Showing papers by "University of Michigan published in 1977"

The measurement of observer agreement for categorical data

Abstract: This paper presents a general statistical methodology for the analysis of multivariate categorical data arising from observer reliability studies. The procedure essentially involves the construction of functions of the observed proportions which are directed at the extent to which the observers agree among themselves and the construction of test statistics for hypotheses involving these functions. Tests for interobserver bias are presented in terms of first-order marginal homogeneity and measures of interobserver agreement are developed as generalized kappa-type statistics. These procedures are illustrated with a clinical diagnosis example from the epidemiological literature.

Telling more than we can know: Verbal reports on mental processes.

Abstract: Evidence is reviewed which suggests that there may be little or no direct introspective access to higher order cognitive processes. Subjects are sometimes (a) unaware of the existence of a stimulus that importantly influenced a response, (b) unaware of the existence of the response, and (c) unaware that the stimulus has affected the response. It is proposed that when people attempt to report on their cognitive processes, that is, on the processes mediating the effects of a stimulus on a response, they do not do so on the basis of any true introspection. Instead, their reports are based on a priori, implicit causal theories, or judgments about the extent to which a particular stimulus is a plausible cause of a given response. This suggests that though people may not be able to observe directly their cognitive processes, they will sometimes be able to report accurately about them. Accurate reports will occur when influential stimuli are salient and are plausible causes of the responses they produce, and will not occur when stimuli are not salient or are not plausible causes.

Self-schemata and processing information about the self.

Abstract: Attempts to organize, summarize, or explain one's own behavior in a particular domain result in the formation of cognitive structures about the self or selfschemata. Self-schemata are cognitive generalizations about the self, derived from past experience, that organize and guide the processing of the self-related information contained in an individual's social experience. The role of schemata in processing information about the self is examined by linking self-schemata to a number of specific empirical referents. Female students with schemata in a particular domain and those without schemata are selected and their performance on a variety of cognitive tasks is compared. The results indicate that self-schemata facilitate the processing of information about the self (judgments and decisions about the self), contain easily retrievable behavioral evidence, provide a basis for the confident self-prediction of behavior on schema-related dimensions, and make individuals resistant to counterschematic information. The relationship of self-schemata to cross-situational consistency in behavior and the implications of self-schemata for attribution theory are discussed.

An application of hierarchical kappa-type statistics in the assessment of majority agreement among multiple observers.

Abstract: This paper presents a general statistical methodology for the anialysis of mnultivariate categorical data involving agreement among nmore than two observers Since these situations give rise to very large contingency tables in which mi0ost of the observed cell frequencies are zero, procedures based on indicator variables of the raw data for individual subjects are used to genierate first-order margins and main diagonal sums from the conceptual multidinmenisional contingency table From these quantities, estimates are generated to reflect the strenlgth of'an internlal mlajority decision on each subject Moreover, a subset of 'observers who demonstrate a high level of interobserver agreement can be identified by using pairwise agreement statistics betweeni each observer and the internal majority standard opinion on each subject These procedures are all illustrated within the context of'a clinical diagnosis examiiple involving seven pathologists

The halo effect: Evidence for unconscious alteration of judgments.

Abstract: Although the halo effect is one of the oldest and most widely known of psychological phenomena, surprisingly little is known about its nature. The halo effect is generally defined as the influence of a global evaluation on evaluations of individual attributes of a person, but this definition is imprecise with respect to the strength and character of the influence. At one extreme, the halo effect might be due simply to an extrapolation from a general impression to unknown attributes. Global evaluations might color presumptions about specific traits or influence interpretation of the meaning or affective value of ambiguous trait information. Thus, if we like a person, we often assume that those attributes of the person about which we know little are also favorable. (Politicians often seem to capitalize on this tendency by appearing warm and friendly but saying little about the issues.) Such a phenomenon could best be described as a de

The Health Belief Model and prediction of dietary compliance: a field experiment.

