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PubMed2000

The role of comparison in the extension of novel adjectives.

Previous reseach has documented that basic-level object categories provide an initial foundation for mapping adjectives to object properties. Children ranging from 21 months to 3 years can successfully extend a novel adjective (e.g., transparent) to other objects sharing a salient property if the objects are all members of the same basic-level category; if the objects are members of different basic-level categories, they fail to extend adjectives systematically (R. S. Klibanoff & S. R. Waxman, 2000a; S. R. Waxman & D. B. Markow, 1998). The present study proposed that the process of comparison is instrumental in children's ability to move beyond this foundation. To promote comparison, 2 target objects were introduced to 3-year-olds. In Experiment 1, the targets had contrastive properties (e.g., 1 transparent and 1 opaque object); in Experiment 2, the targets had consistent properties (e.g., 2 transparent objects). The results of both experiments illustrate that comparison--a general psychological process--operates in conjunction with naming to support the extension of novel adjectives to properties of objects from diverse basic-level categories.

Child, Preschool↗

PubMed2002

Job-decision inconsistencies involving social comparison information: the role of dominating alternatives.

Previous research on joint versus separate preference reversals has demonstrated that individuals focus on social comparison information when they are evaluating a single option but focus on absolute salary when they are considering more than 1 option. Study 1 demonstrates that social comparison information is important in multiple option scenarios when an option favorable on social comparison dominates an inferior, 3rd alternative. Study 2 examines why dominating alternatives are so attractive by investigating the role that the value-shift, weight-change, and emergent-value models play in explaining the pattern of results obtained in Study 1. Results provide support for the value-shift and emergent-value models and further suggest that these 2 models may be interrelated, with justification (emergent-value model) mediating the relationship between the attractiveness of the attributes (value-shift model) and the attractiveness of the dominating alternative.

Competitive Behavior↗

PubMed1994

Initial sociometric impressions of attention-deficit hyperactivity disorder and comparison boys: predictions from social behaviors and from nonbehavioral variables.

This study systematically compared the influence of naturalistic social behaviors and nonbehavioral variables on the development of peer status in 49 previously unfamiliar boys, aged 6-12 years, who attended a summer research program. Twenty-five boys with attention-deficit hyperactivity disorder (ADHD) and 24 comparison boys participated. Physical attractiveness, motor competence, intelligence, and academic achievement constituted the nonbehavioral variables; social behaviors included noncompliance, aggression, prosocial actions, and isolation, measured by live observations of classroom and playground interactions. As early as the first day of interaction, ADHD and comparison boys displayed clear differences in social behaviors, and the ADHD youngsters were overwhelmingly rejected. Whereas prosocial behavior independently predicted friendship ratings during the first week, the magnitude of prediction was small. In contrast, the boys' aggression (or noncompliance) strongly predicted negative nominations, even with nonbehavioral factors, group status (ADHD versus comparison), and other social behaviors controlled statistically. Implications for understanding and remediating negative peer reputations are discussed.

Attention Deficit Disorder with Hyperactivity↗

PubMed2003

What friends are for! The use of routine standards in social comparison.

Social comparisons are frequently used for self-evaluation. As a consequence, judges have to be efficient in each comparison step. Standard selection, however, is traditionally seen as an elaborate process in which judges deliberately select similar standards. We propose that often judges do not engage in such deliberate selection processes. Instead, they use routine standards--standards that have frequently been used for self-evaluation. Consistent with this assumption, Studies 1-3 demonstrate that student participants activate knowledge about their best friend--a likely routine standard--during self-evaluation. In Study 1, lexical decisions for the best friend's name are facilitated after self-evaluation. In Study 2, participants judge their best friend faster after evaluating themselves on the same dimension. In Study 3, this is even the case if the best friend is dissimilar and consequently undiagnostic. Finally, in Study 4, self-evaluations are primarily influenced by comparison information about an experimentally created routine standard.

Adult↗

PubMed2006

Social comparison, self-stereotyping, and gender differences in self-construals.

