Individual and Developmental Differences in Interpersonal Understanding

In the study of personality as a subject reflecting knowledge, work, and interaction, the totality of internal conditions through which all external influences on the personality are refracted is a prime consideration. An individual, who for others is an object of cognition and activity, is reflected in their consciousness and determines their behavior only as "refracted" through their internal world, i.e., their set of ideas and attitudes. The same person is seen differently by people having different experiences in work, knowledge, and social interactions. In addition to our ideas concerning perception and conception of a personality, which has been formed, for example, in a young schoolchild, and in addition to the ideas of similarity between the perception and concepts of children and adults, we must always consider special features connected with the development of the youngest child as a personality, as a subject reflecting knowledge.     

Individual Differences in the Recognition of Facial Expressions: An Event-Related Potentials Study

Previous studies have shown that early posterior components of event-related potentials (ERPs) are modulated by facial expressions. The goal of the current study was to investigate individual differences in the recognition of facial expressions by examining the relationship between ERP components and the discrimination of facial expressions. Pictures of 3 facial expressions (angry, happy, and neutral) were presented to 36 young adults during ERP recording. Participants were asked to respond with a button press as soon as they recognized the expression depicted. A multiple regression analysis, where ERP components were set as predictor variables, assessed hits and reaction times in response to the facial expressions as dependent variables. The N170 amplitudes significantly predicted for accuracy of angry and happy expressions, and the N170 latencies were predictive for accuracy of neutral expressions. The P2 amplitudes significantly predicted reaction time. The P2 latencies significantly predicted reaction times only for neutral faces. These results suggest that individual differences in the recognition of facial expressions emerge from early components in visual processing.     

Individual and Gender Differences in Subjective and Objective Indices of Pain: Gender,Fear of Pain,Pain Catastrophizing and Cardiovascular Reactivity

According to fear-avoidance models of pain perception, heightened fear of pain may increase disruptive effects of pain; however, the extent to which this affects self-reported pain severity versus physiological indices of pain is not well delineated. The current study examined self-report measures and physiological indices of pain during a cold pressor (CP) task. Individual differences in fear of pain and pain catastrophizing were also assessed via questionnaire. The primary aim of the current study was to examine the extent to which individual differences associated with fear and catastrophizing in response to pain influences subjective and physiological measures of pain. A secondary aim was to examine gender differences associated with response to pain. Average subjective pain ratings were higher for females than males. In contrast, males exhibited higher systolic and diastolic reactivity in response to the CP task relative to females, as well as failure to fully recover to baseline levels. Follow-up correlational analyses revealed that subjective pain ratings were positively associated with fear of pain in both sexes, but were not associated with cardiovascular indices. These results suggest that fear of pain and pain catastrophizing do not influence cardiovascular responses to induced pain. Further research is necessary in order to determine whether these gender differences in blood pressure and heart rate response profiles are due to biological or psychosocial influences. Results support the notion that fear of pain increases subjective pain ratings, but does not influence cardiovascular responses during CP pain-induction.     

Working Memory in the Processing of the Iowa Gambling Task: An Individual Differences Approach

The Iowa Gambling Task (IGT) is a sequential learning task in which participants develop a tendency towards advantageous options arising from the outcomes associated with their previous decisions. The role of working memory in this complex task has been largely debated in the literature. On one hand, low working memory resources lead to a decrease in the number of advantageous decisions and make a significant part of participants unable to report explicitly which options are the most profitable. On the other hand, several studies have shown no contribution of working memory to the IGT decision patterns. In order to investigate this apparent incompatibility of results, we used an individual differences approach, which has proven an effective method to investigate the role of working memory in cognition. We compared the IGT decision patterns of participants as a function of their working memory capacity (WMC). As expected, contrary to low WMC participants, high WMC participants developed a tendency towards advantageous decisions. These findings lead us to discuss the role of WMC in decision making tasks.     

Dynamic Neural Processing of Linguistic Cues Related to Death

Behavioral studies suggest that humans evolve the capacity to cope with anxiety induced by the awareness of death’s inevitability. However, the neurocognitive processes that underlie online death-related thoughts remain unclear. Our recent functional MRI study found that the processing of linguistic cues related to death was characterized by decreased neural activity in human insular cortex. The current study further investigated the time course of neural processing of death-related linguistic cues. We recorded event-related potentials (ERP) to death-related, life-related, negative-valence, and neutral-valence words in a modified Stroop task that required color naming of words. We found that the amplitude of an early frontal/central negativity at 84–120 ms (N1) decreased to death-related words but increased to life-related words relative to neutral-valence words. The N1 effect associated with death-related and life-related words was correlated respectively with individuals’ pessimistic and optimistic attitudes toward life. Death-related words also increased the amplitude of a frontal/central positivity at 124–300 ms (P2) and of a frontal/central positivity at 300–500 ms (P3). However, the P2 and P3 modulations were observed for both death-related and negative-valence words but not for life-related words. The ERP results suggest an early inverse coding of linguistic cues related to life and death, which is followed by negative emotional responses to death-related information.     

