The main objectives of the study were: to investigate whether training on working memory (WM) could improve fluid intelligence, and to investigate the effects WM training had on neuroelectric (electroencephalography - EEG) and hemodynamic (near-infrared spectroscopy - NIRS) patterns of brain activity. In a parallel group experimental design, respondents of the working memory group after 30 h of training significantly increased performance on all tests of fluid intelligence. By contrast, respondents of the active control group (participating in a 30-h communication training course) showed no improvements in performance. The influence of WM training on patterns of neuroelectric brain activity was most pronounced in the theta and alpha bands. Theta and lower-1 alpha band synchronization was accompanied by increased lower-2 and upper alpha desynchronization. The hemodynamic patterns of brain activity after the training changed from higher right hemispheric activation to a balanced activity of both frontal areas. The neuroelectric as well as hemodynamic patterns of brain activity suggest that the training influenced WM maintenance functions as well as processes directed by the central executive. The changes in upper alpha band desynchronization could further indicate that processes related to long term memory were also influenced.
In two experiments the neuronal mechanisms of sex differences in mental rotation were investigated. In Experiment 1 cortical activation was studied in women and men with similar levels of mental rotation ability (high, and average to low), who were equalized with respect to general intelligence. Sex difference in neuroelectric patterns of brain activity were observed only in participants with high mental rotation ability. Females displayed more theta synchronization, especially in frontal brain areas. In the second experiment we examined whether training can increase mental rotation performance in females and change their brain activity patterns measuredwith neuroelectric and hemodynamic imaging techniques. In a parallel group experimental design, respondents fromthe origami group (rotation training), after 18 h of training, significantly increased their performance on a test of mental rotation. Females' brain activation patterns on a posttest, as compared with apretest, showed decreased frontal brain activity. Parallel to this, increased activity in parietal brain areas was observed. By contrast, respondents from the active control group (participating in 18-hour communication training) showed no improvements in performance and no pre-/posttest differences in cortical activity.
The study examined individual factors and social factors that influence adolescent studentsʼ achievement in mathematics. The predictive model suggested direct positive effects of student intelligence, self-rated openness and parental education on achievement in mathematics, whereas direct effects of extraversion on measures of achievement were negative. Indirect positive effects of intelligence, self-rated conscientiousness, student-perceived mathematics teacherʼs press for understanding and mastery goal, and a negative effect of student-rated parental academic pressure on course achievement were mediated through the studentsʼ self-efficacy in mathematics. The findings highlight the important role that individual differences in ability and personality, as well as student perceptions of parent and teacher academically related variables, play in the studentsʼ performance in mathematics.
A large body of research shows that vocabulary does not develop independently of grammar, representing a better predictor of the grammatical complexity of toddlersʼ utterances than age. This study examines for the first time the characteristics of vocabulary and grammar development in Slovenian-speaking infants and toddlers using the Slovenian adaptation of the MacArthur-Bates Communicative Development Inventories (CDI). The sample included 512 Slovenian-speaking infants and toddlers aged 0;8 to 2;6. The findings suggest that between age 0;8 and 2;6 the development of vocabulary is best described using a quadratic function. The results also show that nouns predominate in the vocabularies of infants and toddlers of various ages; as they age and with the increasing size of their vocabularies, the share of interjections decreases and the share of verbs and adjectives increases. The size of vocabulary was also found to be related to the grammatical structure of toddlersʼ utterances.
Aim: To examine the role of 5-HTTLPR, rs25531 and 5-HTT VNTR Intron 2 variants in subjects with psychotic disorders manifesting suicide ideation and behaviour. Methods: The study included 519 subsequently hospitalized subjects who were genotyped for 5-HTTLPR, rs25531 and 5-HTT VNTR In2 variants. Clinical assessments included structured psychiatric interview, sociodemographic characteristics, suicide ideation and behaviour (SIBQ), severity of psychopathology (PANSS) and depression (CDSS). Results: Three subgroups were identified: suicide attempters (N = 161), suicide ideators (N =174) and subjects who never reported suicide ideation or behaviour (comparative group, N = 184). Major findings: 1) Suicide attempters scored highest on the CDSS, while no differences between the three clinical subgroups were detected in the PANSS scores; 2) Suicide attempters were more frequently the carriers of LA allele, while subjects in the comparative group were more frequently the carriers of low expression 5-HTTLPR/5-HTT rs25531 haplotype SLG; 3) No difference was found between the three clinical groups inthe 5-HTT VNTR In2 variants; 4) Subjects with 5-HTTLPR/5-HTT rs25531 intermediate expression haplotype (LALG,SLA) scored higher on the PANSS general psychopathology subscale; 5) There was no association between suicide attempt or ideation and 5-HTTLPR/In2 or 5-HTTLPR/rs25531/In2 haplotype distribution. Conclusion: The suicide ideators, attempters and controls did not differ significantly in 5-HTTLPR or 5-HTT VNTR In 2 variants, but 5-HTTLPR/5-HTT rs25531 haplotype might be a useful genetic marker in distinguishing these three clinical groups.