Guillermo Vallejo

• Professor at University of Oviedo

In a rapidly evolving world, human agency serves as a driving force to shape a more sustainable future. The climate crisis is an example of how individuals must be proactive and take action to mitigate this environmental problem through three modes of agency advocated by Bandura: individual, proxy, and collective. This is even more relevant for ado...

Abstract Introduction The aim of this study was to examine longitudinal changes in past-month cannabis use and hazardous cannabis use over 1 year in emerging adults and to examine the prospective associations between changes in depression, anxiety, stress and hazardous cannabis use, using age, sex and impulsivity as potential moderators. Methods P...

Rehabilitation aims to increase individuals’ ability to interact with their environment. Focusing on the paediatric context, rehabilitation is likely to optimise children’s development while improving and maintaining their functioning. However, children with neurodevelopmental disabilities, such as cerebral palsy, often show low engagement in rehab...

Critical thinking is key for discerning the usefulness of the available information in an ever-changing world. Research is needed to understand further critical thinking and variables likely to explain this construct. Extant literature lacks research focused on elementary school children; findings would help to improve educators’ practice because t...

Multivariate analysis of variance (MANOVA) is the analysis strategy usually chosen in Psychological and Educational research to test the effect of an intervention on a set of dependent variables that are related. Three aspects are common in applied research: First, intervention is determined by the combination of more than one variable and, therefo...

Prolonged daily intake of Western-type diet rich in saturated fats and sugars, and exposure to early life stress have been independently linked to impaired neurodevelopment and behaviour in animal models. However, sex-specific effects of both environmental factors combined on spatial learning and memory, behavioural flexibility, and brain oxidative...

Introduction: Cyberbullying is a complex phenomenon that has significant consequences for the victims. Understanding it requires a systemic-ecological approach, aiming to identify both individual and contextual predictors. During adolescence, peer group influence becomes particularly important, especially the influence of classmates, who spend much...

An experimental study was designed to analyze the effect of school-based training in self-regulation learning strategies on academic performance (Mathematics, Sciences, Language, and English). Class-level variables (i.e., gender, the teacher’s teaching experience, class size) were considered and the effects of the intervention were measured at the...

Many young students experience difficulties mastering writing, and are designated as students struggling with writing. Teacher feedback on writing is an educational tool suited to address this challenge, playing a pivotal role in promoting student proficiency in writing. The current study tests a writing intervention plus teacher feedback, over the...

The present study developed a brief school-based intervention focused on raising awareness about Cerebral Palsy. To assess the effectiveness of the intervention, 91 classes from the fourth and fifth grades were randomly assigned to one of three conditions: Control, Focused on the Domain (Cerebral Palsy), and Non-Focused on the Domain (promotion of...

Gypsy children low school engagement, high rates of school dropout, and pervasive school failure are relevant societal challenges that may be explained by Gypsy people cultural mores, but also by the discriminatory behaviors of school peers. The latter may be a consequence of insufficient accurate knowledge of Gypsy culture. The present study devel...

Computer-Based Learning Environments (CBLEs) have emerged as an almost limitless source of education, challenging not only students but also education providers; teaching and learning in these virtual environments requires greater self-regulation of learning. More research is needed in order to assess how self-regulation of learning strategies can...

Classical MANOVA tests do not pose any difficulty when the assumptions on which they are based are satisfied, while the modified Brown-Forsythe (MBF) procedure has low sensitivity to the lack of multivariate normality and homogeneity of covariance matrices. Both methods assume complete data for all subjects. In this paper, we present combination ru...

Backgrounds: This study analyzes the effectiveness of different information criteria for the selection of covariance structures, extending it to different missing data mechanisms, the maintenance and adjustment of the mean structures, and matrices. Method: The Monte Carlo method was used with 1,000 simulations, SAS 9.4 statistical software and a...

SPIRALS program was designed in accordance with the inclusive Universal Design for Learning approach and the social cognitive model of self-regulated learning. This project aims to promote cognitive, emotional, and behavioral engagement among elementary students, and especially those at high risk of dropping out (such as Roma students). To test the...

