CT scan and neuropsychological correlates of Alzheimer's disease and Huntington's disease

"Cortical" and "subcortical" dementia syndromes differ in areas of primary neuropathology and clinical characteristics. Conventional CT scan interpretation, visual inspection of pictures, has not been useful in studying dementia. Recent studies of the digitally stored CT attenuation values have found systematic variations with normal aging and aphasia subtypes. In this study of numerical CT scan information in four Alzheimer's Disease and two Huntington's Disease patients, a double dissociation of frontal and temporal lobe density values was found, and a significant correlation was found between left temporal lobe density and verbal ability measures in the Alzheimer's Disease patients.     

Attribution bias: On the inconclusiveness of the cognition-motivation debate

Social psychologists have given considerable theoretical and research attention to whether motivational variables bias the attributions people make for behavior. Some theorists maintain that motivational constructs must be invoked to explain certain attributional phenomena; other theorists maintain that information-processing variables can adequately explain these phenomena. The present article critically examines existing cognitive and motivational approaches to attribution and analyzes the assumptions underlying the cognition-motivation debate. We argue that cognitive and motivational theories are currently empirically indistinguishable. In particular, its is possible to construct information-processing explanations for virtually all evidence for motivated bias. We conclude by examining the implications of this indeterminacy of cognitive and motivational explanations. Future research in the area can most profitably be addressed to improving the specificity of cognitive and motivational theories rather than to resolving the between-theory confrontation.     

Teaching autistic children to use extra-stimulus prompts

Autistic children often do not transfer from extra-stimulus prompts, and thus do not utilize a frequent learning aid. It has been hypothesized that this is due to stimulus overselectivity; a failure to respond to simultaneous multiple cues. This study was designed to determine if autistic children who initially respond only to single cues can be taught a set to respond to two cues and subsequently utilize an extra-stimulus (pointing) prompt. Four autistic children were pretested to determine if they could learn a complex visual discrimination by either trial and error or an extra-stimulus prompt fading procedure. Since they did not, the children were then taught to respond to two cues through a multiple-cue training procedure and subsequently tested to determine if they could now utilize a pointing prompt. Results indicated that while all four children initially did not transfer from an extra-stimulus (pointing) prompt, they did so subsequent to multiple-cue training. The results are discussed in terms of implications for treatment (remediating overselectivity) and in relation to normal child development.     

Differences in spatial knowledge acquired from maps and navigation

Models of the spatial knowledge people acquire from maps and navigation and the procedures required for spatial judgments using this knowledge are proposed. From a map, people acquire survey knowledge encoding global spatial relations. This knowledge resides in memory in images that can be scanned and measured like a physical map. From navigation, people acquire procedural knowledge of the routes connecting diverse locations. People combine mental simulation of travel through the environment and informal algebra to compute spatial judgments. An experiment in which subjects learned an environment from navigation or from a map evaluates predictions of these models. With moderate exposure, map learning is superior for judgments of relative location and straight-line distances among objects. Learning from navigation is superior for orienting oneself with respect to unseen objects and estimating route distances. With extensive exposure, the performance superiority of maps over navigation vanishes. These and other results are consonant with the proposed mechanisms.     

Sign-based short-term coding of American Sign Language signs and printed English words by congenitally deaf signers

A short-term serial recall task consisting of lists of five American Sign Language signs and lists of five printed English words was administered to eight congenitally deaf subjects. For both modes of presentation, the stimuli in a given list were (1) high in phonological relatedness, (2) high in cherological relatedness (i.e., they were similar in terms of the formational attributes of their sign-equivalents), or (3) low in both phonological and cherological similarity (control). For both modes of presentation, recall accuracy was significantly lower on cherologically related lists than on both phonologically related lists and control lists. Phonologically related lists did not differ significantly from control lists. These results suggest the possibility that ways of looking at human memory which rely on a preference for phonological coding in short-term memory processes may reflect the audiocentricity of the experimenter rather than the inherent nature of such processes.     

Developmental differences in the role of detail in picture recognition memory

Two experiments assess the effect of the amount of physical detail in pictures on picture recognition memory. Children and adults were presented simple and complex line drawings. A “same-different” recognition test followed in which the distractor items were original pictures from the presentation phase with the amount of physical detail altered. For second- and fourth-grade subjects, recognition sensitivity, measured in terms of d′, was similar for pictures in the simple and complex presentation conditions. For adults, however, recognition sensitivity was greater for pictures in the simple than complex presentation condition. This finding with adults was replicated in Experiment 2. Interpretations of this age difference in picture memory processing are discussed, as well as the constraints imposed by various dependent measures used in picture memory studies.     

A study of the relationship between individual differences in nonverbal expressiveness and factors of personality and social interaction

Some theoretical and applied implications of individual differences in nonverbal expressiveness were investigated in a medical setting. In Study I, the abilities of 21 physicians to express different emotions through voice tone were assessed and related to physician personality and to actual patient ratings of the physician. Study II replicated Study I using visual as well as vocal cues (i.e., videotapes) of a new sample of physicians, and added a study of physician greetings. It was found that: (1) Aspects of expressive ability were reliably correlated with a cluster of personality traits, thus supporting the notion that nonverbal affective style may be a window to inner dispositions; and (2) expressive ability was related to patient satisfaction with the interpersonal manner of their physicians and to the judged likeability of the physician's greeting, thus providing evidence for the importance of this ability for social interaction.     

Reading between the lines: Event-related brain potentials during natural sentence processing

Event-related potentials (ERPs) were recorded from subjects as they silently read 160 different seven-word sentences, presented one word at a time. Each sentence was in itself a natural, meaningful phrase. Substantial intersubject variability was observed in the ERP waveshapes following the words. More than half of the subjects generated P3 components to word stimuli, but those who did showed similar responses to repeated control presentations of a single word. In addition, it was found that all but the first word in the sentence elicited an ERP with a significant left-greater-than-right asymmetry in the late positivity over temporo-parietal regions. The ERPs to the last words were associated with more late positivity than those to the preceding words. One quarter of the sentences, at random, ended with a word printed in a typeface that was different from that of the preceding words. This infrequent change in typeface elicited a complex ERP having three consistent late positive components.