An fMRI Study Exploring the Overlap and Differences between Neural Representations of Physical and Recalled Pain

Implementing a recall paradigm without hypnosis, we use functional MRI (fMRI) to explore and compare nociceptive and centrally-driven pain experiences. We posit that a trace of a recent nociceptive event can be used to create sensory-re-experiencing of pain that can be qualified in terms of intensity and vividness. Fifteen healthy volunteers received three levels of thermal stimuli (warm, low pain and high pain) and subsequently were asked to recall and then rate this experience. Neuroimaging results reveal that recalling a previous sensory experience activates an extensive network of classical pain processing structures except the contralateral posterior insular cortex. Nociceptive-specific activation of this structure and the rated intensity difference between physical and recalled pain events allow us to investigate the link between the quality of the original nociceptive stimulus and the mental trace, as well as the differences between the accompanying neural responses. Additionally, by incorporating the behavioural ratings, we explored which brain regions were separately responsible for generating either an accurate or vivid recall of the physical experience. Together, these observations further our understanding of centrally-mediated pain experiences and pain memory as well as the potential relevance of these factors in the maintenance of chronic pain.     

Sex Differences in the Neural Processing of Aversive Interoceptive Events: The Benefit of Relief

Do men and women process and experience unpleasant bodily states differently? We used fMRI to determine brain processing before, during and after an aversive respiratory stimulation. No sex difference emerged during anticipation or stimulation. However, after the offset of the stimulation, men but not women showed enhanced activation of brain regions that are important for interoception and reward processing. Moreover, this activation was highest in those males who rated the preceding stimulation as most unpleasant. These results indicate that men are particularly sensitive to reward associated with the termination of an aversive event, which may signal relief.     

Categorical Perception of Fear and Anger Expressions in Whole,Masked and Composite Faces

Human observers are remarkably proficient at recognizing expressions of emotions and at readily grouping them into distinct categories. When morphing one facial expression into another, the linear changes in low-level features are insufficient to describe the changes in perception, which instead follow an s-shaped function. Important questions are, whether there are single diagnostic regions in the face that drive categorical perception for certain parings of emotion expressions, and how information in those regions interacts when presented together. We report results from two experiments with morphed fear-anger expressions, where (a) half of the face was masked or (b) composite faces made up of different expressions were presented. When isolated upper and lower halves of faces were shown, the eyes were found to be almost as diagnostic as the whole face, with the response function showing a steep category boundary. In contrast, the mouth allowed for a substantially lesser amount of accuracy and responses followed a much flatter psychometric function. When a composite face consisting of mismatched upper and lower halves was used and observers were instructed to exclusively judge either the expression of mouth or eyes, the to-be-ignored part always influenced perception of the target region. In line with experiment 1, the eye region exerted a much stronger influence on mouth judgements than vice versa. Again, categorical perception was significantly more pronounced for upper halves of faces. The present study shows that identification of fear and anger in morphed faces relies heavily on information from the upper half of the face, most likely the eye region. Categorical perception is possible when only the upper face half is present, but compromised when only the lower part is shown. Moreover, observers tend to integrate all available features of a face, even when trying to focus on only one part.     

Reduced Neural Integration of Letters and Speech Sounds in Dyslexic Children Scales with Individual Differences in Reading Fluency

The acquisition of letter-speech sound associations is one of the basic requirements for fluent reading acquisition and its failure may contribute to reading difficulties in developmental dyslexia. Here we investigated event-related potential (ERP) measures of letter-speech sound integration in 9-year-old typical and dyslexic readers and specifically test their relation to individual differences in reading fluency. We employed an audiovisual oddball paradigm in typical readers (n = 20), dysfluent (n = 18) and severely dysfluent (n = 18) dyslexic children. In one auditory and two audiovisual conditions the Dutch spoken vowels/a/and/o/were presented as standard and deviant stimuli. In audiovisual blocks, the letter ‘a’ was presented either simultaneously (AV0), or 200 ms before (AV200) vowel sound onset. Across the three children groups, vowel deviancy in auditory blocks elicited comparable mismatch negativity (MMN) and late negativity (LN) responses. In typical readers, both audiovisual conditions (AV0 and AV200) led to enhanced MMN and LN amplitudes. In both dyslexic groups, the audiovisual LN effects were mildly reduced. Most interestingly, individual differences in reading fluency were correlated with MMN latency in the AV0 condition. A further analysis revealed that this effect was driven by a short-lived MMN effect encompassing only the N1 window in severely dysfluent dyslexics versus a longer MMN effect encompassing both the N1 and P2 windows in the other two groups. Our results confirm and extend previous findings in dyslexic children by demonstrating a deficient pattern of letter-speech sound integration depending on the level of reading dysfluency. These findings underscore the importance of considering individual differences across the entire spectrum of reading skills in addition to group differences between typical and dyslexic readers.     

