Time for auditory processing of object names by aphasics

Ten Wernicke's and ten Broca's aphasics were compared with normal controls and brain-damaged nonaphasics with respect to the time required for the auditory decoding of object names. This value was obtained by using a subtraction method with two reaction time determinations, one of which included an auditory processing phase while the other did not. The overall mean of approximately 200 msec for Broca's aphasics did not differ significantly from the normal, while the mean of 650 msec for the Wernicke aphasics was much slower. All groups responded more quickly to high-frequency than low-frequency words and all but the Wernicke aphasics improved in the second trial block over their performance in the first trial block.     

A transfer of functions through derived arbitrary and nonarbitrary stimulus relations

During Experiments 1 and 2, subjects were trained in a series of related conditional discriminations in a matching-to-sample format (A1-B1, A1-C1 and A2-B2, A2-C2). A low-rate performance was then explicitly trained in the presence of B1, and a high-rate performance was explicitly trained in the presence of B2. The two types of schedule performance transferred to the C stimuli for all subjects in both experiments, in the absence of explicit reinforcement through equivalence (i.e., C1 = low rate and C2 = high rate). In Experiment 2, it was also shown that these discriminative functions transferred from the C1-C2 stimuli to two novel stimuli that were physically similar to the C stimuli (SC1 and SC2, respectively). For both these experiments, subjects demonstrated the predicted equivalence responding during matching-to-sample equivalence tests. In Experiments 3 and 4, the conditional discrimination training from the first two experiments was modified in that two further conditional discrimination tasks were trained (C1-D1 and C2-D2). However, for these tasks the D stimuli served only as positive comparisons, and ND1 and ND2 stimuli served as negative comparisons (i.e., C1 × ND1 and C2 × ND2). Subsequent to training, the negatively related stimuli (ND1 and ND2) did not become discriminative for the schedule performances explicitly trained in the presence of B1 and B2, respectively. Instead, the ND1 stimulus became discriminative for the schedule performance trained in the presence of B2, and ND2 became discriminative for the schedule performance trained in the presence of B1. All subjects from Experiment 4 showed that the novel stimulus SND1, which was physically similar to ND1, became discriminative for the same response pattern as that controlled by ND1. Similarly, SND2, which was physically similar to ND2, became discriminative for the same response pattern as that controlled by ND2. Subjects from both Experiments 3 and 4 also produced equivalence responding on matching-to-sample equivalence tests that corresponded perfectly to the derived performances shown on the transfer of discriminative control tests.     

TESTS FOR CONTROL BY EXCLUSION AND NEGATIVE STIMULUS RELATIONS OF ARBITRARY MATCHING TO SAMPLE IN A “SYMMETRY-EMERGENT” CHIMPANZEE

In the present experiments, controlling relations in arbitrary matching-to-sample performance were tested in a 9-year-old female chimpanzee who showed statistically significant emergence of symmetry in previous two-choice conditional discrimination experiments. In Experiment 1, a novel (undefined) sample stimulus was followed by a pair of trained (defined) and undefined comparison stimuli to assess the control by exclusion in arbitrary matching. The chimpanzee selected the undefined shape comparison, excluding the defined one, in color-sample-to-shape-comparison probe trials, although stimulus preferences were relatively stronger than control by exclusion in shape-sample trials. An additional test for control by relations of the sample to the positive comparison (S+ control) showed that her behavior was also under the control of relations of the sample to the positive comparison. In Experiment 2, a defined sample was followed by a pair of negatively defined and undefined comparisons to test control by the relations of the sample to the negative comparison. (S- control). The subject selected undefined comparisons in both color-shape and shape-color test trials. These results clearly indicate that the conditional discrimination behavior of this “symmetry-emergent” chimpanzee was under both S+ and S- control. Furthermore, her performance was also under control by exclusion in color-shape arbitrary matching, unlike other chimpanzees who showed no evidence of symmetry but only S+ control of arbitrary matching.     

