Models of central capacity and concurrency

According to single channel theory, the ability of humans to perform concurrent mental operations is limited by the capacity of a central mechanism. The theory was developed by analogy with early computers which had a single central processing unit and required sequential processing. These limitations are not likely to be properties of the mind. But now computers have begun to employ extensive concurrent processing, because of the decreasing cost of the necessary hardware. In this review we will try to bring the computer analogy up to date. Theoretical issues important for concurrent systems may be of interest to psychologists and have applications to such problems as the speed-accuracy trade-off. Several hypotheses about the way signals gain access to the central mechanism are reviewed. Recent variations of the single channel theory are discussed, including the hypotheses that more than one process can use the central mechanism at a time, and that some processes do not use the central mechanism and can be executed concurrently with those that do. In addition, relevant concepts from scheduling theory and operating systems theory are introduced and difficulties encountered by concurrent systems, namely complexity, deadlocks, and thrashing, are discussed.     

Children's relative number judgments: One-to-one correspondence,recognition of noncorrespondence,and the influence of cue conflict

Although one-to-one correspondence can be seen as a component of successful counting, number conservation, and relative number judgments, there is evidence of considerable discrepancies between children's competencies in these different tasks. Concerning relative number judgments there are strikingly different claims concerning the ability of young children to make one-to-one correspondence-based judgments. In part these discrepancies reflect differences in criteria. Four experiments are reported in which 5-year-olds' relative number judgments of small and large number displays with and without perceptual aids were studied. Children were found to respond to local rather than global density differences and to benefit from the provision of perceptual aids on both small and large number displays with one exception, namely, large number displays where the longer row is less numerous.     

Agreement between observers when the categories are not specified in advance

To test the agreement between two observers who categorize a number of objects when the categories have not been specified in advance, Brennan & Light (1974) developed a statistic A′ and suggested a normal approximation for its distribution. In this paper it is shown that this approximation is inadequate particularly when one, or both, of the observers place a fairly equal number of objects in all of their categories. A chi-squared approximation to the distribution of A′ is developed and is shown to work well in a variety of situations. The relative powers of A′ and the ordinary X² test for association are dependent on the type of ‘agreement between the observers’ that is assumed. However a simulation for a fairly general type of agreement indicates that the X² test is more powerful. As the X² test is also much easier to apply, it would seem preferable in most situations.     

SEX DIFFERENCES IN THE ATTRIBUTION OF SOCIALLY DESIRABLE AND UNDESIRABLE TRAITS TO OUT-GROUP MEMBERS*

One hundred and forty-four male and female Australian subjects rated an Australian or a Vietnamese target group on the possession of five socially desirable and five socially undesirable personality traits. As predicted, the out-group was perceived less favourably than the in-group, but only by the males, the females not making the distinction.     

Comparing the Effects of Monetary Incentives and Foot-in-the-Door Strategies in Promoting Residential Electricity Conservation

The relative effectiveness of incentive and minimal justification techniques in promoting electrical energy conservation among 90 homeowners was investigated. Subjects in the Questionnaire condition were asked to complete a short energy conservation survey. Those in the Commitment condition were asked to curtail their consumption of electricity by 15%. In the Questionnaire + Commitment condition, subjects received both requests. These three groups were compared to an Incentive condition, where individuals were offered a highly attractive monetary incentive for conserving electricity, a Questionnaire + Commitment + Incentive condition, and a Control condition. The groups did not differ in electricity consumption during baseline, initial request, or follow-up periods. However, during the conservation period, homeowners in the Commitment and the combined treatment groups conserved more electricity and contained more conservers than either of the remaining groups. These outcomes were discussed in terms of the comparative effectiveness of minimal justification and incentive strategies for inducing behavioral change.     

Attitudes toward women,personality rigidity,and idealized physique preferences in males

The idealized physique preferences of a group of 94 male college students were measured and correlated with scales measuring attitudes toward women and personality rigidity. Three hypotheses, derived from sex-role research, were tested and confirmed: (1) Males who have negative attitudes toward women would like most to have a tapering V physique. (2) Males who have a rigid personality structure have stronger preference for an idealized muscular physique than males with more flexible personalities. (3) Males have a generally greater preference for a tapering V physique than women. It was concluded, from the results of this and other studies, that body preference is related to certain aspects of sex-role attitudes.     

The American plan completed: Alternative classical-style semantics,without stars,for relevant and paraconsistent logics

American-plan semantics with 4 values 1, 0, { {1, 0}} {{}}, interpretable as True, False, Both and Neither, are furnished for a range of logics, including relevant affixing systems. The evaluation rules for extensional connectives take a classical form: in particular, those for negation assume the form 1 (A, a) iff 0 (A, a) and 0 (A, a) iff 1 (A, a), so eliminating the star function *, on which much criticism of relevant logic semantics has focussed. The cost of these classical features is a further relation (or operation), required in evaluating falsity assignments of implication formulae.Two styles of 4 valued relational semantics are developed; firstly a semantics using notions of double truth and double validity for basic relevant systemB and some extensions of it; and secondly, since the first semantics makes heavy weather of validating negation principles such as Contraposition, a reduced semantics using more complex implicational rules for relevant systemC and various of its extensions. To deal satisfactorily with elite systemsR,E andT, however, further complication is inevitable; and a relation of mateship (suggested by the Australian plan) is introduced to permit cross-over from 1 to 0 values and vice versa.