Four studies examined gender differences in self-construals and the role of social comparison in generating these differences. Consistent with previous research, Study 1 (N=461) showed that women define themselves as higher in relational interdependence than men, and men define themselves as higher in independence/agency than women. Study 2 (N=301) showed that within-gender social comparison decreases gender differences in self-construals relative to a control condition, whereas between-genders comparison increases gender differences on both relational interdependence and independence/agency. Studies 3 (N=169) and 4 (N=278) confirmed these findings and showed that changing self-construal changes gender differences in social dominance orientation. Across the 4 studies, strong evidence for the role of in-group stereotyping as mediator of the effect of gender on self-construal was observed on the relational dimension but not on the agentic dimension.

Adolescent↗

PubMed2003

When egocentrism breeds distinctness--comparison processes in social prediction: comment on Karniol (2003).

In contrast with R. Karniol's (2003) protocentric model, this article proposes an egocentric comparison model of social prediction. To predict the experiences and reactions of a target other, judges are assumed to relate self-knowledge to the target via a process of comparing the target with the self. Two alternative comparison processes are distinguished. Similarity testing yields target judgments that are consistent with the self, whereas dissimilarity testing leads to target judgments that are inconsistent with the self. From this perspective, social prediction is egocentric in that it makes use of self-knowledge as its primary representational basis. At the same time, egocentric prediction does not require the self to be seen and judged as similar to the target other. Conceptualizing social predictions as social comparison suggests that predicting the experiences and reactions of others is a highly flexible process.

Ego↗

PubMed1990

Comparable measurement scales in task-comparison experiments.

The primary goal of this comment on the article by Schacter, Cooper, and Delaney (1990) is to illustrate two kinds of advantages of comparable measurement scales for task-comparison experiments. First, a comparable metric allows quantitative comparisons of the degree of accurate performance across tasks, which yields more information than the qualitative conclusions from tests of significance on noncomparable measurement scales. Second, such a scale can highlight situations in which fundamentally different kinds of comparisons are being attempted. A few remarks about the inferences drawn from the research are also offered.

Adult↗

PubMed2003

Effect of valued activity disability, social comparisons, and satisfaction with ability on depressive symptoms in rheumatoid arthritis.

This longitudinal study identified a model through which function affects the psychologicalwell-being of individuals with rheumatoid arthritis (RA). Results of hierarchical linear regression analyses (N = 436) demonstrated that greater physical impairment resulted in greater disability in valued activities and engagement in unfavorable social comparisons. All 3 factors--greater physical impairment, greater disability in valued activities, and unfavorable comparison evaluations--predicted low satisfaction with abilities. Low satisfaction with abilities was the most important predictor of higher depressive symptoms and mediated the impact of physical impairment, valued activity disability, and unfavorable comparisons on depressive symptoms. Results highlight the role of personal meaning attached to changes in functional status in predicting the long-term psychological well-being of individuals with chronic illnesses such as RA.

Activities of Daily Living↗

PubMed2004

Delay discounting of potentially real and hypothetical rewards: II. Between- and within-subject comparisons.

Prior studies comparing discounting of delayed hypothetical or potentially real rewards have reported no differences, but they used within-subjects designs. This raises the possibility that participants remembered their choices in one condition and repeated them in the other. In Experiment 1, between-subjects comparisons were made with an adjusting-amount procedure. No significant effect of reward type on delay discounting was detected. Experiment 2 increased the proportion of real rewards and made between- and within-subject comparisons. These comparisons also failed to reveal a significant effect of reward type. Although these findings are consistent with prior findings, caution is urged because choices involving hypothetical rewards have yet to be compared with choices involving real rewards (i.e., the consequences of every choice are obtained) in an experiment using forced-choice trials and steady-state methodology.

Adolescent↗

PubMed2001

Hierarchical modeling of paired comparison data.

The method of paired comparisons belongs to a small group of techniques that provide explicit information about the consistency of individual and aggregated choices. This article investigates the link between the individual- and group-level judgments by extending R. D. Luce's (1959) model, which was originally developed for individual choice behavior, to a mixed-effects paired comparison model. It is shown that standard multilevel software for binary data can be used to estimate the model. The interpretation of the paired comparison parameters and statistical model tests are discussed in detail. An extensive analysis of an experimental study illustrates the usefulness of a hierarchical approach in modeling multiple pairwise judgments.

Choice Behavior↗

PubMed1993

Cell kinetic analysis of murine squamous cell carcinomas: a comparison of single versus double labelling using flow cytometry and immunohistochemistry.

