Jana Uher

Comparative Personality Research: Methodological Approaches

In the broadest sense, personality refers to stable inter‐individual variability in behavioural organisation within a particular population. Researching personality in human as well as nonhuman species provides unique possibilities for comparisons across species with different phylogenies, ecologies and social systems. It also allows insights into mechanisms and processes of the evolution of population differences within and between species. The enormous diversity across species entails particular challenges to methodology. This paper explores theoretical approaches and analytical methods of deriving dimensions of inter‐individual variability on different population levels from a personality trait perspective. The existing diversity suggests that some populations, especially some species, may exhibit different or even unique trait domains. Therefore, a methodology is needed that identifies ecologically valid and comprehensive representations of the personality variation within each population. I taxonomise and compare current approaches in their suitability for this task. I propose a new bottom–up approach—the behavioural repertoire approach—that is tailored to the specific methodological requirements of comparative personality research. Initial empirical results in nonhuman primates emphasise the viability of this approach and highlight interesting implications for human personality research. Copyright

Personality in the behaviour of great apes: temporal stability, cross-situational consistency and coherence in response

Using a multidisciplinary approach, the present study complements ethological behaviour measurements with basic theoretical concepts, methods and approaches of the personality psychological trait paradigm. Its adoptability and usefulness for animal studies are tested exemplarily on a sample of 20 zoo-housed great apes (five of each of the following species): bonobos, Pan paniscus; chimpanzees, Pan troglodytes verus; gorillas, Gorilla gorilla gorilla; and orang-utans, Pongo pygmaeus abelii. Data on 76 single trait-relevant behaviours were recorded in a series of 14 laboratory-based situations and in two different group situations. Data collection was repeated completely after a break of 2 weeks within a 50-day period. All behaviour records were sufficiently reliable. Individual- and variable-oriented analyses showed high/substantial temporal stability on different levels of aggregation. Distinctive and stable individual situational and response profiles clarified the importance of situations and of multiple trait-relevant behaviours. The present study calls for a closer collaboration between behavioural biologists and personality psychologists to tap the full potential of animal personality research.

Individual behavioral phenotypes: an integrative meta-theoretical framework. Why "behavioral syndromes" are not analogs of "personality".

Animal researchers are increasingly interested in individual differences in behavior. Their interpretation as meaningful differences in behavioral strategies stable over time and across contexts, adaptive, heritable, and acted upon by natural selection has triggered new theoretical developments. However, the analytical approaches used to explore behavioral data still address population-level phenomena, and statistical methods suitable to analyze individual behavior are rarely applied. I discuss fundamental investigative principles and analytical approaches to explore whether, in what ways, and under which conditions individual behavioral differences are actually meaningful. I elaborate the meta-theoretical ideas underlying common theoretical concepts and integrate them into an overarching meta-theoretical and methodological framework. This unravels commonalities and differences, and shows that assumptions of analogy to concepts of human personality are not always warranted and that some theoretical developments may be based on methodological artifacts. Yet, my results also highlight possible directions for new theoretical developments in animal behavior research.

How the great apes (Pan troglodytes, Pongo pygmaeus, Pan paniscus, and Gorilla gorilla) perform on the reversed contingency task: the effects of food quantity and food visibility

S. T. Boysen and G. G. Berntson (1995) found that chimpanzees performed poorly on a reversed contingency task in which they had to point to the smaller of 2 food quantities to acquire the larger quantity. The authors compared the performance of 4 great ape species (Pan troglodytes, Pongo pygmaeus, Pan paniscus, and Gorilla gorilla) on the reversed contingency task while manipulating food quantity (0-4 or 1-4) and food visibility (visible pairs or covered pairs). Results showed no systematic species differences but large individual differences. Some individuals of each species were able to solve the reversed contingency task. Both quantity and visibility of the food items had a significant effect on performance. Subjects performed better when the disparity between quantities was smaller and the quantities were not directly visible.

