The plausibility transition model for sensemaking.

When people make plausibility judgments about an assertion, an event, or a piece of evidence, they are gauging whether it makes sense that the event could transpire as it did. Therefore, we can treat plausibility judgments as a part of sensemaking. In this paper, we review the research literature, presenting the different ways that plausibility has been defined and measured. Then we describe the naturalistic research that allowed us to model how plausibility judgments are engaged during the sensemaking process. The model is based on an analysis of 23 cases in which people tried to make sense of complex situations. The model describes the user's attempts to construct a narrative as a state transition string, relying on plausibility judgments for each transition point. The model has implications for measurement and for training.

Executive Functions and Psychopathology Dimensions in Deficit and Non-Deficit Schizophrenia.

This study: (a) compared executive functions between deficit (DS) and non-deficit schizophrenia (NDS) patients and healthy controls (HC), controlling premorbid IQ and level of education; (b) compared executive functions in DS and NDS patients, controlling premorbid IQ and psychopathological symptoms; and (c) estimated relationships between clinical factors, psychopathological symptoms, and executive functions using structural equation modelling. Participants were 29 DS patients, 44 NDS patients, and 39 HC. Executive functions were measured with the Mazes Subtest, Spatial Span Subtest, Letter Number Span Test, Color Trail Test, and Berg Card Sorting Test. Psychopathological symptoms were evaluated with the Positive and Negative Syndrome Scale, Brief Negative Symptom Scale, and Self-evaluation of Negative Symptoms. Compared to HC, both clinical groups performed poorer on cognitive flexibility, DS patients on verbal working memory, and NDS patients on planning. DS and NDS patients did not differ in executive functions, except planning, after controlling premorbid IQ and negative psychopathological symptoms. In DS patients, exacerbation had an effect on verbal working memory and cognitive planning; in NDS patients, positive symptoms had an effect on cognitive flexibility. Both DS and NDS patients presented deficits, affecting the former to a greater extent. Nonetheless, clinical variables appeared to significantly affect these deficits.

Assessment of Motor Planning and Inhibition Performance in Non-Clinical Sample-Reliability and Factor Structure of the Tower of London and Go/No Go Computerized Tasks.

In two studies, we examine the test-retest reliability and factor structure of the computerized Tower of London (TOL) and Go/No Go (GNG). Before analyses, raw results of variables that were not normally distributed were transformed. Study 1 examined the reliability of a broad spectrum of indicators (Initial Time Thinking, ITT; Execution Time, ET; Full Time, FT; Extra Moves, EM; No Go Errors, NGE; Reaction Time for Go Responses, RTGR) across an eight-week delay in a sample of 20 young adults. After correction for multiple comparisons and correlations, our results demonstrate that the tasks have ambiguous test-retest reliability coefficients (non-significant r for all indicators, and interclass correlation (ICC) for TOL; significant ICC for GNG; show lack of reliable change over time for all indicators in both tasks); moreover, ITT exhibits strong practice effects. Study 2 investigated both tasks' factor structure and conducted a more detailed analysis of indicators for each trial (ITT, ET, EM) in the TOL task in the group of 95 young adults. Results reveal a satisfactory 2-factor solution, with the first factor (planning inhibition) defined by ITT, NGE, and RTGR, and the second factor (move efficiency) defined by EM and ET. The detailed analysis identified a 6-factor solution with the first factor defined by ITT for more difficult trials and the remaining five factors defined by EM and ET for each trial, reflecting move efficiency for each trial separately.

The relationship between cingulum bundle integrity and different aspects of executive functions in chronic schizophrenia.

BACKGROUND: Evidence suggests that disruption in the cingulum bundle (CB) may influence executive dysfunctions in schizophrenia, but findings are still inconsistent. Using diffusion tensor imaging tractography, we investigated the differences in fiber integrity between schizophrenia patients and healthy controls together with the association between fiber integrity and executive functions. METHODS: Thirty-two patients with chronic schizophrenia and 24 healthy controls took part in the study. Both groups were matched for age, sex, and years of education. Assessment of cognitive functions was performed using the Berg Card Sorting Test (BCST), the Color Trail Test (CTT), and the Stroop Color-Word Test (SCWT). RESULTS: Results showed group differences, bilaterally (left and right) in fractional anisotropy (FA) of the CB, where patients showed less anisotropy than controls. Moreover, normal asymmetry (left FA > right FA) in the CB in schizophrenia was found. There were no group differences in mean diffusivity (MD). Patients had a similar but reduced profile of executive functions compared to healthy controls. However, when premorbid IQ was controlled for, the differences were no longer statistically significant. In schizophrenia patients, a negative correlation was found between FA of the left CB and perseverative errors in the BCST. CONCLUSIONS: These findings provide evidence that CB disruption appears in schizophrenia patients and might account for impairments of executive processes, including concept formation.

