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The Transdisciplinary Philosophy-of-Science Paradigm for Research on Individuals (TPS-Paradigm)


TPS-Paradigm: Theoretical, metatheoretical and methodological papers

Empirical studies with nonhuman primates using the TPS-Paradigm

Personality questionnaires for nonhuman primates

TPS-Paradigm: Theoretical, metatheoretical and methodological papers

Research on individuals (behaviour, psyche) 

Research on individual-specificity ("personality")

Comparative research methodologies

Behavioural Repertoire x Behavioural Situations Approach (BRxBS-Approach)

Observations versus assessments

 

  

Publication abstracts and PDF-Downloads   

Uher, J. (2018a). Taxonomic models of individual differences: A guide to transdisciplinary approaches. Philosophical Transactions of the Royal Society B: Biological Sciences, 373 (1744). DOI 10.1098/rstb.2017-0171

Models and constructs of individual differences are numerous and diverse. But detecting commonalities, differences and interrelations is hindered by the common abstract terms (e.g. ‘personality’, ‘temperament’, ‘traits’) that do not reveal the particular phenomena denoted. This article applies a transdisciplinary paradigm for research on individuals that builds on complexity theory and epistemological complementarity. Its philosophical, metatheoretical and methodological frameworks provide concepts to differentiate
various kinds of phenomena (e.g. physiology, behaviour, psyche, language). They are used to scrutinize the field’s basic concepts and to elaborate methodological foundations for taxonomizing individual variations in humans and other species. This guide to developing comprehensive and representative models explores the decisions taxonomists must make about which individual variations to include, which to retain and how to model them. Selection and reduction approaches from various disciplines are classified by their underlying rationales, pinpointing possibilities and limitations. Analyses highlight that individuals’ complexity cannot be captured by one universal model. Instead, multiple models phenotypically taxonomizing different kinds of variability in different kinds of phenomena are needed to explore their causal and functional interrelations and ontogenetic development that are then modelled in integrative and explanatory taxonomies. This research agenda requires the expertise of many disciplines and is inherently transdisciplinary.

  

Uher, J., Tofimova, I., Sulis, W., Netter, P., Pessoa, L., Posner, M. I., Rothbart, M. K., Rusalov, V., Petersen, I. T., & Schmidt, L. A. (2018). Diversity in action: Exchange of perspectives and reflections on taxonomies of individual differences. Philosophical Transactions of the Royal Society B: Biological Sciences, 373 (1744). DOI 10.1098/rstb.2017-0172

Throughout the last 2500 years, the classification of individual differences in healthy people and their extreme expressions inmental disorders has remained one of the most difficult challenges in science that affects our ability to explore individuals’ functioning, underlying psychobiological processes and pathways of development. To facilitate analyses of the principles required for studying  individual differences, this theme issue brought together prominent scholars from diverse backgrounds of which many bring unique combinations of cross-disciplinary experiences and perspectives that help establish connections and promote exchange across disciplines. This final paper presents brief commentaries of some of our authors and further scholars exchanging perspectives and reflecting on the contributions of this theme issue.

  

Trofimova, I., Robbins, T.W., Sulis, W., Uher, J. (2018). Taxonomies of psychological individual differences: Biological perspectives on millennia-long challenges. Philosophical Transactions of the Royal Society B: Biological Sciences, 373 (1744). DOI 10.1098/rstb.2017-0152

This Editorial highlights a unique focus of this theme issue on the biological perspectives in deriving psychological taxonomies coming from neurochemistry, neuroanatomy, neurophysiology, genetics, psychiatry, developmental and comparative psychology—as contrasted to more common discussions of socio-cultural concepts (personality) and methods (lexical approach). It points out the importance of the distinction between temperament and personality for studies in human and animal differential psychophysiology,
psychiatry and psycho-pharmacology, sport and animal practices during the past century. It also highlights the inability of common statistical methods to handle nonlinear, feedback, contingent, dynamical and multi-level relationships between psychophysiological systems of consistent psychological traits discussed in this theme issue. This article is part of the theme issue ‘Diverse perspectives on diversity: Multi-disciplinary approaches to taxonomies of individual differences’.

