Individual Differences In Rate Research Articles

Individual differences in visual information processing rate and the prediction of performance differences in team sports: a preliminary investigation.

This study used a backward-masking paradigm to examine individual differences in rate of visual information processing among university basketball, ice hockey and Canadian football players. Displays containing four letters were presented for stimulus durations ranging from 25 to 300 ms. Following stimulus offset, a masking stimulus was presented for 200 ms. The subjects were instructed to write down as many letters as possible from the briefly presented stimulus display on a specially prepared response grid. The results indicated consistent individual differences in rate of visual information processing. More importantly, it was found that rate of visual information processing as indexed by the backward-masking technique, has promising validity for predicting general performance excellence in university ice hockey and basketball players. Individual differences in rate of visual information processing were interpreted as reflecting the operation of attentional factors.

Effects of early environmental experience on self-administration of amphetamine and barbital.

Rats were housed after weaning in isolation, with a same-sex sibling, or in a group in an enriched environment for 60 days. Then, subjects were trained to consume all of their fluids during a daily 2-h drinking session, habituated to drinking solutions of both d-amphetamine sulfate and sodium barbital, and then given a choice between drinking water, the stimulant amphetamine and the depressant barbital. Drug choice was affected by both sex and previous housing condition. Males raised in social isolation preferred the stimulant, while females raised in isolation preferred the depressant. Both males and females raised in enriched environments expressed no drug preference, and had the lowest overall drug intake. These results suggest that individual differences in rates of initiation, choice of abusing agent, and maintenance of drug self-administration may be partially determined by pre-existing differences in central nervous system functioning due to early experiences. Differential early experience, particularly the stress of social isolation, can influence drug self-administration behaviour, but the effect may be sex-dependent.

Individual Behavioural Strategies Associated with Predator Inspection in Minnow Shoals

AbstractWhen confronted with a live pike, Esox lucius, European minnows, Phoxinus phoxinus, showed individual differences in rate of predator inspection. Predator inspection behaviour, in which single individuals or small groups approached the predator, was ordinated with several other behavioural parameters using principal components analysis. Individual minnows showed one of two strategies. Fish with high inspection rates were bolder, skittered more frequently and fed more persistently than fish with low inspection rates. Fish with low inspection rates showed the opposite strategy. Individuals did not show habituation of predator inspection during trials or over the experimental period.

Inability to predict the adult sexual performance of bulls by prepuberal sexual behaviors.

The objective of this investigation was to determine the extent to which the sexual performance of adult bulls (18 to 24 mo of age) can be predicted by prepuberal sexual behaviors. Tests were administered to 121 polled Hereford bulls to determine whether adult sexual performance (especially serving capacity or ejaculation rate) was related to 1) whether or not the subjects mounted estrous females at 6 mo of age, 2) the age at which the bulls attained their first ejaculation, 3) the frequency of sexual behaviors exhibited in heterosexual interactions and 4) the frequency of male-male mounting exhibited in all-male groups. None of the above measures reliably predicted adult serving capacity. Prepuberal interest in mounting other males and estrous females and the age at which ejaculatory competence was attained bore little relationship to serving capacity at 18 to 24 mo. Individual differences in rate of ejaculation were consistent from one age to another only after the bulls had reached 18 mo. We concluded that the sexual behaviors of prepuberal beef bulls were of limited usefulness in predicting adult sexual performance.

Visual monitoring of threatening objects by captive tamarins (Saguinus labiatus).

Captive social groups of red-bellied tamarins (Saguinus labiatus) were observed in the presence of threatening, inanimate objects. The tamarins monitored the stimuli over the course of the 20-minute trials by conducting brief, periodic visual checks of the objects. The average number of checks per subject per trial was stable both across trials and between groups, and individual differences in rates varied relatively little around the group means. These data generate the hypothesis that there is a species-typical execution of vigilance in the presence of mildly threatening objects. This execution takes the form of brief visual inspections of the stimulus, usually by one tamarin at a time, at a fairly consistent rate. The discussion of the data takes place in the context of the behavioral ecology of callitrichid species.

