The ability to tickle oneself is associated with level of psychometric schizotypy in non-clinical individuals

A recent study (Lemaitre et al., 2016, Consciousness and Cognition, 41, 64–71) found that non-clinical individuals who scored highly on a psychometric scale of schizotypy were able to tickle themselves. The present study aimed to extend this finding by investigating whether the ability to tickle oneself was associated with level of psychometric schizotypy considered as a continuous variable. One hundred and eleven students completed the Schizotypal Personality Questionnaire (SPQ). A mechanical device delivered tactile stimulation to participants’ palms. The device was operated by the experimenter (External) or the participant (Self). Participants were asked to rate the intensity, ticklishness and pleasantness of the stimulation. A significant association was observed between participants’ tactile self-suppression (External minus Self) and their score on the SPQ. These results suggest that the ability to suppress the tactile consequences of self-generated movements varies across the general population, and maps directly onto the personality dimension of schizotypy.     

Confirmatory factor analysis of the three-factor structure of the schizotypal personality questionnaire and Chapman schizotypy scales

We examined the factor structure of the Schizotypal Personality Questionnaire (SPQ; Raine, 1991), using confirmatory factor analysis in 3 experiments, with an aim to better understand the construct of schizotypy. In Experiment 1 we tested the fit of 2-, 3-, and 4-factor models on SPQ data from a normal sample. The paranoid 4-factor model fit the data best but not adequately. Based on the strong basis for the Raine 3-factor model we attempted to improve the fit of the 3-factor model by making 3 modifications to the Raine model. These modifications produced a well-fitting model. In Experiment 2 the good fit of this modified 2-factor model to SPQ scores was replicated in an independent normal sample. In Experiment 3, the modified 3-factor model was successfully extended to include the 3 Chapman schizotypy scales. Together these 3 experiments indicate that the 3-factor model of the SPQ, albeit with some slight modifications, is a good model for schizotypy structure that is not restricted to 1 measure of schizotypal personality traits.     

Do sex differences in emotionality mediate sex differences in traits of psychosis-proneness?

The aim of the study was to determine if sex differences in emotionality might account for sex differences in distinct traits of proneness to psychosis (or "schizotypy"). Females report higher levels of "positive" schizotypy (e.g., magical thinking) than males, along with a tendency toward greater schizotypal disorganisation, whereas males report higher levels of "negative" schizotypal traits, such as social anxiety (Jackson & Claridge, 1991; Raine, 1992). Given the affect-oriented nature of "negative" schizotypal traits, we tested the hypothesis that higher levels of "negative" schizotypy among males would be accounted for by more general sex differences in emotionality; that is, by less frequent and less intense emotional experiences. A total of 81 student participants were administered the Cognitive-Perceptual Deficits, the Disorganisation, and the Interpersonal Deficits components of Raine's (1991) Schizotypal Personality Questionnaire (SPQ), indexing respectively, "positive" schizotypy, schizotypal disorganisation, and "negative" schizotypy. Frequency of emotional experience was assessed using the Emotionality subscale (Buss & Plomin, 1984) and intensity, the Affect Intensity Measure (Larsen & Diener, 1987). As predicted, males scored significantly higher than females on the SPQ Interpersonal Deficits component but no sex differences emerged for the other two components. Males reported significantly less intense, although not less frequent, experiences than females. A reduced intensity of positive emotions in particular was found to mediate the sex difference in "negative" schizotypy. Our results suggest that a less intense experience of positive affect might contribute to males' propensity to develop negative symptoms should a schizophrenic breakdown occur.     

Effects of increasing cognitive load on sustained attention tasks in schizophrenic disorders and schizotypy

In this study we analyze the attentional performance using different cognitive load attentional tasks: low-load cognition (0-CPT) and high-load cognition (DS-CPT). Participants were a group of schizophrenic patients and two groups of normal population psychometrically classified as low schizotypy and high schizotypy according to the SPQ. Our results show that schizophrenic patients were more sensitive to increments on cognitive load, being their attentional performace worse than the rest of the groups. The lack of significant findings in vigilance on the schizotypal traits group is discussed in terms of conceptual and methodological issues about the utility of psychometric strategies to identify vulnerable populations within the spectrum of the schizophrenic disorders.     