  

Uher, J. (2018b). Data generation methods across the empirical sciences: Differences in the study phenomena's accessibility and the processes of data encoding. Quality & Quantity. International Journal of Methodology. [Springer Nature SharedIt initiative]  DOI: 10.1007/s11135-018-0744-3

Data generation methods differ across the empirical sciences. Today’s physicists and engineers primarily generate data with automated technologies. Behavioural, psychological and social scientists explore phenomena that are not technically accessible (e.g., attitudes, social beliefs) or only in limited ways (e.g., behaviours) and therefore generate data primarily with persons. But human abilities are involved in any data generation, even when technologies are used and developed. This article explores concepts and methods of data generation of different sciences from transdisciplinary and philosophy-of-science perspectives. It highlights that empirical data can reveal information about the phenomena under study only if relevant properties of these phenomena have been encoded systematically in the data. Metatheoretical concepts and methodological principles are elaborated that open up new perspectives on methods of data generation across the empirical sciences, highlighting commonalities and differences in two pivotal points: (1) in the accessibility that various kinds of phenomena have for the persons generating the data and for the researchers, and (2), as a consequence thereof, in the processes involved in the encoding of information from these phenomena in the signs (symbols) used as data. These concepts and principles cut across establish method categorisations (e.g., human-generated versus instrument-generated data; quantitative versus qualitative methods), highlighting fundamental issues equally important in all sciences as well as essential differences. They also provide novel lines of argumentation that substantiate psychologists’ and social scientists’ increasing criticism of their own disciplines’ focus on standardised assessment methods and establish connections to concepts of data generation developed in metrology.

  

Uher, J. (2018c). The Transdisciplinary Philosophy-of-Science Paradigm for Research on Individuals: Foundations for the Science of Personality and Individual Differences. In V. Zeigler-Hill & T. K. Shackelford (Eds). The SAGE Handbook of Personality and Individual Differences. Vol. 1. The Science of Personality and Individual Differences. Part 1: Theoretical Perspectives on Personality and Individual Differences (Chapter 4, pp. 84-109). London, UK: Sage.  DOI: 10.4135/9781526451163.n4

The Transdisciplinary Philosophy-of-Science Paradigm for Research on Individuals (TPS-Paradigm) builds on established concepts, approaches, and methods from various disciplines that are systematically integrated into coherent philosophical, metatheoretical, and methodological frameworks and that are further developed and complemented by novel ones. The TPS-Paradigm is aimed at supporting scientists exploring individuals to tackle the particular challenges of their field and to make explicit and critically reflect on their philosophical presuppositions, metatheories, and methodologies. The metatheoretical definition of 'personality' as individual-specificity is elaborated, highlighting that 'personality' is conceived and studied differently because different paradigms focus on individual-specificity in different kinds of phenomena. Critical analyses of the field's strong reliance on assessments methods reveal fallacies, circular explanations in 'trait' concepts, and the fact that taxonomic models of most of the phenomena in which individual-specificity is conceived as 'personality' still need to be developed. The TPS-Paradigm is therefore aimed at reviving and broadening the portfolio of methodologies that can and should be complementarily applied to comprehensively explore individuals and their 'personality.' Such broad paradigms are needed to enable transdisciplinary collaboration and research that embraces the complex reality of individuals and their 'personality.'

  

Uher, J. (2017). Basic Definitions in Personality Psychology: Challenges for Conceptual Integrations. European Journal of Personality, 31, 572-573. [Download]  DOI: 10.1002/per.2128

Personality psychology is fragmented across heterogeneous subfields each focussing on particular aspects of individuals and from particular paradigmatic perspectives. Attempts for integration into overarching theories as that presented in the target article are therefore important. But the ideas proposed build on vague and often circular definitions of basic terms and concepts that hamper advancement and integration. My critique from philosophy-of-science perspectives pinpoints central problems and presents alternative concepts to help overcome them. A metatheoretical definition highlights the core ideas underlying common personality concepts and opens new avenues for conceptual integration.

  

Uher, J. (2016b). What is behaviour? And (when) is language behaviour? Journal for the Theory of Social Behaviour, 46, 475-501.   [download]  DOI: 10.1111/jtsb.12104  

Behaviour is central to many fields, but metatheoretical definitions specifying the most basic assumptions about what is considered behaviour and what is not are largely lacking. This transdisciplinary research explores the challenges in defining behaviour, highlighting anthropocentric biases and a frequent lack of differentiation from physiological and psychical phenomena. To meet these challenges, the article elaborates a metatheoretical definition of behaviour that is applicable across disciplines and that allows behaviours to be differentiated from other kinds of phenomena. This definition is used to explore the phenomena of language and to scrutinise whether and under what conditions language can be considered behaviour and why. The metatheoretical concept of two different levels of meaning conveyed in language is introduced, highlighting that language inherently relies on behaviours and that the content of what-is-being-said, in and of itself, can constitute (interpersonal) behaviour under particular conditions. The analyses reveal the ways in which language meaningfully extends humans' behavioural possibilities, pushing them far beyond anything enabled by non-language behaviours. These novel metatheoretical concepts can complement and expand on existing theories about behaviour and language and contribute a novel piece of theoretical explanation regarding the crucial role that language has played in human evolution.

