Design and power analysis: n and confidence intervals of means

In this study, we analyzed the validity of the conventional 80% power. The minimal sample size and power needed to guarantee non-overlapping (1-alpha)% confidence intervals for population means were calculated. Several simulations indicate that the minimal power for two means (m = 2) to have non-overlapping CIs is .80, for (1-alpha) set to 95%. The minimal power becomes .86 for 99% CIs and .75 for 90% CIs. When multiple means are considered, the required minimal power increases considerably. This increase is even higher when the population means do not increase monotonically. Therefore, the often adopted criterion of a minimal power equal to .80 is not always adequate. Hence, to guarantee that the limits of the CIs do not overlap, most situations require a direct calculation of the minimum number of observations that should enter in a study.     

Classification statistical techniques: an applied and comparative study

The aim of this article is to assess and compare three classification statistical techniques--logistic regression, discriminant analysis and classification trees--to identify the personality characteristics associated with the risk of suffering from ischemic cardiovascular acute episodes (ICAE). The sample comprised 313 participants, men and women, aged from 36 to 80. Participants were divided into two groups: a clinical group of patients (n = 143) who were diagnosed as suffering from ICAE, and a control group (n = 170). Both groups were equated in gender, age, socio-economic and educational level. In view of the comparative study of the analytical procedures, we recommend classification trees as the best choice, as it was the most accurate for the individuals in the clinical group, a simple data analysis and a meaningful clinical interpretation. The predictive validity analysis of the MCMI-II allowed the construction of a reduced version made up of 9 personality scales from the 22 scales in the original version. Thus, we could identify the patients with a higher probability of suffering from ICAE, and additionally, generate an empirical model comprising seven and five personality profiles associated, respectively, with the increase and the decrease of the probability of suffering from ICAE.     

The easy-to-hard effect in human (Homo sapiens) and rat (Rattus norvegicus) auditory identification

The authors examined whether progressively training humans and rats to perform a difficult auditory identification task led to larger improvements than extensive training with highly similar sounds (the easy-to-hard effect). Practice improved humans' ability to distinguish sounds regardless of the training regimen. However, progressively trained subjects were more accurate and showed more generalization, despite significantly less training with the stimuli that were the most difficult to distinguish. Rats showed less capacity to improve with practice but still benefited from progressive training. These findings indicate that transitioning from an easier to a more difficult task during training can facilitate, and in some cases may be essential for, auditory perceptual learning. The results are not predicted by an explanation that assumes interaction of generalized excitation and inhibition but are consistent with a hierarchical account of perceptual learning in which the representational precision required to distinguish stimuli determines the mechanisms engaged during learning.     

Using morphology when spelling in a shallow orthographic system: The case of Spanish

Deep orthographies usually represent morphology and phonology simultaneously; both resources are necessary for spelling. In shallow orthographies, such as Spanish, phonology would be enough to spell most words. However, morphological knowledge may also take part in spelling. This study examined how Spanish children in 1st (N = 148), 2nd (N = 155) and 3rd grade (N = 155) use morphological information to spell plural nouns and verbs. A word dictation task was designed. The task included high and low frequency plural nouns ending in “s” (morphological “-s” condition) and verbs in the 2nd person ending in “s” (morphological “-s” condition). A lexical condition including words with a final “s” which was not morphologically motivated was used as a control condition (lexical “-s” condition). The results show that, although Spanish spelling is influenced by phonology, morphological information is also used. These results are discussed in relation to current models of word spelling.     

ONESC: A database of orthographic neighbors for Spanish read by children

In this article, we present a database of orthographic neighbors for words that Spanish children read during elementary education. The reference dictionary for lexical entries and frequencies (which had its origin in Martínez & García, 2004) comprises approximately 100,000 words and is the result of accumulating the words read by a sample of children from first to sixth grades. Using the criterion for orthographic neighbors described by Coltheart, Davelaar, Jonasson, and Besner (1977), we present basic statistics related to neighborhood size as a function of the positions of divergent letters, the cumulative frequency of the neighbors, and the numbers of neighbors of higher, lower, and equal frequency. We also attempt to illustrate and unravel the nature of the relationships among the variables neighborhood size, length, and frequency in the distribution of neighbors. The database described in this article is available at www.psychonomic.org/archive.     

Body Image Assessment Software: Psychometric data

The aim of the present study was to analyze the psychometric characteristics of the Body Image Assessment Software (BIAS), an innovative interactive computer program developed to assess body image disturbances. The program was tested on 252 psychology students at the University of Barcelona and 51 patients with an eating disorder (ED). The subjects filled in the Eating Attitudes Test-26, the Body Shape Questionnaire, the body dissatisfaction scale of the Eating Disorders Inventory-2, and the Body Image Assessment-Revised (a test of silhouettes). Results showed good validity and very high reliability. Furthermore, BIAS was able to discriminate between people who were at risk of an ED and those who were not, as well as between people with and without a history of an ED. Those at risk of having an ED and those with a current ED showed more body image distortion (overestimation of body size) and higher levels of body image dissatisfaction.     

Effects of viewing videos of bullfights on Spanish children

Some of the psychological effects of viewing bullfights on children 8–12 years old are described. Two hundred and forty subjects (120 girls and 120 boys) aged between eight and twelve from a variety of socioeconomic backgrounds were selected from three public or private elementary / secondary schools in Madrid, Spain. The first study used a questionnaire to examine the children's attitudes towards bullfighting by looking at their acceptance and cognitive‐emotional appraisal of the event. Videotapes of bullfights with differing commentaries were then used, along with a battery of questionnaires, to assess the emotional impact of these events, as well as the impact of narrative explanations on aggression and anxiety. Most children were not very positive about bullfights in the initial questionnaire. Viewing of tapes with ‘festive’ or aggressive dialogues (but not tapes without a justification) resulted in more expressed aggression in boys than girls. There was also evidence that age had a significant effect, and that some children appeared disturbed by the exposure. Aggr. Behav. 30:16–28, 2004. © 2004 Wiley‐Liss, Inc.     

Parents Taking Action: A Psycho‐Educational Intervention for Latino Parents of Children With Autism Spectrum Disorder

The increased prevalence of autism spectrum disorder (ASD) among Latino children, later diagnosis, limited access to bicultural specialist support, and worsened health outcomes when compared to non‐Latinos points to the need for a culturally relevant parent education intervention. This pilot study examined the feasibility, acceptability, and preliminary outcomes of a culturally derived intervention, Parents Taking Action, for 19 Spanish‐speaking mothers of children with ASD. This study introduces the Promotora de Salud Model of intervention delivery to the autism field. A mixed‐methods design including one group pre‐ and posttest design and focus groups was used to evaluate the outcomes of PTA. We found that the intervention was both feasible to implement and acceptable to participants. We also found significant increases in empowerment oriented outcomes for parents between pre‐ and posttest suggesting that the intervention is promising. Suggestions for future research and practice are offered.