Individual Differences (individual + difference)

Distribution by Scientific Domains
Distribution within Psychology

Kinds of Individual Differences

  • stable individual difference

  • Terms modified by Individual Differences

  • individual difference measure
  • individual difference perspective
  • individual difference variable

  • Selected Abstracts


    Article first published online: 12 AUG 200
    No abstract is available for this article. [source]

    Personality types as derived from parental reports on 3-year-old

    Maja Zupan
    Abstract Three internally replicable clusters of personality were empirically derived in a sample of 3-year-old children who were assessed by mothers and fathers using the Inventory of Child Individual Differences (Halverson et al., 2003). The clusters were structurally consistent across the parental data sources and did not, except for resilients, fully overlap with the under- and overcontrolled types. The average children scored within less than half of a standard deviation from the mean across the ICID dimensions, while the wilful 3-year-old appeared extraverted and disagreeable. Child type membership was moderately consistent across the spouses and it predicted teacher-reported child social behaviour. Compared to the dimensions, the predictive utility of the types was lower, but considerably improved with consistently classified children. Copyright © 2006 John Wiley & Sons, Ltd. [source]

    Measuring Individual Differences in Content via Changing Person,Context Interaction


    Individual Differences in the Contribution of Maternal Soothing to Infant Distress Reduction

    INFANCY, Issue 3 2007
    Laudan B. Jahromi
    This study investigates individual differences in the contribution of specific maternal regulatory behaviors to the mother-infant dyad's regulation of infant distress response. Additionally, we examined the stability of infants' stress responses and the stability of specific maternal soothing behaviors. The sample included 128 mother-infant dyads that were observed during an inoculation at 2 and 6 months. The average intensity of infant cry response showed modest stability across age only before controlling for the infant's general state of irritability, and the duration of crying was not stable. Of the 8 specific maternal regulatory behaviors studied, affection, touching, and vocalizing showed the strongest stability across infant age. Finally, an index of the contingency between maternal soothing and infant cry reduction at 2 months predicted shorter cry duration but not cry intensity at 6 months. The results of this study indicate that infants whose mothers showed a greater contribution to reducing their distress at 2 months showed a shorter duration of crying 4 months later. This suggests a possible longitudinal influence of maternal regulation on infants' distress responses. [source]

    Predicting Individual Differences in Recall by Infants Born Preterm and Full Term

    INFANCY, Issue 1 2006
    Carol L. Cheatham
    A heterogeneous sample of infants with preterm histories and infants born full term participated in a study of declarative memory and rate of encoding, as measured in an imitation task and an examining task, respectively. Here we report the comparisons of the performances of infants born very preterm (27,34 weeks gestation) and moderately preterm (35,37 weeks gestation) to infants born full term (38,41 weeks gestation) and tested at 12 months corrected age (from due date). Lower levels of recall were seen among the infants born very preterm. Rate of encoding, weeks gestation, and score on the Mental Development Index (MDI) of the Bayley Scales of Infant Development were tested as possible sources of individual differences in recall. Rate of encoding and MDI predicted delayed ordered recall. Implications for early detection of cognitive difficulties in children with preterm histories are discussed. [source]

    Individual Differences in Infants' Recognition of Briefly Presented Visual Stimuli

    INFANCY, Issue 3 2001
    Janet E. Frick
    Infants' recognition memory has been shown to be related to individual differences in look duration and level of heart period variability. This study examined the effect of individual differences in these 2 measures on infants' recognition of briefly presented visual stimuli using a paired-comparison recognition-memory paradigm. A sample of 35 full-term infants was studied longitudinally at 14, 20, and 26 weeks of age. Recognition memory for briefly presented stimuli was tested in 6 experimental conditions, with delays corresponding to different heart-rate-defined phases of attention. The 20-and 26-week-old infants, and infants with high levels of heart period variability, generally showed more evidence of recognition memory for briefly presented visual stimuli. Greater evidence of recognition memory was observed when stimuli were presented during sustained attention. Infants with more mature baseline physiological responses show greater evidence of recognition memory, and stimulus and procedural factors may be more important for the study of individual differences in infant visual attention than has previously been suggested. [source]

