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Hofstee and Ten Berge (2004a) have proposed a new look at personality assessment data, based on a bipolar proportional (-1, .. . 0, .. . +1) scale, a corresponding coefficient of raw-scores likeness L = ΢XY/N, and raw-scores principal component analysis. In a normal sample, the approach resulted in a structure dominated by a first principal component, according to which most people are faintly to mildly socially desirable. We hypothesized that a more differentiated structure would arise in a clinical sample. We analyzed the scores of 775 psychiatric clients on the 132 items of the Dutch Personality Questionnaire (NPV). In comparison to a normative sample (N = 3140), the eigenvalue for the first principal component appeared to be 1.7 times as small, indicating that such clients have less personality (social desirability) in common. Still, the match between the structures in the two samples was excellent after oblique rotation of the loadings. We applied the abridged m-dimensional circumplex design, by which persons are typed by their two highest scores on the principal components, to the scores on the first four principal components. We identified five types: Indignant (1-), Resilient (1-2+), Nervous (1-2-), Obsessive-Compulsive (1-3-), and Introverted (1-4-), covering 40% of the psychiatric sample. Some 26% of the individuals had negligible scores on all type vectors. We discuss the potential and the limitations of our approach in a clinical context.

Trait structures resulting from personality assessments on Likert scales are affected by the additive and multiplicative transformations implied in interval scaling and correlational analysis. The effect comes into view on selecting a plausible alternative scale. To this end, we propose a bipolar bounded scale ranging from -1 to +1 representing an underlying process in which the assessor would review and discount positive and negative behavioral instances of a trait. As an appropriate index of likeness between variables X and Y we propose L-XY = SigmaXY/N, the average of the raw scores cross products. Using this index, we carried out a raw scores principal component analysis on data consisting of 133 participants who had each been rated by 5 assessors including self on 914 items. Contrary to the Big-Five structure that was found in these data on standard analysis, the results showed a relatively large first principal component F-1 and 2 very small ones, F-2 and F-3. The sizes L-FE = SigmaF(2)/N, the averages of the squared component scores, were modest to small. It thus appears that the scale, bipolar proportional versus standard, has a profound impact on the size and structure of personality assessments. The dissimilarity remains on analyzing self-ratings rather than averaged (over the 5 assessors) ratings.

Hofstee and Ten Berge (2004/this issue) present procedures based on an absolute conception of scales in personality assessment as distinct from the dominant interval-scale interpretation. On application, these procedures resulted in a contraction of a 5-dimensional structure into essentially I personality dimension. McGrath (2004/this issue) and Ozer (2004/this issue) comment on the various aspects of these procedures: the transformation of data onto a bipolar proportional scale, the adoption of the raw scores product average as an index of association, and raw scores principal component analysis. In reply to these comments, we emphasize that the central ingredient in our procedures is the interpretation of the midpoint on a bipolar scale as a threshold. We provide further arguments for that interpretation and demonstrate the robustness of the simplified structure under that central assumption. We acknowledge the comment that our conception does not fit in comparative contexts capitalizing on individual differences but argue that other contexts involving thresholds are relevant to the study of personality. We also acknowledge that item pools should be sufficiently homogeneous for scales to be meaningful.

Standard procedures for processing and interpreting data in personality assessment run the risk of losing their audience. Most notably, relative scaling of data, whether through interindividual or intra‐individual comparison, leads to losing either the persons or the variables from view. I set out an alternative, more congenial procedure for handling personality data, consisting of (i) translating assessments to a bipolar bounded scale running from − 1 to + 1, (ii) adopting the uncorrected average cross‐product (ACP) as the index of association or correspondence between variables and between individuals, and (iii) applying raw‐scores principal component analysis to find factors and types. The ACP index appears eminently fit for handling individual (N = 1) cases. Adoption of the congenial procedure would imply a substantive correction of one's views of individual differences in personality and their structure. Copyright © 2002 John Wiley & Sons, Ltd.

