Loose but normal: a semantic association study

The Experience of Meaningful Coincidences Is Associated with Stronger Alpha Power Increases during an Eyes-closed Resting Condition: A Bayesian Replication Approach

Recognizing and perceiving meaningful patterns in an ever-changing environment is fundamental to (human) beings. Apophenia, patternicity, and the propensity to perceive meaningful coincidences might result from the human brain working as a prediction machine that constantly matches sensory information to prior expectations. The propensity for Type I errors varies between people and, at its extreme, is associated with symptoms of schizophrenia. However, on a nonclinical level seeing meaning in randomness might be benevolent and was found to be associated with creativity and openness. However, hardly any neuroscientific investigation has examined EEG patterns of the propensity to experience meaningful coincidences in this manner. We hypothesized deviations in brain functions as one potential reason why some people experience more meaning in random arrangements than others. The gating by inhibition theory suggests that alpha power increases represent basic control mechanisms of sensory processes during varying task requirements. We found that people perceiving more meaningful coincidences had higher alpha power during an eyes-closed versus eyes-opened condition compared with people experiencing less meaningful coincidences. This indicates deviations in the sensory inhibition mechanism of the brain, which are critically relevant for higher cognitive functions. Applying Bayesian statistics, we replicated this finding in another independent sample.

Schizophrenia patients perform as well as healthy controls on creative problem solving when fluid intelligence is accounted for

INTRODUCTION

This study examined creative problem solving in schizophrenia. We aimed to verify three hypotheses: (H1) schizophrenia patients differ from healthy controls in the accuracy of creative problem solving; (H2) schizophrenia patients are less effective at evaluating and rejecting incorrect associations and (H3) have a more idiosyncratic way of searching for semantic associations compared to controls.

METHODS

Six Remote Associates Test (RAT) items and three insight problems were applied to schizophrenia patients and healthy controls. We compared groups on the overall accuracy in the tasks to verify H1 and developed a novel method of comparing the patterns of errors in the RAT to verify H2 and H3. We controlled for fluid intelligence to eliminate this significant source of variation, as typically creativity and intelligence are significantly related.

RESULTS

Bayesian factor analysis did not support the group differences in either insight problems and RAT accuracy or the patterns of RAT errors.

CONCLUSIONS

The patients performed as well as the controls on both tasks. Analysis of RAT errors suggested that the process of searching for remote associations is comparable in both groups. It is highly improbable that individuals with schizophrenia benefit from their diagnosis during creative problem solving.

Thinking style and psychosis proneness do not predict false insights

The FIAT paradigm (Grimmer et al., 2021) is a novel method of eliciting 'Aha' moments for incorrect solutions to anagrams in the laboratory, i.e. false insights. There exist many documented reports of psychotic symptoms accompanying strong feelings of 'Aha!' (Feyaerts, Henriksen, Vanheule, Myin-Germeys, & Sass, 2021; Mishara, 2010; Tulver, Kaup, Laukkonen, & Aru, 2021), suggesting that the newly developed FIAT could reveal whether people who have more false insights are more prone to psychosis and delusional belief. To test this possibility, we recruited 200 participants to take an adapted version of the FIAT and complete measures of thinking style and psychosis proneness. We found no association between experimentally induced false insights and measures of Schizotypy, Need for Cognition, Jumping to Conclusions, Aberrant Salience, Faith in Intuition, or the Cognitive Reflection Task. We conclude that experiencing false insights might not be constrained to any particular type of person, but rather, may arise for anyone under the right circumstances.

Creative, yet not unique? Paranormal belief, but not self-rated creative ideation behavior is associated with a higher propensity to perceive unique meanings in randomness

Apophenia, patternicity, and the experience of meaningful coincidences describe the propensity to perceive meaning in random arrangements, which is known to be linked with paranormal beliefs. Additionally, this trait of combining unrelated elements to create new meanings suggests an association with creativity. However, studies indicating a relationship between creativity and apophenia are scarce. To gain empirical evidence, the present study (n = 77) assessed the propensity to experience meaningful patterns in random arrangements by means of a questionnaire (coincidence questionnaire) and a behavioral measure. The applied figural association task allows to reliably differentiate between the perception of idiosyncratic/unique and intersubjective meaningful/non-unique patterns. Self-rated creative ideation behavior and paranormal beliefs were positively associated with the subjectively rated frequency of meaningful coincidences. Furthermore, participants high in both creative ideation behavior and paranormal beliefs perceived a higher number of non-unique meanings in the figural association task. Yet, participants high in paranormal beliefs additionally perceived a higher number of unique meanings. This divergence in findings suggests that creative ideation behavior and paranormal belief are associated with the perception of partly different meanings in random arrangements. In paranormal believers, this pattern of findings may indicate a lower threshold to detect meaning in meaninglessness, leading to more idiosyncratic/unique perceptions. Altogether, slight reductions of this threshold to detect meaningfulness may increase a persons’ creativity; however, excessive pattern recognition may facilitate paranormal beliefs.