    The Relation between Individual Differences and Accountants' Fraud Detection Ability

    Firhana M. Fathil
    This report examines the potential application of the deception detection literature to auditing research. A pilot study focusing on auditor quality perceptions post Enron is used to explore the potential relevance of deception detection research theory and techniques. The pilot study findings highlight some potential areas for researchers to focus on in terms of construct, internal, external and statistical validity. [source]

    The Influence of Gender, Ethnicity, and Individual Differences on Perceptions of Career Progression in Public Accounting

    D. Jordan Lowe
    Prior research examining gender and diversity issues has generally lacked supporting theory and experimental investigation. This study provides theory-based experimental evidence regarding the effects of gender, ethnicity, and other individual differences on performance evaluations of audit seniors. We utilized organizational socialization theory in examining the accounting profession's view of diversity issues. The process model of performance evaluation provided guidance in the selection of ratee, rater, and contextual characteristics as factors to analyze. An experiment was conducted with 95 audit seniors from one of the Big 5 public accounting firms. Results indicate that gender and ethnic heritage are important factors in the career prospects of audit seniors. The demeanor of an auditor was also important as an interactive factor and influences judgments differently depending on the gender or ethnic origin of the auditor evaluated. These results suggest that diversity is a very complex issue. Examining single factors without considering the interactions of a variety of factors may lead to incorrect conclusions. [source]

    Self-Regulation in Goal Striving: Individual Differences and Situational Moderators of the Goal-Framing/Performance Link,

    Christopher J. R. Roney
    We propose that negative goal framing (i.e., defining a goal as a negative state to be avoided) can adversely affect performance. Study 1 (N = 133) revealed that negative goal framing predicted poorer future performance independent of goal level, expectancy, and earlier performance. Study 2 (N = 188) examined the relation between goal framing and performance at 2 times in the academic year, and with respect to individual differences in defensive pessimism. As predicted, the negative goal-framing/poorer-performance link was greater on a later exam (after receiving feedback) than an earlier one, and was greater for nondefensive pessimists than for defensive pessimists. The findings implicate self-regulatory processes in understanding how goal framing affects performance. [source]

    Individual Differences in Attitudes Relevant to Juror Decision Making: Development and Validation of the Pretrial Juror Attitude Questionnaire (PJAQ),

    Len Lecci
    This study involves scale development using theoretically derived items from previous measures and a lay consensual approach for generating new items. Confirmatory factor analysis was used to validate the emergent constructs assessing individual differences in attitudes of prospective jurors. Using case summaries, the Pretrial Juror Attitude Questionnaire (PJAQ) demonstrates superior predictive validity over commonly employed measures of pretrial bias. The PJAQ confirms the importance of theoretically derived constructs assessed by other scales and introduces new constructs to the jury decision-making literature. The attitudes assessed by the PJAQ are conviction proneness, system confidence, cynicism toward the defense, racial bias, social justice, and innate criminality. Implications for assessing such attitudes and for better understanding the decision-making process of jurors are discussed. [source]

    Individual Differences in Approach and Avoidance Movements: How the Avoidance Motive Influences Response Force

    Rosa Maria Puca
    ABSTRACT The present research is based on the assumption that people differ in their responsiveness to incentives and threats. In two experiments we examined whether the trait corresponding to the responsiveness to threats (avoidance motive) and the trait corresponding to the responsiveness to incentives (approach motive) influence voluntary motor behavior toward or away from stimuli. In Experiment 1, stimuli consisted of positive and negative words within a lexical decision task. Participants moved their arms backward in order to withdraw from the stimuli or forward in order to approach them. In Experiment 2, participants responded with forward or backward arm movements to neutral sounds coming from behind or in front of them. The main dependent variable was the strength of the approach and avoidance movements. In both experiments this variable was related to participants' avoidance-motive disposition but not to their approach-motive disposition. Avoidance-motivated individuals generally showed more forceful avoidance movements than approach movements. There was no effect of stimulus valence on the strength of the movements in Experiment 1. Furthermore, the results of Experiment 2 suggest that it is not the physical direction (forward or backward) but rather the movement's effect of distance reduction (approach) or distance increase (avoidance) in regard to the stimulus that defines a movement as an approach or an avoidance movement. [source]

