Impact of experimental design on effect size: Findings from the research literature on training.

This article examines whether differences in the equations commonly used to calculate effect size for single group pretest-posttest (SGPP) designs versus those for control group designs can account for the finding that SGPP designs yield larger mean effect sizes (e.g., M. S. Lipsey & D. B. Wilson, 1993). It was found that the assumptions of no control group effect and the equivalence of pretraining and posttraining dependent variable standard deviations required for these equations to produce equivalent estimates of effect size were violated for some dependent variable types. Results indicate that control group effects and inflation in the standard deviation of the posttraining dependent variable measure account for most of the observed difference in effect size. The most severe violations occurred when the dependent variable was a knowledge assessment. Methods for including data from SGPP designs in meta-analyses that minimize potential biases are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Work-family enrichment and job performance: A constructive replication of affective events theory.

Based on affective events theory (AET), we hypothesize a four-step model of the mediating mechanisms of positive mood and job satisfaction in the relationship between work-family enrichment and job performance. We test this model for both directions of enrichment (work-to-family and family-to-work). We used two samples to test the model using structural equation modeling. Results from Study 1, which included 240 full-time employees, were replicated in Study 2, which included 189 matched subordinate-supervisor dyads. For the work-to-family direction, results from both samples support our conceptual model and indicate mediation of the enrichment-performance relationship for the work-to-family direction of enrichment. For the family-to-work direction, results from the first sample support our conceptual model but results from the second sample do not. Our findings help elucidate mixed findings in the enrichment and job performance literatures and contribute to an understanding of the mechanisms linking these concepts. We conclude with a discussion of the practical and theoretical implications of our findings. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Meta-insight: Do people really know how others see them?

Although people can accurately guess how others see them, many studies have suggested that this may only be because people generally assume that others see them as they see themselves. These findings raise the question: In their everyday lives, do people understand the distinction between how they see their own personality and how others see their personality? We examined whether people make this distinction, or whether people possess what we call meta-insight. In 3 studies, we assessed meta-insight for a broad range of traits (e.g., Big Five, intelligent, funny) across several naturalistic social contexts (e.g., first impression, friends). Our findings suggest that people can make valid distinctions between how they see themselves and how others see them. Thus, people seem to have some genuine insight into their reputation and do not achieve meta-accuracy only by capitalizing on the fact that others see them similarly to how they see themselves. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Genetics of prion diseases and prion diversity in mice

Linkage of the prion protein (PrP) and scrapie incubation time genes in mice provided strong evidence for the central role of PrP in determining susceptibility to prion disorders. Considerable evidence now argues that the prion protein and incubation time genes are identical. The mouse prion protein gene (Prn-p) may act both quantitatively and qualitatively in modulating prion incubation time. Differences at positions 108 and 189 between PrP-A and PrP-B allotypes can place constraints on interaction between the normal cellular and the scrapie-specific isoforms of PrP (PrPC and PrPSc), although the supply of PrPC available for post-translational conversion to PrPSc can also influence incubation time. Results using transgenic (Tg) mice in studies on scrapie 'strains' or isolates suggest that incubation time characteristics of scrapie isolates can be explained by these two properties of PrP. The final section of this report discusses the novel finding that uninoculated Tg mice overexpressing wild-type (wt) PrP transgenes spontaneously develop a late-onset degenerative neuromyopathy, broadening the spectrum of prion diseases and providing new information on PrP function in both normal and pathological states.     

Expression, purification, and functional characterization of the carboxyl-terminal domain fragment of bacteriophage 434 repressor