Constructive episodic simulation in dreams

Memories of the past help us adaptively respond to similar situations in the future. Originally described by Schacter & Addis in 2007, the "constructive episodic simulation" hypothesis proposes that waking thought combines fragments of various past episodes into imagined simulations of events that may occur in the future. This same framework may be useful for understanding the function of dreaming. N = 48 college students were asked to identify waking life sources for a total of N = 469 dreams. Participants frequently traced dreams to at least one past or future episodic source (53.5% and 25.7% of dreams, respectively). Individual dreams were very often traced to multiple waking sources (43.9% of all dreams with content), with fragments of past memory incorporated into scenarios that anticipated future events. Waking-life dream sources are described in terms of their phenomenology and distribution across time and sleep stage, providing new evidence that dreams not only reflect the past, but also utilize memory in simulating potential futures.

A word is worth a thousand pictures: A 20-year comparative analysis of aberrant abstraction in schizophrenia, affective psychosis, and non-psychotic depression

thinking is a cognitive process that involves the assimilation of concepts reduced from diffuse sensory input, organized, and interpreted in a manner beyond the obvious. There are multiple facets by which abstraction is measured that include semantic, visual-spatial and social comprehension. This study examined the prevalence and course of abstract and concrete responses to semantic proverbs and aberrant abstraction (composite score of semantic, visual-spatial, and social comprehension) over 20 years in 352 participants diagnosed with schizophrenia, affective psychosis, and unipolar non-psychotic depression. We utilized linear models, two-way ANOVA and contrasts to compare groups and change over time. Linear models with Generalized Estimation Equation (GEE) to determine association. Our findings show that regardless of diagnosis, semantic proverb interpretation improves over time. Participants with schizophrenia give more concrete responses to proverbs when compared to affective psychosis and unipolar depressed without psychosis. We also show that the underlying structure of concretism encompasses increased conceptual overinclusion at index hospitalization and idiosyncratic associations at follow-up; whereas, abstract thinking overtime encompasses increased visual-spatial abstraction at index and rich associations with increased social comprehension scores at follow-up. Regardless of diagnosis, premorbid functioning, descriptive characteristics, and IQ were not associated with aberrant abstraction. Delusions are highly and positively related to aberrant abstraction scores, while hallucinations are mildly and positively related to this score. Lastly, our data point to the importance of examining the underlying interconnected structures of 'established' constructs vis-à-vis mixed methods to provide a description of the rich interior world that may not always map onto current quantitative measures.

Antagonism between brain regions relevant for cognitive control and emotional memory facilitates the generation of humorous ideas

The ability to generate humor gives rise to positive emotions and thus facilitate the successful resolution of adversity. Although there is consensus that inhibitory processes might be related to broaden the way of thinking, the neural underpinnings of these mechanisms are largely unknown. Here, we use functional Magnetic Resonance Imaging, a humorous alternative uses task and a stroop task, to investigate the brain mechanisms underlying the emergence of humorous ideas in 24 subjects. Neuroimaging results indicate that greater cognitive control abilities are associated with increased activation in the amygdala, the hippocampus and the superior and medial frontal gyrus during the generation of humorous ideas. Examining the neural mechanisms more closely shows that the hypoactivation of frontal brain regions is associated with an hyperactivation in the amygdala and vice versa. This antagonistic connectivity is concurrently linked with an increased number of humorous ideas and enhanced amygdala responses during the task. Our data therefore suggests that a neural antagonism previously related to the emergence and regulation of negative affective responses, is linked with the generation of emotionally positive ideas and may represent an important neural pathway supporting mental health.

The structure of semantic representation shapes controlled semantic retrieval

An essential aim in the research on semantic cognition is to understand the interplay between the structure of semantic representation and controlled processes that operate on it to generate flexible behaviours. To evaluate the link between semantic network connectivity and semantic control functions (semantic inhibition and switching), we employed a network theory approach and revealed that controlled semantic processing was reliably associated with connectivity of conceptual representation. In particular, our results show that efficient information flow afforded by high connectivity of semantic network is coupled with superior switching but poor inhibition ability. These findings suggest that the network architectures that facilitate efficient semantic activation spreading aid flexible transitions between semantic clusters but impede inhibition employed to suppress inappropriate or interfering semantic representations. Overall, our study provides a novel insight into the mechanisms underlying controlled semantic processing that is recruited to disentangle from habitual structure of semantic representation.