Abstract: In the context of a prospective experimental design, a psychosocial approach to understanding individual health-related actions (the Health Belief Model) was evaluated in terms of its ability to predict and explain mothers' adherence to a diet prescribed for their obese children. The study also tested the efficacy of two levels of fear-arousing communications in enhancing compliance with the regimen. After physician diagnosis and nutritionist counseling, an interview was conducted with each mother. Data were gathered on sociodemographic characteristics, and on attitudinal dimensions (general and obesity-specific) of the Model: health motivation; illness threat; potential diet benefits and success; barriers to compliance; and control over health matters. Subjects were then randomly assigned to three intervention groups: high fear, low fear, and control. Dependent variables included changes in child's weight over a two-month period and mother's previous appointment-keeping behaviors. Significant correlations were obtained between each major dimension of the Model and the outcome measures, and findings from multiple regression analyses support the usefulness of the Model as a whole. Further, ANOVA's revealed significant independent effects of the emotion-arousing messages on weight loss, and other tests found the influence of the intervention to be generally independent of belief affects.

The Interface Crack

Abstract: It is known that oscillatory singularities appear in problems involving interface cracks that are assumed to have open tips. An unsatisfacory aspect of the oscillatory singularities is that they lead to overlapping of the crack faces. The interface crack in a tension field, originially treated by England among others, is thus reconsidered on the basis that the crack is not completely open and that its faces are in frictionless contact near the tips. The formulation leads to a pair of coupled singular integral equations. The singularities, no longer oscillatory, exhibit some unusual features and indicate that the spreading of the interface crack in a tension field is intimately connected with failure in shear. A new stress-intensity factor is obtained and compared to the stress-intensity factors for the completely open crack. /Author/

Sex differences in empathy and related behaviors.

Abstract: According to the prevailing cultural stereotype as well as various psychological theories, empathy (the vicarious affective response to another person's feelings) is more prevalent in females than in males. A review of the research indicates that females do indeed appear to be more empathic than mal

Cognitive systems based on adaptive algorithms

Abstract: The type of cognitive system (CS) studied here has four basic parts: (1) a set of interacting elementary productions, called classifiers, (2) a performance algorithm that directs the action of the system in the environment, (3) a simple learning algorithm that keeps a record of each classifier's success in bringing about rewards, and (4) a more complex learning algorithm, called the genetic algorithm, that modifies the set of classifiers so that variants of good classifiers persist and new, potentially better ones are created in a provably efficient manner.

Institutionalized Organizations: Formal Structure as Myth and Ceremony

Abstract: Argues that the formal structure of many organizations in post-industrial society dramatically reflect the myths of their institutional environment instead of the demands of their work activities. The authors review prevailing theories of the origins of formal structures and the main problem which those theories confront -- namely, that their assumption that successful coordination and control of activity are responsible for the rise of modern formal organization is not substantiated by empirical evidence. Rather, there is a great gap between the formal structure and the informal practices that govern actual work activities. The authors present an alternative source for formal structures by suggesting that myths embedded in the institutional environment help to explain the adoption of formal structures. Earlier sources understood bureaucratization as emanating from the rationalization of the workplace. Nevertheless, the observation that some formal practices are not followed in favor of other unofficial ones indicates that not all formal structures advance efficiency as a rationalized system would require. Therefore another source of legitimacy is required. This is found in conforming the organization's structure to that of the powerful myths that institutionalized products, services, techniques, policies, and programs become. (CAR)