Situation Awareness Performance in Healthy Young Adults Is Associated With a Serotonin Transporter Gene Polymorphism.

Background Situation awareness (SA) is defined in three levels: SA1 is the perception of the elements in a specific context, SA2 is the comprehension of their meaning, and SA3 is the projection of their status. Purpose To analyze the possible association of a genetic polymorphism in the serotonin transporter ( SLC6A4) gene and performance on the Situational Awareness test (SAtest). Methods SAtest was applied to a sample of 230 healthy Colombian subjects, using the Psychology Experiment Building Language platform and a functional polymorphism in the SLC6A4 gene was genotyped by polymerase chain reaction. Results In the SA1 level, s/s genotype carriers had worse accuracy, in comparison with s/l and l/l genotypes. At SA2 level, l/l genotype carriers had better accuracy than s/s and s/l individuals and that in the SA3 level, l/l carriers also had better accuracy. These associations were significant after correction for multiple testing. Conclusions It is possible that l/l carriers have a better ability to perceive and focus their attention on the elements of their environment and to have the capacity to understand and predict what will happen with those elements. This is the first genetic study of SA performance in healthy participants. Additional investigations of other genes could contribute to the understanding of the molecular correlates of SA in healthy subjects and in neuropsychiatric patients.

Evaluation of the validity of the Psychology Experiment Building Language tests of vigilance, auditory memory, and decision making.

Background. The Psychology Experimental Building Language (PEBL) test battery (http://pebl.sourceforge.net/) is a popular application for neurobehavioral investigations. This study evaluated the correspondence between the PEBL and the non-PEBL versions of four executive function tests. Methods. In one cohort, young-adults (N = 44) completed both the Conner's Continuous Performance Test (CCPT) and the PEBL CPT (PCPT) with the order counter-balanced. In a second cohort, participants (N = 47) completed a non-computerized (Wechsler) and a computerized (PEBL) Digit Span (WDS or PDS) both Forward and Backward. Participants also completed the Psychological Assessment Resources or the PEBL versions of the Iowa Gambling Task (PARIGT or PEBLIGT). Results. The between-test correlations were moderately high (reaction time r = 0.78, omission errors r = 0.65, commission errors r = 0.66) on the CPT. DS Forward was significantly greater than DS Backward on the WDS (p < .0005) and the PDS (p < .0005). The total WDS score was moderately correlated with the PDS (r = 0.56). The PARIGT and the PEBLIGTs showed a very similar pattern for response times across blocks, development of preference for Advantageous over Disadvantageous Decks, and Deck selections. However, the amount of money earned (score-loan) was significantly higher in the PEBLIGT during the last Block. Conclusions. These findings are broadly supportive of the criterion validity of the PEBL measures of sustained attention, short-term memory, and decision making. Select differences between workalike versions of the same test highlight how detailed aspects of implementation may have more important consequences for computerized testing than has been previously acknowledged.

Adapting cultural mixture modeling for continuous measures of knowledge and memory fluency.

Previous research (e.g., cultural consensus theory (Romney, Weller, & Batchelder, American Anthropologist, 88, 313-338, 1986); cultural mixture modeling (Mueller & Veinott, 2008)) has used overt response patterns (i.e., responses to questionnaires and surveys) to identify whether a group shares a single coherent attitude or belief set. Yet many domains in social science have focused on implicit attitudes that are not apparent in overt responses but still may be detected via response time patterns. We propose a method for modeling response times as a mixture of Gaussians, adapting the strong-consensus model of cultural mixture modeling to model this implicit measure of knowledge strength. We report the results of two behavioral experiments and one simulation experiment that establish the usefulness of the approach, as well as some of the boundary conditions under which distinct groups of shared agreement might be recovered, even when the group identity is not known. The results reveal that the ability to recover and identify shared-belief groups depends on (1) the level of noise in the measurement, (2) the differential signals for strong versus weak attitudes, and (3) the similarity between group attitudes. Consequently, the method shows promise for identifying latent groups among a population whose overt attitudes do not differ, but whose implicit or covert attitudes or knowledge may differ.