  

Uher, J. (2016a). Exploring the workings of the psyche: Metatheoretical and methodological foundation. In J. Valsiner, G. Marsico, N. Chaudhary, T. Sato, and V. Dazzani (Eds.). Psychology as the Science of Human Being: the Yokohama Manifesto. Annals of theoretical psychology, Vol 13 (pp. 299-324). Cham, Springer International. DOI: 10.1007/978-3-319-21094-0_18 

Introspection is considered a key method for exploring the workings of the psyche because psychical phenomena are accessible only by the individual him- or herself. But this epistemological concept, despite its importance, remained unclear and contentious. Its scientificity is often questioned, but still introspective findings from psychophysics are widely accepted as the ultimate proof of the quantifiability of psychical phenomena. Not everything going on in individuals' minds is considered introspection, but clear criteria that qualify explorations as introspective are still missing. This research applies the Transdisciplinary Philosophy-of-Science Paradigm for Research on Individuals (TPS-Paradigm) to metatheoretically define the peculiarities of psychical phenomena of which various kinds are differentiated and to derive therefrom basic methodological principles and criteria applicable to any investigation. Building on these foundations, the TPS-Paradigm introduces the concepts of introquestion versus extroquestion and reveals that introspection cannot be clearly differentiated from extrospection and that psychophysical experiments and some first-person perspective methods are not introspective as often assumed. The chapter explores the challenges that arise from the fact that psychical phenomena can be explored only indirectly through individuals' behavioural and semiotic externalisations and scrutinises what, when, where and how to externalise in introquestive explorations. The basic principles and criteria elaborated also allow for determining which kind of psychical phenomenon can be explored by using which kind of method for establishing an appropriate phenomenon-methodology match.

  

Uher, J., & Visalberghi, E. (2016). Observations versus assessments of personality: A five-method multi-species study reveals numerous biases in ratings and methodological limitations of standardised assessments. Journal of Research in Personality, 61, 61-79.  [Download]  [Supplemental Material]  DOI: 10.1016/j.jrp.2016.02.003  
Personality assessments and observations were contrasted by applying a philosophy-of-science paradigm and a study of 49 human raters and 150 capuchin monkeys. Twenty constructs were operationalised with 146 behavioural measurements in 17 situations to study capuchins' individual-specific behaviours and with assessments on trait-adjective and behaviour-descriptive verb items to study raters' pertinent mental representations. Analyses of reliability, cross-method coherence, taxonomic structures and demographic associations highlighted substantial biases in assessments. Deviations from observations are located in human impression formation, stereotypical biases and the findings that raters interpret standardised items differently and that assessments cannot generate scientific quantifications or capture behaviour. These issues have important implications for the interpretation of findings from assessments and provide an explanation for their frequent lack of replicability.

  

Uher, J. (2015a). Conceiving "personality": Psychologists’ challenges and basic fundamentals of the Transdisciplinary Philosophy-of-Science Paradigm for Research on Individuals. Integrative Psychological and Behavioral Science, 49, 398-458. [download]  DOI: 10.1007/s12124-014-9283-1
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.

 

Uher, J. (2015b). Developing "personality" taxonomies: Metatheoretical and methodological rationales underlying selection approaches, methods of data generation and reduction principles. Integrative Psychological and Behavioral Science, 49, 531-589. [download]  DOI: 10.1007/s12124-014-9280-4

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”.

 

Uher, J. (2015c). Interpreting "personality" taxonomies: Why previous models cannot capture individual-specific experiencing, behaviour, functioning and development. Major taxonomic tasks still lay ahead. Integrative Psychological and Behavioral Science, 49, 600-655. [download]  DOI: 10.1007/s12124-014-9281-3

As science seeks to make generalisations, a science of individual peculiarities encounters intricate challenges. This article explores these challenges by applying the Transdisciplinary Philosophy-of-Science Paradigm for Research on Individuals (TPS-Paradigm) and by exploring taxonomic “personality” research as an example. Analyses of researchers’ interpretations of the taxonomic “personality” models, constructs and data that have been generated in the field reveal widespread erroneous assumptions about the abilities of previous methodologies to appropriately represent individual-specificity in the targeted phenomena. These assumptions, rooted in everyday thinking, fail to consider that individual-specificity and others’ minds cannot be directly perceived, that abstract descriptions cannot serve as causal explanations, that between-individual structures cannot be isomorphic to within-individual structures, and that knowledge of compositional structures cannot explain the process structures of their functioning and development. These erroneous assumptions and serious methodological deficiencies in widely used standardised questionnaires have effectively prevented psychologists from establishing taxonomies that can comprehensively model individual-specificity in most of the kinds of phenomena explored as “personality”, especially in experiencing and behaviour and in individuals' functioning and development. Contrary to previous assumptions, it is not universal models but rather different kinds of taxonomic models that are required for each of the different kinds of phenomena, variations and structures that are commonly conceived of as “personality”. Consequently, to comprehensively explore individuals and individual-specificity, researchers have to apply a portfolio of complementary methodologies and develop different kinds of taxonomies, most of which have yet to be developed. Closing, the article derives some meta-desiderata for future research on individuals' “personality”.

