Árpád Csathó

Sex role identity related to the ratio of second to fourth digit length in women

Prenatal gonadal hormones have been implicated as important factors in the development of sex-role identity. The aim of the study reported here was to examine the relationship between adult sex-role preference and the second to fourth digit ratio (2D:4D ratio) in healthy women. There is evidence that the ratio of the length of second and fourth digits associates negatively with prenatal testosterone and positively with prenatal oestrogen. In this study the 2D:4D ratio was measured on a sample of 46 female university students. The subjects completed the form of the Bem Sex Role Inventory (BSRI). It was found that the lower 2D:4D ratios associated significantly with higher, masculinized bias scores in BSRI indicating that 2D:4D ratio predicts the female or male self-reported sex-role identity in females.

Cognitive and affective aspects of thigmotaxis strategy in humans.

The present article describes the cognitive and emotional aspects of human thigmotaxis (a wall-following spatial strategy) during exploration of virtual and physical spaces. The authors assessed 106 participants with spatial and nonspatial performance-based learning-memory tasks and with fear and anxiety questionnaires. The results demonstrate that thigmotaxis plays a distinct role at different phases of spatial learning. The 1st phase shows a positive correlation between thigmotaxis and general phobic avoidance, whereas there is no association between thigmotaxis and general phobic avoidance during later phases of learning. Furthermore, participants who underperformed in working memory tests and in a spatial construction task exhibited greater thigmotaxis and a higher potential for fear response. Findings are interpreted in the framework of interactions among emotion-, action-, and knowledge-controlled spatial learning theories.

MRI-assessed volume of left and right hippocampi in females correlates with the relative length of the second and fourth fingers (the 2D: 4D ratio)

Atrophy of the left or right side of the hippocampus has been related to cognitive deficits and psychiatric disease. In this study, we examined the correlation between the hippocampal volume laterality index and the relative lengths of the second (index finger) and fourth (ring finger) digits (2D:4D) in healthy female subjects. The 2D:4D ratio is fixed in utero, and the ratio is higher in women than in men. There is evidence that this ratio is an indicator of the intrauterine concentration of testosterone, which influences the development of different regions of the brain. Assessing the volume of different parts of the brain of 40 healthy adult female students by magnetic resonance imaging (MRI), we found that the 2D:4D ratio was associated with an asymmetry in the hippocampal sub-regions. Smaller volume on the left side was found in the posterior part of the hippocampus in females with a low (masculine type) 2D:4D ratio. On the other hand, smaller volume on the left side was found in the middle part of the hippocampus in females with a high (female type) 2D:4D ratio. Thus, the development of the middle and posterior regions of the hippocampal formation may respond in opposite ways to prenatal levels of testosterone. Other brain regions such as the amygdala, the cerebral cortex, the total volume hippocampus, and the head of the hippocampus did not show such a difference.

The ratio of the 2nd to 4th finger length predicts spatial ability in men but not women

On average men score higher on time-constrained tests of spatial ability than women. Both brain and behaviour are influenced by prenatal and adult exposure to gonadal steroid hormones. In humans the ratio of the 2nd to 4th finger length (2D:4D) is a sexually dimorphic character that is lower in men than women and negatively correlated with testosterone levels. We report three independent studies from Sweden/London, Hungary and Liverpool confirming that 2D:4D is generally larger in women than men, that men obtain higher MRT scores than women, and demonstrating that 2D:4D is negatively correlated with MRT score in men but not women. We argue that this negative correlation between 2D:4D and spatial ability reflects the association between 2D:4D and prenatal, rather than adult, exposure to testosterone and conclude that testosterone exposure influences brain development leading to better performance on male-favouring spatial tasks.

Blobs strengthen repetition but weaken symmetry

The human visual system is more sensitive to symmetry than to repetition. According to the so-called holographic approach [J. Math. Psychol. 35 (1991) 151; Psychol. Rev. 103 (1996) 429; Psychol. Rev. 106 (1999) 622], however, this perceptual difference between symmetry and repetition depends strongly on spatial scaling. This was tested in three experiments, using symmetry and repetition stimuli that consisted of black and white patches, with patch size as the critical variable. In Experiment 1, patch size was increased in the entire pattern, yielding fewer but larger patches (or blobs). This is known to have hardly any effect on symmetry but, as found now, it does have a strengthening effect on repetition. In the second experiment, we increased patch size in subpatterns only, yielding salient blob areas. This again strengthens repetition but, as double-checked in experiment 3, it can weaken symmetry. These results agree with the holographic approach, and enable an integration of computational, algorithmic, and implementational aspects of vision.