Resting frontal EEG asymmetry and schizotypal traits: a test-retest study

Introduction: Increase in right relative to left frontal electroencephalography (EEG) activity has been observed in patients with schizophrenia, both in cognitive tasks and during rest; and this lateralisation may be related to the severity of schizotypal traits. Methods: We used the Schizotypal Personality Questionnaire (SPQ) to assess schizotypal traits, and examined the correlation between these traits and resting EEG frontal asymmetry (left-right) in 52 college students, as well as the reliability of this correlation over a three-month interval. Results: A higher total score on the SPQ was correlated with reduced asymmetry in different frequency bands: gamma and beta2 frequency bands at baseline, and delta and alpha frequency bands three months later. Additionally, the reduced left relative to right frontal gamma and beta2 asymmetry was correlated with the participants' verbal fluency ability. However, this correlation was no longer statistically significant after the total SPQ score was controlled. Conclusions: These findings suggest that resting frontal EEG asymmetry is correlated with powers in different frequency bands, and may be an endophenotype for schizophrenia spectrum disorders.

Semantic priming and schizotypal personality: reassessing the link between thought disorder and enhanced spreading of semantic activation

The term schizotypy refers to a group of stable personality traits with attributes similar to symptoms of schizophrenia, usually classified in terms of positive, negative or cognitive disorganization symptoms. The observation of increased spreading of semantic activation in individuals with schizotypal traits has led to the hypothesis that thought disorder, one of the characteristics of cognitive disorganization, stems from semantic disturbances. Nevertheless, it is still not clear under which specific circumstances (i.e., automatic or controlled processing, direct or indirect semantic relation) schizotypy affects semantic priming or whether it does affect it at all. We conducted two semantic priming studies with volunteers varying in schizotypy, one with directly related prime-target pairs and another with indirectly related pairs. Our participants completed a lexical decision task with related and unrelated pairs presented at short (250 ms) and long (750 ms) stimulus onset asynchronies (SOAs). Then, they responded to the brief versions of the Schizotypal Personality Questionnaire and the Oxford-Liverpool Inventory of Feelings and Experiences, both of which include measures of cognitive disorganization. Bayesian mixed-effects models indicated expected effects of SOA and semantic relatedness, as well as an interaction between relatedness and directness (greater priming effects for directly related pairs). Even though our analyses demonstrated good sensitivity, we observed no influence of cognitive disorganization over semantic priming. Our study provides no compelling evidence that schizotypal symptoms, specifically those associated with the cognitive disorganization dimension, are rooted in an increased spreading of semantic activation in priming tasks.

Apophenia as the disposition to false positives: A unifying framework for openness and psychoticism

Positive symptoms of schizophrenia and its extended phenotype-often termed psychoticism or positive schizotypy-are characterized by the inclusion of novel, erroneous mental contents. One promising framework for explaining positive symptoms involves apophenia, conceptualized here as a disposition toward false-positive errors. Apophenia and positive symptoms have shown relations to openness to experience (more specifically, to the openness aspect of the broader openness/intellect domain), and all of these constructs involve tendencies toward pattern seeking. Nonetheless, few studies have investigated the relations between psychoticism and non-self-report indicators of apophenia, let alone the role of normal personality variation. The current research used structural equation models to test associations between psychoticism, openness, intelligence, and non-self-report indicators of apophenia comprising false-positive error rates on a variety of computerized tasks. In Sample 1, 1,193 participants completed digit identification, theory of mind, and emotion recognition tasks. In Sample 2, 195 participants completed auditory signal detection and semantic word association tasks. Psychoticism and the openness aspect were positively correlated. Self-reported psychoticism, openness, and their shared variance were positively associated with apophenia, as indexed by false-positive error rates, whether or not intelligence was controlled for. Apophenia was not associated with other personality traits, and openness and psychoticism were not associated with false-negative errors. Findings provide insights into the measurement of apophenia and its relation to personality and psychopathology. Apophenia and pattern seeking may be promising constructs for unifying the openness aspect of personality with the psychosis spectrum and for providing an explanation of positive symptoms. Results are discussed in the context of possible adaptive characteristics of apophenia as well as potential risk factors for the development of psychotic disorders. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Positive Schizotypy Increases the Acceptance of Unpresented Materials in False Memory Tasks in Non-clinical Individuals

Enhanced spreading of semantic activation has been hypothesized to underlie some of the most significant symptoms of schizotypal personality, like thought disorder, odd speech, delusion, or magical thinking. We applied the Deese/Roediger-McDermott false memory task to the study of semantic activation in a group of 123 non-clinical individuals varying in the three dimensions of schizotypal personality: positive, negative and disorganized schizotypy. In the study phase, we presented them with lists composed of words semantically associated to unpresented critical words. Then, they responded to a recognition questionnaire including previously presented words and critical unpresented lures, as well as weakly related and unrelated unpresented lures. Participants rated their confidence in recognizing each word. They also filled in a standardized schizotypal personality questionnaire. Confirming the false memory effect, recognition ratings provided in response to critical words were higher than those produced for both weakly related and unrelated items. Crucially, scores in the positive dimension increased recognition percentages and confidence ratings for weakly related and unrelated lures. This study indicates that high levels of positive schizotypy might influence the tendency to accept false memories of unrelated unpresented material.