Problems in the Integrated Study of Individual Differences

The properties of all the stages of evolution of matter, from the chemical to the sociohistorical, are part of man as well. In each of these properties, in addition to what is common and typical for groups of people, there is something that is unique to the individual and irreproducible. One characteristic noted in theoretical conceptions of individual differences is that they tend to study properties relating to different stages in the development of matter in isolation from one another. In most studies of differential psychophysiology, the biochemical and endocrine properties of the organism and the bioelectric properties of the nervous system are examined as if they had nothing to do with individual characteristics in the formation of classical Pavlovian conditioned reflexes. The psychological properties of the personality are examined in the Vygotsky and Leont'ev school independently of their relationship to somatic, neurophysiological, and psychodynamic properties (the properties of temperament).     

Neural Bases for Individual Differences in the Subjective Experience of Short Durations (Less than 2 Seconds)

The current research was designed to establish whether individual differences in timing performance predict neural activation in the areas that subserve the perception of short durations ranging between 400 and 1600 milliseconds. Seventeen participants completed both a temporal bisection task and a control task, in a mixed fMRI design. In keeping with previous research, there was increased activation in a network of regions typically active during time perception including the right supplementary motor area (SMA) and right pre-SMA and basal ganglia (including the putamen and right pallidum). Furthermore, correlations between neural activity in the right inferior frontal gyrus and SMA and timing performance corroborate the results of a recent meta-analysis and are further evidence that the SMA forms part of a neural clock that is responsible for the accumulation of temporal information. Specifically, subjective lengthening of the perceived duration were associated with increased activation in both the right SMA (and right pre-SMA) and right inferior frontal gyrus.     

Epigenetics and Neural Developmental Disorders

Neural developmental disorders, such as autism, Rett Syndrome, Fragile X syndrome, and Angelman syndrome manifest during early postnatal neural development. Although the genes responsible for some of these disorders have been identified, how the mutations of these genes affect neural development is currently unclear. Emerging evidence suggest that these disorders share common underlying defects in neuronal morphology, synaptic connectivity and brain plasticity. In particular, alterations in dendritic branching and spine morphology play a central role in the pathophysiology of most mental retardation disorders, suggesting that common pathways regulating neuronal function may be affected. Epigenetic modulations, mediated by DNA methylation, RNA-associated silencing, and histone modification, can serve as an intermediate process that imprints dynamic environmental experiences on the “fixed” genome, resulting in stable alterations in phenotypes. Disturbance in epigenetic regulations can lead to inappropriate expression or silencing of genes, causing an array of multi-system disorders and neoplasias. Rett syndrome, the most common form of mental retardation in young girls, is due to germline mutation of MECP2, encoding a methylated DNA binding protein that translates DNA methylation into gene repression. Angelman syndrome is due to faulty genomic imprinting or maternal mutations in UBE3A. Fragile X Syndrome, in most cases, results from the hypermethylation of FMR1 promoter, hence the loss of expression of functional FMRP protein. Autism, with its complex etiology, may have strong epigenetic link. Together, these observations strongly suggest that epigenetic mechanisms may play a critical role in brain development and etiology of related disorders. This report summarizes the scientific discussions and major conclusions from a recent conference that aimed to gain insight into the common molecular pathways affected among these disorders and discover potential therapeutic targets that have been missed by looking at one disorder at a time.     

Developmental Neurobiology of Pain in Neonatal Rats

The authors examine the biological basis for the behavioral evidence of pain perception in neonatal rats, and discuss the potential link to a greater understanding of chronic pain     

The Neuropsychology of Individual Differences

Russian neuropsychology, created by the works of A.R. Luria and his students, is currently undergoing a period of differentiation. In addition to the two main themes—clinical and experimental neuropsychology (with their practical applications, i.e., the diagnosis and restoration of higher mental functions)—developmental neuropsychology (of childhood and old age), the neuropsychology of borderline states, the psychophysiological aspects of neuropsychology, and a number of other areas are also in the midst of a process of formation. Among the new themes that have gained importance in the past few years we have the neuropsychology of individual differences, based on application of the theories, methods, and procedures of neuropsychology to study of the mental functions of normal people.     

