Heart rate conditioning in newborn infants: Relationships among conditionability, heart rate variability, and sex.

Evaluated trace conditioning in 20 newborn infants by examining heart rate responses to the conditioned stimulus (CS), in anticipation of the unconditioned stimulus (UCS) and in the absence of the UCS. 2 sets of analyses were performed using subgroups based on preexperimental heart rate variability and sex. Preexperimental heart rate variability was related only to the response to the CS, with only the high-variance Ss showing a conditioned deceleration and exhibiting a change in response across trial blocks. Only the females exhibited conditioned decelerations in response to the CS and in anticipation of the UCS. In the absence of the UCS, only the experimental group as a whole responded with a deceleration. The relationship between sex and heart rate variability was also examined. Data suggest that females tend to have higher levels of heart rate variability which parallels their greater conditionability. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Human operant heart rate conditioning: The importance of individual differences.

Respiratory, somatic-muscular, and CNS responses have all been suggested as possible mediators of operant heart rate changes. A review of studies concerned with each proposed mediator indicates that such responses can mediate heart rate change, but no studies have demonstrated the necessity for such mediation. Current hypotheses concerning mediating variables appear to oversimplify the complex interactions of autonomic and CNS modalities. A review of research on physiological patterns of response during stress, classical conditioning, and avoidance conditioning indicates that there are considerable individual differences in automatic and CNS responses during those tasks. It is suggested that individual differences in physiological responding also occur during operant heart rate conditioning and that E's should utilize such differences in constructing models of events that might mediate operant heart rate changes. (21/2 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention, attraction, and individual differences in reaction to criticism.

82 female undergraduates were classified as repressors or sensitizers (by scores on the Repression-Sensitization Scale) and led to expect either some future interaction or no future interaction with negative and positive evaluators. It was predicted that repressors would avoid attending to negative evaluators when no future interaction was anticipated more than sensitizers would, but that the groups would not differ when interaction was anticipated. This first prediction was not confirmed: The negative evaluator received more attention than the positive evaluator across all conditions. It was also predicted that repressors would react more positively to the negative evaluator than sensitizers when there was a prospect of future interaction, but that repressors would react less positively to the negative evaluator than sensitizers when there was no prospect of future interaction. This prediction was confirmed. Utility and individual differences in perception processes are discussed. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Voluntary alcohol consumption in vervet monkeys: individual, sex, and age differences

The patterns of voluntary alcohol consumption were studied in 35 vervet monkeys (Cercopithecus aethiops), classified into four groups. Each monkey showed a fairly steady rate during the studied period, resulting in individual differences that became more evident as the treatment evolved. Females showed higher alcohol intake frequencies than males. This sexual difference was maintained among adults and juveniles. Age differences were also observed: juveniles showed higher frequencies of intake than adults, both in general and in each sex group. Intake frequency was not related to age in prepubertal subjects, neither in general nor in each particular sex. The origin of these sex and age alcohol consumption differences remains to be studied, but differences in alcohol metabolism and factors related to puberty are possible influences.     

Metaiodobenzylguanidine and heart rate variability in heart failure

It is assumed that the low-frequency power (LF) of heart rate variability (HRV) increases with progress of congestive heart failure (CHF), therefore positively correlating with cardiac 123I-metaiodobenzylguanidine (MIBG) washout. It is demonstrated here that HRV, including normalized LF, correlated inversely with MIBG washout and positively with the ratio of heart-to-mediastinum MIBG activity in controls and CHF patients, whereas these correlations were not observed within CHF patients. Thus MIBG washout may increase and HRV including normalized LF may decrease with CHF, although the HRV and MIBG measures may not similarly change in proportion to the severity of the cardiac autonomic dysfunction in CHF.     

