Potentiation of responding on a VR schedule by a stimulus correlated with reinforcement: Effects of diffuse and localized signals

In Experiment 1, rats were trained to leverpress on a variable ratio (VR) 30 schedule with a 500-msec delay between the reinforced response and food delivery. Subjects that experienced a signal during the delay responded faster than did control subjects that received the stimulus un-correlated with reinforcement. Higher response rates were obtained when the stimulus used to signal reinforcement was auditory rather than visual. Experiments 2 and 3 compared the effects of signaling reinforcement with either a localized or a diffuse light on responding maintained by VR schedules of reinforcement. Elevated response rates were observed with the diffuse stimulus, but the localized stimulus failed to produce such potentiation. Experiment 3 also examined the conditioned reinforcing power of localized and diffuse visual stimuli. These results are discussed with reference to (1) theories of selective association and sign tracking and (2) their implications for current theories of signaling reinforcement.     

Enacting silence: Residual categories as a challenge for ethics,information systems,and communication

Residual categories are those which cannot be formally represented within a given classification system. We examine the forms that residuality takes within our information systems today, and explore some silences which form around those inhabiting particular residual categories. We argue that there is significant ethical and political work to be done in exploring residuality.     

Evolution and validation of a personal form of an instrument for assessing science laboratory classroom environments

The research reported in this article makes two distinctive contributions to the field of classroom environment research. First, because existing instruments are unsuitable for science laboratory classes, the Science Laboratory Environment Inventory (SLEI) was developed and validated. Second, a new Personal form of the SLEI (involving a student's perceptions of his or her own role within the class) was developed and validated in conjunction with the conventional Class form (involving a student's perceptions of the class as a whole), and its usefulness was investigated. The instrument was cross-nationally fieldtested with 5,447 students in 269 senior high school and university classes in six countries, and cross-validated with 1,594 senior high school students in 92 classes in Australia. Each SLEI scale exhibited satisfactory internal consistency reliability, discriminant validity, and factorial validity, and differentiated between the perceptions of students in different classes. A variety of applications with the new instrument furnished evidence about its usefulness and revealed that science laboratory classes are dominated by closed-ended activities; mean scores obtained on the Class form were consistently somewhat more favorable than on the corresponding Personal form; females generally held more favorable perceptions than males, but these differences were somewhat larger for the Personal form than the Class form; associations existed between attitudinal outcomes and laboratory environment dimensions; and the Class and Personal forms of the SLEI each accounted for unique variance in student outcomes which was independent of that accounted for by the other form.     

The influence of pictures on the derivation of meaning from children's reading materials

This discussion is a review of experimental work designed to determine whether pictures have an effect upon the derivation of meaning from the text printed in children's reading materials. Many reading schemes emphasize the use of illustration, but for a number of different purposes ranging from the provision of a referent for a specific word, to the provision of' contextual support, and the generation of motivation for reading. Experimental studies of the interactions between pictures arid words in the cognitive system go some way to supporting three uses of illustration in (a) the provision of meanings against which the print may be compared, (b) in the development of an organized understanding of the meaning of the text, and (c) in the enhancement of subsequent recall. The danger of distraction arising from the pictures has also been investigated, and been found to lead to decoding errors in young children presented with one word at a time. An analysis of mutual interference effects between pairs of pictures and words leads to the conclusion that the cognitive representations of meanings arc organized in a semantic system common to pictures and words. Thus, any decoding errors due to interference effects are of more than local importance—they can affect comprehension and influence the stored representation.     

A Panic about School Choice

It is now widely recognised that Britain's comprehensive system was never truly comprehensive. Families with sufficient financial capital were always able to ensure the entry of their children to particularly prestigious ‘comprehensive’ schools by purchasing a home within the appropriate catchment areas. According to government rhetoric, recent legislation established a market of schools, removed catchment areas and gave parents greater choice of school. This case‐study examines the workings of the local quasi‐market of schools within a prosperous town (Sutton Coldfield, England) which is part of the larger metropolitan area of the West Midlands. Because of a change in the age of entry to secondary education, Sutton Coldfield was first plunged into the market in 1992. This case‐study shows that the new situation initially caused confusion and anger. Some Sutton Coldfield residents were denied places for their children within the town and were instead offered places for their children in Birmingham working‐class estate schools. The article describes the formation and activities of a local pressure group which opposed these changes, and reports the results of a small‐scale study of a sample of parents’ choice‐making processes in 1993. It is shown that access to financial and cultural capital had become more, rather than less, important in the process of allocating children to secondary schools.