The Structure of Adult Friendship Choices

Abstract: This paper examines bias toward status-similarity in adult friendships in Detroit and a West German city. Principles of meeting and "mating," by which strangers are converted to acquaintances and acquaintances to friends, are stated. One of these, the proximity principle, claims that the more similar people are, the more likely they will meet and become friends. This principle is tested in matrices of friendship choice for twelve social characteristics. Two statistical measures of bias are used (odds ratio and marginal ratio) and their properties discussed. Compared to a random-choice model, adult friendships show strong bias toward status similarity for all social characteristics. Bias is strongest for "edge" categories of ranked statuses and for "best" friends. The less similar two people are in social characteristics, the less likely they are to be close friends. Demographic characteristics tend to show more bias toward homogeneous choices than other characteristics. These findings are explained and further analyses of adult friendship structure and dynamics are discussed. Urban research has shown that friendship ties among adults are pervasive and active, particularly when compared to neighbor and coworker ties (Axelrod; Bell and Boat; Bell and Force; Jitodai; Tomeh, a, b). These friendships are sources of social contact, intimacy, and assistance. They are considered primary ties, because of their emphasis on face-to-face contact and positive affect (Cooley; K. Davis; Parsons and Shils). Despite friendship's prevalence and assumed importance, little is known about the social structure of adult friendships. Who is chosen? What goods and services are exchanged? How large and heterogeneous are friendship networks? In this paper, one feature of these primary ties is examined: the structure of friendship choice. Most studies of friendship choice involve children or young adults, often college students (Lindzey and Byrne). There are relatively few reports of friendship choice by adults (Barnes; Berkun and Meeland; Curtis; Ellis; Gans, a, b; Greer; Kahl and Davis; Laumann, a, b; Lazarsfeld and *I thank E. 0. Laumann and F. U. Pappi for use of the Detroit and Altneustadt data sets. Laumann was principal investigator of the Detroit study; Laumann and Pappi, of the Altneustadt study.

PSL/PSA: A Computer-Aided Technique for Structured Documentation and Analysis of Information Processing Systems

Abstract: PSL/PSA is a computer-aided structured documentation and analysis technique that was developed for, and is being used for, analysis and documentation of requirements and preparation of functional specifications for information processing systems. The present status of requirements definition is outlined as the basis for describing the problem which PSL/PSA is intended to solve. The basic concepts of the Problem Statement Language are introduced and the content and use of a number of standard reports that can be produced by the Problem Statement Analyzer are briefly described.

Mild high-renin essential hypertension. Neurogenic human hypertension?

Abstract: To determine whether the elevated plasma renin activity in some cases of mild essential hypertension expresses sympathetic-nervous-system over-activity, we compared indexes of sympathetic activity in 16 patients with mild high-renin essential hypertension, 15 hypertensive patients with normal plasma renin activity and 20 normal subjects. Patients with elevated activity exhibited a raised plasma norepinephrine concentration (P less than 0.05), a greater fall in cardiac output with cardiac beta-adrenergic blockade by intravenous propranolol (P less than 0.01), reduction in total peripheral vascular resistance with alpha-adrenergic blockade produced by intravenous phentolamine (P less than 0.01), and reduction to normal of blood pressure by "total" autonomic blockade (atropine, propranolol and phentolamine). On psychometric testing, patients with high-renin hypertension, but not those with normal plasma renin activity, exhibited suppressed hostility (P less than 0.01), a behavioral pattern linked to increased sympathetic activity. The hypertension in these patients with high renin activity is neurogenic and possibly psychosomatic in origin.

The Differential Impact of Abstract vs. Concrete Information on Decisions

Abstract: Recent findings from research on judgment and attribution processes indicate that people regard base rate data, i.e., statistical summaries of populations, as if they were uninformative. It is suggested that base rate information lacks impact because of its abstract, pallid nature. In a demonstration of the inefficacy of abstract information, undergraduates were given mean course evaluations based on ratings of students who previously took the courses. This information had little impact on course choices. In contrast, brief, face-to-face comments about the courses had a substantial impact on course choices. The results suggest that information is utilized in proportion to its vividness.

Cognitive Social Psychology

Abstract: Social psychology is presently dominated by cognitive theories that emphasize the importance of personal beliefs and in tellective processes as the immediate determinants of behavior. The present paper explores two areas of.research within this tra dition : (1) beliefs about the external world, and (2) beliefs about the self. The paper concludes with a brief critique of the cognitive approach to social psychology.

Thallium-201 myocardial perfusion imaging at rest and during exercise. Comparative sensitivity to electrocardiography in coronary artery disease.