Personality Psychology: Lexical Approaches, Assessment Methods, and Trait Concepts Reveal Only Half of the Story—Why it is Time for a Paradigm Shift

This article develops a comprehensive philosophy-of-science for personality psychology that goes far beyond the scope of the lexical approaches, assessment methods, and trait concepts that currently prevail. One of the field’s most important guiding scientific assumptions, the lexical hypothesis, is analysed from meta-theoretical viewpoints to reveal that it explicitly describes two sets of phenomena that must be clearly differentiated: 1) lexical repertoires and the representations that they encode and 2) the kinds of phenomena that are represented. Thus far, personality psychologists largely explored only the former, but have seriously neglected studying the latter. Meta-theoretical analyses of these different kinds of phenomena and their distinct natures, commonalities, differences, and interrelations reveal that personality psychology’s focus on lexical approaches, assessment methods, and trait concepts entails a) erroneous meta-theoretical assumptions about what the phenomena being studied actually are, and thus how they can be analysed and interpreted, b) that contemporary personality psychology is largely based on everyday psychological knowledge, and c) a fundamental circularity in the scientific explanations used in trait psychology. These findings seriously challenge the widespread assumptions about the causal and universal status of the phenomena described by prominent personality models. The current state of knowledge about the lexical hypothesis is reviewed, and implications for personality psychology are discussed. Ten desiderata for future research are outlined to overcome the current paradigmatic fixations that are substantially hampering intellectual innovation and progress in the field.

How the great apes (Pan troglodytes, Pongo pygmaeus, Pan paniscus, Gorilla gorilla) perform on the reversed reward contingency task II: transfer to new quantities, long-term retention, and the impact of quantity ratios

We tested 6 chimpanzees (Pan troglodytes), 3 orangutans (Pongo pygmaeus), 4 bonobos (Pan paniscus), and 2 gorillas (Gorilla gorilla) in the reversed reward contingency task. Individuals were presented with pairs of quantities ranging between 0 and 6 food items. Prior to testing, some experienced apes had solved this task using 2 quantities while others were totally naïve. Experienced apes transferred their ability to multiple-novel pairs after 6 to 19 months had elapsed since their initial testing. Two out of 6 naïve apes (1 chimpanzee, 1 bonobo) solved the task--a proportion comparable to that of a previous study using 2 pairs of quantities. Their acquisition speed was also comparable to the successful subjects from that study. The ratio between quantities explained a large portion of the variance but affected naïve and experienced individuals differently. For smaller ratios, naïve individuals were well below 50% correct and experienced ones were well above 50%, yet both groups tended to converge toward 50% for larger ratios. Thus, some apes require no procedural modifications to overcome their strong bias for selecting the larger of 2 quantities.

Three methodological core issues of comparative personality research

Comparative personality research in human and nonhuman species advances many areas of empirical and theoretical research. The methodological foundations underlying these attempts to explain personality, however, remain an unpopular and often ignored topic. The target paper and this rejoinder explore three methodological core issues in the philosophy of science for comparative personality research: Conceptualising personality variation, identifying domains of variation and measuring variation. Clear distinctions among these issues may help to avoid misunderstandings among different disciplines concerned with personality. Copyright

Conceiving “personality”: Psychologist’s challenges and basic fundamentals of the Transdisciplinary Philosophy-of-Science Paradigm for Research on Individuals

Scientists exploring individuals, as such scientists are individuals themselves and thus not independent from their objects of research, encounter profound challenges; in particular, high risks for anthropo-, ethno- and ego-centric biases and various fallacies in reasoning. The Transdisciplinary Philosophy-of-Science Paradigm for Research on Individuals (TPS-Paradigm) aims to tackle these challenges by exploring and making explicit the philosophical presuppositions that are being made and the metatheories and methodologies that are used in the field. This article introduces basic fundamentals of the TPS-Paradigm including the epistemological principle of complementarity and metatheoretical concepts for exploring individuals as living organisms. Centrally, the TPS-Paradigm considers three metatheoretical properties (spatial location in relation to individuals’ bodies, temporal extension, and physicality versus “non-physicality”) that can be conceived in different forms for various kinds of phenomena explored in individuals (morphology, physiology, behaviour, the psyche, semiotic representations, artificially modified outer appearances and contexts). These properties, as they determine the phenomena’s accessibility in everyday life and research, are used to elaborate philosophy-of-science foundations and to derive general methodological implications for the elementary problem of phenomenon-methodology matching and for scientific quantification of the various kinds of phenomena studied. On the basis of these foundations, the article explores the metatheories and methodologies that are used or needed to empirically study each given kind of phenomenon in individuals in general. Building on these general implications, the article derives special implications for exploring individuals’ “personality”, which the TPS-Paradigm conceives of as individual-specificity in all of the various kinds of phenomena studied in individuals.