The repressor protein of bacteriophage 434 binds to DNA as a dimer of identical subunits. Its strong dimerization is mediated by the carboxyl-terminal domain. Cooperative interactions between the C-terminal domains of two repressor dimers bound at adjacent sites can stabilize protein-DNA complexes formed with low-affinity binding sites. We have constructed a plasmid, pCT1, which directs the overproduction of the carboxyl-terminal domain of 434 repressor. The protein encoded by this plasmid is called CT-1. Cells transformed with pCT1 are unable to be lysogenized by wild-type 434 phage, whereas control cells are lysogenized at an efficiency of 1 to 5%. The CT-1-mediated interference with lysogen formation presumably results from formation of heteromeric complexes between the phage-encoded repressor and the plasmid-encoded carboxyl-terminal domain fragment. These heteromers are unable to bind DNA and thereby inhibit the repressor's activity in promoting lysogen formation. Two lines of evidence support this conclusion. First, DNase I footprinting experiments show that at a 2:1 ratio of CT-1 to intact 434 repressor, purified CT-1 protein prevents the formation of complexes between 434 repressor and its OR1 binding site. Second, cross-linking experiments reveal that only a specific heterodimeric complex forms between CT-1 and intact 434 repressor. This latter observation indicates that CT-1 interferes with 434 repressor-operator complex formation by preventing dimerization and not by altering the conformation of the DNA-bound repressor dimer. Our other evidence is also consistent with this suggestion. We have used deletion analysis in an attempt to define the region which mediates the 434 repressor-CT-1 interaction. CT-1 proteins which have more than the last 14 amino acids removed are unable to interfere with 434 repressor action in vivo.     

Attenuation of "acute" habituation by scopolamine in the black-tailed prairie dog (Cynomys ludovicianus).

Tested and confirmed the hypothesis that scopolamine attenuates habituation occurring within a training session as well as that occurring between training sessions. Subcutaneous scopolamine injections (.5 mg/kg) reduced spontaneous wheel running in 8 female prairie dogs. The same dosage did not affect the threshold for wheel running induced by electrical brain stimulation (EBS) in 6 Ss in Exp II. Exp III (n = 6) demonstrated that EBS-induced running declined during a 10-min stimulation period and indicated that the decline was habituative since the response was repeatedly dishabituated. In Exp IV .5 mg/kg of scopolamine reduced habituation of EBS-induced wheel running during 10-min sessions with the 6 Ss used in Exp II. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cardiovascular reactivity and interpersonal influence: Active coping in a social context.

Previous studies have demonstrated that effortful attempts to secure positive outcomes or avoid negative outcomes produce significant increases in systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR). Although these effects of active coping on cardiovascular reactivity are central in current psychosomatic theories, virtually all of the research to date has used impersonal, asocial tasks. Our two studies examined the cardiovascular effects of effortful attempts to influence other people. In Study 1, male subjects attempting to influence the opinions of their discussion partner to improve their own chances of winning money displayed significantly greater SBP, DBP, and HR reactivity. In Study 2, we obtained similar effects on SBP and DBP reactivity in men and women, while both preparing an influence attempt and making that attempt. Furthermore, reactivity levels were larger as the magnitude of incentive for successful persuasion increased. Implications of this interpersonal equivalent of active coping for the development of cardiovascular disease are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Runway alternation and discrimination of mice with limbic lesions.

Trained 7 normal male HS mice (Norm), and 18 mice with septal (Sept) and cingulate-anterior limbic cortex lesions (Cing) in a straight-alley single-alternation task. Sept Ss performed significantly better than Norms, running faster on reinforced trials and slower on nonreinforced trials. Cing Ss performed as well as Norms. In a 2nd experiment with 64 Ss, Norm and Sept Ss learned a discrimination task using a food pellet or sound of a buzzer as a cue for either reinforced or nonreinforced trials. Sept Ss learned the food-cued task faster than Norms when nonreinforced trials were cued; Norms performed better when reinforced trials were cued with the buzzer. Results suggest that septal lesions enhance the cue value of food, and contradict the hypothesis that the septum is involved in response inhibition. (19 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of applicant sample on ratings of valid information in an employment setting.

Studied the effect of the previous job applicant upon ratings of test results for the following applicant. 2 informational aspects of the previous job applicant were varied: overall level of information favorability, and order of information within the previous job applicant. Interviewers were life insurance agency managers who through classroom instruction had been trained in the interpretation of test results. Results indicate that 55% of the criterion variance was accounted for by the test results while the favorability of the previous job applicant accounted for 4%. Thus, although the quality of the previous job applicant had a statistically significant effect on the evaluation of valid test results, its effect on the employment decision was negligible. By implication, the results also points to the necessity of building models on additional criteria than statistical significance. (25 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)