 

Uher, J. (2015d). Agency enabled by the psyche: Explorations using the Transdisciplinary Philosophy-of-Science Paradigm for Research on Individuals. In C. W. Gruber, M. G. Clark, S. H. Klempe & J. Valsiner (Eds.). Constraints of Agency: Explorations of Theory in Everyday Life. Annals of theoretical psychology, Vol 12 (pp. 177-228). Cham, Springer International [download]  DOI: 10.1007/978-3-319-10130-9_13   
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.

 

Uher, J. (2015e). Comparing individuals within and across situations, groups and species: Metatheoretical and methodological foundations demonstrated in primate behaviour. In D. Emmans & A. Laihinen (Eds.). Comparative Neuropsychology and Brain Imaging (Vol. 2), Series Neuropsychology: An Interdisciplinary Approach (Chapter 14, pp. 223-284). Berlin: Lit Verlag. [download]  ISBN 978-3-643-90653-3  DOI: 10.13140/RG.2.1.3848.8169
Individuals are explored in various kinds of phenomena and contexts. But how can scientists compare individual variations across phenomena with heterogeneous properties that require different methods for their exploration? How can measurements of individual variations be made directly comparable between different studies, groups of individuals or even species? This research applies the Transdisciplinary Philosophy-of-Science Paradigm for Research on Individuals (TPS-Paradigm) to elaborate metatheoretical concepts and analytical methodologies for quantitative comparisons of individual variations within and across situations, groups and species using behavioural phenomena as examples. Established concepts from personality psychology, differential psychology and cross-cultural and cross-species research are systematically integrated into coherent frameworks and extended by adding concepts for comparing individual-specific variations (i.e., “personality”) between species. Basic principles for establishing the functional comparability of behavioural and situational categories are elaborated while considering that individuals from different groups and species often show different behaviours and encounter different situations and therefore cannot be studied with identical variables as is done in assessment-based research. Building on these principles, the chapter explores methodologies for the statistical analyses of the configurational comparability of constructs and of mean-level differences between groups and species. It highlights that situational properties are crucial for quantitative comparisons of individual variations. Fundamental differences between observational methods and assessment methods are explored, revealing serious limitations and fallacies inherent to comparisons of individuals on the basis of assessments. Implementations of the methodological principles and concepts presented are illustrated with behavioural data from four primate species (weeper capuchins, mandrills, toque macaques and rhesus macaques).

 

Uher, J. (2014). Fundamental challenges of contemporary "personality" research (Comment). Physics of Life Reviews, 11, 695-696. [download]  DOI: 10.1016/j.plrev.2014.10.005 
The growing interest in “personality” from scientists of ever more diverse fields demands conceptual integrations—and reveals fundamental challenges. For what is “personality” given that “it” is explored in humans and nonhuman species, that people encode “it” in their everyday language, scientists seek “it” in the brain and study “it” primarily with rating scales?

 

Uher, J. (2013). Personality psychology: Lexical approaches, assessment methods, and trait concepts reveal only half of the story. Why it is time for a paradigm shift. Integrative Psychological and Behavioral Science, 47, 1-55. [download]   DOI: 10.1007/s12124-013-9230-6 
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. 

 

Uher, J. (2011a). Individual behavioral phenotypes: An integrative meta-theoretical framework. Why 'behavioral syndromes' are not analogues of 'personality'. Developmental Psychobiology, 53, 521–548.  [download]  DOI: 10.1002/dev.20544
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. 

Uher, J. (2011b). Personality in nonhuman primates: What can we learn from human personality psychology? In A. Weiss, J. King, & L. Murray (Eds.). Personality and Temperament in Nonhuman Primates (pp. 41-76). New York, NY: Springer. [downloadDOI: 10.1007/978-1-4614-0176-6_3  

Primate personality research encounters a number of puzzling methodological challenges. Individuals are unique and comparable at the same time. They are characterized by relatively stable individual-specific behavioral patterns that often show only moderate consistency across situations. Personality is assumed to be temporally stable, yet equally incorporates long-term change and development. These are all déjà-vus from human personality psychology. In this chapter, I present classical theories of personality psychology and discuss their suitability for nonhuman species. Using examples from nonhuman primates, I explain basic theoretical concepts, methodological approaches, and methods of measurement of empirical personality research. I place special emphasis on theoretical concepts and methodologies for comparisons of personality variation among populations, such as among species. 

Uher, J. (2008a). Comparative personality research: Methodological approaches (Target article). European Journal of Personality, 22, 427-455. [download]  DOI: 10.1002/per.680
  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. 

Uher, J. (2008b). Three methodological core issues in comparative personality research. European Journal of Personality, 22, 475-496. [download]  DOI: 10.1002/per.688
  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 article 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. 

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