Application of the π* goodness-of-fit index to latent structure models

Existen pocos estadísticos de bondad de ajuste aplicables a modelos de estructura latente. En este artículo se describe la aplicación del estadístico π*, que se basa en el concepto de clases latentes, por lo que su interpretación resulta natural en este tipo de modelos. El estadístico π* asume que la población está dividida en varias clases que siguen un modelo paramétrico, más una clase residual fuera del modelo. Se define π* como la proporción de la población en la clase residual. En el artículo se describen los algoritmos de estimación de π* en modelos de rasgo y clase latente, y se muestra un ejemplo con datos reales procedentes de una escala de hábitos de estudio. Se ha encontrado que hay una clase de malos y otra de regulares estudiantes, las cuales se relacionan con un criterio de responsabilidadTesting model fit for latent structure models (latent trait models and latent class models) is difficult because of the lack of goodnessof-fit statistics with a known distribution. This paper describes the application of the π* goodness-offit statistic to latent structure models. The statistic π* is based on the concept of latent classes and has a natural interpretation when applied to these models. This statistic assumes that the population is made up of several classes that follow a parametric model, and a residual class outside the model. The value of π* is the population proportion in the residual class. This paper describes the estimation algorithms of π* for latent trait and latent class models and an empirical example with a scale of study habits. There are two latent classes in these data: bad and regular students, which are related to the student’s responsibilit

The upside-down self: One's own face recognition is affected by inversion

One's own face is recognized more efficiently than any other face, although the neural mechanisms underlying this phenomenon remain poorly understood. Considering the extensive visual experience that we have with our own face, some authors have proposed that self-face recognition involves a more analytical perceptual strategy (i.e., based on face features) than other familiar faces, which are commonly processed holistically (i.e., as a whole). However, this hypothesis has not yet been tested with brain activity data. In the present study, we employed an inversion paradigm combined with event-related potential (ERP) recordings to investigate whether the self-face is processed more analytically. Sixteen healthy participants were asked to identify their own face and a familiar face regardless of its orientation, which could either be upright or inverted. ERP analysis revealed an enhanced amplitude and a delayed latency for the N170 component when faces were presented in an inverted orientation. Critically, both the self and a familiar face were equally vulnerable to the inversion effect, suggesting that the self-face is not processed more analytically than a familiar face. In addition, we replicated the recent finding that the attention-related P200 component is a specific neural index of self-face recognition. Overall, our results suggest that the advantage for self-face processing might be better explained by the engagement of self-related attentional mechanisms than by the use of a more analytical visuoperceptual strategyThis work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) (UAMA13-4E- 2192) and FEDER/Ministry of Science, Innovation and Universities (MCIU)—National Research Agency (AEI) (PGC2018-100682- B- I00), and the Community of Madrid (SAPIENTIA-CM H2019/HUM-570), under agreement with the Autonomous University of Madrid (2017-T2/ SOC-5569; SI1-PJI- 2019- 00011

Exogenous and endogenous attention to emotional stimuli, behavioral and electrophysiological correlates

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Psicología, Departamento de Psicología Biológica de la Salud. Fecha de lectura: 27-03-2017Esta tesis tiene embargado el acceso al texto completo hasta el 27-09-201

Retinotopic mapping of visual event-related potentials

Visual stimulation is frequently employed in electroencephalographic (EEG) research. However, despite its widespread use, no studies have thoroughly evaluated how the morphology ofthe visual event-related potentials (ERPs) varies according to the spatial location of stimuli. Hence, the purpose of this study was to perform a detailed retinotopic mapping of visual ERPs. We recorded EEG activity while participants were visually stimulated with 60 pattern-reversing checkerboards placed at different polar angles and eccentricities. Our results show five pattern-reversal ERP components. C1 and C2 components inverted polarity between the upper and lower hemifields. P1 and N1 showed higher amplitudes and shorter latencies to stimuli located in the contralateral lower quadrant. In contrast, P2 amplitude was enhanced and its latency was reduced by stimuli presented in the periphery of the upper hemifield. The retinotopic maps presented here could serve as a guide for selecting optimal visuo-spatial locations in future ERP studiesThis work was supported by the Spanish Ministry of Science and Innovation/Economy and Competitiveness (MICINN/MINECO) (PSI2011-26314, PSI2012-34558 and PSI2014-54853-P