    Self-Monitoring: Individual Differences in Orientations to the Social World

    Christopher Leone
    ABSTRACT In their articles in this special section of the Journal of Personality, the authors have focused their attention on the role of individual differences in self-monitoring for a variety of interpersonal phenomena. In so doing, the authors have provided an overview of the theoretical and empirical contributions of the psychology of self-monitoring to the domains of interest: close relationships, consumer behavior, behavior in the workplace, and social interaction. As each of the contributing authors to this special section suggests, much more theoretical and empirical work is in order if the impact of individual differences in self-monitoring for the phenomena reviewed here is to be fully appreciated. Moreover, the four domains of interest represented in this special section by no means exhaust the areas to which theorists and researchers have applied or can apply the psychology of individual differences in self-monitoring. Given the large nomological network that currently exists involving the self-monitoring construct, it is anticipated that the breadth and depth of applications of the psychology of self-monitoring will only continue to expand as it has in the last 30 years since the appearance of the construct in the literature. [source]

    Functional Brain Mapping of Extraversion and Neuroticism: Learning From Individual Differences in Emotion Processing

    Turhan Canli
    Studies using functional magnetic resonance imaging have shown that individual differences in participants' E and N scores are correlated with individual differences in brain activation in specific brain regions that are engaged during cognitive-affective tasks. Imaging studies using genotyped participants have begun to address the molecular mechanisms that may underlie these individual differences. The multidisciplinary integration of brain imaging and molecular genetic methods offers an exciting and novel approach for investigators who seek to uncover the biological mechanisms by which personality and health are interrelated. [source]

    The Need for Affect: Individual Differences in the Motivation to Approach or Avoid Emotions

    Gregory R. Maio
    The present research developed and tested a new individual-difference measure of the need for affect, which is the motivation to approach or avoid emotion-inducing situations. The first phase of the research developed the need for affect scale. The second phase revealed that the need for affect is related to a number of individual differences in cognitive processes (e.g., need for cognition, need for closure), emotional processes (e.g., affect intensity, repression-sensitization), behavioral inhibition and activation (e.g., sensation seeking), and aspects of personality (Big Five dimensions) in the expected directions, while not being redundant with them. The third phase of the research indicated that, compared to people low in the need for affect, people high in the need for affect are more likely to (a) possess extreme attitudes across a variety of issues, (b) choose to view emotional movies, and (c) become involved in an emotion-inducing event (the death of Princess Diana). Overall, the results indicate that the need for affect is an important construct in understanding emotion-related processes. [source]

    Subjective Overachievement: Individual Differences in Self-Doubt and Concern With Performance

    Kathryn C. Oleson
    We discuss the construct of doubt about one's competence and suggest that doubt can have myriad consequences (e.g., self-handicapping, defensive pessimism). We focus on the effect of self-doubt when it is combined with a concern with performance and assert that this combination leads to the phenomenon of subjective overachievement. In two studies, we present a new 17-item Subjective Overachievement Scale (SOS), which includes two independent subscales measuring individual differences in self-doubt and concern with performance. The first study, consisting of two large samples (Ns = 2,311 and 1,703), provides evidence that the scale has high internal consistency and a clear two-factor structure. Additionally, the subscales have adequate test-retest reliability (Ns = 67 and 115). A second study reveals that the SOS has good convergent and discriminant validity. Both subscales are unrelated to social desirability but exhibit the predicted patterns of associations with other related constructs. The Concern with Performance Subscale is correlated with achievement motivation, whereas the Self-Doubt Subscale is correlated with scales assessing negative affectivity (e.g., self-esteem, social anxiety) and other self-related strategies associated with concerns about one's competence (e.g., self-handicapping, defensive pessimism, impostor phenomenon). The SOS, which combines the two subscales, appears to tap a unique strategy that individuals may use to deal with doubts about their own competence. [source]