Population Dynamics Based on Individual Size Rather than Age: A General Model with a Reef Coral Example

Models of population dynamics based on age-related parameters do not provide accurate predictions if within-age-class variance in those parameters is high. Often the demographic fate of an individual or population may be predicted more accurately using size rather than age classifications. I describe here a general model of size-related population dynamics, based on a modified Leslie matrix. The model is designed to include demographic processes, such as fragmentation and shrinkage, which are excluded from conventional age-related demographic analysis. The parameters of the model were measured during a calm and a stormy year in a field study of a colonial, sessile coral. These data were used in computer simulations to predict the fate of a cohort over long periods of time. Measured differences in individual rates of growth and shrinkage resulted in huge long-term variations in calculated colony size, fecundity, and mortality rates, between corals of equal age. Therefore, individuals of the same age will have widely differing probabilities of obtaining representation in subsequent generations. Population growth was simulated by adding a constant number of juvenile corals every year to the smallest size class. Although the model has no density-dependent parameters, population growth stops. The population size attained depends on the number of settling juveniles. Local populations of sessile organisms may be regulated by larval input, as well as by recurring disturbances or density-dependent interactions.

Personality and the perception of TV violence

An experiment was carried out to investigate relationships between individuals' personality characteristics and their perceptions of violent TV portrayals. A panel of 40 viewers rated brief violent episodes from five categories of programming, contemporary British crime-detective series, American police series, westerns, science-fiction series and cartoons on eight scales. These responses were then related to viewers' scores on the N, E and P dimensions of the EPQ. Results showed that violent scores from contemporary settings were rated as more serious than scores from non-contemporary and fantastic settings. In addition, viewers exhibited individual differences in ratings of TV violence which were related to certain of their EPQ scores. In particular, high N scorers tended to perceive violence generally, but especially that from contemporary British drama, as more serious than did low N scorers. This study indicates the need to include personality measures in the analysis of audience reactions to TV violence.

Differences in Long-Term Retention in Relation to Early School Achievement

On two widely separated occasions (referred to as Experiments 1 and 2), children in grades 2 and 3 were given three study-recall trials on a list of familiar words, with a retention test 24 hr. later. Percentage retained, a measure that was independent of original scores, showed significant stability over the two occasions, indicating the existence of individual differences in rates of forgetting. Further evidence of such differences accrued from group differences found within each experiment; children judged by teachers to forget unusually rapidly did display more rapid forgetting than did unselected children. However, children labeled learning disabled by the schools failed to display unusually rapid forgetting, despite common proposals to the contrary. An encoding deficit hypothesis was proposed to account for unusually rapid forgetting, and issues regarding the measurement of individual differences in forgetting were addressed.

Personality and perceptions of harmful and harmless TV violence

A study was carried out to examine viewers' perceptions of violent TV portrayals characterized by different degrees of observable harm to victims and by different programme settings. These perceptions were also related to viewers' personality scores on the EPQ. A panel of 40 individuals rated 18 brief TV scenes depicting violence in American crime-detective or science-fiction settings which resulted in fatal or non-fatal injury, or no observable harm to victims. Results showed that harmful violence was rated as significantly more serious than harmless violence in American crime-detective settings, but that the perceived consequences of violence were less salient discriminating attributes of content in science-fiction settings. There were also individual differences in ratings in that older people and lower P scores tended to perceive harmful violence as more violent, frightening and likely to disturb others than were younger people with higher P scores.