Menstrual cycle and exogenous attention toward emotional expressions

Several studies suggest that the menstrual cycle affects emotional processing. However, these results may be biased by including women with premenstrual syndrome (PMS) in the samples. PMS is characterized by negative emotional symptomatology, such as depression and/or anxiety, during the luteal phase. This study aimed to explore the modulation of exogenous attention to emotional facial expressions as a function of the menstrual cycle in women without PMS. For this purpose, 55 women were selected (from an original volunteer sample of 790) according to rigorous exclusion criteria. Happy, angry, and neutral faces were presented as distractors, while both behavioral performance in a perceptual task and event-related potentials (ERPs) were recorded. This task was applied during both phases of the menstrual cycle (luteal and follicular, counterbalanced), and premenstrual symptomatology was monitored daily. Traditional and Bayesian ANOVAs on behavioral data (reaction times and errors in the task) and ERP indices (P1, N170, N2, and LPP amplitudes) confirmed the expected lack of an interaction of phase and emotion. Taken together, these results indicate that women free of PMS present steady exogenous attention levels to emotionally positive and negative stimuli regardless of the menstrual phaseThis research was supported by Ministerio de Ciencia, Innovacion ´ y Universidades of Spain (Grant no. PID2021-124420NB-100) and Comunidad de Madrid (Grants no. HUM19-HUM5705 and SI1-PJI-2019- 00011) in collaboration with the Universidad Autonoma de Madrid (Grant no. 2017-T2/SOC-5569

Spanish forest firesetter profile: An application of inductive criminal profiling

La técnica del perfil criminológico, entendida como el proceso de inferir características identificativas de un delincuente analizando las evidencias obtenidas en la escena del delito que ha cometido, ha recibido críticas por su dudoso carácter científico y su falta de apoyo teórico y empírico. No obstante, en la actualidad ha surgido un modelo que trabaja en la profesionalización del análisis del comportamiento delictivo en los cuerpos policiales mediante la aplicación de los conocimientos de la psicología a la investigación criminal. Una línea de trabajo iniciada por Canter consiste en la aplicación de la estadística multivariante a hechos criminales esclarecidos para crear tipologías (perfilamiento inductivo), de modo que se pueda ver si existen tipos de personas que cometen con más probabilidad determinados tipos de hechos. En este trabajo se utilizó el análisis de conglomerados bietápico en una muestra de 117 incendios ocurridos durante el año 2011 que ofreció una solución de cinco tipos de incendio (perfiles). Dicho modelo mostraría consistencia con el de años anteriores y es fácilmente interpretable por los agentes policiales, por lo que podría utilizarse ante incendios nuevos cuando se desconozca la identidad de sus responsablesThe criminal profiling, understood as the process of inferring identifying offender features by analyzing evidences from the crime scene, has been criticized for its doubtful scientific nature, along with its lack of theoretical and empirical support. However, at present a model has emerged that works on the professionalization of the analysis of criminal behavior in police forces, through a rigorous application of the psychological knowledge to the criminal investigation. This line of working, initiated by Canter, involves the multivariate statistical application to solved criminal acts, thereby creating typologies (inductive profiling). Thus, it is possible to see if there are types of people most likely to commit certain sort of events. In this paper, a two-stage cluster analysis is used in a sample of 117 fires occurred in 2011. The results show five types of fire profiles. This model would show consistence with the results of previous years, and it is easily interpretable by police officers so that it could be used to new fires when the identity of perpetrators is unknow

Magnocellular bias in exogenous attention to biologically salient stimuli as revealed by manipulating their luminosity and color

This is the author’s final version of the article, and that the article has been accepted for publication in Journal of Cognitive NeuroscienceExogenous attention is a set of mechanisms that allow us to detect and reorient toward salient events—such as appetitive or aversive—that appear out of the current focus of attention. The nature of these mechanisms, particularly the involvement of the parvocellular and magnocellular visual processing systems, was explored. Thirty-four participants performed a demanding digit categorization task while salient (spiders or S) and neutral (wheels or W) stimuli were presented as distractors under two figure–ground formats: heterochromatic/isoluminant (exclusively processed by the parvocellular system, Par trials) and isochromatic/heteroluminant (preferentially processed by the magnocellular system, Mag trials). This resulted in four conditions: SPar, SMag, WPar, and WMag. Behavioral (RTs and error rates in the task) and electrophysiological (ERPs) indices of exogenous attention were analyzed. Behavior showed greater attentional capture by SMag than by SPar distractors and enhanced modulation of SMag capture as fear of spiders reported by participants increased. ERPs reflected a sequence from magnocellular dominant (P1p, ≃120 msec) to both magnocellular and parvocellular processing (N2p and P2a, ≃200 msec). Importantly, amplitudes in one N2p subcomponent were greater to SMag than to SPar and WMag distractors, indicating greater magnocellular sensitivity to saliency. Taking together, results support a magnocellular bias in exogenous attention toward distractors of any nature during initial processing, a bias that remains in later stages when biologically salient distractors are presen

