Sample duration and type of stimuli in delayed matching-to-sample in rhesus monkeys

Two experiments were performed to determine the effect of sample duration (0.1, 2, and 4 sec), delay interval (.03, 4, 8, 16, and 32 sec), and type of stimulus (color and shape) on the matching performance of rhesus monkeys. In Experiment 1, the 15 possible delay-duration combinations were randomly presented in blocks of 15 trials. In Experiment 2, each duration was held constant and the five delays randomly presented. Then each delay interval was held constant with the three durations randomly varied. Matching performance increased as sample duration increased (ps < .01 and .005), while length of delay did not significantly affect performance. The type of stimuli paired in the matching test significantly affected performance (ps < .05 and .10) with the shape/shape choices leading to the poorest performance. Stimulus discriminability and amount of training with brief sample durations were implicated as significant determinants of matching performance.     

The Impact of an SES-Based Model on a College's Undergraduate Admissions Outcomes

In Grutter vs. Bollinger, the U.S. Supreme Court ruled that the use of race as one factor, among many in admissions decisions is constitutional. It is not known, however, whether future legal opinions will continue to uphold the use of affirmative action policies. Some have argued that class-based preferences can achieve many of the same goals as in affirmative action while being more likely to withstand legal challenges. To date, no empirical studies have been conducted on the potential impact of a class-based admissions policy if implemented at an undergraduate institution. This paper reports on a study at a selective public college and compares a number of outcomes under three admissions models: the original admissions decisions, a purely academic model, and an socio-economic status (SES)-based model. The findings showed that use of the SES-based model would have led to a more academically qualified class than in the original admitted class while maintaining substantially greater student diversity that was found under the academic model. An admissions policy based on preferences for socio-economically disadvantaged applicants appears to hold promise for other colleges and universities with similar institutional and applicant characteristics. The ideas and research design reported in this paper are based on the doctoral dissertation study of the second author, Undergraduate Admissions Models Incorporating Socioeconomic Factors (Johnson, 2000).     

Blocking in eyelid conditioning: Effect of changing the CS-US interval and introducing an intertriai stimulus

Kamin’s three-stage blocking paradigm was investigated in rabbit eyelid conditioning, Two manipulations were examined. A change in the CS-US interval from Stage 1 to Stage 2 did not attenuate blocking. The introduction of a salient stimulus during the intertriai interval in Stage 2 also failed to attenuate blocking. The first result is not consistent with Kamin’s interpretation of the blocking effect in terms of US surprisingness. The second resuit is inconsistent with a prediction based on the Rescorla-Wagner model.     

Improving quality of the child care environment through a consultancy programme for centre directors

This study examined the effects of a newly developed on-site consultancy programme to improve global quality of the child care environment in non-parental child care centres for 0- to 4-year-old children as measured with the ITERS-R/ECERS-R. Using a randomised controlled trial with a pretest, posttest, and follow-up test, we compared 35 experimental group with 33 control group. The consultancy programme comprised three consultations in total. Analysis on the items that were specifically targeted during the consultancy showed a significant improvement on these targeted items between pretest and posttest and between posttest and follow-up. The effect of the consultancy programme on the total scores (including the non-targeted items) was not significant.