Effects of Moderate Aerobic Exercise Training on Hemorheological and Laboratory Parameters in Ischemic Heart Disease Patients

Background and Design In this study we set out to determine the effects of long-term physical training on hemorheological, laboratory parameters, exercise tolerability, psychological factors in cardiac patients participating in an ambulatory rehabilitation program. Methods Before physical training, patients were examined by echocardiography, tested on treadmill by the Bruce protocol, and blood was drawn for laboratory tests. The enrolled 79 ischemic heart disease patients joined a 24-week cardiac rehabilitation training program. Blood was drawn to measure hematocrit (Hct), plasma and whole blood viscosity (PV, WBV), red blood cell (RBC) aggregation and deformability. Hemorheological, clinical chemistry and psychological measurements were repeated 12 and 24 weeks later, and a treadmill test was performed at the end of the program. Results After 12 weeks Hct, PV, WBV and RBC aggregation were significantly decreased, RBC deformability exhibited a significant increase (p<0.05). Laboratory parameters (triglyceride, uric acid, hsCRP and fibrinogen) were significantly decreased (p<0.05). After 24 weeks the significant results were still observed. By the end of the study, IL-6 and TNF-α levels displayed decreasing trends (p<0.06). There was a significant improvement in MET (p<0.001), and the BMI decrease was also significant (p<0.05). The vital exhaustion parameters measured on the fatigue impact scale indicated a significant improvement in two areas of the daily activities (p<0.05). Conclusions Regular physical training improved the exercise tolerability of patients with ischemic heart disease. Previous publications have demonstrated that decreases in Hct and PV may reduce cardiovascular risk, while a decrease in RBC aggregation and an increase in deformability improve the capillary flow. Positive changes in laboratory parameters and body weight may indicate better oxidative and inflammatory circumstances and an improved metabolic state. The psychological findings point to an improvement in the quality of life.

Effects of mental fatigue on the capacity limits of visual attention

The literature indicates that mental fatigue, due to Time-on-Task (ToT), compromises the ability to ignore distractors. The present study elaborates on this effect by testing whether perceptual load of the target stimuli moderates the ability to ignore distractors under fatigue. Participants (N = 27) performed a visual attention task (an Eriksen flanker task) for 2.5 hours without rest. Target letters were presented at three different perceptual loads and with a peripheral distractor letter. Three target–distractor conditions were tested: congruent, incongruent, and neutral. Results showed that, overall, error rates and reaction times increased with ToT. The detrimental effect of fatigue on performance was most pronounced in the high perceptual load condition. Importantly, however, we also found that fatigue-related ignorance of distractors was compromised in the low perceptual load condition, but not in the medium or high perceptual load condition. This finding is in accordance with the perceptual load theory and refines the knowledge about the declining cognitive performance under fatigue.

Exposure to an inhomogeneous static magnetic field increases thermal pain threshold in healthy human volunteers

In the present experiment, the effect of a single 30 min inhomogeneous static magnetic field (SMF) exposure on thermal pain threshold (TPT) was examined in 15 young healthy human volunteers. The SMF had a maximum peak-to-peak amplitude of 330 mT with a maximum gradient of 13.2 T/m. In either of two experimental sessions (SMF or SHAM), four blocks of 12 TPT trials were carried out under SMF or SHAM exposure on all fingertips of the dominant hand, excluding the thumb. TPT and visual analog scale (VAS) data were recorded at 0, 15, and 30 min exposure time, and 30 min following exposure. SMF treatment resulted in a statistically significant increase in TPT during the entire exposure duration and diminished within-block thermal habituation, leaving pain perception unchanged. These results indicate that SMF-induced peripheral neuronal or circulatory mechanisms may be involved in the observed TPT increase by setting the pain fibre adaptation potential to higher levels.

Temperament and psychopathological syndromes specific susceptibility for rubber hand illusion

The aim of this study is to explore individual capacity for self-integration, susceptibility to the Rubber Hand Illusion (RHI) and the role of temperament factors in the emergence of body schema and body image dissociation. The RHI factors, proprioceptive drift, body ownership and body disownership were assessed in 48 university students. Personality and psychiatric vulnerability were measured by the Temperament and Character Inventory (TCI-R) and the Symptom Checklist-90-R (SCL-90-R). Our study pointed to the fact that the extent of behaviourally defined proprioceptive drift was associated with temperament factors, especially with Novelty Seeking and Harm Avoidance. Further, the ownership was associated with Symptom Checklist factors, especially with elevated Interpersonal Sensitivity and vulnerability to Schizotypy and Paranoid Ideation and elevated disownership score was found in the case of elevated Schizotypy, including a depersonalisation feeling when the RHI was induced. The RHI may be considered as a conflicting situation, in which a way to cope with incongruent multimodal, visual, haptic and proprioceptive stimulation provides an opportunity to test body integration and embodiment processes in healthy participants and patients without disadvantageous outcomes. The results support and replenish the two opposite processing models of the RHI with a third, temperament-based procedural mechanism.

Dancing Shapes: A Comparison of Luminance-Induced Distortions

We present an illusory display in which a grid of outlined squares is positioned in front of a moving luminance gradient. Observers perceive a strong, illusory, ‘wavelike’ motion of the superimposed squares. We compared luminance effects on dynamic and static aspects of this illusion. The dynamic aspect was investigated by means of a temporal gradient, which induced an illusory pulsing of the outlined squares. The static aspect was investigated in two different ways. In one experiment, the outlined squares were positioned on a spatial gradient, which caused the squares to look like trapezoid shapes. In another experiment, the squares were positioned on different luminance fields, which affected their apparent size. In all experiments, luminance settings were the same, and observers were asked to indicate the direction and strength of the induced distortions. The overall results show large agreements between the dynamic distortion and the first-mentioned static distortion, whereas different tendencies emerged for the second static distortion. In a second series of experiments, we examined these distortions for various ranges of the luminance gradient and for border gradients as well. On the basis of these data, we explored how the directions of the perceived distortions of the single-gradient displays examined in this paper could be related to each other.