    Individual Differences in Alcohol Drinking Frequency Are Associated With Electrophysiological Responses to Unexpected Nonrewards

    ALCOHOLISM, Issue 4 2010
    Ingmar H. A. Franken
    Background:, It has been suggested that alcohol use is related to sensitivity of the reward system. Although there are several studies using self-reported measures supportive of this notion, objective biological data in humans on this issue are lacking. Aims:, This study is designed to test whether alcohol drinking frequency is associated with electrophysiological indices of reward processing. Materials and Methods:, In a passive gambling task, stimuli predicted the presence (reward) and absence (nonreward) of rewards resulting in P2 and medial frontal negativity (MFN) indices of reward processing. Forty-seven undergraduate students were asked about their habitual drinking frequency and the P2 and MFN to stimuli predicting reward were measured. Results:, Most importantly, the MFN to unpredicted nonrewards at the frontal midline (Fz) location correlated significantly with drinking frequency, with frequent drinkers showing larger MFN amplitudes. The results did not show a significant association between frequency and alcohol drinking and P2. Discussion:, Although several studies showing increased reward-sensitivity in addictive behaviors, the present results indicate that, in frequent alcohol drinkers, electrophysiological responsiveness is particularly activated by unpredicted nonrewards. In general, this may point to the involvement of the reward system in alcohol drinking frequency. Conclusion:, More specifically, the results demonstrate an increased vulnerability of high frequency drinkers to signals of (frustrative) nonrewards. [source]

    Induction and Maintenance of Ethanol Self-Administration in Cynomolgus Monkeys (Macaca fascicularis): Long-Term Characterization of Sex and Individual Differences

    ALCOHOLISM, Issue 8 2001
    J. A. Vivian
    Background: Investigations of oral ethanol self-administration in nonhuman primates have revealed important parallels with human alcohol use and abuse, yet many fundamental questions concerning the individual risk to, and the biological basis of, excessive ethanol consumption remain unanswered. Moreover, many conditions of access to ethanol in nonhuman primate research are largely unexplored. This set of experiments extends within- and across-session exposure to ethanol to more fully characterize individual differences in oral ethanol self-administration. Methods: Eight male and eight female adult cynomolgus monkeys (Macaca fascicularis) were exposed to daily oral ethanol self-administration sessions for approximately 9 months. During the first 3 months, a fixed-time (FT) schedule of food delivery was used to induce the consumption of an allotted dose of ethanol in 16-hr sessions. Subsequently, the FT schedule was suspended, and ethanol was available ad libitum for 6 months in 16- or 22-hr sessions. Results: Cynomolgus monkeys varied greatly in their propensity to self-administer ethanol, with sex and individual differences apparent within 10 days of ethanol exposure. Over the last 3 months of ethanol access, individual average ethanol intakes ranged from 0.6 to 4.0 g/kg/day, resulting in blood ethanol concentrations from 5 to 235 mg/dl. Males drank approximately 1.5-fold more than females. In addition, heavy-, moderate-, and light-drinking phenotypes were identified by using daily ethanol intake and the percentage of daily calories obtained from ethanol as criteria. Conclusions: Cynomolgus monkeys displayed a wide intersubject range of oral ethanol self-administration with a procedure that used a uniform and prolonged induction that restricted early exposure to ethanol and subsequently allowed unlimited access to ethanol. There were sex and stable individual differences in the propensity of monkeys to consume ethanol, indicating that this species will be important in characterizing risk factors associated with heavy-drinking phenotypes. [source]

    Individual Differences in Responses to Ethanol and d-Amphetamine: A Within-Subject Study

