Reaction time slowing during high-load, sustained-attention task performance in relation to psychometrically identified schizotypy

Prior research has demonstrated a reliable deficit in performance accuracy (e.g., d') on sustained-attention tasks in relation to psychometrically identified schizotypy and clinically diagnosed schizotypal psychopathology. The present study sought to expand the understanding of sustained-attention performance in relation to psychometric schizotypy through a study of reaction time (RT) performance. In this study, the author examined performance accuracy and RT on a high-load, sustained-attention task, the Continuous Performance Test-Identical Pairs (CPT-IP) version, in 31 high Perceptual Aberration Scale (PAS) and 26 normal control (control PAS) subjects from a large university population. High PAS (psychometric schizotypy) subjects displayed significantly longer RT performance on the CPT-IP relative to controls. The RT slowing was not explained by mental state or general intellectual ability factors. Contrary to expectation, a difference in performance accuracy (e.g., d') was not observed between the groups; however, power and other considerations cloud the interpretation of this finding. The meaning of the observed RT slowing is examined and its relation to current models of the development of schizophrenia is discussed.     

Poorer divided attention in children born very preterm can be explained by difficulty with each component task,not the executive requirement to dual-task

Children born very preterm (VP, ≤ 32 weeks) exhibit poor performance on tasks of executive functioning. However, it is largely unknown whether this reflects the cumulative impact of non-executive deficits or a separable impairment in executive-level abilities. A dual-task paradigm was used in the current study to differentiate the executive processes involved in performing two simple attention tasks simultaneously. The executive-level contribution to performance was indexed by the within-subject cost incurred to single-task performance under dual-task conditions, termed dual-task cost. The participants included 77 VP children (mean age: 7.17 years) and 74 peer controls (mean age: 7.16 years) who completed Sky Search (selective attention), Score (sustained attention) and Sky Search DT (divided attention) from the Test of Everyday Attention for Children. The divided-attention task requires the simultaneous performance of the selective- and sustained-attention tasks. The VP group exhibited poorer performance on the selective- and divided-attention tasks, and showed a strong trend toward poorer performance on the sustained-attention task. However, there were no significant group differences in dual-task cost. These results suggest a cumulative impact of vulnerable lower-level cognitive processes on dual-tasking or divided attention in VP children, and fail to support the hypothesis that VP children show a separable impairment in executive-level abilities.     

The Effect of Anxiety on the Cognitive Functioning in Non-clinical Schizotypal Individuals

Schizotypal personality disorder (SPD) is characterized by eccentric behavior and perceptual distortions that closely resemble the patterns observed in those with schizophrenia. Schizophrenia and related personality disorders (i.e., SPD) are associated with deficits in sustained attention, slower than normal reaction times, and manifestations of working memory deficits and erratic cognitive tasks. The present study used the schizotypal personality scale (STA) to compare cognitive abilities of self-reported low schizotypic tendency subjects with high schizotypic tendency subjects. The group scores on the STA differed significantly. Those with high STA scores also tended to have higher state and trait anxiety scores based on the State-Trait Anxiety Inventory (STAI). The groups did not significantly differ on any of the demographic variables tested, including age, education, self-rated health status, and medication. Along with an executive function test, two computerized tasks tested subjects on reaction time and memory. Even when covariates (i.e., state, trait anxiety scores) were analyzed, there were no significant differences between the groups and tasks, although the gathered data showed trends in the expected direction.     

The Effect of Anxiety on the Cognitive Functioning in Non-clinical Schizotypal Individuals

Schizotypal personality disorder (SPD) is characterized by eccentric behavior and perceptual distortions that closely resemble the patterns observed in those with schizophrenia. Schizophrenia and related personality disorders (i.e., SPD) are associated with deficits in sustained attention, slower than normal reaction times, and manifestations of working memory deficits and erratic cognitive tasks. The present study used the schizotypal personality scale (STA) to compare cognitive abilities of self-reported low schizotypic tendency subjects with high schizotypic tendency subjects. The group scores on the STA differed significantly. Those with high STA scores also tended to have higher state and trait anxiety scores based on the State-Trait Anxiety Inventory (STAI). The groups did not significantly differ on any of the demographic variables tested, including age, education, self-rated health status, and medication. Along with an executive function test, two computerized tasks tested subjects on reaction time and memory. Even when covariates (i.e., state, trait anxiety scores) were analyzed, there were no significant differences between the groups and tasks, although the gathered data showed trends in the expected direction.     