High Schizotypal Individuals Are More Creative? The Mediation Roles of Overinclusive Thinking and Cognitive Inhibition

Although a theoretical link between positive schizotypy and heightened creativity has been established in the literature, little empirical research has been conducted to examine the underlying cognitive processes that contribute to this association. In addition, previous studies found a negative relationship between positive schizotypy and cognitive inhibition; however, they often used the paradigm of latent inhibition. This study used the paradigm of prepotent response inhibition indicated by Stroop interference effect and examined the mediation effects of overinclusive thinking (OT) and cognitive inhibition on the creativity of schizotypal individuals. Two groups of low and high schizotypal individuals (N = 78) participated in the study. Each participant completed one OT task, one color-word Stroop task, three other executive functioning (EF) control tasks, and two creativity tasks. The results indicated that the high schizotypal group outperformed the low schizotypal group in the creativity tasks. They also exhibited higher OT as indicated by faster reaction time and higher cognitive inhibition as indicated by lower Stroop interference effect. Further, participant's levels of OT and cognitive inhibition partially mediated the relationship between schizotypy and creativity. The results were discussed under the context of schizotypy and creativity research and implications for rehabitation were further provided.

Hemispheric Asymmetries in Striatal Reward Responses Relate to Approach-Avoidance Learning and Encoding of Positive-Negative Prediction Errors in Dopaminergic Midbrain Regions

Some individuals are better at learning about rewarding situations, whereas others are inclined to avoid punishments (i.e., enhanced approach or avoidance learning, respectively). In reinforcement learning, action values are increased when outcomes are better than predicted (positive prediction errors [PEs]) and decreased for worse than predicted outcomes (negative PEs). Because actions with high and low values are approached and avoided, respectively, individual differences in the neural encoding of PEs may influence the balance between approach-avoidance learning. Recent correlational approaches also indicate that biases in approach-avoidance learning involve hemispheric asymmetries in dopamine function. However, the computational and neural mechanisms underpinning such learning biases remain unknown. Here we assessed hemispheric reward asymmetry in striatal activity in 34 human participants who performed a task involving rewards and punishments. We show that the relative difference in reward response between hemispheres relates to individual biases in approach-avoidance learning. Moreover, using a computational modeling approach, we demonstrate that better encoding of positive (vs negative) PEs in dopaminergic midbrain regions is associated with better approach (vs avoidance) learning, specifically in participants with larger reward responses in the left (vs right) ventral striatum. Thus, individual dispositions or traits may be determined by neural processes acting to constrain learning about specific aspects of the world.

Increasing breadth of semantic associations with left frontopolar direct current brain stimulation: a role for individual differences

The aim of this study was to evaluate the influence of left frontopolar versus auditory (control) cortex transcranial direct current stimulation (tDCS) on the breadth of semantic associations produced in a cued free association task. A within-participants design administered anodal tDCS over the left frontopolar or auditory cortex, centered at electrode site AFZ or T7 using a 4×1 targeted stimulation montage. During stimulation, participants produced free associates in response to cues designed to promote narrow, moderate, or broad semantic associations. We measured the latent semantic associative strength of generated words relative to cues. The cue manipulation produced expected effects on the associative breadth of generated words, but there was no main effect of stimulation site, and calculated Bayes factors showed strong support for the null hypothesis. However, individual differences in creative potential, as assessed by the remote associates test, reliably and positively predicted increases in associative breadth under the frontopolar versus the auditory control condition, but only in response to narrow cues. In conclusion, the present data support neuroimaging studies demonstrating the involvement of left frontopolar cortical regions in generating relatively broad semantic associations. They also provide novel evidence that individual differences in creative potential may modulate the influence of brain stimulation on the breadth of generated semantic associations.