The interaction of emotional stress and language development: Case studies of three visually impaired children

The diagnostic assessment of speech and language function in the first 6 years of life is an important clinical procedure. Although scales measuring verbal and communication skills, and articulatory competence, exist, their value as predictive instruments has not been generally accepted by clinicians. We assume that this is due to the wide individual differences in rate of acquisition of language, and the vulnerability to stress of any function in the process of development. These factors, the child’s rate of acquisition and response to stress and stimulation, are part of the diagnostic assessment. We view stress and stimulation as having a nonspecific cause and effect relationship. For example, one child may respond to separation from the maternal figure by deviation in pronunciation, another by mutism, and still another by behavioral symptoms, while there are other children who would show no observable consequence to such trauma. Likewise, the stimulation of an intervention program may be responded to in different ways. These assumptions have been used as guidelines in the Pre-School Program for Visually Handicapped Children at the New York Association for the Blind, where longitudinal as well as cross-sectional studies are used for the full evaluation of language function. The visually impaired child relies to an even greater extent than the sighted child on verbal language. For him in particular, the ability to develop language will determine the extent of his successful adaptation to life. Attention to early development of language and the design of early intervention procedures are of central importance to our work with preschool children. There are three groups of children in which language and speech may not develop adequately or at all. The first are those who have impaired auditory functions. The second are those who have central nervous system dysfunctions, and the third are those who have experienced serious emotional deprivation or trauma. When language development is deficient, the child’s intellectual and emotional growth may be seriously affected.

Individual differences in ratings of words combined in sentences

To examine the efficiency of regression-compounded group means as predictors of individual ratings of words combined in sentences, a study by Heise (1969) was replicated and extended to obtain pre- and postcombination ratings from the same subjects. Heise's model efficiently predicted group ratings for words combined in sentences (R2=0.86), but neither group-weighted (R2=0.19) nor individually weighted (R2=0.28) regression equations efficiently predicted the rating of individual subjects. The findings are consistent with several findings that question the applicability of widely studied models of attitude change to individual differences and alternative approaches to this problem are discussed.

Individual differences in habituation: Some methodological and conceptual issues

The personality correlates of habituation were investigated. A moderate intensity tone was presented 20 times on each of three sessions, and skin conductance and heart rate were recorded. There were no relationships between individual differences in rate of habituation and any of the personality dimensions assessed (which included, among others, manifest anxiety and introversion-extraversion). Some possible reasons are discussed for this lack of results, as well as for conflicting findings which fill the literature. Specifically, various methods of measuring habituation are examined and their interrelationships described. None of the measures derived showed adequate consistency either across sessions or over response modalities.

Dominance status and certain operants in a communal colony of rhesus macaques

This study was designed to test the hypothesis that in some species of primates individual differences in responsiveness to certain situations is related to dominance status. During the first phase of the study, the existence of a linear dominance hierarchy was confirmed by ratings of agonistic interactions. In the second phase, bar-pressing behavior was recorded on a cumulative recorder while the experimenter simultaneously rated, at 30-second intervals, all animals present in the research setting. Results indicated that dominance status was systematically related both to rate of bar-pressing and to duration of response blocks, with the more dominant animals bar-pressing at slower rates for longer blocks of time. The finding that individual differences in rate did not vary with social context suggests that dominance-related differences in responsiveness may be quite stable. Certain dominancerelated trends in the variation of social context in the research setting were also noted.

Mechanism of hepatic drug oxidation and its relationship to individual differences in rates of oxidation in man.

Mechanism of hepatic drug oxidation and its relationship to individual differences in rates of oxidation in man.

Genetic and environmental factors affecting ethanol metabolism in man.

The relative contribution of genetic and environmental factors to maintaining twofold differences in rates of ethanol elimination from plasma was examined in 14 sets of nonmedicated, nonhospitalized healthy twins. After a single oral dose of 1 ml. per kilogram of 95 per cent ethanol, intrapair differences in rates of elimination were less in identical than in fraternal twins. Thew results indicate that individual differences in rates of ethanol elimination among the 28 twins were genetically controlled and that environmental factors played a negligible role. In 6 prisoners in solitary confinement, rates of ethanol metabolism increased in 3 but declined in the remaining 3 after 21 days of ethanol administration. Rates of antipyrine elimination from plasma were accelerated by ethanol administration in each of the 6 volunteers. Considerable individual variation occurred in the degree to which ethanol shortened plasma antipyrine half‐lifes; reduction ranged from 4 to 37 per cent of the initial antipyrine half‐life. These results suggest that ethanol administration for 21 days at this dosage fails to alter consistently the rate of its own metabolism but increases antipyrine metabolism in all subjects to varying extents.