The study was originally set up to measure accurate cell kinetic parameters in two murine squamous cell carcinomas (scc) for comparison with radiobiological data on proliferation during radiotherapy. The tumours, AT84 and AT478, were both moderately well differentiated aneuploid scc. In the course of the study, several comparisons of techniques were made in two different centres. This paper reports on the results of those comparisons involving two different detection methods (flow cytometry and immunohistochemistry), single vs double labelling, and in vivo and in vitro labelling, the latter using tissue slices incubated under high pressure oxygen. Pulse labelling studies with bromodeoxyuridine (BrdUrd) showed that the labelling indices (LI) were not significantly different after in vitro or in vivo labelling. In addition, the flow cytometry (FCM) and immunohistochemistry (IHC) methods also gave labelling indices which were not significantly different. Only tumour cells were analysed in these studies by selecting cells on the basis of aneuploidy (FCM) or morphology (IHC). The DNA synthesis time of the tumour cells were analysed by both techniques. For FCM, the Relative Movement method was used (Begg et al., 1985). For IHC, a double labelling method was used, employing BrdUrd and triated thymidine (3H-TdR) administered several hours apart, detected simultaneously using immunoperoxidase and autoradiography, respectively. When both labels were administered in vivo, there was good agreement for Ts between the FCM and IHC methods. Attempts were also made to measure Ts in vitro using both techniques. With double labelling, it was found that cells did not take up the second label, implying a failure of cycle progression. This was confirmed by FCM results, showing no movement of labelled cells through the S-phase, despite an initially high uptake. This could not be influenced by lowering the DNA precursor concentration or by adding foetal calf serum. This indicates that DNA synthesis times are difficult or impossible to measure in vitro in fresh tumour explants. Finally, the double labelling IHC method allowed intratumoural variations of both LI and Ts to be studied. Both parameters were found to vary markedly throughout the tumour volume, particularly for larger tumours (600 mg), giving calculated local potential doubling time values (Tpot) ranging from 1-7 days.

Animals↗

PubMed1999

A comparison of visual performance between a rigid PMMA and a foldable acrylic intraocular lens.

PURPOSE: To examine post-operative visual outcomes when using micro-incision surgery and a three-piece, foldable acrylic intraocular lens (IOL) and when using small-incision surgery and a one-piece, rigid polymethyl-methacrylate (PMMA) IOL. METHODS: Phacoemulsification and IOL implantation was conducted by one surgeon on 86 subjects (aged 50-89 years) with cataracts. Of these subjects, 67 completed the study. Subjects were implanted either with a foldable IOL (n = 38) or a rigid IOL (n = 29). Best corrected Snellen visual acuity and contrast sensitivity (2-28 cycles/degree) were measured approximately 2 months post-operatively. Comparisons were made between the pseudophakic groups and an additional group of 28 age-matched, normal subjects (aged 58-81 years). Non-parametric (Kruskal-Wallis and Mann-Whitney U) as well as parametric (ANOVA and Pearson) statistics tests were used in the analysis of results. RESULTS: All pseudophakes had corrected visual acuity of 6/9 or better. There were no significant differences in visual acuity (Kruskal-Wallis, p = 0.61) or contrast sensitivity (ANOVA, p = 0.33) between the three groups. The mean residual refractive error of the foldable IOL group was hypermetropic in comparison with the rigid IOL group but not significant at the 99% level of probability (Mann-Whitney U, p = 0.02). There was no significant difference in astigmatism between the groups. CONCLUSIONS: Implanting a foldable acrylic IOL gave no post-operative benefit in visual acuity and contrast sensitivity to pseudophakes over a less expensive rigid PMMA IOL, within this post-operative period. This study did not provide a comparison between the two lenses regarding post-operative complications, in particular the important long-term complication of posterior capsular opacification (PCO). Until and if any particular advantage of a given IOL in reduced incidence of PCO is confirmed, it appears more economical to implant the conventional rigid PMMA IOL using small-incision surgery.

Acrylic Resins↗

PubMed1991

Quantitative comparison of measurements of cerebral glucose metabolic rate made with two positron cameras.