Creativity and positive symptoms in schizophrenia revisited: Structural connectivity analysis with diffusion tensor imaging

Both creativity and schizotypy are suggested to be manifestations of the hyperactivation of unusual or remote concepts/words. However, the results of studies on creativity in schizophrenia are diverse, possibly due to the multifaceted aspects of creativity and difficulties of differentiating adaptive creativity from pathological schizotypy/positive symptoms. To date, there have been no detailed studies comprehensively investigating creativity, positive symptoms including delusions, and their neural bases in schizophrenia. In this study, we investigated 43 schizophrenia and 36 healthy participants using diffusion tensor imaging. We used idea, design, and verbal (semantic and phonological) fluency tests as creativity scores and Peters Delusions Inventory as delusion scores. Subsequently, we investigated group differences in every psychological score, correlations between fluency and delusions, and relationships between these scores and white matter integrity using tract-based spatial statistics (TBSS). In schizophrenia, idea and verbal fluency were significantly lower in general, and delusion score was higher than in healthy controls, whereas there were no group differences in design fluency. We also found positive correlation between phonological fluency and delusions in schizophrenia. By correlation analyses using TBSS, we found that the anterior part of corpus callosum was the substantially overlapped area, negatively correlated with both phonological fluency and delusion severity. Our results suggest that the anterior interhemispheric dysconnectivity might be associated with executive dysfunction, and disinhibited automatic spreading activation in the semantic network was manifested as uncontrollable phonological fluency or delusions. This dysconnectivity could be one possible neural basis that differentiates pathological positive symptoms from adaptive creativity.

Schizotypy--do not worry, it is not all worrisome

A long-standing tradition in personality research in psychology, and nowadays increasingly in psychiatry, is that psychotic and psychotic-like thoughts are considered common experiences in the general population. Given their widespread occurrence, such experiences cannot merely reflect pathological functioning. Moreover, reflecting the multi-dimensionality of schizotypy, some dimensions might be informative for healthy functioning while others less so. Here, we explored these possibilities by reviewing research that links schizotypy to favorable functioning such as subjective wellbeing, cognitive functioning (major focus on creativity), and personality correlates. This research highlights the existence of healthy people with psychotic-like traits who mainly experience positive schizotypy (but also affective features mapping onto bipolar disorder). These individuals seem to benefit from a healthy way to organize their thoughts and experiences, that is, they employ an adaptive cognitive framework to explain and integrate their unusual experiences. We conclude that, instead of focusing only on the pathological, future studies should explore the behavioral, genetic, imaging, and psychopharmacological correlates that define the healthy expression of psychotic-like traits. Such studies would inform on protective or compensatory mechanisms of psychosis-risk and could usefully inform us on the evolutionary advantages of the psychosis dimension.

Investigating word associations in a schizotypy sample: contrasting implicit and explicit processing

INTRODUCTION

Schizotypy is a useful schizophrenia analogue that controls for confounding factors such as medication and general intellectual decline. In the current study this analogue approach was used to examine implicit/explicit and direct/indirect semantic memory function. This is the first study to examine both implicit and explicit semantic access in the same schizotypy sample.

METHODS

Participants completed four semantic tasks: (1) implicit indirect priming, (2) implicit direct priming, (3) explicit object (indirect) task, and (4) explicit association (direct) task. The schizophrenia literature suggests that semantic impairments are associated with thought disorder. As such, participants were divided into low (n=18) and high (n=18) schizotypy groups based on their responses to a thought disorder subscale of the Oxford Liverpool Inventory of Feelings and Experiences (O-Life) scale.

RESULTS

In terms of implicit performance, the high schizotypy group demonstrated increased direct priming but nonsignificant indirect priming. The low schizotypy group demonstrated no significant difference in direct and indirect priming. Performance on the explicit tasks was equivalent between the two groups for direct stimuli. On the indirect explicit task, high schizotypy was associated with an increase in errors.

CONCLUSIONS

Increased direct priming in high schizotypy is equivalent to that seen in schizophrenia, which has been interpreted as increased spreading of activation. Abnormal performance using the indirect stimuli was found across implicit and explicit versions. The relevance of these findings to schizophrenia are discussed.

An Overview of the Association between Schizotypy and Dopamine

Schizotypy refers to a constellation of personality traits that are believed to mirror the subclinical expression of schizophrenia in the general population. Evidence from pharmacological studies indicates that dopamine (DA) is involved in the etiology of schizophrenia. Based on the assumption of a continuum between schizophrenia and schizotypy, researchers have begun investigating the association between DA and schizotypy using a wide range of methods. In this article, we review published studies on this association from the following areas of work: (1) experimental investigations of the interactive effects of dopaminergic challenges and schizotypy on cognition, motor control, and behavior (2), dopaminergically supported cognitive functions (3), studies of associations between schizotypy and polymorphisms in genes involved in dopaminergic neurotransmission, and (4) molecular imaging studies of the association between schizotypy and markers of the DA system. Together, data from these lines of evidence suggest that DA is important to the expression and experience of schizotypy and associated behavioral biases. An important observation is that the experimental designs, methods, and manipulations used in this research are highly heterogeneous. Future studies are required to replicate individual observations, to enlighten the link between DA and different schizotypy dimensions (positive, negative, cognitive disorganization), and to guide the search for solid DA-sensitive behavioral markers. Such studies are important in order to clarify inconsistencies between studies. More work is also needed to identify differences between dopaminergic alterations in schizotypy compared to the dysfunctions observed in schizophrenia.

