

“…Buenhombre et al ( 2024 ) provide a more targeted picture of the relation, in fish, between personality traits, cognitive bias processes (CBP), and stress resilience (including psychopathology). They start (p. 1) from the same fundamental position as Luchiari and Maximino ( 2023 ): “…the functional homology of neural regions in fish is well-conserved in rodents, and their behaviour exhibits sufficient complexity to enable translation to both rodents and humans (Khan & Echevarria, 2017 ). As such, biological traits that are similar between fish and mammals have been widely utilized in models of anxiety and stress neurobiology.…”