Formal systems of dialogue rules

Section 1 contains a survey of options in constructing a formal system of dialogue rules. The distinction between material and formal systems is discussed (section 1.1). It is stressed that the material systems are, in several senses, formal as well. In section 1.2 variants as to language form (choices of logical constants and logical rules) are pointed out. Section 1.3 is concerned with options as to initial positions and the permissibility of attacks on elementary statements. The problem of ending a dialogue, and of infinite dialogues, is treated in section 1.4. Other options, e.g., as to the number of attacks allowed with respect to each statement, are listed in section 1.5. Section 1.6 explains the concept of a chain of arguments.From section 2 onward four types of dialectic systems are picked out for closer study: D, E, Di and Ei. After a preliminary section on dialogue sequents and winning strategies, the equivalence of derivability in intuitionistic logic and the existence of a winning strategy (for the Proponent) on the strength of Ei is shown by simple inductive proofs.Section 3 contains a — relatively quick — proof of the equivalence of the four systems. It follows that each of them yields intuitionistic logic.     

Age-related decrement in auditory selective attention

Young (n = 30), middle-aged (n = 32), and old (n = 28) adults repeated (shadowed) words presented to the left ear at 60 words per minute with and without distracter words presented to the other ear. Dichotic shadowing error rate increased with age. An attempt to eliminate the age effect by adjusting for age differences in monaural shadowing errors, fluid intelligence, and pure-tone hearing loss did not succeed. When the analyses were confined to subjects who made no monaural shadowing errors, dichotic shadowing errors still increased linearly with age. These results showed that there are selective-attention deficits in older adults that cannot be accounted for by the uncertainty of the target location.     

On the relationship between category intensions and extensions in children

We contrasted four theories of natural language category acquisition by investigating the relation between category intensions and extensions in children (kindergarteners, second graders, fifth graders) and in college students. Everyone was asked to define a category term, to make category membership judgments of possible exemplars, and to judge whether the possible exemplars possessed features generated by them and by previous adult subjects. Adult judges were also asked to judge whether the possible exemplars possessed the features generated by the subjects. Children's intensions and extensions were very consistent. In addition, children's extensions were reliably smaller than adults', and the features which children generated were more specific than those generated by adults. None of the existing theories discussed can explain this pattern of results. An exemplar-based model is proposed to do so.     

The effects of facial control and facial mimicry on subjective reactions to comedy routines

The impact of facial control on subjective reactions to dubbed (created with inserts of smiling people) and undubbed comedy routines was examined. The presence of dubs increased EMG activity over thezygomaticus major andorbicularis oculi muscle regions for spontaneous-condition subjects, but not for inhibit-condition subjects. Analyses also showed that spontaneous-condition subjects exhibited increased smiling at dub points, a finding that is consistent with the notion that subjects mimicked the inserted facial displays. Self-report findings revealed that spontaneous-condition subjects reported significantly greater amusement to the dubbed compared with the undubbed routines, whereas inhibit-condition subjects' self-reports of amusement did not differentiate dub conditions. Furthermore, spontaneous-condition subjects reported significantly more amusement to the dubbed routines than did inhibit-condition subjects. Despite strong facial control effects on facial EMG activity, no main effect of facial condition on self-reported amusement was found, and therefore, the data provide no support for a general version of facial feedback theory. The data are consistent with the view that mimetic responses enhanced subjective reactions, and they are compatible with the Leventhal and Tomkins versions of facial feedback theory.The research was supported by NSF Grant No. BNS-8507600 and the Lincoln Filene Endowment to Dartmouth College. The authors wish to acknowledge helpful comments provided by Ursula Hess, Timothy L. Hubbard, Arvid Kappas, and two anonymous reviewers.