Inferring about individual drug and schizotypy effects on cognitive functioning in polydrug using mephedrone users before and after clubbing

OBJECTIVE

Mephedrone has been recently made illegal in Europe, but little empirical evidence is available on its impact on human cognitive functions. We investigated acute and chronic effects of mephedrone consumption on drug-sensitive cognitive measures, while also accounting for the influence of associated additional drug use and personality features.

METHOD

Twenty-six volunteers from the general population performed tasks measuring verbal learning, verbal fluency and cognitive flexibility before and after a potential drug-taking situation (pre-clubbing and post-clubbing at dance clubs, respectively). Participants also provided information on chronic and recent drug use, schizotypal (Oxford-Liverpool Inventory of Feelings and Experiences) and depressive symptoms (Beck Depression Inventory), sleep pattern and premorbid IQ.

RESULTS

We found that (i) mephedrone users performed worse than non-users pre-clubbing and deteriorated from the pre-clubbing to the post-clubbing assessment; (ii) pre-clubbing cannabis and amphetamine (not mephedrone) use predicted relative cognitive attenuations; (iii) post-clubbing, depression scores predicted relative cognitive attenuations; and (iv) schizotypy was largely unrelated to cognitive functioning, apart from a negative relationship between cognitive disorganisation and verbal fluency.

CONCLUSION

Results suggest that polydrug use and depressive symptoms in the general population negatively affect cognition. For schizotypy, only elevated cognitive disorganisation showed potential links to a pathological cognitive profile previously reported along the psychosis dimension.

Semantic processing impairment in individuals with schizotypal personality disorder features: a preliminary event-related potential study

OBJECTIVE

This study aimed to examine semantic processing features in individuals with and without schizotypal personality disorder (SPD) features.

METHODS

An implicit semantic task was used to examine the automatic spreading semantic activation process which is relatively free from the influence of attention. An explicit semantic task was used to examine the controlled semantic processing which requires high involvement of attention. Individuals with stable SPD features (n=17) were those who scored higher than 36 on the schizotypal personality questionnaire (SPQ) at two time points. Individuals with unstable SPD features (n=15) were defined as participants who scored higher than 36 at the baseline time point but lower than 36 at the second time point. Their performances in the two semantic tasks were then compared to 17 individuals without SPD features (scoring below 36 at both time points). Event-related potentials (ERP) were recorded when participants were performing the two tasks.

RESULTS

Behavioral data, early ERP components and N400s were analyzed in each experiment. No between-group difference was observed in the implicit semantic task. In the explicit semantic task, the differences involved only the N400 component. When compared to the group without SPD features, participants with stable and unstable SPD features showed enhanced N400 effects (difference wave), while there was no difference between the two groups with SPD features. Moreover, the larger N400 effects were found to be due to less negative N400 amplitudes to related target words.

CONCLUSION

These findings suggest that individuals with SPD features were impaired in processing of context-related stimuli. The inhibition function to contextually unrelated materials in participants with SPD features appeared intact.

Neuropsychological differentiation of adaptive creativity and schizotypal cognition

Both creativity and schizophrenia-spectrum disorders have been associated with activation of remote semantic concepts, but this activation results in innovative output in one case and communication disturbances in the other. The present study examined the relationship between monitoring semantic information (which relies on executive brain function), creativity, and characteristics of schizotypy in an undergraduate population. Results indicate that executive function differentiates the use of semantic information in creativity and schizotypy. Specification of the balance between executive monitoring and activation of semantic information is important for determining how communication disturbances manifest, and for the measurement of creativity and schizotypy in the general population.

Recall of false memories in individuals scoring high in schizotypy: memory distortions are scale specific

BACKGROUND AND OBJECTIVES

Previous research has indicated abnormal semantic activation in individuals scoring higher in schizotypy. In the current experiment, semantic activation was examined by using the Deese-Roediger-McDermott paradigm of false memories.

METHODS

Participants were assessed for schizotypy using the Oxford-Liverpool Inventory of Feelings (OLIFE). Participants studied lists of semantically related words in which a critical and highly associated word was absent. Participants then recalled the list.

RESULTS

Participants high in Unusual Experiences and Cognitive Disorganization recalled more critical non-presented words, weakly related studied words, and fewer studied words than participants who scored low on these measures.

LIMITATIONS

Previous research using the cognitive-perceptual factor of the Schizotypy Personality Questionnaire found reduced false memories, while the Unusual Experiences subscale of the OLIFE was associated with more false memories. Both scales cover similar unusual perceptual experiences and it is unclear why they led to divergent results.

CONCLUSIONS

The findings suggest that subtypes of schizotypy are associated with abnormal semantic activation.

