Continuity effects with alternately sounding tones under dichotic presentation

An experiment is reported in which 10 Ss possessing normal hearing were required to make discriminations of continuity or interruption in a longer less intense signal (Tone A) which alternated in time with a shorter more intense signal (Tone B). The signals were presented dichotically with Tone A at the right ear. Three Tone B frequencies of 300, 1000, and 4000 cps and five Tone A frequencies somewhat near each of the Tone B frequencies were employed. The results demonstrated that as Tone A was nearer to Tone B in frequency, continuity thresholds in Tone A occurred at longer durations of Tone B. The results are discussed in terms of a central neural model.     

Prototyping “Intelligent” applications for interactive multimedia systems

The termmultimedia refers to the combined use of different media of communication, and originally belonged primarily to the fields of entertainment and education. Advances in computer, audio, and video technology have now brought multimedia possibilities to the individual. Further, they give the user control over what happens. Suchinteractive multimedia systems offer the user personal access to large amounts of information, including pictures, graphics, video, text, and audio. The potential range of applications is very broad, from simple interactions where the user will merely make occasional choices and then sit back and view sections of program material, to more purposeful interactions where the application can help the user to achieve a goal. This article describes research onknowledge-based interactive multimedia systems. Targeted on the new Compact Disc Interactive format, we have protyped an advisor which will help the user to tackle a typical domestic task. The necessary decision-making process can be enlivened by multimedia interaction, and placed on solid ground by the inclusion of expert advice.     

Inverses for Normal Modal Operators

Given a 1-ary sentence operator , we describe L - another 1-ary operator - as as a left inverse of in a given logic if in that logic every formula is provably equivalent to L. Similarly R is a right inverse of if is always provably equivalent to R. We investigate the behaviour of left and right inverses for taken as the operator of various normal modal logics, paying particular attention to the conditions under which these logics are conservatively extended by the addition of such inverses, as well as to the question of when, in such extensions, the inverses behave as normal modal operators in their own right.     

Stimulus-independent thought depends on central executive resources

Stimulus-independent thoughts (SITs) are streams of thoughts and images unrelated to immediate sensory input. Four experiments examined the contribution of aspects of working memory to production of SITs. In Experiments 1 and 2, interventions that were targeted on, respectively, phonological and visuospatial components of working memory both interfered with production of SITs, but there was evidence that these tasks also made demands on central executive resources. Experiments 3 and 4 specifically examined the hypothesis that production of SITs and control of nonproceduralized tasks both depend on central executive resources, and so should show mutual interference. In Experiment 3, prior practice on pursuit rotor and memory tasks reduced the interference with SITs from concurrent task performance. In Experiment 4, randomness within a task involving random-number generation was less when SITs were being produced concurrently than it was when they were not. The results suggest that production of SITs depends on central executive resources.