Acquisition and extinction of differential responses to signals paired with shock or shock omission in goldfish: Evidence for truly discriminated avoidance learning

Goldfish trained to discriminate between signals paired with shock (S?) and signals paired with shock omission (S+) with a linear presentation procedure, originally learned (OL) to control the signal state of a shuttle box and showed a decided preference for the S+ signal. In Experiment 1, following OL, groups had one OL signal replaced (S+ or S?), both signals replaced (S+ and S?), or the OL signals reversed (S+ and S? reversed) and were then tested in a transfer training procedure. In transfer, groups with one signal replaced maintained discriminated performance at OL levels; the S+ replaced group was slightly superior to the S? replaced group on the first day of transfer. With both OL signals replaced, discrimination dropped to chance performance levels, whereas, with OL signal shock pairing reversed, discrimination performance dropped below chance levels. In Experiment 2, following OL, extinction procedures consisted of turning off the shocker (0% shock) or of shocking 100% or a random 25% of the trials. A fourth extinction procedure (R,) retained the trial start response-dependent shock-omission contingency, but shock differentiating the S+ and S? signals was eliminated entirely. Extinction of the S+/S? discrimination was measured both during extinction training per se and with reversal retraining of the S+/S? discrimination later. Groups for which the OL S+ was paired with shock during extinction extinguished on both measures, but groups for which the OL S? was paired with shock omission did not extinguish, especially as shown by the reversal test procedure. Theoretical implications and the implications for several conditioning procedures are discussed.     

The interdependence of language and translational math skills among bilingual hispanic engineering students

The performance of 43 Hispanic engineering and science majors on a task that consists of reading a sentence describing a mathematical relationship between two variables, and then writing an equation describing the relationship, is investigated in both English and Spanish. Results are compared with grade point average and with language proficiency. Comparison of the bilingual group to a monolingual group consisting of 52 engineering and science students shows that performance, as measured by either the mathematical translation task or grade point average, is more strongly correlated with language proficiency for the bilingual group. Clinical interviews conducted with samples from each group reveal large differences in the interpretation of the mathematical task between Hispanics and monolinguals. Suggestions are made for the improvement of the technical education of Hispanics.     

Increased consultation opportunities for school psychologists: A service delivery model

A model of delivery of services that enables school psychologists to meet testing demands while initiating a broad range of consultative services is described. Requirements of the model include: (a) having funds available for contract testing, (b) having conferences with teachers prior to formal referral of children, and (c) having qualified contract evaluators available. Benefits, as well as obstacles to be expected in implementing the model, are discussed.     

Integration of reinforcement effects over time

Two accounts of how density of reinforcement affects steady-state performance on probabilistic schedules were compared: the real-time linear operator (RTLO) model and a temporal control model (in which response strength is determined by reinforcement probability as a function of postreinforcement time). In Experiment 1, the probability of reinforcement repeatedly cycled between extinction and a random-ratio 10 schedule. Response-rate gain and phase did not change with period of the cycle as predicted by the RTLO model, nor did either model predict the differences in response rate following reinforcement at different points in the cycle. In Experiment 2, the probability of reinforcement was elevated immediately following a reinforcement but fell after a few seconds. Previous reinforcements had no effect upon responding. An extension of the temporal control model, the cumulative impulse model, allowed for the summing of response strength over successive reinforcements and was consistent with the data of both experiments.     

Supervision of Doctoral Students in the Natural Sciences: expectations and experiences

Within the natural sciences and engineering, literature relating to postgraduate education, in particular the process of completing a doctorate, remains generally scarce. That which does exist emphasises the role of the supervisor in effecting successful completion and points to a wide range of activities performed by supervisors. There remains, however, little by way of accounts of the actual experiences of supervisors or students when engaged in the process of doctoral supervision. It is these experiences which form the basis of this paper which focuses upon doctoral students and their supervisors in the disciplines of physics, mathematics and engineering science. Data for the paper have been collected, as part of an ESRC funded project, by means of in‐depth interviews with students and supervisors in nine universities in England. In particular, we address students expectations of PhD supervision, the extent to which expectations have been met, and within the context of the ‘career’ of the PhD, the ways in which supervision changes as the doctoral process progresses. Important issues relating to the need for training for PhD supervisors and their capacity to meet the expectations of their students are raised, together with those which question the relationship between the PhD and the culture of academic work.     

Training of poor readers' phonological decoding skills: Evidence for syllable-bound processing

A flash card computer program designed to increase decoding speed in reading was evaluated with a sample of 55 eight- to twelve-year-old Dutch poor readers by using a pretest-training-posttest control group design. The reading level of the poor readers was comparable to the reading level of normal readers in grade two. After 8 weeks of practicing (twice a week) for 30 minutes per session, children in the training group showed substantial improvements in decoding speed not only on pseudowords directly practiced during the training, but also in untrained pseudowords and in existing words. The no-training control group did not improve in decoding speed from pre- to posttest. The results, furthermore, indicate that syllable-bound processes play a role in phonological decoding in Dutch, and that the flash card method used in this study stimulates poor readers to decode letter strings into syllabic units, which leads to an increase in decoding speed. The role of the syllable in phonological decoding and the potential of a specific flash card technique as a means to improve decoding skills of poor readers are discussed.     

Development of Automated Scoring Algorithms for Complex Performance Assessments: A Comparison of Two Approaches

Performance assessments are typically scored by having experts rate individual performances. The cost associated with using expert raters may represent a serious limitation in many large-scale testing programs. The use of raters may also introduce an additional source of error into the assessment. These limitations have motivated development of automated scoring systems for performance assessments. Preliminary research has shown these systems to have application across a variety of tasks ranging from simple mathematics to architectural problem solving. This study extends research on automated scoring by comparing alternative automated systems for scoring a computer simulation test of physicians'patient management skills; one system uses regression-derived weights for components of the performance, the other uses complex rules to map performances into score levels. The procedures are evaluated by comparing the resulting scores to expert ratings of the same performances.     

Feedback factorizing control of 3-D transfer functions via a canonical state-space model

The problem factorizing (separating) the transfer function of a given SISO 3-D discrete system, ie of a system depending on three independent variables, is considered. The 3-D system is assumed to be available in its transfer function representation, which is converted to a canonical state-space model by a simple inspection procedure. Then applying state-feedback to this canonical model we choose the feedback matrix gain (under certain conditions) such that the transfer function of the closed-loop system has the desireed factorized form, ie a product of three 1-D transfer functions each one being dependent on a single variable. The method is illustrated by a nontrivial numerical example.