Comparing demand functions when different price manipulations are used: Does unit price help?

Six hens pecked a key (Experiment 1) or pushed a door (Experiment 2) to obtain food reinforcement. In both experiments and as an analogue of price changes, the response requirements were varied in two ways: by increasing the number of responses required and by increasing the required force of each response. The two price manipulations (response number and response force) had different effects on behavior and produced different-shaped demand functions when the rates of consumption were plotted logarithmically against the price analogues. Irrespective of response topography, when the number of required responses was varied, the data paths appeared linear, with slopes close to −1.0. When the required force of each keypeck and doorpush was varied, the data paths were clearly curved, with increasingly steep downward slopes as the force increased. Using the concept ofunit price did not fully remove the different effects of the two price manipulations. Those differences are best attributed to the differing times needed in order to complete each response unit under those price manipulations.     

Keywords and vocabulary acquisition: Some words of caution about words of assistance

Consistent results of two experiments with relatively technical, native language vocabulary, showed that effectiveness of keyword methods depended upon whether meanings of words to be learned were abstract or concrete and whether comprehension was assessed immediately or after a delay. Keywords bearing acoustical similarities to vocabulary items whose meanings were presented as sentences consistently facilitated students’ retention of the meanings of concrete items on immediate posttests. However, in contrast to recent research on foreign language vocabulary having simpler definitions, these experiments showed that it may be difficult to use the keyword method to aid long-term retention with moderately complex. abstract, native language vocabulary. Parts of this study, which was partially supported by the Kansas State University Bureau of General Research, were presented at the Annual Meeting of the American Educational Research Association, Boston, 1980.     

Ureaplasma urealyticum and large colony mycoplasma colonization in female children and its relationship to sexual contact, age, and race.

In order to determine if Ureaplasma urealyticum (Uu) or large colony mycoplasma (LCM) colonization was related to a history of sexual abuse, the type of sexual contact, an enlarged vaginal introitus transverse diameter (greater than 4 mm), age or race, 452 female children, ages 1-12 years, were evaluated by the Child Sexual Abuse Team at Wake Medical Center in Raleigh, NC. Thirty-six girls were deleted because of inadequate cultures. When controlled for race and age, Uu throat (T), vaginal (V), and rectal (R) colonization and LCM vaginal and rectal colonization were not related to any of the other variables listed above. The enlarged vaginal introital diameter was related to a history of sexual abuse (p less than .001). Uu and LCM vaginal colonization rates were increased in black girls as compared to white girls (p less than .05). Uu V, Uu R, LCM V, and LCM R colonization increased with age. In our study population, Uu and LCM colonization was not a useful marker of sexual contact.     

Influences affecting the development of students' critical thinking skills

This study estimates the relative and unique effects on changes in critical thinking of three dimensions of students' college experience: curricular exposure, formal classroom and instructional experiences, and out-of-class experiences. Students' classroom/instructional and out-of-class experiences both make positive, statistically significant, and unique contributions to gains in critical thinking above and beyond students' precollege characteristics and level of critical thinking. Theoreticians have long speculated that students' academic and nonacademic experiences jointly influence change, and this study supports that belief. The design and instruments in this study may be of interest to persons involved in assessment or the study of college impact.Paper presented at the meeting of the Association for Institutional Research, New Orleans, LA, May 1993.The National Center on Postsecondary Teaching, Learning, and Assessment is funded by the U.S. Department of Education, Office of Educational Research and Improvement (OERI), under Grant No. R117G10037. The opinions herein do not necessarily reflect the position or policies of OERI, and no official endorsement should be inferred.     

The rhythmic structure of mother-infant interaction in term and preterm infants

The purpose of this study was to quantify social interaction rhythms in 3- and 5-month-old term and preterm infants and their mothers. Infant-mother dyads were videotaped in a 3-min face-to-face paradigm. For each second of the interaction, separate scores were assigned to infant and mother indicating levels of affective involvement, creating 2 180-sec time series. Spectral and cross-spectral techniques were used to quantify periodicities in each member of the dyad and to estimate the synchrony or coherence of interactional rhythms between each infant and mother. Results showed the existence of periodicities in the behavior of each infant and mother at 3 and 5 months, with most subjects showing spectral peaks between .022 and .10 Hz. Increases from 3 to 5 months in behavioral periodicities were found for infants and mothers as well as for the coherence between infant-mother dyads. Term dyads showed higher coherence than preterm dyads at both 3 and 5 months. Term infants more often led the interaction at both ages. These results were taken as evidence that behavioral periodicities, which may be biologically based, underlie early mother-infant interaction and provide a temporal structure for the organization of cognitive and affective experience. Differences in synchrony between term and preterm infants may explain later reported differences in language between these groups.     

Mental health services in schools: A qualitative analysis of challenges to implementation,operation, and sustainability

Schools are increasingly recognized as a critical venue for the provision of comprehensive behavioral and mental health services for students. Unfortunately, difficulties associated with operating programs in schools often prevent evidence‐based practices from being implemented and sustained as intended. In this study, the experiences of school and community providers who were funded through the Safe Schools/Healthy Students Initiative to implement mental health services in a large, urban school district were investigated using a qualitative focus group methodology. Providers identified the major challenges they encountered with implementing, operating, and sustaining their programs as well as the strategies that they used to overcome those challenges. Strategies to enhance support of school‐based mental health programs are discussed. © 2005 Wiley Periodicals, Inc. Psychol Schs 42: 361–372, 2005.     

Sex differences in the environments of graduate students and faculty

This paper considers some important psychological aspects of the academic experience for male and female graduate faculty members and students. Drawing on data collected in a recent national study of doctoral program quality, information pertaining to the graduate department's environment for learning, the extent of faculty members' concern for students, graduate student assistantship experiences, and faculty members' satisfactions and views about various departmental practices and policies are examined. Gender differences in both student and faculty member perceptions of their environments were found to be generally slight and to vary by discipline.     

Effects of a prenatal care intervention on the self-concept and self-efficacy of adolescent mothers

The objective of this study was to examine changes in self-concept and self-efficacy during the childbearing year among adolescent mothers (defined as young mothers up to age 20) who were involved in a behavioral intervention. Subjects included a sample of 282 urban, pregnant adolescents (94% African American, 4% white, 2% other). The Tennessee Self-Concept Scale (TSCS) was used to measure self-concept. A scale to measure the self-efficacy of the adolescent mother during the childbearing year was developed and evaluated. Questionnaires were administered during intake for prenatal care and in the postpartum period. In the larger study, the intervention was a peer-centered, mastery modeling intervention designed to increase self-efficacy, improve self-concept, and improve long- and short-term perinatal outcomes. The results in this portion of the data showed that self-concept increased significantly for young women in the experimental group but did not change significantly for young women in the control group. Changes were noted in the TSCS for overall self-concept as well as for several subscores, including identity, self-satisfaction, behavior, the personal self, the family self, and the social self. However, differences between groups did not reach significance once age, parity, site, and time were accounted for, except on TSCS subscales of identity and personal self. Between intake for prenatal care and postpartum, self-efficacy changed significantly for both the experimental and the control groups. Both groups increased in self-efficacy for labor and delivery and decreased in self-efficacy for infant care. In this group of mostly African American teens, peer support and small group care demonstrated positive effects on self-concept. Professional and peer interactions were equally associated in intervention and nonintervention groups with regard to self-efficacy.