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At least 19 recordsLinked to original sources
PubMed1975

Waiting for a crowd: the behavioral and perceptual effects of anticipated crowding.

An experiment was conducted in which subjects were convinced that crowding was imminent. It was hypothesized that the arousal of expectations of crowding would cause subjects to behave in ways suggesting that they were preparing for the experience of crowding by taking steps to reduce the impact of crowding before its onset. Similarly, it was predicted that anticipation of crowding would influence subject perceptions of the experimental room, interpersonal affect, and general levels of discomfort. Data collected indicated that these predictions were accurate; subjects anticipating crowding chose more socially isolated seat positions, avoided contact with others, experienced crowding and discomfort, and rated others in the setting as well as the room in ways generally consistent with definitions of crowding.

Adolescent↗
PubMedDate not supplied

Crowding and mental health.

An epidemiologic investigation of the mental needs and services of 1645 respondents, aged 17 to 92 years and living in a representative southeastern county in Florida, revealed that 7.8% of the sample lived in crowded conditions. The crowded respondents scored significantly higher than did the uncrowded on both a depression scale and on the Health Opinion Survey. Associations between crowding and high scores on both scales were strongest among: respondents in the childrearing and middle years of life, blacks at all income levels, whites in the intermediate annual family income range of $6000 to $9999, and especially, females rather than males. Consistently, the crowded black population, and particularly, crowded white women, had much higher scores than did the uncrowded women. A multiple regression analysis showed that three variables--being a female, having a lower income, and crowding--accounted for 16.5% of the variance. The discussion emphasizes that the relationship between crowding and higher scores on indices of emotional distress is quite complicated. In crowded situations, depression may be a costly, semi-adaptive reaction to excessive interpersonal stimulation. Women living in crowded situations appear to be at high risk for depressive illness; their plight brings to mind the classic animal experiments which showed that the maternal behavior of females deteriorated in crowded situations.

Adolescent↗
PubMed1985

Prediction of mandibular incisor and canine crowding changes in the mixed dentition.

To test the hypothesis that preeruptive tooth positions and dental arch parameters might forecast crowding changes, a sample of 47 aboriginal children (26 males, 21 females) was selected stringently on the basis of Class 1 characteristics and an untreated dentition unaffected by caries or attrition. Crowding scores, radiographic relationships of 765E, and dental arch dimensions were evaluated for the mixed dentition (Stage 1, 8.91 +/- 1.05 years) and earliest emergence of the permanent dentition (Stage 2, 12.48 +/- 0.97 years). Changes between the stages were calculated and the sample was divided into two groups, according to an increase (Group 1) or decrease (Group 2) in incisor and canine crowding. Multivariate and multiple regression analyses were used to identify predictors (Stage 1 radiographic and dental arch parameters) of incisor and canine crowding behavior. Dental arch form and tooth size were important factors in measuring the amount of incisor or canine crowding at Stage 1 and Stage 2. Neither the radiographic nor the dental arch predictors proved useful in forecasting crowding changes. Group 2 dental arches tended to be initially narrower, shallower, and more crowded; however, they showed greater molar and canine width expansion and lessened arch depth reduction than Group 1 cases. Many cases showed a reduction in canine crowding from mixed to permanent dentition. This appeared to be largely independent of the observed incisor crowding. Sexual, racial, and individual variations in dentofacial pattern reinforce the need to carefully consider interceptive extraction or space-regaining therapy for each patient because of the unpredictability of crowding behavior during the transition from mixed to permanent dentition.

Australia↗
PubMed1989

[Gnathometric changes in examinees with and without early findings of crowding--a longitudinal study].