Background Delay discounting (DD) has been identified as a trans-disorder process underlying addictive behaviors, including smoking. Previous studies have evaluated how different treatments for drug dependence have affected DD, showing mixed results. Furthermore, no study has examined the effects of changes in depression on DD rates. The aim of thi...

Early life stress is associated with long-term and pervasive adverse effects on neuroendocrine development, affecting normal cognitive and emotional development. Experimental manipulations like environmental enrichment (EE) may potentially reverse the effects of early life stress induced by maternal separation (MS) paradigm in rodents. However, the...

This study assessed the efficacy of an educational program focused on the promotion of school engagement in children with Cerebral Palsy. A 9 weeks, narrative-based intervention program, with a pre-post neuropsychological and self-report evaluation, was developed with a dual focus: a self-regulation theoretical model and executive function stimulat...

The effectiveness of homework on improving student academic achievement depends on several factors; for example, feedback provided by the teacher (i.e. grading) and student engagement are important moderators in this process. However, the relationships between the types of homework feedback commonly used by teachers and student school engagement ha...

Background: Depression and smoking co-occur at high rates and there is a lack of evidence on the efficacy of treatments specifically tailored to this population. This randomized controlled trial sought to compare the effectiveness of cognitive behavioural treatment (CBT) combined with behavioural activation (BA) and the same treatment protocol plu...

Students’ writing constitutes a topic of major concern due to its importance in school and in daily life. To mitigate students’ writing problems, school-based interventions have been implemented in the past, but there is still a need to examine the effectiveness of different types of writing interventions that use robust design methodologies. Hence...

Background: Exposure to maternal separation (MS) in rodents may have long-lasting consequences for the structure and function of several brain regions, eventually associated with alterations in cognition and emotion later in life. Post-weaning environmental enrichment (EE) has been reported to ameliorate the detrimental effects of exposure to earl...

The importance of personal psychological resources in preventing academic stress has enjoyed little attention to date, despite the high rates of stress that exist among university students. This article analyzes the effect of eudaimonic well-being on the use of adaptive strategies for coping with academic stress. Moreover, it analyzes the role of s...

Background: A multivariate extension of the Brown-Forsythe (MBF) procedure can be used to the analysis of partially repeated measure designs (PRMD) when the covariance matrices are arbitrary. However, the MBF procedure requires complete data across time for each subject, which represents an important limitation of this procedure. This article provi...

Background Students commonly struggle with mathematics and mathematical problem‐solving. Therefore, it is necessary to design and implement interventions aimed at improving these essential components of learning. Furthermore, the outcomes of these interventions can vary significantly and appear to be a function of a student's initial competencies i...

In this study, two approaches were employed to calculate how large the sample size needs to be in order to achieve a desired statistical power to detect a significant group-by-time interaction in longitudinal intervention studies—a power analysis method, based on derived formulas using ordinary least squares estimates, and an empirical method, base...

It is practically impossible to avoid losing data in the course of an investigation, and it has been proven that the consequences can reach such magnitude that they could even invalidate the results of the study. This paper describes some of the most likely causes of missing data in research in the field of clinical psychology and the consequences...

A multi-level structural equation model was used to examine the relationships between the homework purposes reported by teachers (i.e. practice, preparation, participation, and personal development), homework quality perceived by students (e.g., homework related to the class material taught) and homework variables (i.e. effort, and homework perform...

Introduction: Despite previous evidence supporting the use of the Cigarette Purchase Task (CPT) as a valid tool for assessing smoking reinforcement, research assessing how environmental changes affect CPT performance is scarce. Aims: This study addressed for the first time the differential effect of treatment condition [Cognitive Behavioral Trea...

This study investigated how students’ prior achievement is related to their homework behaviors (i.e., time spent on homework, homework time management, and amount of homework), and to their perceptions of parental involvement in homework (i.e., parental control and parental support). A total of 1250 secondary students from 7 to 10th grade participa...