Abstract: The sensitivity of myocardial perfusion imaging (MPI) using thallium-201 injected both at rest and during peak exercise was compared to simultaneously recorded 12 lead electrocardiography (ECG) for the detection of transient ischemia in 20 normal subjects and 63 patients with coronary artery disease (CAD). No significant perfusion defects or ECG changes were seen on either the rest or exercise studies in any of the normal subjects. Fifty-six percent of patients with CAD developed new perfusion defects with exercise compared to 38% who developed ischemic ST-segment depression (P less than 0.02). However, when chest pain and/or ST depression were considered indices of ischemia, the sensitivity of exercise testing and thallium-201 MPI was similar. The increased sensitivity of MPI compared to ST-segment depression on the ECG was due to patients with baseline ECG abnormalities and those who failed to achieve 85% of predicted maximum heart rate with exercise. Analysis of the exercise results according to the extent of coronary artery disease revealed a progressive increase in both positive ECGs and MPI with the number of vessels involved. In patients with single vessel disease the MPI was more sensitive than the ECG (P less than 0.02). The combination of the rest and exercise ECG, MPI and chest pain during exercise failed to identify 11% of patients with CAD. Exercise thallium-201 MPI is a useful adjunct to conventional exercise testing particularly when evaluating patients with abnormal resting ECGs, those who develop ventricular conduction defects of arrhythmias during exercise, and those who fail to achieve their predicted heart rate because of fatigue or breathlessness.

Growth of the adult goldfish eye. III. Source of the new retinal cells

Abstract: The manner in which new cells are added to the growing adult goldfish retina was examined using 3H-thymidine radioautography. Cell proliferation leading to the formation of neurons is restricted to the retinal margin at the ora terminalis. New retina is added in concentric rings, with slightly more growth dorsonasally. The rate of cell addition is variable, averaging 12,000 cells/day. These new cells account for about 20% of the total increase in retinal area; the remaining 80% is due to hypertrophy, or expansion, of the retina. In contrast to all of the other retinal cells, the rods do not appear to participate in the retinal expansion. This hypothesized immobility of the rods would create a shearing strain between the retinal layers resulting in a shift in their position relative to the other cells. Were they to maintain synaptic contacts with the same horizontal and bipolar cells, the rod axons would have to be elongated peripherally or the post-synaptic cell dendrites displaced centrally. Since neurons with this morphology have not been found in the goldfish retina, these observations suggest that the rods must be changing their synaptic connections as the retina grows.

Growth of the adult goldfish eye. II. Increase in retinal cell number

Abstract: The retinas of adult goldfish, one to four years of age, 4-23 cm in length, were examined with standard paraffin histology to determine if new cells were being added with growth. Retinal cell nuclei were counted and the area of the retina was measured. An analysis of cell densities in various regions throughout the retina showed that the cells are distributed nearly homogeneously. The density (No./mm2 of retinal surface) of ganglion cells, inner nuclear layer cells and cones decreases with growth, but the density of rods remains constant. Thus the rods account for a larger proportion of the cells in larger retinas; The total number of cells per retina increases: the ganglion cells from 60,000 to 350,000; the inner nuclear layer cells from 1,500,000 to 4,000,000; the cones from 250,000 to 1,400,000; the rods from 1,500,000 to 15,000,000. This increase in the number of retinal neurons implies the formation of even more new synapses, and suggests the adult goldfish retina as a model for both neuro- and synaptogenesis.