The longitudinal sample of children of both sexes (31 without crowding and 39 with crowding) has been investigated to examine the influence of clinically estimated findings in the deciduous dentition in the volume of jaw growth as well as in the occurrence of some malocclusions in the mixed dentition. The children were examined for the first time at the age of 4.5 and again 3 years later. The results have pointed out the following: there was no essential difference in the volume of transversal and sagittal jaw growth in reference to early findings; in both groups the significant enlargement of transversal and sagittal dimensions was recorded; mean of the width of the upper dental arch are significantly higher in the group without crowding in primary dentition; mean of the length of the upper dental arch are somewhat higher in the examinees with early findings of crowding at the first examination, namely in the examinees without early finding of crowding at the second examination; mean of the overjet are somewhat higher in the group with early finding of crowding; distribution of the examinees in the mixed dentition according the orthodontic diagnosis does not show essential differences in regard to early finding; the largest number of the examinees in the mixed dentition shows the symptoms of the primary crowding regardless of the earlier findings; only 29.1% examinees without early finding of crowding, maintain the same characteristic in the mixed dentition; in the 26.4% examinees with early finding of crowding, there comes to the spontaneous loss of the primary symptoms during the change of teeth namely to the transfer to the group with no crowding.

Child↗
PubMed1987

Crowding-induced changes in basal and stress levels of thyrotropin and somatotropin in male rats.

The effects of crowding on thyrotropin (TSH) and somatotropin (GH) secretion were studied in two-month-old male rats. Crowded rats (9-10 per cage) showed lower serum GH levels than controls (3 per cage). Likewise, serum GH was lower in crowded rats after acute exposure to stress. However, percentage inhibition of GH secretion induced by acute stress was similar in crowded and control rats. Crowding reduced the TSH response to acute stress. The results found with the administration of hypothalamic regulatory factors suggest that the impaired GH and TSH secretion observed in crowded rats was not likely to be at the pituitary level. Therefore, altered neuroendocrine control of GH and TSH secretion appears to exist in crowded rats. Preliminary results obtained in rats crowded from weaning to adulthood suggest that food restriction only partially accounts for the changes observed in crowded rats.

Animals↗
PubMed1989

Comparison of crowding and food restriction effects on growth, body weight gain and endocrine status in the rat.

The present work compares the effects of post-weaning crowding and those of food restriction on growth, body weight gain and the levels of several hormones, in male Sprague-Dawley rats. Crowding resulted in reduced food intake and diminished body weight gain. Rats daily receiving the same amount of food as that eaten by crowded rats (food-restricted group) showed similar body weight gain as crowded rats, but higher growth rate. Neither crowding nor food restriction altered the pituitary-adrenal axis. In contrast, both treatments decreased serum insulin, growth hormone (GH), somatomedin C (Sm-C) and thyroid-stimulating hormone (TSH) as compared to control rats. The reduction of GH and Sm-C levels was similar in crowded and food-restricted rats but that of TSH was higher in food-restricted, rather than in crowded rats. The present data indicate that the effects of crowding could only be partially explained by the concomittant reduction of food intake and that the serum levels of the hormones studied could not explain the differences between the crowded and food-restricted rats with regard to growth.

Animals↗
PubMed1977

A clinical study of the relationship between crowding of teeth, plaque and gingival condition.

A clinical trial was undertaken to assess whether crowded teeth were more likely to accumulate plaque and develop gingivitis than non-crowded teeth. A tooth was considered crowded if it was displaced by 2 mm and/or rotated 15 degrees or more from the normal position in the arch. The material consisted of 50 dental students aged 21 to 32 years. An initial examination comprised assessment of Plaque Index, Gingival Index and pocket depths. After this examination the subjects refrained from using interdental cleaning aids but continued with their normal toothbrushing for 40 days. After re-examination they were instructed in the effective use of dental floss. A final examination was carried out after 140 days. At the start of the trial no difference was found in regard to the Plaque Index between crowded and non-crowded teeth. The Gingival Index for growded front teeth, but not for crowded premolars, was somewhat higher than for the corresponding controls. The cessation of interdental cleaning resulted in a similar increase in plaque accumulation and gingival inflammation in both non-crowded and crowded teeth. The use of dental floss for approximal tooth cleaning resulted in a similar decrease in the Plaque- and Gingival Indices for both types of teeth. The results demonstrate that in a group of young adults, crowding of teeth (1) did not favour plaque accumulation on approximal tooth surfaces and (2) influenced the degree of gingival inflammation only to a minor extent.

Adult↗
PubMed1979

Disruptive effects of disconfirmed expectancies about crowding.