Low schooling, high non-attendance and school dropout rates are critical phenomena within disadvantaged groups, especially among the Gypsy community. For example, in the UK, 10%-25% of Gypsy children do not attend school regularly and have significantly higher levels of overall absence from school (percentage of half-day sessions missed) than pupil...

Students’ writing problems are a global educational concern and is in need of particular attention. This study aims to examine the impact of providing extra writing opportunities (i.e., writing journals) on the quality of writing compositions. A longitudinal cluster-randomized controlled design using a multilevel modeling analysis with 182 fourth g...

Students’ writing problems are a global educational concern and is in need of particular attention. This study aims to examine the impact of providing extra writing opportunities (i.e., writing journals) on the quality of writing compositions. A longitudinal cluster-randomized controlled design using a multilevel modeling analysis with 182 fourth g...

Las Tareas para Casa (TPC), en el ámbito anglosajón “homework” y en el español denominadas “deberes escolares”, constituyen una de las actividades más rutinarias del ámbito escolar y es por ello que forman parte de la realidad cotidiana de alumnos y profesores. Pese a su actual presencia en el contexto académico, la necesidad de prescribir TPC a lo...

Low precision of the inferences of data analyzed with univariate or multivariate models of the Analysis of Variance (ANOVA) in repeated-measures design is associated to the absence of normality distribution of data, nonspherical covariance structures and free variation of the variance and covariance, the lack of knowledge of the error structure und...

In the transactional model of stress, coping responses are the key to preventing the stress response. In this study, the possible role of psychological well-being as a personal determinant of coping strategies in the academic context was analyzed. Specifically, the study has two objectives: (a) to identify different profiles of students according t...

Background: S. Usami (2014) describes a method to realistically determine sample size in longitudinal research using a multilevel model. The present research extends the aforementioned work to situations where it is likely that the assumption of homogeneity of the errors across groups is not met and the error term does not follow a scaled identity...

Previous studies showed the involvement of brain regions associated with both spatial learning and associative learning in spatial memory extinction, although the specific role of the dorsal and ventral hippocampus and the extended hippocampal system including the mammillary body in the process is still controversial. The present study aimed to ide...

Background Many studies have explored personal values in nursing, but none has assessed whether the predictions made by the theory of intergenerational value change are true for the different generations of nursing professionals and students. This theory predicts a shift in those personal values held by younger generations towards ones focussed on...

Self-esteem is one of the variables that are most frequently linked to the adoption of self-protection strategies. However, the nature of this relationship continues to be controversial. The present study examines the relationship between self-esteem and the use of behavioral and claimed self-handicapping, as well as of defensive pessimism, and the...

The high rate of school failure among Gypsy children is on the agenda of European policies. The current study assessed the efficacy of an extra-class program, eighteen weeks long, to promote the behavioral and cognitive engagement (self-regulated learning, SRL) of Gypsy children from fourth grade. Gypsy communities were contacted, and the 35 Gypsy...

This study analyzed the effects of five types of homework follow-up practices (i.e., checking homework completion; answering questions about homework; checking homework orally; checking homework on the board; and collecting and grading homework) used in class by 26 teachers of English as a Foreign Language (EFL) using a randomized-group design. Onc...

Despite depressive symptoms being very common among smokers from the general population, few studies have examined the effects of depressive symptoms on smoking treatment outcomes, and even less research has been carried out in the context of contingency management (CM). The authors conducted a secondary analysis to assess the interrelation between...

Mastering the Morris water maze (MWM) requires the animal to consolidate, retain and retrieve spatial localizations of relevant visual cues. However, it is necessary to investigate whether a reorganization of the neural networks takes place when part of the spatial information is removed. We conducted four experiments using the MWM. A classical ref...

This study used a randomized pretest-posttest clustered design to examine the effect of 3 homework purposes (i.e., practice, preparation, and extension) on 6th graders' mathematics achievement and how this relationship was modulated by the amount of completed homework. A total of 27 mathematics teachers and their 638 students participated in this s...