Early cretaceous fossil evidence for angiosperm evolution

Abstract: Morphological, stratigraphic, and sedimentological analyses of Early Cretaceous pollen and leaf sequences, especially from the Potomac Group of the eastern United States, support the concept of a Cretaceous adaptive radiation of the angiosperms and suggest pathways of their initial ecological and systematic diversification. The oldest acceptable records of angiosperms are rare monosulcate pollen grains with columellar exine structure from probable Barremian strata of England, equatorial Africa, and the Potomac Group, and small, simple, pinnately veined leaves with several orders of reticulate venation from the Neocomian of Siberia and the basal Potomac Group. The relatively low diversity and generalized character of these fossils and the subsequent coherent pattern of morphological diversification are consistent with a monophyletic origin of the angiosperms not long before the Barremian. PatuxentArundel floras (Barremian-early Albian?) of the Potomac Group include some pollen and leaves with monocotyledonous features as well as dicotyledonous forms. Patuxent angiosperm pollen is strictly monosulcate and has exine sculpture indicative of insect pollination. Rare Patuxent-Arundel angiosperm leaves are generally small, have disorganized venation, and are largely restricted to sandy stream margin lithofacies; the largest are comparable to and may include ancestors of woody Magnoliidae adapted to understory conditions. Patapsco floras (middle to late Albian?) contain rapidly diversifying tricolpate pollen and several new complexes of locally abundant angiosperm leaves. Ovate-cordate and peltate leaves in clayey pond lithofacies may includeancestors of aquatic Nymphaeales and Nelumbonales. Pinnatifid and later pinnately compound leaves with increasingly regular venation which are abundant just above rapid changes in sedimentation are interpreted as early successional “weed trees” transitional to but more primitive than the modern subclass Rosidae. Apparently related palmately lobed, palinactinodromous leaves which develop rigidly percurrent tertiary venation and become abundant in uppermost Potomac stream margin deposits (latest Albian-early Cenomanian?) are interpreted as riparian trees ancestral to the order Hamamelidales. Comparisons of dated pollen floras of other regions indicate that one major subgroup of angiosperms, tricolpate-producing dicots (i.e., excluding Magnoliidae of Takhtajan) originated in the Aptian of Africa-South America at a time of increasing aridity and migrated poleward into Laurasia and Australasia. However, the earlier (Barremian) monosulcate phase of the angiosperm record is represented equally in Africa-South America and Laurasia before marked climatic differentiation between the two areas. These trends are considered consistent with the hypothesis that the angiosperms originated as small-leafed shrubs of seasonally arid environments, and underwent secondary expansion of leaf area and radiated into consecutively later successional stages and aquatic habitats after entering mesic regions as riparian “weeds,” as opposed to the concept that they arose as trees of mesic forest environments.

A one-way components of variance model for categorical data

Abstract: A components of variance model for categorical data from unbalanced designs which is directly analogous to a one-way random effects ANO VA modelfor quantitative data is proposed. The variance components provide separate reliability measures for each of the response categories and disagreement measures between pairs of response categories in terms of (within subject) intraclass and interclass correlation coefficients. The estimation procedures involve usual MA NOVA calculations which can be expressed as compounded functions of the multinomial observations. Thus, the variances of these estimates can be obtainedfrom linearized Taylor series results. These procedures are illustrated with data from a psychiatric diagnosis study.

Microscopic evaluation of clinical measurements of connective tissue attachment levels

Abstract: . The purpose of this study was to determine how accurately periodontal probes measure connective tissue attachment levels in beagle dogs with (1) clinically healthy gin-givae, (2) experimental gingivitis, and (3) periodontitis. In the healthy and experimental gingivitis specimens die probes were inserted with a standardized force of 25 ponds. In periodontitis specimens the probes were inserted with a gentle, but non standardized force After insertion, 120 plastic periodontal probes (40 in each group) were held in place by fusing them to the teeth. Blocks of periodontal tissue with the probes in situ were subsequently processed and serially sectioned. Histometric measurements were made from the sections in order to compare the level of connective tissue attachment to the level of probe penetration. In healthy specimens the probes consistently failed to reach the apical termination of the junctional epithelium (x =−0.39 mm). In the experimental gingivitis group most probes came closer to the apical termination of the junctional epithelium, but on the average stilt fell short by x =−0.10 mm. In periodontitis specimens the probes consistently went past the most apical cells of the junctional epithelium (x =+0.24 mm). A significant relationship between the degree of inflammation and level of probe penetration was found. No relationship was observed between histological and clinical sulcus depths. It is concluded that in beagle dogs (1) periodontal probes do not precisely measure connective tissue attachment levels, (2) inflammation has a significant influence on the degree of probe penetration, and (3) histological and clinical sulcus depths differ significantly.