Sensitivity to coincidences and paranormal belief

Often it is difficult to find a natural explanation as to why a surprising coincidence occurs. In attempting to find one, people may be inclined to accept paranormal explanations. The objective of this study was to investigate whether people with a lower threshold for being surprised by coincidences have a greater propensity to become believers compared to those with a higher threshold. Participants were exposed to artificial coincidences, which were formally defined as less or more probable, and were asked to provide remarkability ratings. Paranormal belief was measured by the Australian Sheep-Goat Scale. An analysis of the remarkability ratings revealed a significant interaction effect between Sheep-Goat score and type of coincidence, suggesting that people with lower thresholds of surprise, when experiencing coincidences, harbor higher paranormal belief than those with a higher threshold. The theoretical aspects of these findings were discussed.

Leftward bias in number space is modulated by magical ideation

BACKGROUND

Productive symptoms of schizophrenia and positive-symptom schizotypy have both been related to signs of right-sided hemispatial inattention ("pseudoneglect"). We here set out to explore, in healthy subjects, the relationship between one form of mild schizotypy ("magical ideation"; MI) and asymmetries in number space, which is a bias toward relatively small numbers, reportedly represented to the left of larger numbers.

METHODS

Forty right-handed participants filled in the MI scale and performed a number-line bisection (NLB) task and a randomization task (the Mental Dice Task, MDT, requiring randomization of the digits from 1 to 6).

RESULTS

We found pseudoneglect in number space, that is, more errors toward small numbers in the NLB task and an overproduction of small digits in the MDT. Individual participants' MI scores were correlated to the size of pseudoneglect in both numerical tasks.

CONCLUSIONS

Explicit (NLB) and implicit (MDT) assessments of the exploration of number space may be relevant to studies of the mechanisms underlying the formation of delusional and schizotypal beliefs. We propose that, in healthy subjects, a trait-like imbalance in hemispheric cooperation may not only produce asymmetries in physical and representational space, but also predisposes to develop magical ideas. Specifically, an over-proportional influence of the right hemisphere semantic system (preferentially coding oblique and remote associations) leads to the assumption of connections between randomly associated events.

Metaphor processing in high and low schizotypal individuals

Two hypotheses were considered regarding the relationship between positive schizotypy and metaphor processing. On the basis of continuity between schizophrenia and schizotypy, high schizotypal individuals would be expected to be impaired at metaphor processing. However, given the right hemisphere processing bias that has been associated with positive schizotypy, they would be expected to be superior at metaphor processing. A story completion task in which participants judged the appropriateness of literal and metaphoric statements was administered to 30 high and 29 low schizotypal individuals. Contrary to both hypotheses, groups did not differ in their ability to discriminate between appropriate and inappropriate statements, whether literal or metaphoric. However, the high schizotypal group demonstrated a less conservative response bias; they were more likely than the low schizotypal group to identify a statement as appropriate, whether it was or was not. Implications of these results for our understanding of language processing in schizophrenia and schizotypy are discussed.

An event-related brain potential study of schizotypal personality and associative semantic processing

To examine whether schizotypal personality is associated with the degree to which concepts activate each other in semantic memory, event-related brain potentials (ERPs) were recorded during a delayed lexical decision task from healthy volunteers rated for schizotypy. Each target word was directly, indirectly, or not at all related to a prime word preceding it at a 300- or 750-ms stimulus-onset asynchrony (SOA). Overall, N400 amplitudes were largest for unrelated targets, smallest for directly related targets, and intermediate for indirectly related targets. Higher total Schizotypal Personality Questionnaire (SPQ) scores correlated with smaller N400 indirect priming effects (i.e., smaller N400 amplitude differences between unrelated and indirectly related targets) at both SOAs. In addition, schizotypal subscale scores were differentially associated with N400 effects. Higher SPQ Cognitive-Perceptual scores correlated with smaller N400 direct priming effects (smaller N400 amplitude differences between unrelated and directly related targets) at both SOAs, and with smaller N400 indirect priming effects at the shorter SOA. These correlations are consistent with the hypothesis that decreased use of meaningful context to activate related concepts in general, and/or to inhibit unrelated concepts, may play some role in the development of unusual beliefs.

Seeing non-existent events: effects of environmental conditions, schizotypal symptoms, and sub-clinical characteristics

Under conditions of perceptual ambiguity positive schizotypy and positive symptoms of schizophrenia have been associated with a bias towards reporting the presence of an event in its absence. A word detection task was employed (Experiments 1-3; N=211) to explore a number of environmental parameters, such as perceptual ambiguity (speed of stimulus presentation), and the probability of an event, in an effort to identify the empirical laws that modulate this type of bias. Overall, the obtained data suggested that high schizotypy scorers were more prone to false perceptions (false alarms) as compared to their low schizotypy counterparts, although the two groups did not differ with respect to accuracy (correct responses). High perceptual ambiguity increased false perceptions in both high and low schizotypy scorers. False perceptions increased as the probability level of the presented word increased. This tendency was especially pronounced in the high schizotypy group. False perceptions were predicted by positive schizotypy and disposition to hallucinations after controlling for trait anxiety, depression and delusional ideation.