The standard practice in scoring questionnaires consists of adding item scores and standardizing these sums. We present a set of alternative procedures, consisting of (a) correcting for the acquiescence variance that disturbs the structure of the questionnaire; (b) establishing item weights through principal component analysis in order to obtain maximally reliable scale scores; (c) applying a procedure of hierarchically-nested circumplex construction to catch shades of meaning and thus facilitate interpretation; and (d) retaining absolute information by the use of anchored scores in addition to standard scores. In discussing circumplexical representations (c), we provide an illustration linking the three- and five-factorial conceptions of the personality trait domain.

In Northwest Europe there is high need for advanced weed control methods. The use of crop protection chemicals has become stricter, and integrated pest management is required by regulations from the European Union. This need has resulted in the development of several advanced weed control principles based on a combination of proven technologies in combination with decision systems. A major problem with full-field-based methods is that the required settings depend very much on the specific conditions. Use of decision systems helps to improve these methods. Emerging new technologies as machine vision and GPS enabled more precise methods focused on the interrow and intrarow zone and on the plant itself. Some of the methods have already achieved a high level of development and resulted in commercially available weed control equipment with sensors and actuators for precise control. This chapter discusses the advancements achieved in NW Europe on mechanical weed control (full field, interrow and intrarow), physical weed control (steaming and flaming) and chemical weed control (full field, spot and plant oriented).

In a comment on the special issue of the European Journal of Personality on Factor V from the Five‐Factor Model, I argue that attempts to arrive at a definitive interpretation are premature in view of the limitations of the item pools that have been used, arbitrariness in choosing criteria for item selection, and limitations of sample sizes. At present, the best tentative interpretation of V is Creativity/Imagination. However, the relation of this concept to the domain of measured intelligence should be reconsidered. The joint study of temperament (Factors I and IV), character (II and HI), and intelligence factors should provide insight into the fascinating blends that arise between these dimensions. Such blends are captured by the Abridged Big‐Five Dimensional Circumplex approach to personality structure in a parsimonious manner.

The averaged judgment of knowledgeable others provides the best available point of reference both for the definition of personality structure in general and for assessing someone's personality in particular. Self‐judgments, as in personality questionnaires, are intrinsically deficient because judgment errors cannot be averaged out. The recommended procedure for assessing someone's personality is to give a personality questionnaire, phrased in the third person singular, to those who know the target best. This set may or may not include the target person as a judge.

The goal of this article is 2-fold. Firstly to show the utility of the circumplex principles in articulating trait structures, and secondly to show that the use of different word categories as trait descriptors can be exploited for the further refinement of the established Five Factor structure. We discuss simple structure and circumplex models and their integration, the so-called AB5C model. The AB5C model is applied to self-ratings (N = 200) on 551 personality adjectives and 507 personality verbs. The differences between the two data sets, adjective and verb data, are discussed, and the usefulness of both data sets for the mutual articulation of the respective wordclass specific trait structures is demonstrated.

In this article we pursue two goals. The first is a further articulation of the dimensionality of the Dutch trait domain. The second is a detailed mapping of the factorial trait structure, one which includes intelligible and proper niches for various nuances of the trait language and for different interpretations of the main factors of personality language. In realizing these goals, we discuss the reliance on theory in structuring and modelling the domain in question, the type of model to be used, and the comprehensiveness versus the economy of domain representation. The advantages and disadvantages of the simple structure model and the circumplex model are commented upon, and a new framework that integrates these two models is presented. The present results provide confirmation of the existence of five major dimensions that cover the trait domain: (I) Extraversion or Surgency, (II) Agreeableness, (III) Conscientiousness, (IV) Emotional Stability, and (V) Intellect or Openness to Experience. The newly developed representational model, revealing a refined structure of personality characteristics, not only clarifies some of the problems faced in interpreting the Big Five factors, but also forms a starting point for applications.

The major question of the article is whether the natural language of personality provides an adequate point of departure for the construction of a scientific system of personological categories. Five obstacles to this endeavour are: (1) the domain is dificult to delineate, both with respect to its categories and in the choosing of items within categories; (2) the extent to which terms can be translated from one language to another appears to be limited; (3) the overwhelming role of evaluative aspects is embarrassing from a scientific point of view; (4) instead of obeying simple and clear taxonomic principles, the domain appears to be unruly in this respect; and (5) many terms and expressions are paradoxical when used in the first person. Tentative and partial solutions to these problems are proposed.