    ALCOHOLISM, Issue 4 2001
    Louis Holdstock
    Background: In some individuals, ethanol (EtOH) produces marked stimulant-like subjective effects resembling those of stimulant drugs, like d-amphetamine (AMP). In this study, we examined the neurochemical basis of these individual differences by examining the same subjects' responses to both EtOH and AMP. A positive correlation between subjects' responses to the two drugs may suggest that AMP and EtOH produce their stimulant-like subjective effects by a shared mechanism. Methods: Twenty-seven volunteers (17 male, 10 female), aged 21,35, received beverages or capsules containing EtOH 0.8 g/kg, AMP 10 or 20 mg, or placebo on four separate sessions in random order and under double-blind conditions. Various self-reported and objective drug effects were measured, including measures sensitive to subjective and cognitive stimulant-like effects. Results: EtOH and AMP produced their prototypical subjective and behavioral effects, including increased ratings of stimulant-like subjective effects, increased heart rate and blood pressure, and improved vigilance performance after AMP and increased ratings of sedative-like subjective effects, increased heart rate and blood pressure, and impaired vigilance performance after EtOH. Consistent with previous reports, there was substantial intersubject variability in subjective responses to EtOH: some subjects reported primarily stimulant-like effects, whereas others reported primarily sedative-like effects. To examine the relationship between these responses to EtOH and subjects' responses to AMP, correlations were examined between effects of EtOH and AMP. For all subjects together, there was a significant positive correlation between responses to EtOH and 20 mg AMP on the ARCI A scale (a measure of stimulant-like subjective effects;r= 0.41, p < 0.05). Among only those subjects who reported primarily stimulant-like effects from EtOH, the correlation between EtOH and AMP was 0.64 (p < 0.05). Conclusions: Subjects who experience pronounced stimulant-like effects from EtOH also report greater stimulant effects from AMP, suggesting that these effects may be mediated through similar mechanisms. These correlations between the drugs' effects were not observed on other measures, such as DSST or vigilance task performance or heart rate. This may indicate that these other effects are mediated by separate mechanisms. The study illustrates a novel approach to studying the neurochemical basis of drug effects. [source]

    Chivalry and the Moderating Effect of Ambivalent Sexism: Individual Differences in Crime Seriousness Judgments

    LAW & SOCIETY REVIEW, Issue 1 2008
    Sergio Herzog
    Previous studies have shown that female offenders frequently receive more lenient judgments than equivalent males. Chivalry theories argue that such leniency is the result of paternalistic, benevolent attitudes toward women, in particular toward those who fulfill stereotypical female roles. Yet to date, studies have not examined whether such leniency is indeed associated with paternalistic societal attitudes toward women. The present study goes beyond the investigation of demographics and employs Glick and Fiske's (1996) concepts of hostile and benevolent sexism. We use these concepts to highlight the role of individual differences in attitudes toward women as a key to our understanding of lenient attitudes toward female offenders. Eight hundred forty respondents from a national sample of Israeli residents evaluated the seriousness of hypothetical crime scenarios with (traditional and nontraditional) female and male offenders. As hypothesized, hostile and benevolent sexism moderate the effect of women's "traditionality" on respondents' crime seriousness judgments and on the severity of sentences assigned. [source]

    Intuitions and Individual Differences: The Knobe Effect Revisited

    MIND & LANGUAGE, Issue 4 2007
    This paper argues that part of the explanation for this effect is that there are stable individual differences in how ,intentional' is interpreted. That is, in Knobe's cases, different people interpret the term in different ways. This interpretive diversity of ,intentional' opens up a new avenue to help explain Knobe's results. Furthermore, the paper argues that the use of intuitions in philosophy is complicated by fact that there are robust individual differences in intuitions about matters of philosophical concern. [source]

    Individual Differences in EWA Learning with Partial Payoff Information

    THE ECONOMIC JOURNAL, Issue 525 2008
    Teck H. Ho
    We extend experience-weighted attraction (EWA) learning to games in which only the set of possible foregone payoffs from unchosen strategies are known, and estimate parameters separately for each player to study heterogeneity. We assume players estimate unknown foregone payoffs from a strategy, by substituting the last payoff actually received from that strategy, by clairvoyantly guessing the actual foregone payoff, or by averaging the set of possible foregone payoffs conditional on the actual outcomes. All three assumptions improve predictive accuracy of EWA. Individual parameter estimates suggest that players cluster into two separate subgroups (which differ from traditional reinforcement and belief learning). [source]