The endocrine control of seasonal reproductive function in the ewe: A marked change in response to the negative feedback action of estradiol on luteinizing hormone secretion

Abstract: A group of 6 ewes was ovariectomized and treated sc for 20 months with Silastic capsules containing estradiol-17β. Although this treatment maintained serum estradiol concentrations relatively constant at mid-luteal levels (3–5 pg/ml), there was a dramatic seasonal variation in serum LH concentrations. Throughout anestrus, LH levels remained undetectable. At the onset of the breeding season, there was a striking increase in LH concentrations to levels which approached those in untreated ovariectomized ewes. Mean LH concentrations remained high until the beginning of the next anestrous season, when they decreased precipitously to undetectable levels where they remained until the subsequent breeding season. These biannual changes in the negative feedback action of estradiol occurred within 2–3 weeks in each ewe and coincided with the transitions between the breeding season and anestrus in intact ewes. In contrast to the biphasic annual pattern in LH secretion observed in estradiol-treated ovariectomized ewes...

A new concept for control of the estrous cycle of the ewe based on the temporal relationships between luteinizing hormone estradiol and progesterone in peripheral serum and evidence that progesterone inhibits tonic LH secretion.

Abstract: The temporal relationships between LH, estradiol and progesterone in peripheral serum of the ewe were characterized throughout the estrous cycle. Between successive preovulatory LH surges, serum concentrations of LH fluctuated markedly in a manner indicative of pulsatile discharges. Mean serum LH and progesterone concentrations were inversely related, LH being highest during the early and late luteal phases of the estrous cycle and lowest in the mid-luteal phase. A progressive, 5-fold increase in serum LH concentrations occurred between the onset of the precipitous fall in circulating progesterone attendant to luteolysis and the initiation of the preovulatory LH surge. Two major increments in circulating estradiol were observed in each cycle, both occurring when serum LH concentrations were relatively high. One estradiol increment occurred during the early luteal phase, the other during the 2–3 days prior to onset of the preovulatory LH surge. The latter estradiol increment thus accompanied the progressiv...

Analysis of left ventricular function from multiple gated acquisition cardiac blood pool imaging. Comparison to contrast angiography.

Abstract: Global ventricular function was evaluated by both multiple gated cardiac blood pool scans (MUGA) and contrast ventriculograms in a group of 17 patients with suspected coronary artery disease. The contrast ventriculograms were analyzed frame by frame to generate a volume versus time curve for each patient, while the tracer data were analyzed by two methods: 1) the standard method, in which the left ventricle is identified on the end-diastolic frame and the background corrected activity under the region of interest obtained from the entire cardiac cycle, and displayed as a time versus activity curve; and 2) by a semi-automatic method in which the computer applies a threshold detection program to define the ventricular borders, and activity in the chamber at each point in the cardiac cycle is defined after background correction. The tracer data in each patient were analyzed independently by four observers. The tracer data correlated with the contrast data on a point by point basis r = 0.87 for the standard method, and 0.93 for the semi-automatic technique. An F test of variance revealed the semi-automatic method superior to the standard approach (P less than 0.05).

Self-esteem in young men: a longitudinal analysis of the impact of educational and occupational attainment.

Abstract: This paper analyzes relationships among self-esteem, educational attainment, and occupational status. Data from a nationwide longitudinal study of more than 1600 young men show a substantial increase in self-esteem between 19TT (when respondents were beginning tenth grade) and 1974. Reliability and construct validity data for the self-esteem measure are reported. As expected, both educational attainment and occupational status are correlated with self-esteem. Contrary to expectations, educational attainment as of 1974 is more strongly correlated with tenth grade self-esteem than with 1974 self-esteem. A path analysis led to these conclusions: (a) Self-esteem during high school has little or no direct causal impact on later educational and occupational attainment; self-esteem and attainment are correlated primarily because of shared prior causes including family background, ability, and scholastic performance. (b) Occupational status has a direct positive impact on self-esteem. (c) Post high school educational attainment has no direct impact on self-esteem and only a trivial indirect impact via occupational status. Additional findings indicate that factors associated with educational success become less central to the self-evaluations of young men during late high school and the years thereafter.