The rapid progress in PET technology has created the dilemma of how to compare data from old and new tomographs. We examined cerebral metabolic data from two scanners, with different spatial resolutions and methods of attenuation correction, to see if metabolic values from the lower-resolution tomograph (ECAT II) could be adjusted to make them comparable to data from the higher-resolution scanner (Scanditronix PC1024-7B). Nine subjects were scanned on both tomographs after a single injection of [18F]2-fluoro-2-deoxy-D-glucose. Regional and lobar gray matter metabolic rates for glucose were obtained from comparable images from each scanner. Ratios of lobar to global gray matter metabolism also were calculated. Regression coefficients and percent differences were computed to compare ECAT II and PC1024 data. Two-thirds of the region pairs showed significant regressions, although percent differences were quite variable, with measures of glucose utilization ranging from 30 to 120% higher on the PC1024 compared to those from the ECAT II. Comparisons of lobar glucose rates between the two machines were less variable (50 to 80%), and ratios differed by only +/- 5% (except for the temporal ratios). Since there was no simple and consistent relationship between regional metabolic rates on the two tomographs, an overall adjustment of regional ECAT values for comparison to PC1024 values would be impossible. A region-by-region adjustment would be necessary. Lobar ratios are sufficiently similar that direct comparisons might be possible.

Aged↗

PubMed2006

Genome assembly comparison identifies structural variants in the human genome.

Numerous types of DNA variation exist, ranging from SNPs to larger structural alterations such as copy number variants (CNVs) and inversions. Alignment of DNA sequence from different sources has been used to identify SNPs and intermediate-sized variants (ISVs). However, only a small proportion of total heterogeneity is characterized, and little is known of the characteristics of most smaller-sized (<50 kb) variants. Here we show that genome assembly comparison is a robust approach for identification of all classes of genetic variation. Through comparison of two human assemblies (Celera's R27c compilation and the Build 35 reference sequence), we identified megabases of sequence (in the form of 13,534 putative non-SNP events) that were absent, inverted or polymorphic in one assembly. Database comparison and laboratory experimentation further demonstrated overlap or validation for 240 variable regions and confirmed >1.5 million SNPs. Some differences were simple insertions and deletions, but in regions containing CNVs, segmental duplication and repetitive DNA, they were more complex. Our results uncover substantial undescribed variation in humans, highlighting the need for comprehensive annotation strategies to fully interpret genome scanning and personalized sequencing projects.

Base Sequence↗

PubMed2003

The value of comparison.

With the number of published microbial genomes now in excess of 100, any new genome that is sequenced is likely to have a close relative available for comparison. Indeed, it is increasingly difficult to perform any genomic analysis that is not comparative. This should, however, not be seen as a drawback; it is often the case that a large amount of information can be drawn from these comparisons, especially between closely related organisms. Several genome sequences published recently indicate the value of comparisons at the genomic level.

Bacteria↗

PubMed1989

Comparison of several groups.

Techniques for the comparison of several samples are described. If the response is quantitative, comparison of the sample means is achieved by one-way analysis of variance. If the response is qualitative, comparison of several proportions is achieved by chi 2 tests.

Dentistry↗

PubMed1998

Comparison of rSP-C surfactant with natural and synthetic surfactants after late treatment in a rat model of the acute respiratory distress syndrome.