An optimization approach for mapping and measuring the divergence and correspondence between paths.

Many domains of empirical research produce or analyze spatial paths as a measure of behavior. Previously, approaches for measuring the similarity or deviation between two paths have either required timing information or have used ad hoc or manual coding schemes. In this paper, we describe an optimization approach for robustly measuring the area-based deviation between two paths we call ALCAMP (Algorithm for finding the Least-Cost Areal Mapping between Paths). ALCAMP measures the deviation between two paths and produces a mapping between corresponding points on the two paths. The method is robust to a number of aspects in real path data, such as crossovers, self-intersections, differences in path segmentation, and partial or incomplete paths. Unlike similar algorithms that produce distance metrics between trajectories (i.e., paths that include timing information), this algorithm uses only the order of observed path segments to determine the mapping. We describe the algorithm and show its results on a number of sample problems and data sets, and demonstrate its effectiveness for assessing human memory for paths. We also describe available software code written in the R statistical computing language that implements the algorithm to enable data analysis.

BDNF Val66Met is Associated With Performance in a Computerized Visual-Motor Tracking Test In Healthy Adults.

The brain-derived neurotrophic factor gene (BDNF) is known to play an important role in neuroplasticity and cognitive processes. We explored the association of BDNF Val66Met polymorphism with performance in a visual-motor tracking test. One hundred and sixty-seven young, healthy Colombian adults completed a computerized version of the Pursuit Rotor Task, using the Psychology Experiment Building Language (PEBL) platform. DNA genotyping was performed by allele-specific polymerase chain reaction. We found that BDNF Val/Met and Met/Met subjects performed better in the pursuit rotor task (p = .03). Our findings suggest that the BDNF gene is essential to understand differences in motor performance in healthy participants in different populations. This approach could be useful for future fine mapping of genetic modifiers for neuropsychiatric diseases.

Reliability and validity of neurobehavioral function on the Psychology Experimental Building Language test battery in young adults.

Background. The Psychology Experiment Building Language (PEBL) software consists of over one-hundred computerized tests based on classic and novel cognitive neuropsychology and behavioral neurology measures. Although the PEBL tests are becoming more widely utilized, there is currently very limited information about the psychometric properties of these measures. Methods. Study I examined inter-relationships among nine PEBL tests including indices of motor-function (Pursuit Rotor and Dexterity), attention (Test of Attentional Vigilance and Time-Wall), working memory (Digit Span Forward), and executive-function (PEBL Trail Making Test, Berg/Wisconsin Card Sorting Test, Iowa Gambling Test, and Mental Rotation) in a normative sample (N = 189, ages 18-22). Study II evaluated test-retest reliability with a two-week interest interval between administrations in a separate sample (N = 79, ages 18-22). Results. Moderate intra-test, but low inter-test, correlations were observed and ceiling/floor effects were uncommon. Sex differences were identified on the Pursuit Rotor (Cohen's d = 0.89) and Mental Rotation (d = 0.31) tests. The correlation between the test and retest was high for tests of motor learning (Pursuit Rotor time on target r = .86) and attention (Test of Attentional Vigilance response time r = .79), intermediate for memory (digit span r = .63) but lower for the executive function indices (Wisconsin/Berg Card Sorting Test perseverative errors = .45, Tower of London moves = .15). Significant practice effects were identified on several indices of executive function. Conclusions. These results are broadly supportive of the reliability and validity of individual PEBL tests in this sample. These findings indicate that the freely downloadable, open-source PEBL battery (http://pebl.sourceforge.net) is a versatile research tool to study individual differences in neurocognitive performance.

Differences in planning performance, a neurocognitive endophenotype, are associated with a functional variant in PER3 gene.

Performance alterations in executive function have been studied as potential endophenotypes for several neuropsychiatric diseases. Planning is an important component of executive function and has been shown to be affected in diseases such as attention deficit hyperactivity disorder, schizophrenia, obsessive-compulsive disorder and Parkinson's disease. Several genes related to dopaminergic systems, such as COMT, have been explored as candidates for influencing planning performance. The circadian clock gene PERIOD3 (PER3) has been shown to be associated with several complex behaviors in humans and could be involved in different signaling mechanisms. In this study, we evaluated the possible association between a functional polymorphism in the PER3 gene (PER3-VNTR, rs57875989) and performance in a commonly used test of planning (Tower of London, TOL) in 229 healthy subjects from Bogotá, Colombia. PER3-VNTR genotyping was carried out with conventional PCR and all participants completed the TOL test using the computerized Psychology Experiment Building Language (PEBL) battery. A linear regression model was used for the analysis of association with the SNPStats program. We found that 4/4 genotype carriers showed a better performance and made fewer moves, in comparison to 4/5 and 5/5 genotype carriers (p = 0.003). These results appear to be independent from effects of this polymorphism on self-reported average hours of sleep during work days in our sample. This is the first evidence of an association between PER3-VNTR and planning performance in a sample of healthy subjects and our results are consistent from previous findings for alterations in other cognitive domains. Future studies examining additional genes could lead to the identification of novel molecular underpinnings of planning in healthy subjects and in patients with neuropsychiatric disorders.