Correlations between psychometric schizotypy,scan path length,fixations on the eyes and face recognition

Psychometric schizotypy in the general population correlates negatively with face recognition accuracy, potentially due to deficits in inhibition, social withdrawal, or eye-movement abnormalities. We report an eye-tracking face recognition study in which participants were required to match one of two faces (target and distractor) to a cue face presented immediately before. All faces could be presented with or without paraphernalia (e.g., hats, glasses, facial hair). Results showed that paraphernalia distracted participants, and that the most distracting condition was when the cue and the distractor face had paraphernalia but the target face did not, while there was no correlation between distractibility and participants’ scores on the Schizotypal Personality Questionnaire (SPQ). Schizotypy was negatively correlated with proportion of time fixating on the eyes and positively correlated with not fixating on a feature. It was negatively correlated with scan path length and this variable correlated with face recognition accuracy. These results are interpreted as schizotypal traits being associated with a restricted scan path leading to face recognition deficits.     

Schizotypy and mental time travel

Mental time travel is the capacity to imagine the autobiographical past and future. Schizotypy is a dimensional measure of psychosis-like traits found to be associated with creativity and imagination. Here, we examine the phenomenological qualities of mental time travel in highly schizotypal individuals. After recollecting past episodes (autobiographical memory) and imagining future events (episodic future thinking), those scoring highly on positive schizotypy reported a greater sense of ‘autonoetic awareness,’ defined as a greater feeling of mental time travel and re-living/‘pre-living’ imagined events. Furthermore, in contrast to other sensory domains, imagery of the past and future episodes contained more olfactory detail in these high scorers. The results are discussed in relation to previous reports of anomalous olfactory experiences in schizotypy and heightened vividness of olfactory imagery in post-traumatic stress disorder, for which schizotypy is a risk factor.     

Schizotypy facets, cognitive control, and emotion

This research examined whether facets of schizotypy were differentially related to cognitive control and emotion-processing traits. In a confirmatory factor analysis (N = 261), a 3-factor model of schizotypy exhibited good fit and fit significantly better than a 2-factor model. In addition, only disorganized schizotypy was associated with poor cognitive control (specifically, prepotent inhibition). Moreover, disorganized but not positive schizotypy was associated with increased emotional confusion and increased emotionality. In contrast, negative schizotypy was associated with increased emotional confusion but decreased emotionality. These results suggest that disorganized schizotypy is related to dysregulation of both cognition and emotion and that negative schizotypy might reflect deficits in the experience and processing of emotion and not just in emotional expression.     

Development and Initial Validation of an Abbreviated Spider Phobia Questionnaire Using Item Response Theory

An abbreviated Spider Phobia Questionnaire (SPQ) was developed using methods based in item response theory. Fifteen of the 31 SPQ items that demonstrated good to excellent discrimination along the spider fear continuum were retained in Study 1 that consisted of 1,555 nonclinical and clinical participants. The SPQ-15 demonstrated good internal consistency and correlated highly with the full SPQ. Structural equation modeling revealed that the SPQ-15 demonstrated excellent convergent validity, with strong associations with small animal disgust and other phobic symptoms. Supportive evidence was also found for divergent validity in relation to panic-related symptoms. The SPQ-15 was uniquely predictive of avoidance behavior and fear and disgust responding towards spiders in nonclinical, analogue, and treatment-seeking samples in Studies 2, 3, and 4. Lastly, in Study 5, the SPQ-15 was sensitive to the effects of exposure-based treatment. These findings suggest that the SPQ-15 has considerable strengths, including decreased assessment and scoring time while retaining high reliability, validity, and sensitivity.     