Over the past decades, the concept of personality has been subject to implicit redefinition through a set of operations labeled “Big-Five Taxonomy” or “Five-Factor Model” of personality. A first module of the set of operations that constitute this paradigm consists of the questionnaire construction of personality, whereby someone's personality is defined through answers to standardized questions. A second, more specific, operational module contains the lexical approach that consists of selecting items from a corpus of language, particularly a dictionary of that language. A third operational characteristic consists of reliance on the linear model, particularly principal component analysis of Likert item scales. This is probably the most constitutive operation of the paradigm. A fourth set of operations contains models for structuring, interpreting, and communicating trait information. The major rivals are the hierarchical and the circumplex models of personality structure. I judge structure models by their capacity to produce clear and communicable trait concepts. I conclude with sketching a family of models that may serve as a base for capturing personality structure. It consists of a hierarchy of generalized semicircumplexes, with one general p-component of personality at the top and including 2-D circumplex, giant three, 5-D, and other-dimensional structures. Keywords: circumplex models; lexical approach; personality questionnaires; personality structure; personality traits; p-factor of personality; principal component analysis

The present research investigated how individual differences in Extraversion and Agreeableness affect cooperation in an experimental resource dilemma. Manipulated feedback indicated either that the common resource was being used at a sustainable rate or that it was being rapidly depleted. As predicted, Extraversion was generally negatively related to cooperation, whereas Agreeableness was generally positively related to cooperation. Whereas individuals high in Extraversion and individuals low in Agreeableness were unresponsive to feedback regarding collective resource use, individuals low in Extraversion and individuals high in Agreeableness exercised more self-restraint when the common resource was severely threatened. Exploratory analyses revealed neither interactive effects of Extraversion and Agreeableness nor effects of individual differences in Conscientiousness, Emotional Stability, and Intellect. Together, these results highlight the importance of individual differences in Extraversion and Agreeableness in social dilemma settings.

The Five-Factor Personality Inventory (FFPI) assesses the Big Five factors of personality, both for self-ratings and for others' ratings. It consists of 100 brief and concrete statements, and can be administered in 10-15 min. in addition to the five factor scores, the FFPI may be used to assess 40 bipolar facet scores that arise as blends of the Big Five, for the purpose of communicating more specific information about an individual's position in the five-space (applied settings). In the normal population, the five factor scores appear to be internally consistent, stable and valid. As regards specific (e.g. clinical) populations, still further study is needed. The item pool for the FFPI was constructed interactively in Dutch, English and German versions, and proved to be relatively easy to translate into Still other languages. Presently also available are the Brazilian, Chinese, Croatian, Hebrew, Hungarian, Italian, Japanese. Polish, Slovak, Spanish and Swedish versions. (C) 1999 Elsevier Science Ltd. All rights reserved.

Standardized scores including factor scores are insufficient indicators of individuals' positions on personality traits when mean scores deviate considerably from the scale origin. Anchored scores, that is, raw scores expressed as deviations from the scale midpoint and divided by the standard deviation, retain this discrepancy. We argue in favour of reporting in terms of anchored scores in addition to standard scores, and present a solution to the specific problem of finding anchored factor (i.e., principal-component) scores. Such scores are obtained through dividing factor weights by the standard deviation of the variable in question, and applying the corrected weights to the matrix of raw scores, expressed as deviations from the scale midpoint (e.g. -2, -1, 0, +1, +2). (C) 1998 John Wiley & Sons, Ltd.

In the present context, disciplines like biology and subdisciplines like social psychology are auxiliary sciences. The psychology of personality has outgrown the stage in which traits were a dependent variable to be explained as an artifact of social perception, or to be reduced to biological differences. Upon considering personality as a topic in its own right, instead of an epiphenomenon, the question is what other disciplines can contribute to the study of personality. With respect to evolutionism, I shall defend the position that its contribution can be modest at best. In the process, I shall clarify the conception of personality psychology that underlies my argument.