Drifting from slow to "D'oh!": working memory capacity and mind wandering predict extreme reaction times and executive control errors

A combined experimental, individual-differences, and thought-sampling study tested the predictions of executive attention (e.g., Engle & Kane, 2004) and coordinative binding (e.g., Oberauer, Süβ, Wilhelm, & Sander, 2007) theories of working memory capacity (WMC). We assessed 288 subjects' WMC and their performance and mind-wandering rates during a sustained-attention task; subjects completed either a go/no-go version requiring executive control over habit or a vigilance version that did not. We further combined the data with those from McVay and Kane (2009) to (1) gauge the contributions of WMC and attentional lapses to the worst performance rule and the tail, or τ parameter, of reaction time (RT) distributions; (2) assess which parameters from a quantitative evidence-accumulation RT model were predicted by WMC and mind-wandering reports; and (3) consider intrasubject RT patterns--particularly, speeding--as potential objective markers of mind wandering. We found that WMC predicted action and thought control in only some conditions, that attentional lapses (indicated by task-unrelated-thought reports and drift-rate variability in evidence accumulation) contributed to τ, performance accuracy, and WMC's association with them and that mind-wandering experiences were not predicted by trial-to-trial RT changes, and so they cannot always be inferred from objective performance measures.     

Hemispheric visual atentional imbalance in patients with traumatic brain injury

We find a spatially asymmetric allocation of attention in patients with traumatic brain injury (TBI) despite the lack of obvious asymmetry in neurological indicators. Identification performance was measured for simple spatial patterns presented briefly to a locus 5 degrees into the left or right hemifield, after precuing attention to the same (ipsilateral) or opposite (cross-hemifield) side. Though the cue was non-predictive of target location overall, performance was significantly slower for cross than for ipsilateral trials in both patients and controls. We tested 21 TBI patients without overt focal brain damage and nine control subjects. Only patients demonstrated significantly worse performance for left side presentation in the ipsilateral condition. Furthermore, in the cross-hemifield condition, the left-right difference seen in TBI patients was significantly larger-reflecting a failure in producing a leftward attention shift. Again no significant difference was found in controls. These hemifield effects suggest an asymmetry in the ability of TBI patients in shifting attention to the left hemifield, whether from central fixation or from a cue in the contra-lateral hemifield. The results support basic hypotheses regarding visual attention: Attentional control may be asymmetric and attention may be a distributed, rather than localized cortical function.     

Smooth pursuit eye movement and schizotypy in the community

Deficits in smooth pursuit eye movements are well documented in schizophrenia and schizotypic psychopathology. The status of eye tracking dysfunction (ETD) as an endophenotype for schizophrenia liability is relatively robust. However, the relation of ETD to schizophrenia-related deviance in the general population has not been confirmed. This study examined smooth pursuit eye tracking and schizotypal personality features in the general population. Smooth pursuit eye movement and schizotypal features were measured in 300 adult community subjects. The sample included both sexes, subjects with a wide age and educational range, and subjects with no prior history of psychosis. Primary outcome measures were peak gain (eye velocity/target velocity), catch-up saccade rate, and schizotypal feature scores. Total schizotypal features were significantly associated with decreased peak gain and were associated at the trend level with increased catch-up saccade rate. These associations were essentially unchanged after controlling for age, sex, and intellectual level effects. These data confirm a hypothesized association between schizotypal features and poorer eye tracking performance (principally, peak gain) in the general population as well as support the conceptualization of ETD as an endophenotype for schizophrenia liability.     

Effect of attention control on sustained attention during induced anxiety

Anxiety has wide-reaching and complex effects on cognitive performance. Although it can intrude on cognition and interfere with performance, it can also facilitate information processing and behavioural responses. In a previous study, we showed that anxiety induced by threat of shock facilitates performance on the Sustained Attention to Response Task, a vigilance test, which probes response inhibition to infrequent nogo stimuli. The present study sought to identify factors that may have contributed to such improved performance, including on- and off-task thinking (assessed with thought probes) and individual differences in attention control, as measured with the Attention Control Scale. Replicating our prior finding, we showed that shock threat significantly reduced errors of commission on the nogo trials. However, we extended this finding in demonstrating that this effect was driven by subjects with low attention control. We therefore confirm that anxiety increases inhibitory control of prepotent responses—a mechanism which is adaptive under threat—and show that this effect is greater in those who rely more upon such prepotent responding, i.e., those with low attentional control.     