Developing “Personality” Taxonomies: Metatheoretical and Methodological Rationales Underlying Selection Approaches, Methods of Data Generation and Reduction Principles

Taxonomic “personality” models are widely used in research and applied fields. This article applies the Transdisciplinary Philosophy-of-Science Paradigm for Research on Individuals (TPS-Paradigm) to scrutinise the three methodological steps that are required for developing comprehensive “personality” taxonomies: 1) the approaches used to select the phenomena and events to be studied, 2) the methods used to generate data about the selected phenomena and events and 3) the reduction principles used to extract the “most important” individual-specific variations for constructing “personality” taxonomies. Analyses of some currently popular taxonomies reveal frequent mismatches between the researchers’ explicit and implicit metatheories about “personality” and the abilities of previous methodologies to capture the particular kinds of phenomena toward which they are targeted. Serious deficiencies that preclude scientific quantifications are identified in standardised questionnaires, psychology’s established standard method of investigation. These mismatches and deficiencies derive from the lack of an explicit formulation and critical reflection on the philosophical and metatheoretical assumptions being made by scientists and from the established practice of radically matching the methodological tools to researchers’ preconceived ideas and to pre-existing statistical theories rather than to the particular phenomena and individuals under study. These findings raise serious doubts about the ability of previous taxonomies to appropriately and comprehensively reflect the phenomena towards which they are targeted and the structures of individual-specificity occurring in them. The article elaborates and illustrates with empirical examples methodological principles that allow researchers to appropriately meet the metatheoretical requirements and that are suitable for comprehensively exploring individuals’ “personality”.

Agency enabled by the psyche: explorations using the Transdisciplinary Philosophy-of-Science Paradigm for Research on Individuals

A science of the individual encounters the unparalleled challenges of exploring the unique phenomena of the psyche and their workings. This article applies the Transdisciplinary Philosophy–of–Science Paradigm for Research on Individuals (TPS–Paradigm) to specify these challenges. Considering three metatheoretical properties—1) location in relation to the individual’s body, 2) temporal extension and 3) physicality versus “non–physicality”—that can be conceived for various kinds of phenomena explored in individuals (e.g. behaviours, experiencings, semiotic representations), the TPS–Paradigm scrutinises these phenomena’s perceptibility by individuals. From this metatheoretical perspective, the article traces developmental pathways in which psychical phenomena enable individuals to increasingly become actors—as single individuals, communities and species. The explorations first follow microgenetic and ontogenetic pathways in the development of perceptual and psychical representations of the physical phenomena encountered in life. Then the article explores how individually developed psychical properties, which are perceptible only by the individual him- or herself, can be communicated to other individuals and how individuals can develop psychical representations that are socially shared, thus enabling social coordination and the transmission of knowledge to subsequent generations. Many species have evolved abilities for co–constructing psychical representations reactively and based on occasions (e.g. observational learning). The evolution of abilities for co–constructing psychical representations also actively and based on intentions (e.g. instructed learning) entailed the development of semiotic representations through the creation of behavioural and material signs (e.g. language), allowing humans to communicate systematically about psychical abilities despite their imperceptibility by other individuals. This has opened up new pathways through which inventions can be propagated and continuously refined, thus producing cultural evolution. These processes enable humans to develop ever more complex psychical abilities and to become actors in the evolution of life.