El estudio explora el contraste intergeneracional entre valores personales en estudiantes y profesionales de enfermería y su ajuste a las predicciones de la teoría del cambio de valores. La muestra estuvo formada por 369 estudiantes y profesionales de enfermería distri- buidos en tres grupos: estudiantes (n = 150), profesionales menores de 40 años...

This study aims to produce a deeper understanding of the relationship between perceived parental homework involvement (i.e., parental homework control and parental homework support), student homework behaviors (i.e., time spend on homework completion, time management, and amount of homework completed), and student academic achievement. Using Mplus5...

This article uses Monte Carlo techniques to examine the effect of heterogeneity of variance in multilevel analyses in terms of relative bias, coverage probability, and root mean square error (RMSE). For all simulated data sets, the parameters were estimated using the restricted maximum-likelihood (REML) method both assuming homogeneity and incorpor...

Background: Mental health consumers invite us to abandon the pathology model, which is tied to pessimism, and instead to embrace a model of personal recovery that goes beyond being free from symptoms, and involves self-management of the illness. The Stages of Recovery Instrument (STORI) is a measure developed from the perspective of consumers accor...

Reading is a multi-sensory and multi-cognitive task, and its difficulties (e.g., dyslexia) are not a unitary disorder. There are probably a variety of manifestations that relate to the actual site of impairment. A randomized, pre-test/post-test nonequivalent-groups design was conducted over 4 months with three groups aged between 6 and 8 years. One...

The authors intended to (a) identify the association between gender or grade level and teachers’ homework (HW) feedback and (b) examine the relationship between teachers’ HW feedback, HW-related behaviors (e.g., amount of HW completed), and academic achievement. Four hundred fifty-four students (Grades 5-12) participated in this study. The results...

Although there is general agreement the particular brain regions underlying spatial learning, little is known about the changes that take place during the extinction process. This study aimed to evaluate the functional contribution of selected brain regions during the extinction of a previously acquired spatial memory task in the Morris water maze....

The prefrontal cortex has been linked to spatial memory extinction, according to previous research. This study aimed to evaluate the functional contribution of the prelimbic area of the prefrontal cortex during the extinction of a previously acquired spatial memory task. We combined the inactivation of the prelimbic area with the analysis of region...

Background: Although there is a broad consensus on the use of statistical procedures for mediation analysis in psychological research, the interpretation of the effect of mediation is highly controversial because of the potential violation of the assumptions required in application, most of which are ignored in practice. Method: This paper summa...

Investigación cuasi-experimental es aquella que tiene como objetivo poner a prueba una hipótesis causal manipulando (al menos) una variable independiente donde por razones logísticas o éticas no se puede asignar las unidades de investigación aleatoriamente a los grupos. Debido a que muchas decisiones a nivel social se toman en base al resultado de...

Quasi-experimental investigation is that one that has as aim test a causal hypothesis manipulating (at least) an independent variable where for logistic or ethical reasons it is not possible to assign the units of investigation at random to the groups. Due to the fact that many decisions at the social level take on the basis of the result of invest...

La asunción de independencia parece un supuesto razonable al examinar los datos de un diseño experimental de grupos al azar. Probablemente debido a ello, esta asunción raramente es verificada por los investigadores. Por todo ello, realizamos un experimento de simulación Monte Carlo por medio del cual se examinan las tasas de error tipo I y tipo II...

Patients with minimal hepatic encephalopathy exhibit early impairments in their ability to shift attentional set. We employed a task-switching protocol to evaluate brain network changes. Strategy switching requires the modification of both the relevant stimulus dimension and the required memory system. Rats were trained in an allocentric (A) and a...

Se considera el problema de seleccionar el mejor modelo multinivel entre varios modelos candidatos, teniendo en cuenta las variables siguientes: correlación intraclase, número de grupos (m), tamaño del grupo (n), valor de los parámetros y covarianza intercepto-pendiente. Primero se analiza la cuestión reseñada mediante simulación Monte-Carlo, despu...

Es imperativo que los investigadores inviertan tiempo en la planificación de su investigación, y sin duda alguna, detenerse para buscar información es esencial antes de tomar ninguna decisión. Este trabajo está dedicado a orientar a los psicólogos en esta gran tarea. Para ello comenzamos sugiriendo visitar la página de la APA y desde ella abundar e...