Origins and Developmental Potential of the Neural Crest

Neural crest cells are a migratory population that forms most of the peripheral nervous system, facial skeleton, and numerous other derivatives. These cells arise from the neural ectoderm and are first recognizable as discrete cells after neural tube closure. In this review, I summarize the results of studies from our laboratory on neural crest cell lineage and origin. Our recent experiments demonstrate that interactions between the presumptive neural plate and the nonneural ectoderm are likely to be instrumental in the induction of the avian neural crest. Juxtaposition of these tissues at early stages results in the formation of neural crest cells at the interface. However, neural crest cells do not appear to be segregated from other neuroepithelial cells; cell lineage studies have demonstrated that individual precursor cells within the neural tube can give rise to both neural crest and neural tube derivatives as diverse as sensory, commissural, and motor neurons. This suggests that individual neuroectodermal cells are multipotent, such that a precursor within the neural tube has the ability to form both neural tube (central nervous system) and neural crest (peripheral nervous system and other) derivatives. Further support for flexibility in the developmental program of neuroepithelial cells comes from experiments in which the cranial neural folds are ablated; this results in regulation by the remaining ventral neural tube cells to form neural crest cells after the endogenous neural crest is removed. At later stage of development, this regulative capacity is lost. Following their emigration from the neural tube, neural crest cells become progressively restricted to defined embryonic states. Taken together, these experiments demonstrate that: (1) the neural crest is an induced population that arises by interactions within the ectoderm; (2) initially, progenitor cells are multipotent, having the potential to form multiple neural crest and neural tube derivatives; and (3) with time, the precursors become progressively restricted to form neural crest derivatives and eventually to individual phenotypes.     

On the Organization of Individual Differences in Sexual Behavior

SYNOPSIS. Research on the sexual differentiation of mating behaviorhas impeded progress in our understanding of the proximate basesof individual differences in two ways. First, by viewing variationas categorical rather than continuous, and second, by not placingsufficient emphasis on the fact that males and females differgenetically in many vertebrates, environmental contributionsto individual differences cannot be distinguished from geneticcontributions. Just as there are two levels of organizationof sex, so, too, are there two levels of organization of thesexual phenotype. Primary organization is the process of sexualdifferentiation that follows gonadal determination and is manifestas the morphological, physiological and behavioral aspects ofthe sexual phenotype. There is a second, and subsequent, levelof organization, however, that is directly related to primaryorganization and is the basis of individual variation in sexuallydimorphic behaviors. This level can be termed secondary organization.Because individual variation is the substance of evolutionarychange, understanding its organization will require both newparadigms and alternative animal model systems that allow separationof the effects of genes and hormones from environmental andexperiential stimuli. The plasticity of the sexual phenotypeand how each individual emerges from its own unique circumstancesintegrates these different levels of organization. As mightbe predicted, recent research suggests that the relationshipbetween primary and secondary organization and the developmentof individual differences in sociosexual behaviors involvesmore than just sex steroid hormones.     

Sex Differences in the Rapid Detection of Emotional Facial Expressions

Background

Previous studies have shown that females and males differ in the processing of emotional facial expressions including the recognition of emotion, and that emotional facial expressions are detected more rapidly than are neutral expressions. However, whether the sexes differ in the rapid detection of emotional facial expressions remains unclear.

Methodology/Principal Findings

We measured reaction times (RTs) during a visual search task in which 44 females and 46 males detected normal facial expressions of anger and happiness or their anti-expressions within crowds of neutral expressions. Anti-expressions expressed neutral emotions with visual changes quantitatively comparable to normal expressions. We also obtained subjective emotional ratings in response to the facial expression stimuli. RT results showed that both females and males detected normal expressions more rapidly than anti-expressions and normal-angry expressions more rapidly than normal-happy expressions. However, females and males showed different patterns in their subjective ratings in response to the facial expressions. Furthermore, sex differences were found in the relationships between subjective ratings and RTs. High arousal was more strongly associated with rapid detection of facial expressions in females, whereas negatively valenced feelings were more clearly associated with the rapid detection of facial expressions in males.

Conclusion

Our data suggest that females and males differ in their subjective emotional reactions to facial expressions and in the emotional processes that modulate the detection of facial expressions.     

Individual Differences in the Discrimination of Novel Speech Sounds: Effects of Sex,Temporal Processing,Musical and Cognitive Abilities

This study examined whether rapid temporal auditory processing, verbal working memory capacity, non-verbal intelligence, executive functioning, musical ability and prior foreign language experience predicted how well native English speakers (N = 120) discriminated Norwegian tonal and vowel contrasts as well as a non-speech analogue of the tonal contrast and a native vowel contrast presented over noise. Results confirmed a male advantage for temporal and tonal processing, and also revealed that temporal processing was associated with both non-verbal intelligence and speech processing. In contrast, effects of musical ability on non-native speech-sound processing and of inhibitory control on vowel discrimination were not mediated by temporal processing. These results suggest that individual differences in non-native speech-sound processing are to some extent determined by temporal auditory processing ability, in which males perform better, but are also determined by a host of other abilities that are deployed flexibly depending on the characteristics of the target sounds.