A longitudinal study of the effects of experimenter bias on the operant learning of laboratory rats☆

Research on diversity-related burnout has led to a variety of mixed findings. Several factors have been investigated that may come into play in this relationship (e.g., ethnic school composition). In this study, the hypothesis is that the experience of burnout may result from teachers’ own implicit attitudes and expectations towards ethnic minority students, which are usually negative, rather than explicit prejudices, which are found to be positive Two different implicit measures (Implicit Association Test and Relational Responding Task) and a scale to assess ethnic prejudices have been used. Implicit attitudes toward ethnic minority students and implicit expectations of students’ performance were both negative, but only implicit attitudes predicted teachers’ burnout. Explicit prejudice was low and did not predict burnout. These results highlight the role of teachers’ ethnic implicit attitudes towards ethnic minority students in their own well-being. Future research should further investigate this relationship to get a better understanding of how implicit aspects are involved in the development of burnout.

Due to a rising number of product variants and an increase in complexity, manual assembly tasks lead to increasing physical and mental strain on employees. In order to maintain their health, an individual strain-oriented employee scheduling is necessary. In the conducted study, the individual physical and mental strain during manual assembly tasks is determined by using smart sensors and questionnaires. This paper presents the structure and process of the study as well as the first results of the applied questionnaires regarding the differences between the two levels of workload and concerning the validity to capture subjective strain. The performance requirements assembly competence and chronic stress were identified as predictors for perceived subjective physical and mental strain, queried by NASA-RTLX and Borg.

Antenatal detection of small-for-gestational-age fetuses improves outcomes and reduces perinatal mortality rates. However, ultrasonographic estimation of fetal weight is subject to several potential sources of error. One potential source of error is subconscious operator bias towards “normal” measurement values for gestational age (observer-expectancy bias).

We aimed to determine whether the sensitivity of small-for-gestational-age detection is improved by removing real-time display of estimated gestational age during measurement of the abdominal circumference in the third trimester.

This retrospective evaluation (November 2014–May 2018 inclusive) included all singleton infants liveborn at ≥28 weeks gestation in a single United Kingdom obstetrics center. In the preintervention phase, real-time estimated gestational age was displayed to sonographers as they measured fetal abdominal circumference (the key determinant of estimated fetal weight with the use of the INTERGROWTH 21st fetal weight equation) in the third trimester. In the postintervention phase, real-time gestational age information was removed on selected ultrasound machines. Accuracy of birthweight percentile estimation was assessed before and after intervention, both in the full cohort comprising all eligible scans and in a subcohort that was scanned within 4 weeks of delivery. We assessed the accuracy of small-for-gestational-age detection using the sensitivity, positive likelihood ratio, and area under the receiver-operator curve.

Of the 18,342 eligible pregnancies, 9342 (51%) had a third-trimester growth scan. The sensitivity of ultrasonographic estimation of fetal weight for antenatal detection of small-for-gestational-age babies did not change significantly between the before and after intervention phases (31.5% confidence interval, 27.1–36.2 vs 31.7% confidence interval, 20.2–45.0). Although the sensitivity for small-for-gestational-age detection was higher in the subcohort that was scanned within 4 weeks of delivery than in the full cohort (P<.001), there was no significant difference between the before and after intervention phases (58% confidence interval, 50–66 vs 65% confidence interval, 43–84). With the use of an estimation of the abdominal circumference percentile rather than estimated fetal weight percentile significantly decreased the sensitivity for small-for-gestational-age detection in all groups (P<.01), but there was no difference between the before and after intervention phases.

Blinding operators to the estimated gestation of the fetus during abdominal circumference measurement does not significantly alter the antenatal detection rate of small-for-gestational-age babies. The observer-expectancy effect is therefore unlikely to be a significant contributor to the error that is associated with ultrasonographic estimation of fetal weight.