The experiment utilized a 2 (high vs. low room density) X 2 (forewarning of a crowded room vs. no forewarning) X 2 (simple vs. complex task) design to examine the effects of anticipation of crowding on task performance. More tasks were attempted and efficiency was higher when expectancies about the crowd were confirmed. Subjects not told to anticipate a crowd who actually worked under high density and subjects warned about a crowd that did not materialize performed most poorly. These differences were largest for the complex task. Baum and Greenberg's results were replicated with the performance data. Perceptions of the experimental room also differed as a function of anticipation, but failure to obtain a Crowding X Anticipation interaction did not support their hypothesis that anticipating a crowd induces identical perceptions to those obtained under actual crowding. The results are discussed in terms of disconfirmed expectancies being disruptive of performance, particularly complex task performance.

Adult↗
PubMed1979

Effect of crowding on amphetamine-induced disaggregation of brain polyribosomes.

DL-amphetamine's actions on brain polyribosomes were studied in crowded and uncrowded mice. The administration of 20 mg/kg DL-amphetamine induced disaggregation of brain polyribosomes in both crowded and uncrowded mice 30 min post drug administration. However, the magnitude of polysome dissociation was observed to be greater in crowded animals than in uncrowded ones. In studying the dose-response relationship there appears to be a relationship between drug dose and polysome disaggregation in both groups of animals, although the effects were always greater in crowded mice. The magnitude of polysome dissociation appears to parallel both in the intensity of central nervous system stimulation, and degree of crowding. Haloperidol was able to block the increased locomotor activity due to drug dose and crowding at 1 mg/kg, and significatnly suppress disaggregation of brain polysomes in crowded animals. A possible role of the effects of crowding on the central nervous system in the presence of amphetamine as it relates to polysome dissociation has been presented.

Amphetamine↗
PubMed1986

The relationship of dental crowding to tooth size, dental arch width, and arch depth.

This study was undertaken to answer the question, "Are there any differences in the mesiodistal tooth diameters, dental arch width and dental arch depth between the crowded and noncrowded dentitions?" The materials submitted for study consisted of the Orthoscan intraoral occlusograms of 89 subjects with well-aligned dentition and those of 74 subjects with gross dental crowding. The tooth size and arch dimensions were measured from these intraoral occlusograms. The data were subjected to statistical treatment for comparison of noncrowded and crowded groups. The findings in this study lead to the following conclusions: The mesiodistal tooth diameters of the crowded group were significantly larger than those of the noncrowded group. The dental arch widths of the crowded group were significantly smaller than those of the noncrowded group. No substantial or significant difference in dental arch depth between the crowded and noncrowded subjects could be noted. From these findings it seems that tooth size and dental arch width are determining factors in the formation of dental crowding. Clinically, these results suggest that in the treatment of dental crowding, extraction of teeth and/or expansion of dental arches should be considered depending on what is the main causative factor.

Adolescent↗
PubMed1987

Rat cortical morphology following crowded-enriched living conditions.

This experiment studied cerebral cortical morphology in rats living in a crowded-enriched condition. Three groups of 60-day-old, male Long-Evans rats were divided accordingly: 12 rats, 3 per small cage (32 X 20 X 20 cm), standard colony condition; 12 rats in a single, large, enrichment cage with "toys" (70 X 70 X 45 cm), enriched condition; and 36 rats in a large, single, enrichment cage with "toys", crowded-enriched condition. Matched toys for the two enriched cages were changed twice a week at the time of cage cleaning. Measurements on 20-micron, transverse brain sections showed that in both the crowded-enriched and enriched groups the thickness of the medial occipital cortex increased by 4 to 6% compared with the cortex from animals in the standard colony condition. In addition, the crowded-enriched group demonstrated a 4% (P less than 0.05) increase in thickness in area 39 in the left hemisphere compared with the standard control. However, the thickness in area 39 in the crowded group was not significantly different from that of the enriched area 39. These results indicate that the cortex increases in thickness as much with "crowding" and enrichment as with enrichment alone. We hypothesize that diversion through interaction with "toys" mitigates the stress of crowded conditions.