    Individual Differences in Public Opinion about Youth Crime and Justice in Swansea

    Gender and age differences in estimations of youth crime were compared to official and self-reported youth offending statistics nationally and locally. Attitudes to sentencing and preventative measures were evaluated with reference to Swansea's positive, inclusionary approach to young people. Findings indicate that the Swansea public overestimates the extent of youth crime locally, yet it remains ambivalent about appropriate sentencing responses, favouring both punitive and preventative measures. This suggests that local public opinion is shaped by national media and political rhetoric, rather than the local realities of youth offending. [source]

    Workplace Sexual Harassment Perceptions in the Turkish Context and the Role of Individual Differences

    APPLIED PSYCHOLOGY, Issue 4 2010
    Yonca Toker
    The major purpose of this study was to examine perceptions of workplace sexual harassment in the Turkish context. In Study 1, 53 working women were interviewed to identify culture-relevant behaviors that are considered to be sexual harassment. In Study 2, the factor structure of perceptions was explored. In addition, the way in which these perceptions are related to personal variables (i.e. gender role attitudes, self-esteem, and negative affectivity) was investigated. Participants were 353 women currently employed at various organisations. Five factors were identified: sexist hostility, insinuation of interest, sexual hostility, physical sexual offense, and sexual bribery and coercion. Each factor was regressed on the personal variables. After controlling for relevant demographic and organisational variables, gender role attitudes, self-esteem, and negative affectivity predicted sexual harassment perceptions. Specifically, negative affectivity predicted milder forms of harassment, attitudes predicted factors that are considered more severe, and self-esteem predicted all factors but sexist hostility. The extent to which sexual harassment manifestations are universal and how certain manifestations that appeared in the Turkish context broaden the scope of sexual harassment are discussed by referring to the US literature. L'objectif central de cette recherche était l'étude de la perception du harcèlement sexuel au travail en Turquie. Dans une première phase, on a interviewé 53 salariées pour déterminer les comportements relevant du harcèlement sexuel dans ce contexte culturel. Dans une deuxième phase, on a recherché la structure factorielle des perceptions. On a aussi étudié les liens de ces perceptions avec des variables personnelles (Attitudes en rapport avec le rôle découlant du genre, estime de soi et affectivité négative). Les sujets étaient 353 femmes employées dans diverses organisations. Cinq facteurs sont apparus : hostilité sexiste, attirance sous-entendue, hostilité sexuelle, agression sexuelle physique, coercition et corruption sexuelles. Chaque facteur a subi une analyse de régression sur les variables personnelles. En contrôlant de façon appropriée les variables démographiques et organisationnelles, les attitudes en rapport avec le rôle découlant du genre, l'estime de soi et l'affectivité négative prédisent la perception du harcèlement sexuel. En particulier, l'affectivité négative prédit les formes légères de harcèlement, les attitudes prédisent les facteurs considérés comme plus graves et l'estime de soi prédit tous les facteurs sauf l'hostilité sexiste. On discute à partir de la littérature américaine de l'universalité du harcèlement sexuel et du fait que certaines manifestations propres à la Turquie élargissent le champ de ce harcèlement. [source]

    Leadership, Individual Differences, and Work-related Attitudes: A Cross-Culture Investigation

