Testing the indifferentiation hypothesis during childhood, adolescence, and adulthood

The general (g) factor is the most general and relevant cognitive ability. This factor is considered to be one of the most important predictors of academic achievement and of many other socially relevant behavioral outcomes. In the last decades, many researchers have investigated the possible changes in the relevance of the g factor from childhood to adulthood. The indifferentiation hypothesis states that the variance attributed to the g factor and the main cognitive abilities will not change over the life span. In the present study, the authors tested that hypothesis in childhood, adolescence, and adulthood by using 2 different cognitive batteries (Test of Educational Ability [TEA; S. A. TEA, 1999], Wechsler Adult Intelligence Scales [WAIS; D. Wechsler, 1955]), which they administered in 2 different countries--Spain (TEA) and the United States (WAIS). The ages of the participants (N = 2,384) ranged from 8 to 54 years. Results showed that the number of factors extracted and the relevance were the same for every age group in both batteries, as predicted by the indifferentiation hypothesis. The authors discuss implications of intelligence assessment.     

The emergence of symmetry in a conditional discrimination task using different responses as propioceptive samples in pigeons

In Experiment 1, 10 pigeons were exposed to a successive symbolic matching-to-sample procedure in which the sample was generated by the pigeons' own behavior. Each trial began with both response keys illuminated white, one being the "correct" key and the other the "incorrect" key. The pigeons had no way of discriminating which key was correct and which incorrect, since these roles were assigned on a random basis with the same probability of 0.5 for each key. A fixed ratio of five responses was required on the correct key. However, each time the pigeon pecked the incorrect key, the correct key response counter reset. Five consecutive pecks on the correct key was the only way to end this component, and switch off both key lights. Two seconds later, these same keys were illuminated again, one green and the other red (comparison stimuli). Now, if the correct white key had been on the left, a peck at one color produced food, and if the correct white key had been on the right, a peck at the other color produced food. When the pigeons had learned this discrimination, they were exposed to several symmetry tests (simultaneous presentations of both keys illuminated the same color-i.e., both red or both green), in order to interchange the sample with the comparison stimuli. In Experiment 2, the importance of requiring discrimination between the samples and between the comparisons was analyzed. In Experiment 3, we compared the results of Experiment 1 with a slightly different experiment, which resulted in discrimination of key position, an exteroceptive stimulus. The results showed that symmetry emerged only when different responses were used as samples.     

Comparison of several shortened versions of the EMBU: exploratory and confirmatory factor analyses

The aim of the present study was to analyze the psychometric properties of different versions of the EMBU (Egna Minnen av Barndoms Uppfostran – My memories of upbringing) in a non-clinical sample of adolescents. The factor structure of the questionnaire was studied by means of more adequate exploratory and confirmatory factor procedures in order to ascertain which version achieves a better fit to data. The 64-item version of the EMBU was administered to a non-clinical sample of 832 adolescents. Exploratory and Confirmatory factor analyses were carried out for successive versions of 64, 37, 24 and 23 items. The theoretical four-factor structure of the 64-item version is not replicated in a factor analysis through principal axis extraction with direct oblimin rotation. The "Favoring Subject" factor was not found. 37 items present loadings equal to or larger than 0.30 for the "Rejection", "Emotional Warmth" and "Overprotection" factors. A re-analysis of these items shows a clear three-factor structure. When Arrindell et al .'s (1999 ) 23-item version was analysed, the three expected factors were also found. Confirmatory factor analyses allow us to reduce the 36-item version to a shorter one of 24 items. This last version achieves the best fit to data, including the 23-item version. The new 24-item version improves the construct validity of the EMBU and presents similar reliability coefficients.     

Do parents and adolescents differ in their perceptions of rearing styles? Analysis of the EMBU versions for parents and adolescents

In the present study, memories of rearing styles between parents, mother and father, and their son/daughters were explored through the EMBU versions for parents (EMBU-P) and adolescents (EMBU-A). Results show that parents differ in three of the four scales of the EMBU: Emotional Warmth, Control Attempts, and Favoring Subject. Also, mothers score higher on Emotional Warmth, and Control Attempts, but less on Favoring Subject. When parents and adolescents were compared in the common items to both versions, no substantial differences were found, except for the Favoring Subject scale. The sex of the adolescent seems not to play a relevant role in the observed differences. A revision of specialized literature suggested that differences in the fathers' and mothers' perceptions of their rearing styles could be related to differences in personality and marital satisfaction. These hypothetical relationships should be investigated in a parallel study.     