Developmental patterns of heart rate and variability in prematurely-born infants with apnea of prematurity

At equivalent post-conceptional ages, prematurely-born infants have higher heart rates and reduced heart rate variability, relative to full-term neonates. Premature birth might exert long-lasting effects on central and peripheral mechanisms that control cardiovascular activity. We assessed development of heart rate and heart rate variability in symptomatic preterm infants up to 6 months of age. Fifty 6.5-h evening recordings of EKG and breathing were obtained from prematurely-born infants (gestational ages: 24-35 weeks). Cardiac R-R intervals were captured with a resolution of +/- 0.5 msec. One-min epochs were selected from three periods of regular respiration in recordings from premature infants and 72 recordings of full-term infants at comparable post-conceptional ages. Mean heart rate and heart rate variability were determined for each recording. At 40 weeks post-conception, prematurely-born infants with apnea of prematurity showed higher heart rates and reduced heart rate variability than did full-term neonates. These differences between premature and full-term infants persisted throughout the next 6 months in those infants born prior to 30 weeks gestation, and in those infants born at 30-35 weeks who experienced respiratory distress syndrome (RDS) during the neonatal period. The findings suggest that premature delivery, or complications thereof, exerts long-lasting effects on cardiac control.     

Heart rate variability and newborn heart rate responses to illumination changes.

Investigated heart rate (HR) response patterns to the onset and offset of a 30-sec increase in illumination in 16 human newborns. Ss were divided into 2 groups based on a measure of pretrial HR variability. Only Ss with the high pretrial HR variability responded significantly to the change in stimulation. The response to onset was characterized by a significant quartic trend containing both decelerative and accelerative components. The response to offset only approached significance and had a pattern similar to the onset response. Although the occurrence of systematic response patterns was related to the level of pretrial HR variability, this measure of autonomic lability may have been related to influences associated with delivery and not to stable individual differences. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Individual differences in perceptual reactance: A review of the stimulus intensity modulation individual difference dimension.

A. Petrie (1967) proposed a general theory of individual differences in stimulus intensity modulation. The present article reviews and assesses research that has proceeded from Petrie's theorizing. Findings seem to support the concept of a central stimulus intensity control mechanism; correlations among measures that purport to measure stimulus intensity modulation are generally high in normal populations. Predictions made from Petrie's theory have met with moderate success. The final judgment on Petrie's theory, however, awaits the application of the newer methods of testing stimulus intensity modulation to the critical areas for evaluating Petrie's theory. Suggestions for future research are provided. (French abstract) (4 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Women's sexuality: Behaviors, responses, and individual differences.

Classic and contemporary approaches to the assessment of female sexuality are discussed. General approaches, assessment strategies, and models of female sexuality are organized within the conceptual domains of sexual behaviors, sexual responses (desire, excitement, orgasm, and resolution), and individual differences, including general and sex-specific personality models. Where applicable, important trends and relationships are highlighted in the literature with both existing reports and previously unpublished data. The present conceptual overview highlights areas in sexual assessment and model building that are in need of further research and theoretical clarification. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Examination of relationships among trait-like individual differences, state-like individual differences, and learning performance.

Several authors (e.g., J. T. Austin & H. J. Klein, 1996; R. Kanfer, 1990b, 1992) have urged researchers to examine comprehensive models of distal individual differences as predictors of proximal motivational processes and performance. Two field studies in an academic setting tested a model of relationships among trait-like individual differences (cognitive ability, general self-efficacy, and goal orientation), state-like individual differences (state anxiety, task-specific self-efficacy, and goals), and learning performance. Most hypothesized relationships among these constructs received support when tested on 2 samples, when examining different performance episodes, and when using different goal orientation and state-anxiety measures. In general, state-like individual differences were found to mediate the relationships between trait-like individual differences and learning performance. Implications of these results are discussed and suggestions for future research are provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Antecedents of adult interpersonal functioning: Effects of individual differences in age 3 temperament.

We examined whether temperamental differences at age 3 are linked to interpersonal functioning in young adulthood. In a sample of over 900 children, we identified 5 distinct groups of children based on behavioral observations: Well-adjusted, undercontrolled, reserved, confident, and inhibited. At age 21, we assessed the children's interpersonal functioning in 4 social contexts: in the social network, at home, in romantic relationships, and at work. We found 3 patterns of relations: (a) Well-adjusted, reserved, and confident children defined a heterogeneous range of normative adult interpersonal behavior, (b) inhibited children had lower levels of social support but normative adjustment in romantic relationships and at work, and (c) undercontrolled children had lower levels of adjustment and greater interpersonal conflict across adult social contexts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal conditioning of heart rate responses in newborn infants.

