Attentional resource and processing speed limitations during sentence processing in Parkinson's disease

Several studies have suggested that patients with Parkinson's disease (PD) have sentence comprehension difficulty in part because of their limited executive resources. However, these assessments confound the executive resources contributing to sentence comprehension with the resources needed for task performance. In the present study, we used a word detection technique that minimizes task demands in order to evaluate attentional and processing speed resources during the comprehension of simple sentences without subordinate clauses and sentences containing subject-relative and object-relative center-embedded subordinate clauses. We found that PD patients have poor sensitivity to phonetic errors embedded in unbound grammatical morphemes, regardless of the clausal structure of the sentence, suggesting difficulty attending to grammatical morphemes. We also found that PD patients are significantly slowed in their sensitivity to phonetic errors in content words embedded in object-relative center-embedded sentences. Slowed sensitivity to content words in object-relative sentences was correlated with timed executive measures of planning. On a traditional measure of comprehension, these PD patients were impaired for sentences containing object-relative center-embedded clauses compared to sentences with subject-relative center-embedded clauses, and comprehension of object-relative sentences was correlated with executive measures. Our findings are consistent with the claim that limited executive resources for strategic attention and processing speed contribute to the sentence comprehension difficulties of PD patients.     

Verbal and Spatial Short-term Memory: Two Sources of Developmental Evidence Consistent with Common Underlying Processes

Developments in serial short-term memory (STM) typically have been assessed using verbal items, and mechanisms of development unique to the verbal system have been postulated. Here we review two studies of the development of spatial STM. The first (Chuah & Maybery, 1999) showed that variance in spatial span was partitioned among a set of predictor variables in a configuration very similar to that found for verbal span. The second (Maybery & Chuah, 1999) examined the timing of recall for spatial sequences. Intervals between touches as children recalled spatial sequences showed comparable effects to those reported for the oral recall of verbal sequences. Discussion focuses on processes that could serve both verbal and spatial memory and mediate span development.     

Orientation-specific effects in picture matching and naming

In two experiments, subjects made timed decisions about the second of two sequentially presented rotated drawings of objects. When the two objects were physically identical, response times to decide whether the two drawings depicted the same object varied as a function of the shortest distance between the orientation of the second drawing and either the orientation of the previous drawing or the upright. This was found for both short (250-msec) and long (2-sec) interstimulus-intervals. The result was also obtained when subjects named the second drawing after deciding whether the first drawing faced left or right. Following repeated experience with the drawings in the left/right task over four blocks of trials, time to name the second drawing in the same-object sequences was independent of orientation. These results suggest that, initially, object- and orientation-specific representations can be formed following a single presentation of a rotated object and subsequently used to identify drawings of the same object at either the same or different orientations. Alignment of the second drawing with either the canonical representation or the new representation at the previous orientation is achieved by normalization through the shortest path. Following experience with the objects, orientation-invariant representations are formed.     

Charpentier (1891) on the size—weight illusion

This paper offers background for an English translation of an article originally published in 1891 by Augustin Charpentier (1852–1916), as well as a summary of it. The article is frequently described as providing the first experimental evidence for the size—weight illusion. A comparison of experiments on the judged heaviness of lifted weights carried out by Weber (1834) and by Charpentier (1891) supports the view that Charpentiers work deserves priority; review of other experimental studies on the size-weight illusion in the 1890s suggests that the idea that the illusion depended on “disappointed expectations,” especially with respect to speed of lift, became dominant almost immediately following the publication of Charpentiers paper. The fate of this and other ideas, including “motor energy,” in 20th-century research on the illusion is briefly described.     

A partial matching theory of the mirror effect in immediate probed recognition

A set of experiments on immediate probed recognition of digit triples is reported in which the variables were list length (five, six, seven, or eight triples), the probability that a probe was old (.33, .5, or .67), and whether the digit triples were presented with an auditory component or articulatory suppression. Previous work had suggested that the false alarm (FA) rate in this paradigm was lower when auditory information was available than when it was not; this observation had led to the development of thepartial matching theory of immediate probed recognition, according to which FAs could arise not only as a result of unlucky guesses but also when new probes shared a first digit in common with a partially retained target triple. It was argued that partial memory representations were less likely following auditory presentation than following articulatory suppression. Partial matching theory is contrasted with therational response theory, according to which all FAs are unlucky guesses; partial matching theory gave a better account of the present experimental data than did rational response theory. However, a logical relationship between the two theories was suggested, a consequence of which was that rational response theory could be modified to include partial matching in such a way as to account for mirror effects, not only in unusually difficult immediate probed recognition tasks, but also in the more commonly studied mixed test list paradigm involving words of high or low frequency.     

Psychological Adjustment and Coping Styles of Urban African American High School Students

In a study of African American (n = 208) urban high school students, grade point average (GPA) and specific strategies for coping with day-to-day stressors were found to be significantly related to psychological adjustment. Students who had higher GPAs tended to use family members as a means of solving problems, minimized problems by the use of humor, and used relaxation activities less often were found to have the most positive psychological adjustment, as measured by the index score of the Affects Balance Scale (ABS). Reported negative affect was not found to be significantly influenced by coping style, whereas positive affect was.     

Spontaneous private speech and performance on a delayed match-to-sample task

Spontaneous private speech samples were obtained from 65 kindergarten children (mean age 70.3 months) from one suburban (n = 36) and one city (n = 29) school as they worked alone on a delayed match-to-sample (DMS) task with three levels of difficulty (2, 10, and 30 sec delays). As expected increases in DMS delay intervals produced decreased performance and increases in private speech. The expected increased positive relationship between task relevant private speech and performance for longer delays was found in city children but not suburban children. Since mean IQ scores were significantly different for the two groups this variable was further examined in post hoc analyses and discussed along with socio-economic status as possible explanations for the observed school-sample differences. A within-subject comparison for all children showed the percentage of speaking trials correct at 30-sec delay to be significantly greater than the percentage of nonspeaking trials correct. The effect of one experimenter modeled trial on a subsequent 10 trials at 30-sec delay was to increase speech and performance and to show a stronger relationship between speech and performance than for premodeling trials. These exploratory findings with a relatively simple two color matching task suggest further explorations of spontaneous private speech as a way of studying internalization of self regulatory cognitive strategies.     

A right-ear advantage in monotic shadowing

Lists of 30 monosyllabic words drawn at random with replacement from a set of 69 were presented monotically to the right or left ear of 28 subjects for immediate repetition (shadowing) at a rate of 120 words per minute. Each subject shadowed 40 lists. A right-ear advantage was found over the first 1.5 blocks (15 lists) but not for the remaining 2.5 blocks (25 lists). The results are related to previous investigations of monotic and dichotic listening, and are explained by a set (bias) in attention or response which favours the right ear and declines with practice.