Introducción: La recuperación en psicosis puede ser considerada como un proceso que implica el manejo de la propia enfermedad, es decir, el desa-rrollo de habilidades de afrontamiento, el conocimiento de la enfermedad y la búsqueda de un estilo de vida saludable. El objetivo de esta investigación es someter a estudio qué clase de factores son impor...

The current investigation analyzed how student variables and context variables predicted high school students' academic achievement. The participants were 988 twelfth graders and their corresponding 57 Biology teachers. Data were analyzed using the multilevel method. Results indicate that 85.6% of the variation observed in Biology achievement was e...

Introduction: The research about recovery in psychosis could be considered as a process that involves the illness management. It means, the development of coping skills, the disorder knowledge and a healthy lifestyle. The objective of this research is to study what factors are important in personal recovery in a sample of Spanish patients with psyc...

Background: Likelihood-based methods can work poorly when the residuals are not normally distributed and the variances across clusters are heterogeneous. Method: The performance of two estimation methods, the non-parametric residual bootstrap (RB) and the restricted maximum likelihood (REML) for fitting multilevel models are compared through sim...

The Cherenkov Telescope Array is the next generation ground-based observatory for the study of very-high-energy gamma-rays. It will provide an order of magnitude more sensitivity and greater angular resolution than present systems as well as an increased energy range (20 GeV to 300 TeV). For the high energy portion of this range, a relatively large...

Resumen En el presente estudio se analiza la contribución de variables del alumno y variables del contexto en la predicción del rendimiento académico en Bachillerato. Se han obtenido información de 988 estudian-tes, de último curso de Bachillerato y de sus 57 profesores de Biología. Los datos fueron analizados desde una perspectiva multinivel. Los...

Background: With the 2-way mixed model, one a fixed factor and the other random, the procedure followed to test statistical significance of the random factor has been the focus of a heated controversy in theoretical and applied statistics, and the debating continues even now. One of the main consequences of this controversy is that the position de...

Se investigó la influencia que tienen los valores perdidos sobre la estimación de las propiedades psicométricas de los tests de personalidad. Se ha utilizado un enfoque aplicado, simulando situaciones que puedan te-ner relevancia cara a la práctica profesional. Se diseñaron dos estudios de simulación a partir de datos reales obtenidos de la aplicac...

Several studies suggest a time-dependent involvement of different brain networks during the acquisition of spatial learning. However, little is known about the brain networks activated during the extinction of spatial memory. This study aimed to evaluate the functional contribution of selected brain regions during the extinction of a previously acq...

We examined the selection of covariance structures and the Type I error rates of the Criterion Selector Akaike’s (Akaike’s Information Criteria, AIC) and the Correctly Identified Model (CIM). Data were analyzed with a split-plot design through the Monte Carlo simulation method and SAS 9.1 statistical software. We manipulated the following variables...

Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor...

Missing data are a pervasive problem in many psychological applications in the real world. In this article we study the impact of dropout on the operational characteristics of several approaches that can be easily implemented with commercially available software. These approaches include the covariance pattern model based on an unstructured covaria...

The question of how to analyze several multivariate normal mean vectors when normality and covariance homogeneity assumptions are violated is considered in this article. For the two-way MANOVA layout, we address this problem adapting results presented by Brunner, Dette, and Munk (BDM; 1997) and Vallejo and Ato (modified Brown-Forsythe [MBF]; 2006)...

Given a causal relationship between an independent variable (X) and a response variable (Y), the interest of some applied researchers is sometimes focused on knowing the role playing for alternative intervening variables (third variables or Z-variables), and particularly the role of mediating and moderating variables. Some influential works have re...

Theoretical elements inherent to the motivation in general and the professional one in particular were reviewed and analyzed with a view to determining the implication of the latter on academic performance of medical students, but at the same time the relationship between motivation and attitudes is explored, as well as their importance in the proc...