Evaluated temporal heart rate conditioning in 32 newborns (16 experimental and 16 control) by examining responses to the UCS, in anticipation of the UCS, and in its absence. There was weak evidence, only in the females, of a conditioned anticipatory deceleration immediately before the UCS. Response differences between the experimental and control groups following the UCS and in its absence were also found. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reading comprehension: Developmental processes, individual differences, and interventions.

Research on the typical development of reading comprehension, individual differences in comprehension, and reading comprehension interventions is less common than research on word reading. The authors present an overview of research on the development of reading comprehension skills and sources of individual differences in comprehension with reference to cognitive models of comprehension. Methodological issues particular to developmental and individual difference research on comprehension are also described. The article ends with a selective review of research programmes that illustrate effective comprehension interventions for typically developing children and for children who struggle to understand what they read. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Arousal, extraversion, and individual differences in resource availability.

Three studies of the effects of extraversion and self-report arousal on attentional task performance were conducted, using sustained attention, visual/memory search, and letter transformation tasks. Differing predictions were derived from the Yerkes-Dodson Law (R. M. Yerkes and J. D. Dodson, 1908) and from M. S. Humphreys and W. Revelle's (see record 1984-16903-001) theory of individual differences in multiple attentional resources. Higher arousal was consistently associated with more efficient performance of demanding versions of the attentional tasks. This finding supports Humphreys and Revelle's hypothesis that arousal is positively associated with the resources required for sustained information transfer. No support for the Yerkes-Dodson Law was found in any study: Relationships between arousal and performance were largely linear. Interactive effects of extraversion and arousal on response criterion were found with self-paced tasks. Extraversion may affect more than 1 type of cognitive process, with the strategic demands of the task influencing the kind of extraversion effect found in any given experiment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Everyday memory performance across the life span: Effects of age and noncognitive individual differences.

Gerontologists have long been concerned with the impact of individual-difference factors on memory. This study used a large sample (N?=?2,495) of adult volunteers (aged 18–90 yrs) to determine if a set of individual-difference variables (vocabulary, education, depression, gender, marital status, and employment status) mediated the effects of aging on a wide range of laboratory-analog tests of everyday memory. The data indicated that age was consistently the most significant predictor of memory performance, followed by vocabulary and gender. Vocabulary totally mediated age effects on a prose memory measure, and partial mediation of aging effects, primarily by vocabulary and gender, was observed on 5 other memory tests. These data suggest that when healthy samples of volunteers serve as research Ss, these individual differences can affect some memory test scores, but age remains the best overall predictor of memory performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extended visual fixation in young infants: look distributions, heart rate changes, and attention

Feeding a high-carbohydrate (CHO) diet and administration of alkalinizing agents have both been shown to improve performance in high-intensity exercise. The effect of these treatments in combination was investigated in the present study. Six healthy male subjects exercised to exhaustion on an electrically braked cycle ergometer at a power output equivalent to 100% of their maximum oxygen uptake (VO2,max) on four separate occasions. Each subject consumed either a diet with the same composition as his normal diet (termed the experimental normal (N) diet; 54 +/- 7% CHO, 13 +/- 2% protein, 33 +/- 7% fat) or a high-CHO diet (81 +/- 2% CHO, 13 +/- 2% protein, 6 +/- 1% fat) that had the same energy and protein content for the 3 days prior to the exercise tests. Subjects then ingested either a placebo (CaCO3) or trisodium citrate (0.3 g (kg body mass)-1) 3 h before exercise. Time to fatigue was not different between experimental conditions. Consumption of the high-CHO diet had no effect on blood acid-base status, but the ingestion of sodium citrate induced a mild metabolic alkalosis after both the N diet and the high-CHO diet. This alkalinizing effect was also evident after exercise, since blood pH, plasma bicarbonate and blood base excess were higher (P < 0.05) after the ingestion of sodium citrate than under the placebo conditions. The changes in blood lactate, pyruvate and glucose and plasma glycerol after exercise were similar for all experimental conditions. Blood lactate, glucose and pyruvate and plasma glycerol concentrations increased from resting values (P < 0.01) following exercise but this increase was similar under all experimental conditions. These data demonstrate that when the energy and protein content of the diets is the same, exercise capacity and the metabolic response to intense exercise are similar following consumption either of a high-CHO diet or a more normal diet. Acute ingestion of sodium citrate prior to exercise resulted in a reduction in post-exercise acidosis despite a blood lactate concentration that was similar to that observed after the ingestion of a placebo, but did not affect exercise performance under the conditions of this study.     