The Contributions of Creative Cognition and Schizotypal Symptoms to Creative Achievement

Although previous research has suggested that people with subclinical levels of schizophrenic symptoms achieve a greater number of creative accomplishments, the contention that there is a creative cognitive advantage in schizotypy has received mixed support. It was hypothesized that accounting for complex relationships between (a) creative cognition abilities (moderated relationships), and (b) creative cognition and schizotypy variables (mediated, moderated, and curvilinear relationships) would significantly increase the ability to predict creative performance and provide a more accurate survey of the schizotypic creative cognitive advantage. One hundred and fourteen participants completed a creative problem solving measure, measures of cognitive creative abilities (Remote Associates Test, a divergent thinking task, and a deductive reasoning task) and measures of positive and negative symptoms of schizotypy. Regression analyses supported the conception of a multistage process in which creative cognition variables interact with each other to predict performance on a creative problem solving task. There was no evidence of a creative cognitive advantage in schizotypy: People high in schizotypy performing the same or worse than people reporting few schizotypic symptoms on measures of creative cognition and creative problem solving performance. If people with schizotypy are, indeed, more creative than those without, it is because of factors other than the cognitive processes surveyed in this investigation.     

An Eye-tracking Analysis of the Effect of Prior Comparison on Analogical Mapping

The present research examined the effect of prior experience on the distribution of attention during judgments of analogical similarity. Identifying analogical similarity requires mapping a set of relations in one situation onto a matching set of relations in an analogous situation. Analogical mapping is difficult when the common relational structure is embedded in contexts with dissimilar surface features and irrelevant surface similarities. Prior comparison of analogs may help subjects find future relational correspondences and ignore surface similarity (Markman and Gentner 1993). In the present study, attention was measured with eye tracking, which was monitored while subjects rated the similarity of analogous scenes. Experimental but not control subjects had previously compared scenes with the same structure. Eye fixation data indicated that prior comparison did not affect attention to structure-relevant objects, but significantly reduced attention to irrelevant surface-similar objects. Scanning data showing that both groups scanned within scenes more than between scenes were consistent with structure-mapping models of analogy.     

Evidence for a cognitive control network for goal-directed attention in simple sustained attention

The deterioration of performance over time is characteristic for sustained attention tasks. This so-called “performance decrement” is measured by the increase of reaction time (RT) over time. Some behavioural and neurobiological mechanisms of this phenomenon are not yet fully understood. Behaviourally, we examined the increase of RT over time and the inter-individual differences of this performance decrement. On the neurophysiological level, we investigated the task-relevant brain areas where neural activity was modulated by RT and searched for brain areas involved in good performance (i.e. participants with no or moderate performance decrement) as compared to poor performance (i.e. participants with a steep performance decrement). For this purpose, 20 healthy, young subjects performed a carefully designed task for simple sustained attention, namely a low-demanding version of the Rapid Visual Information Processing task. We employed a rapid event-related functional magnetic resonance imaging (fMRI) design. The behavioural results showed a significant increase of RT over time in the whole group, and also revealed that some participants were not as prone to the performance decrement as others. The latter was statistically significant comparing good versus poor performers. Moreover, high BOLD-responses were linked to longer RTs in a task-relevant bilateral fronto-cingulate-insular-parietal network. Among these regions, good performance was associated with significantly higher RT-BOLD correlations in the pre-supplementary motor area (pre-SMA). We concluded that the task-relevant bilateral fronto-cingulate-insular-parietal network was a cognitive control network responsible for goal-directed attention. The pre-SMA in particular might be associated with the performance decrement insofar that good performers could sustain activity in this brain region in order to monitor performance declines and adjust behavioural output.     