The Cherenkov Telescope Array is the next generation ground-based instrument for the observation of veryhigh- energy gamma-rays. It will provide an order of magnitude more sensitivity and better angular and energy resolution than present systems as well as an increased energy range. For the high energy portion of this range, the construction of ~6m...

This study examined the performance of selection criteria available in the major statistical packages for both mean model and covariance structure. Unbalanced designs due to missing data involving both a moderate and large number of repeated measurements and varying total sample sizes were investigated. The study also investigated the impact of usi...

Un tema que ha suscitado mayor interés entre los investigadores del análisis de datos longitudinales ha sido el desarrollo, a través de estudios de simulación, de modelos de análisis que incorporen aquellas estructuras de covarianza que mejor se ajusten a los datos. Al analizar las estructuras de covarianza en el ámbito de datos longitudinales, nos...

A topic that has aroused great interest among researchers who analyse longitudinal data has been the development, by means of simulation studies, of analytic models that incorporate the covariance structures which best fit the data. When analysing covariance structures within the context of longitudinal data one finds that the variances are not alw...

A topic that has aroused great interest among researchers who analyse longitudinal data has been the development, by means of simulation studies, of analytic models that incorporate the covariance structures which best fit the data. When analysing covariance structures within the context of longitudinal data one finds that the variances are not alw...

This article evaluated the robustness of several approaches for analyzing repeated measures designs when the assumptions of normality and multisample sphericity are violated separately and jointly. Specifically, the authors' work compares the performance of two resampling methods, bootstrapping and permutation tests, with the performance of the usu...

In this research we examine the behaviour of five univariate statistics for analyzing the data of a Split-Plot design. Four of them assume that the dispersion matrix underlying is not spherical. However, they do so with a clear distinction between two alternatives, insofar as two of them presuppose that the correlation between the data does not hav...

Knowledge of the subject matter plays a vital role when attempting to choose the best possible linear mixed model to analyze longitudinal data. To date, in the absence of strong theory, much of the work has focused on modeling the covariance matrix by comparing non-nested models using selection criteria. In this paper, we compare the performance of...

The goal of this study was to investigate the performance of Hall's transformation of the Brunner-Dette-Munk (BDM) and Welch-James (WJ) test statistics and Box-Cox's data transformation in factorial designs when normality and variance homogeneity assumptions were violated separately and jointly. On the basis of unweighted marginal means, we perform...

We compared the robustness of univariate and multivariate statistical procedures to control Type I error rates when the normality and homocedasticity assumptions were not fulfilled. The procedures we evaluated are the mixed model adjusted by means of the SAS Proc Mixed module, and Bootstrap-F approach, Brown–Forsythe multivariate approach, Welch–Ja...

The structured practical exam by objectives of the Morphophysiology subject was taken in 12 second year-medical students for the new pedagogic education model, who belonged to "Frank País García" Teaching Polyclinic of Santiago de Cuba in 2008. The method used to develop abilities and to evaluate the results of that educational process through the...

The present study investigates the operating characteristics of several Box-type and Welch-James (WJ) modifications on factorial designs lacking homogeneity, normality, and orthogonality. For comparison purposes the behaviours of Proc Mixed and Proc GLM, available from the SAS program, were also examined. When the shape of the distribution was symm...

The current report assesses the clinical, functioning and demographic data of a cohort enrolled in the P3 prevention program for psychosis; a Spanish National Health System and Ministry of Science funded program. Comparisons are made between those individuals who had converted to psychosis and those who had not at 3years after an average of 24 trea...

This research examines the Type I error rates obtained when using the mixed model with the Kenward-Roger correction and compares them with the Between-Within and Satterthwaite approaches in split-plot designs. A simulated study was conducted to generate repeated measures data with small samples under normal distribution conditions. The data were ob...

Hierarchical linear models have become a very popular tool for analyzing data with a hierarchical structure. This methodology recognizes the nested structure of the data and allows obtaining unbiased estimates of the variations found in the different levels of the hierarchy. The goal of this article is to illustrate the construction of hierarchical...