Disorders of oculomotor scanning and graphic orientation in developmental Gerstmann syndrome

A patient with developmental Gerstmann syndrome who experiences great difficulty in performing tasks requiring visuoconstructive and reading abilities is described. Neuropsychological assessment revealed normal range verbal abilities but severe deficits in directional orientation, finger differentiation, calculational ability, copying, and reading ability. Achievement in reading was measured at the sixth-grade level despite the fact that this patient is a third-year college student. Using infrared photoelectric sensors, we monitored the horizontal saccades of this patient while reading from a standardized reading test. Fixation durations were not abnormal. However, instances of reverse-staircase movement were exhibited. While reading from an inverted test, she showed a normal eye-movement pattern (although in the reverse direction since the task now called for right-to-left saccades). The processing of spatial information in this patient is severely disturbed and this may account for the apparently abnormal oculomotor scanning, an “irrepressible tendency” to move her eyes in a right-to-left direction.     

Visual angle and the word superiority effect

Two experiments are reported in which a word superiority effect is obtained under conditions where a fixed set of alternatives are employed with positional certainty as to the critical letter, trial type (word or nonword) is mixed, and the subject is told to fixate the position of the critical letter. A third experiment employed the same methodology except for the fact that the stimuli subtended a larger retinal angle. No word superiority effect was observed in the third experiment. It is suggested that the visual angle of the stimulus display is a crucial factor in experiments on the word superiority effect.     

Positional discriminability in linear orderings

Subjects were taught two eight-term linear orders of the form “A taller than B taller than C ….,” They were then asked to choose the “taller” term in all possible pairwise combinations within each series, and reaction time was measured for each pair. In addition, subjects performed a further task in which they judged whether or not two terms were adjacent in the ordering. In subsequent sessions, subjects were told that the “shortest” term on one list was taller than the “tallest” term on the other, so that the two lists were merged into a single 16-term series. They were then required to choose the “taller” term for both within-groups and between-groups pairs. Subjects did not appear to use the initial groupings in performing this task, even when given training on differential categorical codes (“tall” vs. “short”) for the two sublists. Rather, subjects in all tasks appeared to represent the items as ordered positions along an internal array, so that comparison times depended largely on the differential discriminability of the item positions. In each task decisions were made more quickly if the terms being compared were near the ends of the ordering, rather than near the middle.     

Thematic fame and melodic originality in classical music: A multivariate computer-content analysis1

In order to understand the foundation of eminence in cultural activities, an attempt was made at learning why some works creators produce are more famous than others. This paper specifically investigates the differential fame of 5,046 themes by 10 eminent composers of classical music. Hypotheses derived from past research in creativity and esthetics were tested using a computerized content analysis. The results show that (a) the fame of a musical theme is a positive linear function of melodic originality (rather then a curvilinear inverted-U function), and (b) melodic originality is a positive function of biographical stress and of historical time, and an inverted backwards-J function of age.     

Integrating information across eye movements

A series of experiments was conducted in which a word initially appeared in parafoveal vision, followed by the subject's eye movement to the stimulus. During the eye movement, the initially displayed word was replaced by a word which the subject read. Under certain conditions, the prior parafoveal word facilitated naming the foveal word. Three alternative hypotheses were explored concerning the nature of the facilitation. The verbalization hypothesis suggests that information acquired from the parafoveal word permits the subject to begin to form the speech musculature properly for saying the word. The visual features integration hypothesis suggests that visual information obtained from the parafoveal word is integrated with foveal information after the saccade. The preliminary letter identification hypothesis suggests that some abstract code about the letters of the parafoveal word is stored and integrated with information available in the fovea after the saccade. The results of the experiments supported the latter hypothesis in that information about the beginning letters of words was facilitatory in the task. The other two hypotheses were disconfirmed by the results of the experiments.     

Concurrent and predictive validity of the psychopathy checklist: youth version across gender and ethnicity

The concurrent and predictive validity of the Psychopathy Checklist: Youth Version (PCL:YV) were examined across gender and ethnicity using multiple outcome measures on a community-based sample of 130 adjudicated youths. The PCL:YV demonstrated concurrent validity with externalizing behavior problems but, it is important to note, was also associated with internalizing measures of negative affect. With a mean follow-up period of 3 years, the PCL:YV was found to predict general and violent recidivism in male, Native Canadian, and Caucasian youths. However, the PCL:YV demonstrated weaker concurrent and predictive validity with girls and failed to predict nonviolent recidivism in all subgroups. Implications of the findings for clinical practice are discussed.     

The impact of colour, spatial resolution, and presentation speed on category naming

Studies of neurological patients with category-specific agnosia have provided important contributions to our understanding of object recognition, although the meaning of such disorders is still hotly debated. One crucial line of research for our understanding of category effects, is through the examination of category biases in healthy normal subjects. This approach has, however, led to contradictory findings with advantages both for natural kinds and for man-made things being documented in healthy subjects. It has been proposed that task conditions may influence the direction of advantage (Gerlach, 2001) and in particular, that sub-optimal viewing conditions underpin natural kinds advantages, while man-made advantages emerge under more optimal viewing conditions. In two experiments with normal subjects, we examined the roles played by spatial resolution (blurring), stimulus type (colour and texture), and speed of presentation in picture naming across category. In both experiments, healthy subjects showed a natural kind advantage for original stimuli and for blurred colour stimuli (at slow and fast presentation speeds), while an advantage for man-made things emerged for line-drawings that were blurred and presented slowly. The implications for category-specific object recognition deficits are discussed.