Assessing individual differences in knowledge: Knowledge, intelligence, and related traits.

Twenty academic knowledge tests were developed to locate domain knowledge within a nomological network of traits. Spatial, numerical, and verbal aptitude measures and personality and interest measures were administered to 141 undergraduates. Domain knowledge factored along curricular lines; a general knowledge factor accounted for about half of knowledge variance. Domain knowledge exhibited positive relations with general intelligence (g), verbal abilities after g was removed, Openness, Typical Intellectual engagement, and specific vocational interests. Spatial and numerical abilities were unrelated to knowledge beyond g. Extraversion related negatively to all knowledge domains. Results provide broad support for R. B. Cattell's (1971/1987) crystallized intelligence as something more than verbal abilities and specific support for P. L. Ackerman's (1996) intelligence-as-process, personality, interests, and intelligence-as-knowledge theory of adult intelligence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interindividual differences and intraindividual variability in the cortisol awakening response: An examination of age and gender.

This article shows age and gender differences in the magnitude and day-to-day variability of the cortisol awakening response (CAR) using a national sample of 1,143 adults who completed the second wave of the National Study of Daily Experiences, a part of the Midlife Development in the United States survey. Participants between the ages of 33 and 84 years completed 8 consecutive nightly interviews and provided 4 saliva samples (upon waking, 30 min after waking, before lunch, and before bed) on 4 consecutive interview days. Results revealed substantial day-to-day variability in the CAR as well as significant Age × Gender interactions, indicating that although no systematic age-related differences emerged for women, the magnitude and day-to-day variability of the CAR increased with age among men. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hemisphere and stimulus differences as reflected in the cortical responses of newborn infants to speech stimuli.

Auditory evoked potentials were recorded from the left and right temporal regions of 8 male and 8 female Caucasian full-term neonates in response to a series of CV syllables that varied in second formant structure. An early component of the brain's electrical response indicated the presence of a mechanism unique to the left hemisphere. This process is sensitive to second-formant transition differences. A second independent cortical component that occurred later in time appears to behave similarly to the first with the exception that it reflects a process common to both hemispheres. Hemisphere differences related to sex were also isolated. Early hemisphere differences appear in part to be due to the presence of lateralized perceptual mechanisms that are sensitive to specific acoustic cues. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention and heart rate: A critical appraisal of the hypothesis of Lacey and Lacey.

Evaluates the hypothesis concerning attention and heart rate formulated by J. Lacey and B. Lacey (in P. Black (Ed.), Physiological Correlates of Emotion, 1970) with respect to its original and subsequent expressions, its testability, and research results offering confirmation or disconfirmation. Heart-rate deceleration occurs in a variety of situations including many that require attention to the environment, but support for the instrumental role of this reaction in actively facilitating certain kinds of sensory-motor performance is lacking. The major contributions that are needed for the hypothesis to retain its heuristic value are (a) clarification of constructs, e.g., "attention," and greater explicitness of several aspects of the hypothesis; (b) less reliance on heart rate alone as a dependent measure reflecting mediating mechanisms and cortical effects; and (c) more investigation of other hypothesized mediating mechanisms. (42 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)