Animals↗
PubMed1985

Crowding pregnant mice affects attack and threat behavior of male offspring.

Attack and threat behavior of adult male offspring of female mice crowded during the final third of pregnancy was investigated. In 5-min test pairings with an anosmic "standard opponent" which had 50 microliter of male mouse urine applied to its fur, the prenatally stressed group of males showed significantly less attack behavior; attack latency was longer and number of attacks, bites, amount of time spent attacking, and composite aggression scores were all lower, compared with the control group. Similarly, less threat behavior was observed in offspring from crowded dams; there were lower frequencies of tail rattles, rough grooms, and upright threats. Additionally, proportionally fewer males in the prenatally stressed group attacked or displayed threats. A second experiment was designed to investigate the effects of exogenous androgen on the aggressiveness of males from crowded mice: testosterone propionate administration (500 micrograms/animal/day, for 5 days prior to testing) abolished differences both in the proportion of males from crowded mice that fought and also apparently abolished differences in intensities of attack and threat behavior between groups. However, trends toward reduced aggression in prenatally crowded males remained. More detailed analysis of these responses, based only on animals that displayed aggression, revealed significantly reduced intensity of aggression in offspring from females crowded during pregnancy, indicating that testosterone propionate therapy did not completely restore this behavior. In order to reduce postnatal effects due to possible differences in mothering, all offspring were fostered to untreated mothers at birth. The results are discussed in terms of in utero exposure of male fetuses of crowded dams to stress-liberated adrenal steroids of maternal origin, and the possible consequences for the endocrine integrity of these offspring.

Aggression↗
PubMed1991

Emergency departments and crowding in United States teaching hospitals.

STUDY OBJECTIVES: To assess the extent and distribution of hospital and emergency department crowding nationally. DESIGN: The research design consisted of a mailed questionnaire disseminated in the fall of 1988 to the member institutions of the National Association of Public Hospitals (NAPH) and the Council of Teaching Hospitals (COTH). TYPE OF PARTICIPANTS: Study participants included hospital administrators and ED directors from 239 of the non-Veterans Administration, general acute care, US members of COTH and NAPH. MEASUREMENTS: Key measures of hospital and ED crowding including mean ED holding times for floor and ICU beds. MAIN RESULTS: Three fourths of responding hospitals reported increases in ED visits over the preceding three years. Mean ED holding times for admitted patients were 3.5 hours (median, 2.0 hours) for a floor bed and 2.9 hours (median, 1.5 hours) for an ICU bed. Half of all hospitals noted maximum waits for floor and ICU beds of ten hours or more and seven hours or more, respectively. Measures taken by hospitals to manage crowding during August 1988 included restricting access to some types of patients (mean, 3.6 days), actively transferring patients to other hospitals (mean, 2.2 days), transfer refusal (mean, 2.8 days), and total ambulance diversion (mean, 1.6 days). CONCLUSIONS: Our study strongly suggests that ED crowding is not an isolated phenomenon; ED crowding and its attendant problems appear to affect hospitals with similar adverse effects regardless of ownership. Although our results suggest that ED crowding is concentrated in metropolitan areas and in a smaller subset of hospitals, we found instances of crowding among hospitals nationwide.

Bed Occupancy↗
PubMed1976

The experience of crowding: a two-factor theory.

It was proposed that the experience of crowding occurs in a two-step process: First, the individual becomes aroused by violations of his personal space, and then he attributes the cause of this arousal to other people in his environment. Based on this model it was predicted that violations of personal space rather than simple density is the spatial variable associated with crowding. Further, it was predicted that the experience of crowding can be alleviated if the individual is distracted from making the attribution that his arousal is caused by other people. In order to test these prediction, interaction distance (close and far) and density (high and low) were varied separately. In addition, for half of the conditions, pictures (attribution inhibitors) were placed on the walls of the experimental room, and in the other half, the walls were bare. Subjects worked on two tasks and were then questioned about their experience of crowding. The results showed that interaction distance was more closely related to crowding than was density and that the addition of pictures reduced the experience of crowding only in the close interaction conditions. The results were interpreted as supporting the attribution analysis of crowding.

Arousal↗