Attention to errors and learning: Across-task and across-domain analysis of the postfailure reflectivity measure

The ratio between the mean postfailure and postsuccess latencies on a self-paced task (Postfailure Reflectivity) has been proposed as a measure of attention to errors, affecting learning across domains. This study was devised to test the generality of Postfailure Reflectivity (PFR). In Experiment 1, performance on two nonverbal, inference, and induction/deduction tasks was examined. Reading disabled subjects showed significantly less PFR than normally achieving subjects, and PFR correlated positively with the score in two nonverbal tasks, and across two testing times. In Experiment 2, PFR was significantly correlated with performance on two nonverbal tasks and one arithmetic task, and with measures of deep planning during interviews following the learning of a nonverbal inference task, as well as following motor and cognitive learning tasks. PFR also correlated with intentional learning, as measured on the Implicit Theories Interview. Jointly considered, these findings support the view that attention to errors plays a central role in learning, and that PFR is a good measure of attention to errors. It appears that Postfailure Reflectivity is a metacognitive skill which possesses adaptive, generalized, and trans-domain characteristics.     

The Influence of Maternal Schizotypy on the perception of Facial Emotional Expressions during Infancy: an Event-Related Potential Study

Parenting directly affects the developmental and clinical outcomes of children. How parental personality relates to perceptual and cognitive mechanisms during early development is not clear. For parents with traits of the personality dimension schizotypy, would their infant display brain responses similar to those on the schizophrenia-spectrum? This study investigates whether maternal personality influences early social-cognitive awareness during the first 6 postnatal months.Schizotypy is a dimension of personality within the general population. If deficits contribute to the development of schizophrenia-spectrum disorders by influencing the development of symptom-like characteristics, they may be observable in neurotypical individuals with schizotypal characteristics. Parents and their infants were shown standardised positive and negative faces and event-related potential responses were assessed. It was hypothesised that the infants of schizotypic mothers would display differential Negative-central event-related potentials for the happy and fearful expressions when compared to infants of non-schizotypic mothers.Results support prior literature; indicating 6-month-old infants allocate more attentional resources to fearful when contrasted to happy faces. The adult cohort displays this same ability. In addition, schizotypic mothers displayed comparable amplitudes for both expressions in comparison to the control mothers who exhibited larger amplitudes towards the fearful compared to the happy expression. Infants of schizotypic mothers did not show a greater sensitivity to facial expressions at 6-months, but schizotypic mothers showed a generalised response towards facial expressions compared to the typical P600 response illustrated by the control mothers. The present study suggests that development in the higher cognitive domains, such as the allocation of attention to novel stimuli, are not affected at 6 months of age by maternal personality related to schizotypy when examined at the group level. Implications for personality development, maternal-infant interactions and cognitive neuroscience methodologies are discussed.     

Scores for schizotypy and five-factor model of a sample of distant healers: a preliminary study

A preliminary study was conducted to evaluate the personality scores of 18 distant healers on the NEO-Five Factor Inventory and the Schizotypal Personality Questionnaire-Brief. These distant healers differed significantly in their schizotypic tendencies, both in comparison to normed scores and to a control group of 19 masseurs. Further differences were found on scales of Conscientiousness and Openness to experience.     

Mindfulness and mind wandering: The protective effects of brief meditation in anxious individuals

Mind wandering can be costly, especially when we are engaged in attentionally demanding tasks. Preliminary studies suggest that mindfulness can be a promising antidote for mind wandering, albeit the evidence is mixed. To better understand the exact impact of mindfulness on mind wandering, we had a sample of highly anxious undergraduate students complete a sustained-attention task during which off-task thoughts including mind wandering were assessed. Participants were randomly assigned to a meditation or control condition, after which the sustained-attention task was repeated. In general, our results indicate that mindfulness training may only have protective effects on mind wandering for anxious individuals. Meditation prevented the increase of mind wandering over time and ameliorated performance disruption during off-task episodes. In addition, we found that the meditation intervention appeared to promote a switch of attentional focus from the internal to present-moment external world, suggesting important implications for treating worrying in anxious populations.     

Repression-sensitization differences in recovery from learned helplessness.

The performance of repressors and sensitizers on a solvable anagram task was assessed after either a short delay (0 to 30 min) or a long delay (2 to 6 hr) following a standard learned helplessness induction. Results indicated that all subjects exposed to the learned helplessness induction exhibited performance deficits, compared with control subjects exposed to no induction. Furthermore, subjects who were tested after the short delay did not perform as well as subjects tested after a long delay. No difference in overall anagram performance was found between repressors and sensitizers. Consistent with theoretical predictions, however, the anagram performance of repressor subjects was significantly better in the long-delay than in the short-delay condition; this significant recovery effect between short- and long-delay conditions was not obtained for sensitizer subjects. Possible theoretical mechanisms for these effects and implications for future research are noted.     

