On the relationship between task performance and associated verbalizable knowledge

Three experiments explore the relationship between performance on a cognitive task and the explicit or reportable knowledge associated with that performance (assessed here by written post-task questionnaire). They examine how this relationship is affected by task experience, verbal instruction and concurrent verbalization. It is shown that practice significantly improves ability to control semi-complex computer-implemented systems but has no effect on the ability to answer related questions. In contrast, verbal instruction significantly improves ability to answer questions but has no effect on control performance. Verbal instruction combined with concurrent verbalization does lead to a significant improvement in control scores. Verbalization alone, however, has no effect on task performance or question answering.     

Serial,parallel, or holistic identification of single words in the two visual fields?

Subjects made timed manual responses in judging whether laterally presented four-letter words were identical to targets. In Experiment 1, nontargets differed by a single letter from targets. A right-field superiority occurred only for targets (which were detected fastest of all) and for nontargets where a letter changed at Position 2 or Position 3. Changes at initial and final positions were detected faster than the two middle positions, and there were no significant field differences. In Experiment 2, ascenders and descenders were controlled and changes were made in nontargets at all four letter positions, at Positions 1 and 4, at Positions 2 and 3, or at 2 alone. Response times for nontargets varied inversely with the number of differing letters, regardless of position. Significant field differences again only appeared for changes in the two middle positions. Letters at the beginning and end of a word seem to be processed faster than and differently from those within, where field differences are strongest. Vowel-consonant differences probably do not account for these effects, which are more compatible with some form of parallel, rather than either serial or holistic, processing.     

Imitation as a learning strategy in the acquisition of vocabulary

Twenty-four 14- to 30-month-old children observed a model use 20 new words as labels for objects of varied semantic associations. Acquisition of the new words was clear in both elicited and spontaneous imitation by the children and in generalized use of the words. Age was highly and positively correlated with elicited and spontaneous imitation and scores for recognition of the objects associated with the words. Imitation and recognition scores were highest for words associated with food and active objects and low for passive objects and words with no associations. Older children's use of the words immediately after the model's use increased rapidly with the first two presentations, and their use of the words prior to the model's use showed an increasing trend over the series of modeling sessions. Younger children responded at a lower rate.     

Hemispheric differences in picture-word interference

In a picture-word version of the Stroop task, 30 right-handed subjects were tested under each of six conditions in which a picture alone or a picture plus a word were presented to the left, the right, or both hemispheres. In two additional conditions the picture was presented to the right hemisphere and the word was simultaneously presented to the left hemisphere, or vice versa. For all conditions, subjects were instructed to name the picture only, as rapidly as possible. Picture naming times were significantly slower for the conditions in which the pictures were accompanied by words than in the respective picture alone conditions. Moreover, simultaneous presentation of a picture and a word to both hemispheres resulted in greater interference (slower picture naming times) than did the simultaneous presentation of the picture and the word to either the left hemisphere alone or the right hemisphere alone. The latter two conditions, in turn, resulted in significantly more interference than did the simultaneous presentation of the picture to one hemisphere and the word to the other hemisphere. This pattern of results suggests that the Stroop effect obtained under normal circumstances is in large part a function of the interference caused by the simultaneous processing of items in the same hemisphere. In contrast to hemispheric differences reported for the color-word Stroop task, the effect of presenting a picture and word simultaneously to the right hemisphere did not differ reliably from that of presenting a picture and word to the left hemisphere. The failure to replicate this aspect of the color-word Stroop is attributed to differences in the abilities of the two hemispheres to process the respective target items (the color or the picture) of the two tasks.     

Backward and forward masking associated with saccadic eye movement

Visual masking effects on test flash thresholds were measured under real and simulated eye movement conditions to determine whether visual masking is primarily responsible for elevations in threshold that are sometimes associated with saccadic eye movements. Brief luminous flashes presented to the central retina before, during, and after saccades were masked by stimuli presented either pre- or postsaccadically. The amount and time course of masking were quantitatively dependent on stimulus parameters of intensity and temporal separation and were unaffected by eye movement parameters (amplitude, velocity, direction) as long as retinal stimulus conditions were constant. The duration of forward masking was longer than that of backward masking. When retinal conditions during saccades were mimicked while the eyes were held steady, masking interactions were identical to those obtained during real saccades. These results indicate that masking effects during saccades in ordinary environments are determined solely by the stimulus situation at the retina. Putative nonvisual, centrally originating saccadic suppression suggested by other authors is evidently not additive with visually determined masking during saccades.     

Relationship between the Millon Behavioral Health Inventory and the minnesota multiphasic personality inventory (MMPI) in low-back pain patients

The Millon Behavioral Health Inventory (MBHI) is being used with increasing frequency for the assessment of chronic pain, although there is a relative lack of evidence as to its utility, and prior studies have not examined low back pain. This investigation compared the MBHI to the MMPI in a sample of low-back pain patients and analyzed subgroups of pain patients based upon their MBHI responses. Subjects were 60 patients who had been admitted to outpatient multidisciplinary pain clinics of two Chicago-area hospitals. Patients completed both the MMPI and the MBHI and provided demographic information. Results of correlational analyses indicated strong relationships between the MBHI psychogenic attitude, psychosomatic correlate, and prognostic index scales and the validity scales of the MMPI. The MBHI Pain Treatment Responsivity scale (PP) correlated with 16 of the other 19 MBHI scales. PP did not demonstrate specificity with low back pain patients. The results of both the scale comparisons and the exploratory two-group cluster subgroup analysis support the notion that responses to the MBHI are largely affected by the respondent's tendency to deny psychopathology or to admit emotional distress.     

Perceived Consensus in Estimates of the Prevalence of Driving Errors and Violations

This paper reports a study of perceptions of the prevalence of certain driving errors and violations in a large ( N = 1,656) sample of drivers. In keeping with previous research on perceptions of social consensus, it was predicted that (a) drivers who reported that they themselves regularly commit these errors and violations would make larger estimates of the percentage of other road users who regularly engage in these behaviors, by comparison with drivers who reported that they do not regularly commit these errors and violations; (b) comparison of estimates of social consensus for own behavior with the actual numbers of respondents reporting that they did or did not engage in these behaviors would show that those who do commit the behaviors regularly would overestimate consensus for their position, while those who do not commit the behaviors regularly would underestimate consensus for their position; and (c) these tendencies to overestimate or underestimate actual consensus for own position would be correlated with the perceived offensiveness to others of the behavior concerned, such that departures from actual consensus would be greater for behaviors rated as more offensive. The results provide strong support for the first two predictions but none for the third; indeed, the degree of over- or underestimation tended to be inversely related to offensiveness. In addition, there were unanticipated but highly consistent sex and age differences in perceptions of the prevalence of the target behaviors, with female and younger respondents making higher estimates than male and older respondents, respectively. The theoretical and practical implications of these findings are discussed.