    APPLIED PSYCHOLOGY, Issue 2 2007
    Fred O. Walumbwa
    This study builds on previous exploratory research (Walumbwa & Lawler, 2003) that examined allocentrism as a moderator of transformational leadership,work-related attitudes and behaviors. Based on survey data collected from 825 employees from China (n= 213), India (n= 210), Kenya (n= 159), and the US (n= 243), we found that individual differences moderated the relationships between leadership and followers' work-related attitudes. Specifically, allocentrics reacted more positively when they viewed their managers as being more transformational. Idiocentrics reacted more positively when they rated their managers as displaying more transactional contingent reward leadership. The pattern of results was stronger for transformational leadership in more collectivistic cultures among allocentrics and stronger among idiocentrics in individualistic cultures for transactional contingent reward leadership. Implications of these findings for practice and research are discussed. Cette recherche se situe dans le prolongement de travaux exploratoires antérieurs (Walumbwa & Lawler, 2003) qui ont étudié l'allocentrisme comme régulateur de la relation entre le leadership transformationnel et les conduites et attitudes relevant du travail. Nous avons constaté, à partir de données d'enquête recueillies auprès de 825 salariés chinois (n= 213), indiens (n= 210) kényens (n= 159) et américains (n= 243), que les différences individuelles régulaient les relations entre le leader et les attitudes des suiveurs liées au travail. Plus particulièrement, les allocentriques réagissaient plus positivement quand ils percevaient leurs managers comme étant plutôt transformationnel. Les égocentriques réagissaient plus positivement quand ils trouvaient que leurs managers présentaient plutôt un leadership transactionnel offrant des récompenses appropriées. La configuration des résultats parle en faveur du leadership transformationnel pour les allocentriques dans les cultures à tendance communautaire et en faveur du leadership transactionnel pour les égocentriques dans les cultures individualistes. On réfléchit aux implications de ces résultats pour la recherche et la pratique. [source]

    Developmental Change and Individual Differences in Children's Multiplication

    CHILD DEVELOPMENT, Issue 4 2003
    Donald J. Mabbott
    Age-related change and patterns of individual differences in children's knowledge and skill in multiplication were investigated for students in Grades 4 and 6 (approximately ages 9 and 11, respectively) by examining multiple measures of computational skill, conceptual knowledge, and working memory. Regression analyses revealed that indexes reflecting probability of retrieval and special problem characteristics overshadow other, more general indexes (problem size and frequency of presentation) in predicting solution latencies. Some improvement in the use of conceptual knowledge was evident between Grades 4 and 6, but this change was neither strong nor uniform across tasks. Finally, patterns of individual differences across tasks differed as a function of grade level. The findings have implications for understanding developmental change and individual differences in mathematical cognition. [source]

    Family Risk of Dyslexia Is Continuous: Individual Differences in the Precursors of Reading Skill

    CHILD DEVELOPMENT, Issue 2 2003
    Margaret J. Snowling
    The development of 56 children at family risk of dyslexia was followed from the age of 3 years, 9 months to 8 years. In the high-risk group, 66% had reading disabilities at age 8 years compared with 13% in a control group from similar, middle-class backgrounds. However, the family risk of dyslexia was continuous, and high-risk children who did not fulfil criteria for reading impairment at 8 years performed as poorly at age 6 as did high-risk impaired children on tests of grapheme,phoneme knowledge. The findings are interpreted within an interactive model of reading development in which problems in establishing a phonological pathway in dyslexic families may be compensated early by children who have strong language skills. [source]

    Individual difference in the number of chewing strokes and its determinant factors

    T. UEDA
    summary, This study was carried out to clarify the distribution and individual variation of the number of chewing strokes before last swallowing (NCS), as well as to assess the factors that affect NCS, when dentulous adults masticate the same type of food. NCS was measured in 75 dentulous adults using gummy candies. Measurements were repeated five times to obtain the average and variation. Moreover, the correlation of NCS with various physiological factors (lateral width and vertical distance of chewing loop, angle of opening and closing path, opening and closing time, occlusal time, masticatory performance, number of occlusal contact points, occlusal contact area, occlusal force, flow rate of whole saliva and viscosity of whole saliva) and 28 personality factors were analysed by both of the single variate analysis and the multivariate analysis. The results showed that the average NCS was 41·0 ± 16·0, and the coefficient of variation was 0·090 ± 0·040. Additionally, the correlation between NCS and each factor was investigated, and found that any of these factors did not function as a single determinant for NCS. Following, determinant factors were further examined by the stepwise method of linear multiple regression analysis. From these analysis we found that when opening and closing time and four personality factors were combined, they were significantly involved in determining NCS (P < 0·01). Therefore, we conclude that individual NCS until last swallowing is not determined by a sole, specific physiological factor but is affected by multiple factors including personality. [source]