Somatosensory processing in the biological relatives of schizophrenia patients: a signal detection analysis of two-point discrimination

This study examined 2-point discrimination performance in 1 st-degree biological relatives (n = 39) of individuals with schizophrenia and normal adult control participants (n = 30) recruited from the community. They completed an objective 2-point discrimination task, adapted for use with a signal detection approach to permit separation of discriminability (i.e., sensitivity, d') from response bias/ criterion (or motivation, lnbeta). Relatives revealed poorer performance on the d' index compared with controls. The 2 groups did not differ on lnbeta, suggesting a genuine difference in sensitivity but not response bias. The sensitivity deficit might reflect decreased spatial acuity and/or impaired intensity cue processing of tactile stimuli. Poor performance on the d' index was most closely associated with 2 schizotypic features, namely "odd beliefs/magical thinking."     

Natural-scene perception requires attention

Is visual attention required for visual consciousness? In the past decade, many researchers have claimed that awareness can arise in the absence of attention. This claim is largely based on the notion that natural scene (or "gist") perception occurs without attention. This article presents evidence against this idea. We show that when observers perform a variety of demanding, sustained-attention tasks, inattentional blindness occurs for natural scenes. In addition, scene perception is impaired under dual-task conditions, but only when the primary task is sufficiently demanding. This finding suggests that previous studies that have been interpreted as demonstrating scene perception without attention failed to fully engage attention and that natural-scene perception does indeed require attention. Thus, natural-scene perception is not a preattentive process and cannot be used to support the idea of awareness without attention.     

Finding the "genuine" schizotype: a model and method for resolving heterogeneity in performance on laboratory measures in experimental psychopathology research

Heterogeneity in the performance of persons affected with schizophrenia or schizotypic psychopathology on various laboratory tasks has long been recognized, both for its consistency across tasks and studies and for the massive methodological and substantive challenges it poses for experimental psychopathology, genetic, and other investigations. Traditional multivariate techniques, such as factor analysis, discriminant function analysis, and cluster analysis, have all been deemed inadequate for resolving heterogeneity, because of one or another statistical limitation. Here, an objective statistical approach based on a formal statistical model that uses the ubiquitous and well-developed expectation-maximization (EM) algorithm (A. P. Dempster, N. M. Laird, & D. B. Rubin, 1977) is presented, which enables one effectively to partition a group of experimental subjects, in this case identified initially using the well-known Perceptual Aberration Scale (L. J. Chapman, J. P. Chapman, & M. L. Raulin, 1978), in a manner that reduces heterogeneity and allows for the separation of what are termed genuine and false-positive schizotypes. The validity of the parsing strategy was supported by reference to other laboratory indexes of relevance to schizophrenia and schizotypy that were not included in the initial EM-based analyses. The potential utility of this approach is discussed with reference to future schizophrenia and schizotypy research.     

Social facilitation

Video-recording procedures have been used in previous research as a motivational manipulation. The present study investigated the permanent recording of behavior as a manipulation of evaluation apprehension and its effects upon behavioral performance and upon autonomic arousal. Twenty-four subjects (12 males, 12 females) were randomly assigned to one of four conditions formed by completely crossing two levels of audience status (peer or authority) with two levels of behavioral record (non-permanent or permanent). Another 24 subjects were assigned to an external control group to the 2×2 design. Subjects' performance on a hidden-word task and their arousal level (as assessed by the Palmar Sweat Index) were measured. Analyses of variance results showed a significant performance (p<.05) and a significant arousal (p<.05) difference between the behavioral record conditions as predicted. The control group was also found to be significantly (p<.05) different from the experimental groups on the behavioral performance measure. The results were related to previous research findings and interpreted within the context of the evaluation apprehension notion presented within social facilitation research.The author would like to thank Angelia Mellors, Valerie K. Golish, and Judy Cohen for serving as experiments, and Susan L. Doman and Cheryl Primmer for scoring the PSI measures.