Positive schizotypy is not associated with speech abnormality

AIM

This study examined whether speech abnormalities typical of formal thought disorder in schizophrenia vary with the degree of positive schizotypy in the healthy population. We hypothesized that participants with high levels of positive schizotypy would show greater abnormality in speech relative to those with low levels of positive schizotypy.

METHODS

Participants (n=107) were prescreened with a positive schizotypy scale. Those meeting criteria for either high (n=23) or low (n=27) schizotypy provided speech samples which were assessed with a clinical though disorder rating scale (Thought and Language Index) for the presence of abnormality.

RESULTS

No significant differences were found in positive (P=0.25) or negative (P=0.21) speech abnormality between the high and low schizotypy groups.

CONCLUSION

Although schizotypy is normally distributed in the general population, speech abnormality is not. Thus, the presence of aberrations in speech may predict risk of psychosis. Potential implications for risk assessment are discussed.

Schizotypy and pseudoneglect: a critical update on theories of hemispheric asymmetries

INTRODUCTION

Positive schizotypy has been associated with a leftward spatial bias (pseudoneglect) in different tasks and populations. We tested whether this relationship (1) can be observed for two different hemispatial tasks in the same participants, and (2) is specific to positive schizotypy.

METHODS

Forty right-handed men performed a conventional line bisection task and a whole-body movement task. In the latter task, participants were presented with illuminated target locations on the floor, and had to visit the remembered locations (equal number in right and left hemispace) after a short time interval. We assessed side preferences in both tasks. Positive schizotypy, negative schizotypy, and cognitive disorganisation were assessed with a validated self-report questionnaire.

RESULTS

Irrespective of schizotypy, pseudoneglect was observed in both tasks. We found a rightward bisection and walking bias as a function of positive schizotypy, and also as a function of cognitive disorganisation for walking initiation.

DISCUSSION

This unexpected finding resulted in a review of hemispheric asymmetry for function in schizotypy, and in the discussion of potential variables that might account for the present discrepancy. We suggest that different schizotypy questionnaires and their presentation mode might be a potential contributor to the opposite findings in the literature.

Creative thinking in schizophrenia: the role of executive dysfunction and symptom severity

INTRODUCTION

This study examines the notion of enhanced creative thinking in schizophrenia and determines the mediating role of executive dysfunction and symptom severity in this relationship.

METHOD

Patients with chronic schizophrenia (n=28) were assessed on varied facets of creative cognition and standard tests of executive control relative to matched healthy control participants (n=18).

RESULTS

Multivariate analyses revealed poorer performance by the patient group across almost all creative and executive function measures, except in the ability to be unconstrained by the influence of restrictive examples. Symptom-based contrasts using partial correlations revealed that differences were most extensive in the presence of thought disorder. Using hierarchical regression analyses, performance on the executive function tasks was found to play a mediatory role on specific aspects of creative cognition.

CONCLUSIONS

Results are at odds with the popular notion of enhanced creative thinking in schizophrenia, but elucidate complex interactions between executive control and certain facets of creative thinking. In particular, performance of the schizophrenia group on measures that tap creativity elements of fluency and relevance were either partially or fully mediated by their performance on the executive control tasks, but this was not true of measures of originality.

The role of the extrapersonal brain systems in religious activity

The neuropsychology of religious activity in normal and selected clinical populations is reviewed. Religious activity includes beliefs, experiences, and practice. Neuropsychological and functional imaging findings, many of which have derived from studies of experienced meditators, point to a ventral cortical axis for religious behavior, involving primarily the ventromedial temporal and frontal regions. Neuropharmacological studies generally point to dopaminergic activation as the leading neurochemical feature associated with religious activity. The ventral dopaminergic pathways involved in religious behavior most closely align with the action-extrapersonal system in the model of 3-D perceptual-motor interactions proposed by . These pathways are biased toward distant (especially upper) space and also mediate related extrapersonally dominated brain functions such as dreaming and hallucinations. Hyperreligiosity is a major feature of mania, obsessive-compulsive disorder, schizophrenia, temporal-lobe epilepsy and related disorders, in which the ventromedial dopaminergic systems are highly activated and exaggerated attentional or goal-directed behavior toward extrapersonal space occurs. The evolution of religion is linked to an expansion of dopaminergic systems in humans, brought about by changes in diet and other physiological influences.