A much greater positive effect of the program was found with culturally deprived, preschool Negro children than with more advantaged Caucasian children. (Authors)

The present study was concerned with demonstrating that schedule of knowledge of results may enhance resistance to extinction" on the pursuit rotor in a manner analogous to the partial reinforcement effect in conditioning. (Author)

Sees motives of cooperation and noncooperation as a function of the game's reward system and infers that the same motives may operate in real-life situations. Bibliography, tables, and graphs. (RW)

Determined the outcomes of a semester-long encounter group using multiple measures, a sensitive experimental design, tight experimental controls, and an equivalent control group. Only one subscale of the Tennessee Self-Concept Scale and four subscales of the Personal Orientation-Inventory showed a significant difference between experimental and…

College students wrote summaries of short passages to assess their ability to identify important information. Naive summaries judged as "better" contained more major semantic roles, such as agent, than did summaries judged "not as good". Students wrote better summaries when instructed to use major semantic roles within the passage. (Author/RD)

Examines a sociolinguistic thesis on language attrition illustrating first-language (L1) loss in a second-language (L2) environment via interviews conducted with two control groups and L1 German speakers living in Australia. Findings reveal that after 10 to 20 years in the L2 environment, the extent of L1 attrition was such that none of the…

A descriptive analysis of research practices and a meta-analysis of control group effect sizes are used to address Hawthorne effects in educational experiments. The analysis of 86 studies and 256 treatment/Hawthorne/no-treatment control group effect size comparisons indicate that artifact controls have limited utility in dealing with the Hawthorne…

This article examines the status of behavioral research on genetic mental retardation syndromes and finds that the field continues to struggle with three methodological issues: (1) how to think about control or contrast groups, (2) the interplay of behavioral phenotypes with development and other within-group variations, and (3) the efficacy of…

Describes a study of Taiwan university students that investigated the impacts of incorporating email into the classroom on student achievement and attitudes using a posttest-only control-group design. Results showed a statistically significant difference in academic performance but not in student attitudes toward computers. (Author/LRW)

This sequential, three-phase study used quantitative analyses to examine the characteristics of student dropouts and the characteristics of schools successful and unsuccessful in mediating dropouts. Narrative profiles were created to describe types of students and types of dropouts. Phase I consisted of three parts, each using the student as the…

We examined infants' long-term retention of a single unique emotional experience into early childhood. Twenty-month-olds who had participated in a still-face procedure at 5 months (experience group) fixated the face of the person who had instigated the still face significantly less than the faces of 2 other novel persons. Control 20-month-olds…

Type 2 diabetes is increasing among youth, with minority youth at highest risk. This preliminary study tested the feasibility of a school-based program to prevent type 2 diabetes in youth at risk. Forty-one participants (age 12.6 [+ or -] 1.1 years; 63% female, 51% African American, 44% Hispanic, and 5% Caucasian) were randomly assigned to one of…