This chapter is about the conceptual relation between personality and temperament. I propose to define the psychology of personality as the study of traits. I argue against both social and biological conceptions of personality in the context of the psychological subdiscipline of personality. In attempting a restoration of the orthodox personological approach, I enlist the aid of temperamentalists on the one hand, but go against tendencies to explain temperament in biological terms on the other.

In two small-scale investigations, chiasmic configurations of personality traits (e.g., Thrifty/Generous/Stingy/Extravagant) derived from the Peabody and Goldberg (1989) Double-Cone model were compared with chasms derived from the Abridged Big-Five dimensional Circumplex (AB5C) model. To this end, chiasms were decomposed into three kinds of contrasts between traits: content contrast, social desirability contrast, and oppositeness. Inventories of 24 and 90 items, respectively, comparing a Double-Cone contrast and an AB5C-contrast were administered to 12 and 35 subjects, respectively. In both studies, the AB5C chiasms prevailed. As the AB5C model does not generate true chiasms but illusions thereof, we argue that the perception of chiasmic structure is best understood as an illusory phenomenon.

A betting model of empirical research is described. The model requires that opposing parties reach agreement on an operationalization and specify their predictions in terms of a probability distribution over possible research outcomes. Proper decision rules are used to decide on the amounts of reputation that are gained and lost upon observing the data. It is argued that adoption of the model would lead to less trivial research, less selective publication, and a more liberal attitude towards experimental design. The betting model is contrasted with several other methodologies. In these comparisons, methodological models are viewed as policies, i.e., sets of rules which lead to certain predictable consequences if rational individuals exploit these rules to their own advantage. All comparisons reveal that the other models have relatively undesirable properties from this point of view. In discussing criticisms of the betting model, it appears that the model is also not completely water-proof from a policy point of view when participants do not wish to maximize their subjectively expected reputation. Other criticisms are discussed and are found wanting. Bets enter quite naturally into scientific discussions. Some years ago, an American colleague and I were discussing handwriting analysis. We were in general agreement that the usefulness of handwritings for making predictions about persons is very limited at best. As a devil’s advocate, however, I asserted that I could “predict” a person’s nationality from his or her handwriting. My colleague, who probably suspected me of entertaining ideas about national character, disagreed strongly with my assertion, and we decided to bet upon it. Those who have corresponded in handwriting with foreigners will not be surprised that I won this bet.

This article describes the derivation of a taxonomy of personality‐descriptive verbs. In the introduction the verb domain is delineated relative to other domains of the language of personality. It is argued that verbs are theoretically useful in bridging the gap between trait language and act language. The aim is to provide a representative and effective instrument for registering judgements on personality. In a first study the steps are described that were followed to arrive at a list of personality‐descriptive verbs. Both the present authors and layjudges (n=22) took part in this. Five hundred and forty‐three verbs resulted from this study. Study 2 (n=200) describes the determination of the internal structure of the domain of verbs through factor analysis of both self‐ and partner‐ratings. By applying a method of rotation to perfectly congruent weights the verb‐structure turned out to be invariant under the self‐ and partner‐conditions. The last part of the study investigates the relationship between personality‐descriptive verbs and adjectives. Regressions of verb‐ratings on the adjective‐ratings and of adjective‐ratings on the verb‐ratings were calculated and factor analyses were performed on the residual matrices. The results show the existence of additional verb‐dimensions above those already established in the adjective domain.

We compare Big-Five factor structures found in Dutch, American English, and German, and present a joint structure. The data consist of self- and peer ratings of 600 subjects with 551 Dutch trait-descriptive adjectives, 636 subjects with 540 English adjectives, and 802 subjects with 430 German adjectives. On the basis of 126 common items, we assess the congruences between the factors as originally published, as resulting from target rotations, and from simultaneous rotations. With the exception of the Dutch Factor V, the Big-Five factors recur across languages in a relative but not in a strict sense. Moreover, at a more detailed level differences in the positions of the axes are uncovered. By applying a split-sample technique to the three data sets, we verify that these differences do not arise through unreliability. Also, few trait terms appear to have the same precise meaning across these three languages; such labels therefore cannot serve as anchor concepts for an international language of personality. (C) 1997 by John Wiley & Sons, Ltd.