Losing to Terrorism: An American Work in Progress

Abstract: The evolution of the U.S. war on terrorism is on a path that poses a substantial probability of losing to it, although not necessarily of a victory by its declared targets. That conclusion follows from the definition presented of terrorism and thus central questions about the merits of responses justified by an objective of reducing it. Likely American responses to 9/11 are suggested by a review of well‐known policy‐making tendencies from past scholarship and experience, tendencies well‐established prior to 9/11 and by no means unique to the Bush II presidency. The expectations those tendencies suggest have been born out by what the United States has done and not done. Well‐established criteria and their implied rules of practice for security enhancing great‐power statecraft are presented, and the chosen U.S. program of action is found to be counter‐productive in their light.     

Logics of public communications

Multi-modal versions of propositional logics S5 or S4—commonly accepted as logics of knowledge—are capable of describing static states of knowledge but they do not reflect how the knowledge changes after communications among agents. In the present paper (part of broader research on logics of knowledge and communications) we define extensions of the logic S5 which can deal with public communications. The logics have natural semantics. We prove some completeness, decidability and interpretability results and formulate a general method that solves certain kind of problems involving public communications—among them well known puzzles of Muddy Children and Mr. Sum & Mr. Product. As the paper gives a formal logical treatment of the operation of restriction of the universe of a Kripke model, it contributes also to investigations of semantics for modal logics. This paper was originally published as Plaza, J. A. (1989). Logics of public communications. In M. L. Emrich, M. S. Pfeifer, M. Hadzikadic, & Z.W. Ras (Eds.), Proceedings of the fourth international symposium on methodologies for intelligent systems: Poster session program (pp. 201–216). Publisher: Oak Ridge National Laboratory, ORNL/DSRD-24. Research partly supported by NSF Grant CCR-8702307 and PSC-CUNY Grant 668283.     

Weighing evils: the C. S. Lewis approach

It is often argued that the great quantity of evil in our world makes God’s existence less likely than a lesser quantity would, and this, presumably, because the probability that some evils are gratuitous increases as the overall quantity of evil increases. Often, an additive approach to quantifying evil is employed in such arguments. In this paper, we examine C. S. Lewis’ objection to the additive approach, arguing that although he is correct to reject this approach, there is a sense in which he underestimates the quantity of pain. However, the quantity of pain in that sense does not significantly increase the probability that some pain is gratuitous. Therefore, the quantitative argument likely fails.     

On Mill,Infallibility, and Freedom of Expression

Philosophers have tended to dismiss John Stuart Mill’s claim that ‘all silencing of discussion is an assumption of infallibility’. I argue that Mill’s ‘infallibility claim’ is indeed open to many objections, but that, contrary to the consensus, those objections fail to defeat the anti-authoritarian thesis which lies at its core. I then argue that Mill’s consequentialist case for the liberty of thought and discussion is likewise capable of withstanding some familiar objections. My purpose is to suggest that Mill’s anti-authoritarianism and his faith in thought and discussion, when taken seriously, supply the basis for a ‘public interest’ account of ‘freedom of expression as the liberty of thought and discussion’ which is faithful to Mill in spirit, if not to the precise letter. I outline such an account, which – as I say in conclusion – can serve as a valuable safeguard against ad hoc, reactive legislation, and the demands of a spurious communitarianism.     

Disfluent speech associated with brain damage

The frequency and type of disfluencies in the spontaneous speech of 15 people with Broca's aphasia and right hemiplegia was studied. Two aged-matched control groups (15 nonaphasic stroke patients with left hemiplegia and 15 normals) were also studied. The frequency of disfluencies in the speech of aphasics was three times greater than that in the speech of either control group. However, most of the disfluencies uttered by aphasics were of the types commonly found in speech of normals.     

A survey of communicative disorders students' attitudes toward stuttering

Cooper's (1975) Clinician Attitudes Toward Stuttering (CATS) inventories were conpleted by 1,902 speech-language pathology and audiology students from 33 universities, each in a different state. The majority of respondents perceived stutterers as having psychosocial problems and believed that client and parental counseling were essential aspects of treatment. These views were relatively unaffected by student training and clinical exposure. In addition, most of the assumptions of Johnson's diagnosogenic theory of stuttering were held by the majority of the students surveyed. Most of the respondents believed that stuttering was difficult to modify and that speech clinicians were neither adept nor comfortable treating stutterers. These latter attitudes were significantly affected by training, i.e., the more advanced the students' training, the more pessimistic their views on clinician competence. Other professional attitudes and the effect of training on them are also discussed.