Hand preference and its flexibility according to the position of the object: a study in cercopithecines examining spontaneous behaviour and an experimental task (the Bishop QHP task)

The extant literature on manual laterality in non-human primates is inconclusive, plagued by inconsistent or contradictory findings and by disturbing methodological issues (e.g. uncontrolled influential factors, comparability issues). The present study examined hand preference and its flexibility in 15 red-capped mangabeys (C. t. torquatus) and 13 Campbell's monkeys (C. c. campbelli), two species that differ in their degree of arboreality. We investigated the influence of the spatial position of the object on hand preference for reaching. We considered spontaneous behaviour (reaching for food during daily feeding) and an experimental task: the QHP task. The QHP is a task that is used in humans. This is a simple reaching task that involves high spatial constraints on hand use. In our study, the subject had to reach for items that were placed on a semi-circle in front of it on five positions, including in the centre position, in the ipsilateral space and in the contralateral space. We assessed hand preference for reaching in front (baseline condition), and we examined how this preference changed when reaching in lateral positions. For reaching in front, about half of the subjects were lateralized and no group-level bias occurred, for both spontaneous and experimental conditions. When considering reaching in the lateral positions, we observed that the position of the object influenced hand use: individuals used the hand that was closest to the object. The results are discussed in relation to previous findings in humans and in non-human primates and regarding theories on handedness and flexibility of hand preference.     

The Validation of a Five-Item Screening Scale for Personality Disorders in Dutch-Speaking Community Adolescents and Adults

In Section III of the Diagnostic and Statistical Manual of Mental Disorders – fifth edition (DSM-5), an Alternative Model for Personality Disorders (AMPD) is proposed, including a criterion for personality functioning impairment (Criterion A) to assess severity of personality pathology. The present study examined the structure, reliability, and convergent validity of the Dutch version of a five-item screening scale for Criterion A—the Five-Item Screening Scale for Personality Disorders (FISSPD; Skodol et al., in Personality Disorders: Theory, Research, and Treatment, 2, 4-22, 2011)—in a community sample of 1,477 adolescents and 546 adults. To assess convergent validity, identity and personality (pathology) questionnaires were completed by adolescents and adults. Confirmatory factor analysis yielded a single factor structure for the FISSPD, which proved to be (partially) invariant across age and gender. Adequate reliability coefficients were obtained for the FISSPD. In both the adolescent and adult sample, significant correlations were found between the FISSPD and consolidated identity (negative) and disturbed identity/lack of identity (positive). In the adult sample, the FISSPD showed significant correlations with several personality disorders (and especially with the borderline personality disorder), maladaptive personality traits (Criterion B of the AMPD), and general personality impairment. In the adolescent sample, the FISSPD was positively correlated with borderline personality disorder characteristics. Furthermore, significant correlations were found with the Big-Five personality traits in the adolescent sample: the FISSPD correlated significantly positive with neuroticism, and negative with extraversion, agreeableness, and conscientiousness. In sum, the present study supports the reliability and validity of the FISSPD to screen for (severity of) personality pathology.