Functional polymorphisms in BDNF and COMT genes are associated with objective differences in arithmetical functioning in a sample of young adults.

BACKGROUND: Understanding the molecular genetics of complex human behaviors and functions remains a substantial challenge for the neurosciences. Previous studies have shown a genetic basis for individual differences in mathematical functioning; however, the specific genes remain to be completely identified. In the present study, we explored the possibility that 2 functional polymorphisms in candidate genes could be associated with differences in arithmetical performance. METHODS: A computerized test to analyze performance in basic arithmetical calculations (additions and subtractions) was applied to 168 healthy young Colombian participants using the PEBL (Psychology Experiment Building Language) battery. DNA samples were genotyped for 2 functional SNPs in candidate genes: brain-derived neurotrophic factor (BDNF)-Val66Met and catechol-O-methyltransferase (COMT)-Val158Met. RESULTS: We found significant differences for arithmetical processing scores between genotypes. For BDNF, Val/Val subjects had a worse performance (p value: 0.025) and for COMT, Val/Val carriers had a better performance (p value: 0.006). A multivariate model, including both BDNF and COMT genes, accounted for 7.1% of the variance in math processing scores. DISCUSSION: To our knowledge, this is the first study finding associations of polymorphisms in BDNF and COMT genes with quantitative measures of numerical aptitude in healthy young participants. A future study of other genes involved in neural plasticity could be helpful to identify genetic correlates of arithmetical functioning, which will be important for the understanding of normal human behaviors and related neuropsychiatric disorders.

Crossword expertise as recognitional decision making: an artificial intelligence approach.

THE SKILLS REQUIRED TO SOLVE CROSSWORD PUZZLES INVOLVE TWO IMPORTANT ASPECTS OF LEXICAL MEMORY: semantic information in the form of clues that indicate the meaning of the answer, and orthographic patterns that constrain the possibilities but may also provide hints to possible answers. Mueller and Thanasuan (2013) proposed a model accounting for the simple memory access processes involved in solving individual crossword clues, but expert solvers also bring additional skills and strategies to bear on solving complete puzzles. In this paper, we developed an computational model of crossword solving that incorporates strategic and other factors, and is capable of solving crossword puzzles in a human-like fashion, in order to understand the complete set of skills needed to solve a crossword puzzle. We compare our models to human expert and novice solvers to investigate how different strategic and structural factors in crossword play impact overall performance. Results reveal that expert crossword solving relies heavily on fluent semantic memory search and retrieval, which appear to allow experts to take better advantage of orthographic-route solutions, and experts employ strategies that enable them to use orthographic information. Furthermore, other processes central to traditional AI models (error correction and backtracking) appear to be of less importance for human players.

Computerized Testing Software for Assessing Interference Suppression in Children and Adults: The Bivalent Shape Task (BST).

We describe the Bivalent Shape Task (BST), software using the Psychology Experiment Building Language (PEBL), for testing of cognitive interference and the ability to suppress interference. The test is available via the GNU Public License, Version 3 (GPLv3), is freely modifiable, and has been tested on both children and adults and found to provide a simple and fast non-verbal measure of cognitive interference and suppression that requires no reading.

The Psychology Experiment Building Language (PEBL) and PEBL Test Battery.

BACKGROUND: We briefly describe the Psychology Experiment Building Language (PEBL), an open source software system for designing and running psychological experiments. NEW METHOD: We describe the PEBL Test Battery, a set of approximately 70 behavioral tests which can be freely used, shared, and modified. Included is a comprehensive set of past research upon which tests in the battery are based. RESULTS: We report the results of benchmark tests that establish the timing precision of PEBL. COMPARISON WITH EXISTING METHOD: We consider alternatives to the PEBL system and battery tests. CONCLUSIONS: We conclude with a discussion of the ethical factors involved in the open source testing movement.