Logical reasoning in schizotypal personality

It was examined whether psychotic-like personality traits in a sample of 205 college students could predict logical reasoning deficits, akin to those seen in schizophrenia. The participants were tested on their ability to assess the logical validity of premises (Logical Reasoning Task), and completed a multi-dimensional schizotypy inventory (O-LIFE). Low accuracy was associated with increased levels of disorganized schizotypy (‘Cognitive Disorganization’), while elevated errors were associated with increased levels of positive (‘Unusual Experiences’), negative (‘Introvertive Anhedonia’) and impulsive (‘Impulsivity Non-conformity’) schizotypy. Nevertheless, multiple regression analyses revealed that negative schizotypy was retained as the only significant predictor after performance was corrected for random guessing, and the contribution of the average amount of time spent on each premise was controlled. The results suggest that, although most schizotypy dimensions have a detrimental effect on reasoning performance, possibly due to disadvantageous test-taking strategies, negative schizotypy is the most reliable predictor of logical reasoning deficits. It is proposed that social/interpersonal schizotypal traits, like negative symptoms of schizophrenia, are accompanied by deficient executive functions of working memory, which appear to undermine, inter alia, logical reasoning processing.     

Extreme elemental processing in a high schizotypy population: Relation to cognitive deficits

The cognitive deficits observed in schizophrenia have been characterized as a failure to utilize task-setting information to guide behaviour, especially in situations in which there is response conflict. Recently, we have provided support for this account; high schizotypy individuals demonstrated inferior biconditional discrimination performance compared to low scorers, but were not impaired on a simple discrimination that did not require the use of task-setting cues. These results may, however, also be explained by the way in which individuals with high schizotypy process stimulus compounds. Here, we examine the initial approaches to solving biconditional and control discrimination tasks of participants with high and low schizotypy scores. In particular, we focus on performance during the first block of training trials to capture processing style before the acquisition of the discrimination tasks. Participants scoring highly on the introvertive anhedonia subscale (which has been allied to the negative and cognitive symptoms of schizophrenia) demonstrated better biconditional performance during the first block of training trials than did low-schizotypy individuals, consistent with a highly elemental approach to stimulus processing. Subsequent recognition tests confirmed this analysis demonstrating that the pattern of performance observed in participants with high schizotypy was associated with a failure to discriminate conjunctions of items that had been seen before from those that had not. These results suggest that the negative/cognitive symptoms of schizophrenia may reflect an extreme bias towards elemental, as opposed to configural, processing of stimulus conjunctions.     

Deeper into the schizotypy taxon: on the robust nature of maximum covariance analysis

Prior research has suggested that the latent structure of the schizotypy construct (P. E. Meehl, 1990) may be qualitative in nature and have a low base rate (L. Korfine & M. F. Lenzenweger, 1995; M. F. Lenzenweger & L. Korfine, 1992). These studies relied on the application of maximum covariance analysis (MAXCOV) to 8 true-false format items from a schizotypy measure. The current study sought to examine the robustness of those prior findings through MAXCOV analysis of fully quantitative measures of schizotypy. Measures of perceptual aberration, magical ideation, and referential thinking were analyzed using MAXCOV in a sample of 429 persons. The results of these analyses strongly support a latent taxonic structure for schizotypy and a low base rate for the schizotypy taxon. Furthermore, the members of the putative taxon reveal an increased level of deviance on a psychometric measure known to be associated with schizophrenia liability. The possibility that the dichotomous item format of those items analyzed previously with MAXCOV lead to spurious pseudotaxonicity is greatly diminished in light of these results.     

An investigation of schizotypy in injecting amphetamine users

A fully dimensional view of psychiatric disorder conceptualises schizotypy as both a continuous personality trait and an underlying vulnerability to the development of psychotic illness. Such a model would predict that the structure of schizotypal traits would closely parallel the structure of schizophrenia or psychosis. This was investigated in injecting amphetamine users (N = 322), a clinical population who have high rates of acute psychotic episodes and subclinical schizotypal experiences. Schizotypy was assessed using the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE), and psychotic symptoms were assessed using the Brief Psychiatric Rating Scale (BPRS). Using confirmatory factor analysis, O-LIFE subscale scores were mapped onto latent variables with their more clinical counterparts from the BPRS. A four-factor model comprising positive schizotypy, disorganisation, negative schizotypy, and disinhibition provided the best model fit, consistent with prior research into the structure of schizotypy. The model provided a good fit to the data, lending support to the theory that schizotypy and psychotic symptoms map onto common underlying dimensions.     

Increased distractibility in schizotypy: Independent of individual differences in working memory capacity?