DEVELOPMENT OF LOGICAL PROBLEM SOLVING: A ONE-YEAR RETEST

In order to (a) compare development in the same child over a 1-year interval with a previously obtained cross-sectional picture and (b) get at individual differences in rate and course of development, children in the age range of transition from concrete to formal operations were given a series of problems and retested 1 year later. Level of performance was assessed with respect to 3 objective measures as well as a qualitative rating. There was good agreement among the measures. The longitudinal developmental picture was in good accord with the cross-sectional one. Individual developmental patterns were compatible with an interpretation of the development of cognitive structures as progression through a hierarchy of relatively discrete stages.

DEVELOPMENT OF NATIVE LANGUAGE SKILLS BEYOND THE EARLY YEARS

ABSTRACTThis chapter, prepared for a volume on Language Learning to be published by the National Council of Teachers of English, is a review of the development of language competence and performance skills beyond the years of primary language acquisition, i.e., from about the first grade on. First, development of specific skills relating to phonology, syntax, and vocabulary is reviewed, and then attention shifts to the development of “integrated skills”: listening, speaking, reading, and writing. Emphasis is put on identifying dimensions of individual differences in rates of growth and development. Although a substantial degree of basic competence in the rules of the native language is attained by the normal child at school entry age, development is by no means complete at that time. In many aspects of language skill, development continues throughout the years of schooling and to a lesser extent throughout adult life In adult populations, there are enormous individual differences in nearly all aspects of language skill. Gaps in our knowledge of factors in development are pointed out

Reminiscence in the short-term retention of paired-associate lists

In the first experiment, 5-item paired-associate lists, varying in response-term meaningfulness (high, medium, and low), were presented for a single study trial (4 sec per pair), with recall being taken after 4, 19, 64, 184, and 304 sec. Reminiscence was found at each level of meaningfulness, with the peak of the three retention functions occurring at 19 sec. Three additional experiments established the reliability of the reminiscence effect. Subsequent analyses support the conclusion that either individual differences in rate of learning are important for producing reminiscence or that degree of learning is important.

The use of rats as discriminative stimuli.

A FREE OPERANT PROCEDURE WAS USED TO DETERMINE WHETHER OR NOT ONE RAT COULD DISCRIMINATE: (1) between the presence and absence of a second rat, and (2) between two other rats of the same species and sex. The subjects were four male Wistar rats. The discriminatory response was a bar press and food was used as reinforcement during training. Although there were wide individual differences in rate of learning, all subjects learned to make both discriminations.

Skeletal muscle blood flow dumng hypercapnic hyperventilation

Individual differences exist in ventilatory responsiveness to inspired mixtures of carbon dioxide. The data of Schaefer suggest that subjects with high ventilatory responsiveness are ones who store CO 2 in the body at a low rate during acute, mild hypercapnia, while subjects with low ventilatory responsiveness appear to store CO 2 at a high rate under identical conditions. The rate of delivery of CO 2-rich blood to one of the likely sites for major, short-term CO 2 storage was estimated by measuring forearm blood flow using venous-occlusion plethysmography while the skin circulation was minimized with percutaneous electrophoresis of epinephrine. During hypercapnia resulting from breathing 2%, 4% and 6% CO 2 in 21 % oxygen, all subjects showed small significant increases in mean muscle blood flow. The maximum increase was approximately 40% above control levels and was usually seen during exposure to 4% CO 2. No correlation was found between ventilatory responsiveness to CO 2 and muscle blood flow response. The individual differences in rate of storage of CO 2 during hypercapnia cannot be explained by differences in skeletal muscle blood flow response.