Evaluation of a short-form of the Berg Card Sorting Test.

The Psychology Experimental Building Language http://pebl.sourceforge.net/ Berg Card Sorting Test is an open-source neurobehavioral test. Participants (N = 207, ages 6 to 74) completed the Berg Card Sorting Test. Performance on the first 64 trials were isolated and compared to that on the full-length (128 trials) test. Strong correlations between the short and long forms (total errors: r = .87, perseverative response: r = .83, perseverative errors r = .77, categories completed r = .86) support the Berg Card Sorting Test-64 as an abbreviated alternative for the full-length executive function test.

Situation awareness in obsessive-compulsive disorder.

Past studies have suggested that OCD patients suffer memory impairment on tasks using complex stimuli that require memory for combined elements to be maintained, but not for more simplistic memory tests. We tested this with 42 OCD patients and 42 healthy controls performed a computerized situation awareness task. In addition, participants completed the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) and Maudsley Obsessive-Compulsive Inventory (MOCI). The OCD patients had poorer accuracy in integration/comprehension and perception levels than controls. There were significant correlations between situational awareness scores (i.e., visuo-spatial monitoring and processing) and Y-BOCS obsession-compulsion and slowness and doubt scores of MOCI in OCD patients. In addition, there were also significant correlations between situational awareness and controlling, cleaning, slowness, rumination and total scores of MOCI in control group. Results indicated that (I) OCD patients have problems of perception, integration, and comprehension of complex visual perceptions; (II) situation awareness deficits associated with severity and prevalence of obsessions and compulsions.

Executive function on the Psychology Experiment Building Language tests.

The measurement of executive function has a long history in clinical and experimental neuropsychology. The goal of the present report was to determine the profile of behavior across the lifespan on four computerized measures of executive function contained in the recently developed Psychology Experiment Building Language (PEBL) test battery http://pebl.sourceforge.net/ and evaluate whether this pattern is comparable to data previously obtained with the non-PEBL versions of these tests. Participants (N = 1,223; ages, 5-89 years) completed the PEBL Trail Making Test (pTMT), the Wisconsin Card Sort Test (pWCST; Berg, Journal of General Psychology, 39, 15-22, 1948; Grant & Berg, Journal of Experimental Psychology, 38, 404-411, 1948), the Tower of London (pToL), or a time estimation task (Time-Wall). Age-related effects were found over all four tests, especially as age increased from young childhood through adulthood. For several tests and measures (including pToL and pTMT), age-related slowing was found as age increased in adulthood. Together, these findings indicate that the PEBL tests provide valid and versatile new research tools for measuring executive functions.

Alphabetic letter identification: effects of perceivability, similarity, and bias.

The legibility of the letters in the Latin alphabet has been measured numerous times since the beginning of experimental psychology. To identify the theoretical mechanisms attributed to letter identification, we report a comprehensive review of literature, spanning more than a century. This review revealed that identification accuracy has frequently been attributed to a subset of three common sources: perceivability, bias, and similarity. However, simultaneous estimates of these values have rarely (if ever) been performed. We present the results of two new experiments which allow for the simultaneous estimation of these factors, and examine how the shape of a visual mask impacts each of them, as inferred through a new statistical model. Results showed that the shape and identity of the mask impacted the inferred perceivability, bias, and similarity space of a letter set, but that there were aspects of similarity that were robust to the choice of mask. The results illustrate how the psychological concepts of perceivability, bias, and similarity can be estimated simultaneously, and how each make powerful contributions to visual letter identification.

Decision noise: an explanation for observed violations of signal detection theory.

In signal detection theory (SDT), responses are governed by perceptual noise and a flexible decision criterion. Recent criticisms of SDT (see, e.g., Balakrishnan, 1999) have identified violations of its assumptions, and researchers have suggested that SDT fundamentally misrepresents perceptual and decision processes. We hypothesize that, instead, these violations of SDT stem from decision noise: the inability to use deterministic response criteria. In order to investigate this hypothesis, we present a simple extension of SDT--the decision noise model--with which we demonstrate that shifts in a decision criterion can be masked by decision noise. In addition, we propose a new statistic that can help identify whether the violations of SDT stem from perceptual or from decision processes. The results ofa stimulus classification experiment--together with model fits to past experiments--show that decision noise substantially affects performance. These findings suggest that decision noise is important across a wide range of tasks and needs to be better understood in order to accurately measure perceptual processes.