Individuals with schizophrenia typically show increased levels of distractibility. This has been attributed to impaired working memory capacity (WMC), since lower WMC is typically associated with higher distractibility, and schizophrenia is typically associated with impoverished WMC. Here, participants performed verbal and spatial serial recall tasks that were accompanied by to-be-ignored speech tokens. For the few trials wherein one speech token was replaced with a different token, impairment was produced to task scores (a deviation effect). Participants subsequently completed a schizotypy questionnaire and a WMC measure. Higher schizotypy scores were associated with lower WMC (as measured with operation span, OSPAN), but WMC and schizotypy scores explained unique variance in relation to the mean magnitude of the deviation effect. These results suggest that schizotypy is associated with heightened domain-general distractibility, but that this is independent of its relationship with WMC.     

The Spider Phobia Card Sorting Test: An investigation of phobic fear and executive functioning

Recent studies indicate that anxious participants show cognitive biases favouring threat‐related stimuli. However, most of this evidence comes from Stroop tasks, which are believed to tap a narrow range of executive skills. The current study investigated phobic fear and cognitive biases using tasks designed to tap a wider range of executive processes: the standard Wisconsin Card Sorting Test (WCST; Heaton, 1981), a modified version that included emotionally salient pictorial stimuli; the Spider Phobia Card Sorting Test (SPCST); and an emotionally valenced version of a verbal fluency task (VF). A total of 80 female participants (38 lower and 42 higher scorers on the Spider Phobia Questionnaire; SPQ) drawn from a larger sample of 126 completed either the standard WCST or the SPCST, the VF, and several mood measures. On the card sort, the higher SPQ SPCST group showed a significantly lower proportion of conceptual level responses, required a greater number of trials to complete the first category, and sorted significantly fewer stimulus cards to the spider target card than the lower SPQ SPCST group, or than either of the groups in the WCST condition who sorted to neutral target cards. On the VF, the higher SPQ group generated significantly more exemplars to the category “spiders” than the lower SPQ group. Therefore, fearful participants seemed to avoid or neglect the spider cue on the card sort, but performed better in generating “spiders” exemplars on the VF, as compared to the nonfearful group. Implications and limitations of these findings are discussed.     

Dissociations of the night: individual differences in sleep-related experiences and their relation to dissociation and schizotypy.

The author examined the associations among sleep-related experiences (e.g., hypnagogic hallucinations, nightmares, waking dreams, and lucid dreams), dissociation, schizotypy, and the Big Five personality traits in 2 large student samples. Confirmatory factor analyses indicated that (a) dissociation and schizotypy are strongly correlated-yet distinguishable-constructs, and (b) the differentiation between them can be enhanced by eliminating detachment/depersonalization items from the dissociation scales. A general measure of sleep experiences was substantially correlated with both schizotypy and dissociation (especially the latter) and more weakly related to the Big Five. In contrast, an index of lucid dreaming was weakly related to all of these other scales. These results suggest that measures of dissociation, schizotypy, and sleep-related experiences all define a common domain characterized by unusual cognitions and perceptions.     

Schizotypy and hemisphericity

There is considerable evidence that schizophrenia spectrum disorders are associated with a variety of abnormal asymmetries of brain structure, function, and behavior. Schizotypy is a personality trait dimension extending into the normal range, which at its extreme, is associated with a vulnerability to schizophrenia spectrum disorders. Schizotypy in the normal range is also associated with a variety of neurobiological characteristics associated with schizophrenia spectrum disorders, including abnormal brain and behavioral asymmetries. Previous studies have suggested that normal schizotypy (as well as belief in the paranormal) is associated with an increased reliance on the right hemisphere in a variety of tasks. Hemisphericity is a trait-related characteristic preference for the cognitive mode of one or the other cerebral hemispheres, putatively related to hemispheric activation asymmetry. A sample of 256 undergraduates was administered five schizotypy scales, as well as three hemisphericity measures. Higher schizotypy scores were associated with an increase in right hemisphericity and a decrease in integrated hemisphericity. Although the construct of hemisphericity has been criticized, there is evidence to suggest that questionnaire and eye movement measures of hemisphericity may yet have construct validity, and further research on hemisphericity may be warranted.     