Prejudice drives exogenous attention to outgroups

Exogenous attention allows the automatic detection of relevant stimuli and the reorientation of our current focus of attention towards them. Faces from an ethnic outgroup tend to capture exogenous attention to a greater extent than faces from an ethnic ingroup. We explored whether prejudice toward the outgroup, rather than lack of familiarity, is driving this effect. Participants (N= 76) performed a digit categorization task while distractor faces were presented. Faces belonged to (i) a prejudiced outgroup, (ii) a non-prejudiced outgroup and (iii) their ingroup. Half of the faces were previously habituated in order to increase their familiarity. Reaction times, accuracy and event-related potentials (ERPs) were recorded to index exogenous attention to distractor faces. Additionally, different indexes of explicit and implicit prejudice were measured, the latter being significantly greater towards prejudiced outgroup. N170 amplitude was greater to prejudiced outgroup—regardless of their habituation status—than to both non-prejudiced outgroup and ingroup faces and was associated with implicit prejudice measures. No effects were observed at the behavioral level. Our results show that implicit prejudice, rather than familiarity, is under the observed attention-related N170 effects and that this ERP component may be more sensitive to prejudice than behavioral measures under certain circumstances.This work was supported by the Ministerio de Ciencia e Innovación, Spain (PGC2018-093570-B-I00); the Universidad Autónoma de Madrid/Comunidad de Madrid, Spain (2017- T2/SOC-5569); the Comunidad de Madrid (HUM19-HUM5705, SI1-PJI-2019-00011); and by the Ministerio de Educación, Cultura y Deporte, Spain (FPU13/0651

Perception of near‐threshold visual stimuli is influenced by prestimulus alpha‐band amplitude but not by alpha phase

Ongoing brain activity preceding visual stimulation has been suggested to shape conscious perception. According to the pulsed inhibition framework, bouts of functional inhibition arise in each alpha cycle (every ~100 ms), allowing information to be processed in a pulsatile manner. Consequently, it has been hypothesized that perceptual outcome can be influenced by the specific phase of alpha oscillations prior to the stimulus onset, although empirical findings are controversial. In this study, we aimed to shed light on the role of prestimulus alpha oscillations in visual perception. To this end, we recorded electroencephalographic activity, while participants performed three near‐threshold visual detection tasks with different attentional involvement: a no‐cue task, a noninformative cue task (50% validity), and an informative cue task (100% validity). Cluster‐based permutation statistics were complemented with Bayesian analyses to test the effect of prestimulus oscillatory amplitude and phase on visual awareness. We additionally examined whether these effects differed in trials with low and high oscillatory amplitude, as expected from the pulsed inhibition theory. Our results show a clear effect of prestimulus alpha amplitude on conscious perception, but only when alpha fluctuated spontaneously. In contrast, we did not find any evidence that prestimulus alpha phase influenced perceptual outcome, not even when differentiating between low‐ and high‐amplitude trials. Furthermore, Bayesian analysis provided moderate evidence in favor of the absence of phase effects. Taken together, our results challenge the central theoretical predictions of the pulsed inhibition framework, at least for the particular experimental conditions used here

Genome-wide Copy Number Profiling on High-density Bacterial Artificial Chromosomes, Single-nucleotide Polymorphisms, and Oligonucleotide Microarrays: A Platform Comparison based on Statistical Power Analysis

Recently, comparative genomic hybridization onto bacterial artificial chromosome (BAC) arrays (array-based comparative genomic hybridization) has proved to be successful for the detection of submicroscopic DNA copy-number variations in health and disease. Technological improvements to achieve a higher resolution have resulted in the generation of additional microarray platforms encompassing larger numbers of shorter DNA targets (oligonucleotides). Here, we present a novel method to estimate the ability of a microarray to detect genomic copy-number variations of different sizes and types (i.e. deletions or duplications). We applied our method, which is based on statistical power analysis, to four widely used high-density genomic microarray platforms. By doing so, we found that the high-density oligonucleotide platforms are superior to the BAC platform for the genome-wide detection of copy-number variations smaller than 1 Mb. The capacity to reliably detect single copy-number variations below 100 kb, however, appeared to be limited for all platforms tested. In addition, our analysis revealed an unexpected platform-dependent difference in sensitivity to detect a single copy-number loss and a single copy-number gain. These analyses provide a first objective insight into the true capacities and limitations of different genomic microarrays to detect and define DNA copy-number variations