Italian developmental dyslexic and proficient readers: where are the differences?

Italian dyslexic children are characterized by a pervasive reading speed deficit, with relatively preserved accuracy. This pattern has been associated with predominant use of the nonlexical reading procedure. However, there is no evidence of a deficit in the lexical route of Italian dyslexics. We investigated both lexical and nonlexical reading procedures in dyslexic children through two marker effects, namely, the word frequency effect and the effect of contextual grapheme-to-phoneme conversion rules. Although dyslexics were slower and less accurate than controls, they were affected by word frequency, grapheme contextuality, and their interaction in a similar manner as average readers. These results show the use of lexical reading in Italian dyslexics, and refute the claim of a deficit in whole-word processing with consequent over-reliance on the nonlexical route.     

Contextual interference in learning precision skills

This research studied the effect of different organisations of practice (blocked and random) on the learning of three different types of throwing. 35 male students practiced three precise throws for 3 wk. Initially the subjects were separated into two groups who trained under different conditions of practice (blocked and random). All subjects improved significantly from initial performance, with both blocked practice and random practice. At the end of acquisition no differences were found between the groups. No significant differences were found on retention tests carried out 48 hr., 4 wk., and 8 wk. after the training period.     

On the Representation of Inflections and Derivations: Data from Spanish

The four experiments reported in this paper were designed to determine to what extent words are lexically represented in terms of their morphological structure. The experiments are carried out in Spanish, a language with rich morphological resources, using a priming paradigm and a lexical decision task. In particular, they examined the pattern of priming effects in regular inflected words with gender and in derived words, in comparison to those produced by orthographically and semantically related words, by manipulating form similarity and semantic transparency. The results showed, on the one hand, that regular inflected words produced reliable facilitatory effects which are not driven just by form relatedness (Experiments 1 and 2). On the other hand, they showed that both transparent and nontransparent derived forms produced facilitatory effects distinct from purely orthographic and semantic effects (Experiments 3 and 4.). In general, these findings suggest that morphological information is represented in the mental lexicon and may play a central role in the individuation and retrieval of lexical entries.     

Signalization and stimulus-substitution in Pavlov's theory of conditioning

The concept of conditioning as signalization proposed by Ivan P. Pavlov (1927, 1928) is studied in relation to the theory of stimulus-substitution, which is also attributed to him. In the so-called theory of stimulus-substitution a distinction must be made between an empirical principle of substitution and an actual theory of substitution, which can adopt different forms. The Pavlovian theory of substitution--which conceives substitution as a substitution of the unconditioned stimulus (US) by the conditioned stimulus (CS) in the activation of the representation of the former--can be understood as an explanation or model of signalization. Signalization and substitution are answers to different questions, and the level of analysis to which signalization corresponds, is that which concerns the nature of conditioning as an operation of the animal in the environment.     

Attitude to primary prevention advice of the European Code against cancer in relatives of cancer patients: implications for the development of preventive programmes

Achieving a preventive attitude is the first step in eliminating cancer risk behaviours. This cross-sectional study evaluated the attitude towards the European Code against Cancer, in 3,031 relatives of cancer patients. The study looked for keys to improve attitude by means of educational interventions. Attitude was evaluated using a questionnaire with 63 items and a Likert's scale. Measured from -2 to +2 , the mean score was 0.905 [0.894 - 0.971]. Five per cent had a mean score under 0.38 and another 5% over 1.46. A multivariate analysis found that age, sex and level of education were significantly associated with attitude: young men with a low cultural level were those with the lowest preventive attitude. The family history of cancer was not associated with attitude. Educational interventions should modify the perceived advantages of smoking and drinking, and the disadvantages related to preventive diet and sun and workplace protection.     

The differentiation hypothesis and the Flynn effect

Many studies have shown that IQs have been increasing over the last half century. These increases have come to be known as "the Flynn effect". The "Flynn effect" represents a difference on ability-level between groups of the same age but different cohort. The ability-level differentiation hypothesis represents a difference on the relevance of cognitive factors between groups of high and low ability. Hence, it should be possible to imitate the ability-level differentiation effect by comparing groups of the same age but different cohort. The indifferentiation hypothesis represents no differences on the relevance of cognitive abilities in all age groups within the same cohort. The aim of the present study is to test the relationships between these phenomena. For this purpose we analyzed the American standardisation samples of the WISC, WISC-R and WISC-III. Results support the link between the Flynn effect and the differentiation hypothesis. Also, reported evidence replicate previous findings supporting the indifferentiation hypothesis. Implications for the assessment of the intelligence are discussed.