Hallucination proneness, schizotypy and meta-cognition

Disordered or maladaptive meta-cognitive processing appears to be a prominent feature for some individuals with a diagnosis of schizophrenia. We sought to establish whether healthy individuals distinguished either in terms hallucination proneness (HP) or level of schizotypy could also be differentiated on the sub-scales of the Meta-cognitions Questionnaire (MCQ), or a modified version of it in which items about worry were replaced with items specifically related to thinking. A total of 106 healthy volunteers completed the Oxford and Liverpool Inventory of Feelings and Experiences and Launay-Slade hallucination scale, the Schizotypal Personality Questionnaire and two versions of the MCQ: the original which assesses five domains of meta-cognition and an adapted version in which items relating to worry had been replaced by items relating to thinking or reflecting on thinking (MCQ-th). ANOVA indicated highly significant differences between three groups of individuals differentiated in terms of high, medium and low proneness to hallucinations on four of the five MCQ sub-scales, and three of the four MCQ-th factors. Regression analyses indicated that the MCQ factors encompassing (1) a sense of uncontrollability of thinking (and the perceived attendant dangers of this) and (2) negative beliefs about thinking related to suspicion and punishment were the strongest predictors of high schizotypy. Individuals who score higher on a measure of HP are more likely to display patterns of meta-cognitive processing that resemble, in certain respects, those reported in individuals with a diagnosis of schizophrenia. High schizotypy predicts a negative appraisal about both the controllability and consequences of thinking.     

Creative Activity,Personality, Mental Illness,and Short‐Term Mating Success

It has been argued that creativity evolved, at least in part, through sexual selection to attract mates. Recent research lends support to this view and has also demonstrated a link between certain dimensions of schizotypy, creativity, and short‐term mating. The current study delves deeper into these relationships by focusing on engagement in creative activity and employing an expansive set of personality and mental health measures (Five Factor Model, schizotypy, anxiety, and depression). A general tendency to engage in everyday forms of creative activity was related to number of sexual partners within the past year in males only. Furthermore, schizotypy, anxiety, and Neuroticism were all indirectly related to short‐term mating success, again for males only. The study provides additional support for predictions made by sexual selection theory that men have a higher drive for creative display, and that creativity is linked with higher short‐term mating success. The study also provides support for the contention that certain forms of mental illness may still exist in the gene pool because particular personality traits associated with milder forms of mental illness (i.e., Neuroticism & schizotypy) are also associated directly with creativity and indirectly with short‐term mating success.     

A five-factor measure of schizotypal personality traits

The current study provides convergent, discriminant, and incremental validity data for a new measure of schizotypy from the perspective of the five-factor model (FFM) of general personality structure. Nine schizotypy scales were constructed as maladaptive variants of respective facets of the FFM (e.g., Aberrant Ideas as a maladaptive variant of FFM Openness to Ideas). On the basis of data from 143 undergraduates, the convergent validity of these nine scales was tested with respect to seven established measures of schizotypy and the respective facets of the FFM. Discriminant validity was tested with respect to facets from other FFM domains and components of schizotypy. Incremental validity was tested with respect to the ability of the FFM schizotypy scales to account for variance in two established measures of schizotypy, after variance accounted for by respective FFM facets and other established measures of schizotypy were first removed. The findings support the validity of these new scales as measures of schizotypal traits and as maladaptive variants of the FFM.     

Imagery ability and exposure in vivo in spider phobia

The present study deals with the effect of imagery ability on treatment outcome in spider phobias. Thirty-eight spider phobics completed the Questionnaire on Mental Imagery (QMI) and the Spider Questionnaire (SPQ). Subjects also went through a behavioral approach task (BAT) during which heart rate and avoidance behavior were measured. Each subject was then given one-session treatment as described by Ost. Immediately after treatment, SPQ and BAT data were again obtained. On the basis of their QMI scores, subjects were assigned to a 'good', 'moderate', or 'poor' imagers group. Neither pre-treatment nor post-treatment measures were found to vary as a function of imagery ability. Thus it appears that, at least for specific phobias such as spider fear, imagery ability is not a relevant variable for predicting the effects of in vivo exposure.