Aphasia for Morse code

The ability to communicate by Morse code at high speed has, to our knowledge, not been localized within the cerebral cortex, but might be suspected as residing within the left (dominant) hemisphere. We report a case of a 54-year-old male who suffered a left temporal tip intracerebral hematoma and who temporarily lost his ability to communicate in Morse code, but who was minimally aphasic.     

Habituation to irrelevant speech: effects on a visual short-term memory task

The Baddeley and Hitch (1974) formulation of short-term or working memory embodied a phonological store within the articulatory loop component of the model. Later formulations specifically postulated an acoustic filter that endowed only speech-like stimuli with obligatory access to this phonological store. This paper presents evidence that this phonological store may have two filters, one of which is subject to habituation and can therefore attenuate the entry of irrelevant speech, thus undermining the obligatory access assumption of the model. An experiment is reported in which subjects were presented with a habituation period comprising 20 min of irrelevant speech--speech to be ignored by the subject--before a test phase in which a visually presented serial recall task with concurrent irrelevant speech was performed. The effect of irrelevant speech, which impairs performance on the primary task when there is no habituation phase, is reduced markedly in those conditions where the speech used in the habituation phase is the same as that used in the test phase, if the irrelevant speech is in a language different from that presented during the subsequent trials or if the habituator is a hummed version of the irrelevant speech passage. When a nonspeech sound (pink noise) is used in the habituation phase, a large irrelevant speech effect is found in the test phase. Morris, Quayle, and Jones (1989) found that humming did not produce an irrelevant speech effect, which suggests that the first filter is permeable to humming but that the second filter is not.(ABSTRACT TRUNCATED AT 250 WORDS)     

Knowledge and the regularity theory of information

Fred Dretske's Knowledge and the Flow of Information is an extended attempt to develop a philosophically useful theory of information. Dretske adapts central ideas from Shannon and Weaver's mathematical theory of communication, and applies them to some traditional problems in epistemology. In doing so, he succeeds in building for philosophers a much-needed bridge to important work in cognitive science. The payoff for epistemologists is that Dretske promises a way out of a long-standing impasse — the Gettier problem. He offers an alternative model of knowledge as information-based belief, which purports to avoid the problems justificatory accounts face. This essay looks closely at Dretske's theory. I argue that while the information-theoretic framework is attractive, it does not provide an adequate account of knowledge. And there seems to be no way of tightening the theory without introducing some version of a theory of justification — the very notion Dretske's theory was designed to avoid.     

Eye movement guidance in reading: the role of parafoveal letter and space information

The relation between parafoveal letter and space information in eye movement guidance during reading was investigated in 2 experiments. Contingent upon the reader's fixation, the type of parafoveal information available to the right of fixation was varied by (a) space information only, (b) space information with letter information added at some delay, or (c) letter and space information simultaneously. In addition, the onset of the relevant parafoveal information was delayed between 0 and 250 ms into the fixation. The time course of processing the 2 types of information (letters or spaces) differed, as did the nature of their impact on the eye movement record. Although both letter and space information influenced saccade length and initial landing positions within words, only letter information had an effect on fixation duration. In addition, fixation duration was affected only by information entering within the first 50 ms of the fixation, whereas saccade length was affected by information arriving at any time during the fixation. The results are consistent with a model of eye movement control in which 2 independent processes are operating in tandem to determine when and where to move the eyes during reading.     

The socialization of sex-differentiated skills and academic performance: A mediational model

Using a multifactorial model, sex differences in academic performance were examined in a sample of 347 elementary school children. As expected, girls' academic performance averaged higher than boys'. Path analysis confirmed initial hypotheses that girls' advantage is partially due to their characteristic of greater responsiveness to social cues and compliance with adult direction. This advantage was partially offset in this model by boys' greater visual-spatial skill, which also was a predictor of academic success. Access to stereotypic masculine toys and activities at home was, for both sexes, a predictor of children's visual-spatial ability. As expected, socioeconomic variables, including mothers' occupation and fathers' level of education, also influenced the environmental, social, and cognitive factors predicting academic success. These results indicate that boys' and girls' differential development of specific cognitive and social skills may play an important role in establishing sex differences in academic performance.     

The revised conners parent rating scale: Factor structure replication with a diversified clinical sample

The Revised Conners Teacher Rating Scale was completed as part of a comprehensive evaluation of 135 consecutive new patients seen in the Pediatric Neurology Learning Disability Clinic at the Medical College of Georgia. The questionnaires were subjected to principal components analysis with varimax rotation. Item analysis was conducted on the obtained subscales, and convergent validity was determined by correlation with the Revised Behavior Problem Checklist (Quay & Peterson, 1987). Finally, comparisons of the diagnostic groups were carried out across the subscales.I would like to thank Harry Davis, Office of Research Computing and Statistics, Medical College of Georgia, for his invaluable help in carrying out the computer analysis of the data.     

Toward the self-regulation of mood: Theory and research

Moods, defined as diffuse or global feeling states, may lead us to take self-regulatory action designed to maintain them (good moods) or eliminate them (bad moods). This paper first surveys theories that help explain the origin and nature of such feeling states and then goes on to review and evaluate evidence purporting to demonstrate that self-regulation of mood occurs. Some support was found for the idea that people in bad moods will engage in various self-gratifying or self-indulgent acts as therapy. Other techniques that appear to be used are alcohol consumption and self-serving cognitive processes. The evidence regarding other sorts of self-regulation is fragmentary and/or anecdotal. It is argued that research on the self-regulation of mood would profit from better theoretical development, and some ideas along these lines are offered.The authors are grateful to Margaret S. Clark, Jay Hull, Alice Isen, Robert Kleck, Kevin McConkey, and Paula Schnurr for comments on a previous draft of this paper.     

Continuous punishment of free-operant avoidance in the rat

Three groups of albino rats were trained under a free-operant avoidance (Sidman) procedure with equal shock-shock and response-shock intervals. After stable performance was achieved, the animals were concurrently exposed to a brief electric shock after each response. The procedures were as follows: Punishment Schedule I: punishment shock was introduced at an intensity approximately one quarter that of avoidance shock; increments of nearly this same size were made as stable performance was achieved at succeeding punishment shock intensities. Punishment Schedule II: punishment shock was introduced at approximately one-half the intensity of avoidance shock; after stable performance, punishment shock was increased to the same intensity as avoidance shock. Punishment Schedule III: punishment shock was introduced and maintained at the same intensity as avoidance shock. Punishment was continued for all groups until one of two suppression criteria was attained. All animals made fewer responses and received more avoidance shocks as a function of increasing punishment shock. Half of the animals under Punishment Schedule I required punishment shock higher than avoidance shock to meet their assigned suppression criterion. A comparison of all procedures showed that suppression was greater when punishment shock was initially at high intensity.