    Intra-individual variability in infancy: Structure, stability, and nutritional correlates

    Theodore D. Wachs
    Abstract Intra-individual variability (IIV) refers to relatively stable differences between individuals in the degree to which they show behavioral fluctuations over relatively short time periods. Using temperament as a conceptual framework the structure, stability, and biological roots of IIV were assessed over the first year of life. Biological roots were defined by maternal and infant nutrition. The sample was 249 Peruvian neonates, followed from the second trimester of pregnancy through the first 12 months of life. Maternal anthropometry, diet, iron status, and fetal growth were assessed prenatally. Neonatal anthropometry and iron status were assessed at birth. Degree of exclusive breastfeeding was assessed at 3 and 6 months, infant anthropometry was assessed at 3, 6, and 12 months, infant dietary intake was assessed at 6 and 12 months and infant iron status was tested at 12 months. Individual differences in IIV at 3, 6, and 12 months were derived from a residual standard deviation score based on infant behaviors measured using the Louisville Temperament Assessment Procedure. Principal components analysis indicated that individual differences in IIV were defined by two components at 3, 6, and 12 months. There was modest stability between IIV components assessed at 3 and 12 months. Reduced levels of IIV at 3 months were predicted by higher maternal weight and higher fetal weight gains in the first and second trimesters of pregnancy. Higher levels of IIV at 3 months were predicted by higher levels of maternal hemoglobin during pregnancy and higher levels of neonatal ferritin. © 2008 Wiley Periodicals, Inc. Dev Psychobiol 50: 217,231, 2008. [source]

    Embryonic origin of mate choice in a lizard with temperature-dependent sex determination

    Oliver Putz
    Abstract Individual differences in the adult sexual behavior of vertebrates are rooted in the fetal environment. In the leopard gecko (Eublepharis macularius), a species with temperature-dependent sex determination (TSD), hatchling sex ratios differ between incubation temperatures, as does sexuality in same-sex animals. This variation can primarily be ascribed to the temperature having direct organizing actions on the brain. Here we demonstrate that embryonic temperature can affect adult mate choice in the leopard gecko. Given the simultaneous choice between two females from different incubation temperatures (30.0 and 34.0°,C), males from one incubation temperature (30.0°,C) preferred the female from 34.0°,C, while males from another incubation temperature (32.5°,C) preferred the female from 30.0°,C. We suggest that this difference in mate choice is due to an environmental influence on brain development leading to differential perception of opposite-sex individuals. This previously unrecognized modulator of adult mate choice lends further support to the view that mate choice is best understood in the context of an individual's entire life-history. Thus, sexual selection results from a combination of the female's as well as the male's life history. Female attractiveness and male choice therefore are complementary. © 2005 Wiley Periodicals, Inc. Dev Psychobiol 48: 29,38, 2006. [source]

    REVIEW: Ethanol consumption: how should we measure it?

    ADDICTION BIOLOGY, Issue 2 2010
    Achieving consilience between human, animal phenotypes
    ABSTRACT There is only modest overlap in the most common alcohol consumption phenotypes measured in animal studies and those typically studied in humans. To address this issue, we identified a number of alcohol consumption phenotypes of importance to the field that have potential for consilience between human and animal models. These phenotypes can be broken down into three categories: (1) abstinence/the decision to drink or abstain; (2) the actual amount of alcohol consumed; and (3) heavy drinking. A number of suggestions for human and animal researchers are made in order to address these phenotypes and enhance consilience. Laboratory studies of the decision to drink or to abstain are needed in both human and animal research. In human laboratory studies, heavy or binge drinking that meets cut-offs used in epidemiological and clinical studies should be reported. Greater attention to patterns of drinking over time is needed in both animal and human studies. Individual differences pertaining to all consumption phenotypes should be addressed in animal research. Lastly, improved biomarkers need to be developed in future research for use with both humans and animals. Greater precision in estimating blood alcohol levels in the field, together with consistent measurement of breath/blood alcohol levels in human laboratory and animal studies, provides one means of achieving greater consilience of alcohol consumption phenotypes. [source]