1. In a previous paper we showed that an SP-C containing surfactant preparation has similar activity as bovine-derived surfactants in a rat lung lavage model of the adult respiratory distress syndrome. In this study surfactant was given ten minutes after the last lavage (early treatment). In the present investigation we were interested how different surfactant preparations behave when they are administered 1 h after the last lavage (late treatment). 2. Four protein containing surfactants (rSP-C surfactant, bLES, Infasurf and Survanta) were compared with three protein-free surfactants (ALEC, Exosurf and the phospholipid (PL) mixture of the rSP-C surfactant termed PL surfactant) with respect to their ability to improve gas exchange in this more stringent model when surfactant is given one hour after the last lavage. For better comparison of the surfactants the doses were related to phospholipids. The surfactants were given at doses of 25, 50 and 100 mg kg(-1) body weight. The surfactants were compared to an untreated control group that was only ventilated for the whole experimental period. 3. Tracheotomized rats (8-12 per dose and surfactant) were pressure-controlled ventilated (Siemens Servo Ventilator 900C) with 100% oxygen at a respiratory rate of 30 breaths min(-1), inspiration expiration ratio of 1:2, peak inspiratory pressure of 28 cmH2O at positive endexpiratory pressure (PEEP) of 8 cmH2O. Animals were ventilated for one hour after the last lavage and thereafter the surfactants were intratracheally instilled. During the whole experimental period the ventilation was not changed. 4. Partial arterial oxygen pressures (PaO2, mmHg) at 30 min and 120 min after treatment were used for statistical comparison. All protein containing surfactants caused a dose-dependent increase of the reduced PaO2 values at 30 min after treatment. The protein-free surfactants showed only weak dose-dependent increase in PaO2 values at this time. This difference between the protein-containing and the protein-free surfactants was even more pronounced when comparing the PaO2 values at 120 min after treatment. Only rSP-C surfactant, bLES and Infasurf showed a dose-dependent increase in PaO2 at this time. 5. With this animal model of late treatment it is possible even to differentiate between bovine derived surfactants. The differences between protein-containing and protein-free surfactants become even more pronounced. From the comparison of rSP-C surfactant with bovine-derived surfactants and the PL surfactant without rSP-C, it can be concluded that addition of rSP-C is sufficient to achieve the same activity as that of natural surfactants.

Acute Disease↗

PubMed1997

Evaluation of oro-coecal transit time: a comparison of the lactose-[13C, 15N]ureide 13CO2- and the lactulose H2-breath test in humans.

OBJECTIVE: The lactulose H2-breath test is the most widely used non-invasive approach for evaluation of orocoecal transit time (OCTT). In the present study, doubly-labelled lactose-[13C, 15N]ureide (DLLU) was synthesized to investigate the OCTT in comparison to the conventional lactulose H2-breath test. Additionally the bacterial breakdown rate (BBR) and rate of elimination and the metabolic pathways of the cleavage products of DLLU (13CO2, [15N]urea, and 15NH3) were investigated. DESIGN AND SUBJECTS: In a first study, DLLU was administered as a single oral-pulse-labelling (dosage: one gram) either without and after pretreatment of five grams of unlabelled lactoseureide (LU) on the day prior to the study to twelve healthy adult volunteers after breakfast. Breath and urine were collected in one and two hour-intervals, respectively, over a one-day period. 13C-enrichment in breath as well as 15N-enrichment in urine fractions were measured by continuous flow-isotope ratio mass spectrometry (CF-IRMS). In a second study, lactulose was administered to the same subjects (dosage: ten grams). Breath was collected in quarter, half and one hour-intervals over a ten hour-period. Hydrogen concentration in breath was analysed using an electrochemical detector. RESULTS: The comparison of the lactose-[13C]ureide 13CO2-breath test and the lactulose H2-breath test showed that the mean increase of the 13C-enrichment in CO2 occurred 1.18 h later than the mean increase of H2 in breath. The resulting OCTTs derived from the two methods were 3.02 +/- 1.4 and 1.84 +/- 0.5 h (P < 0.05) and the corresponding BRs were 9.63 +/- 3.4 and 6.07 +/- 1.7 h (P < 0.01), respectively. The 15N-enrichment of urinary urea and ammonia without and after pretreatment with LU started between two and three hours after DLLU-administration. The cumulative percentage urinary excretion of the 15N- and 13C-tracer was 29.9% and 13.6% respectively, and was slightly increased after LU-pretreatment to 32.1% and 14.6% of the dose administered. A total of 35.2% of the 13C was found to be exhaled and remained approximately constant after LU-pretreatment (36.2%). CONCLUSIONS: The use of the lactulose H2-breath test for evaluation of the OCTT showed a statistically significant shortening of 1.18 h in comparison to the lactose-[13C]ureide 13CO2-breath test in healthy adults. The most important limitations of the lactulose H2-breath test are its low specificity and sensitivity due to dose-dependent accelerations of OCTT, interfering H2-rise from malabsorbed dietary fibre and H2-non-producers. In contrast, our lactose-[13C]ureide 13CO2-breath test was confirmed to avoid these disadvantages and to yield reliable results. This test is recommended especially if higher sensitivity and specificity is required, if IRMS-technique is available and if lactulose H2-tests lead to insufficient results.

Breath Tests↗