Selective attention in the speeded classification and comparison of multidimensional stimuli

Selective attention was studied when subjects were required to make either speeded classifications of single stimuli or comparisons of pairs of multidimensional stimuli. Experiment 1 established that subjects were able to attend selectively to form when the irrelevant dimension of size or shading varied in a speeded-classification (card-sorting) task. Experiment 2 confirmed this finding in a discrete-trials task. However, subjects werenot able to filter out irrelevant dimensional disparity in a comparably designed simultaneous-comparison (i.e., “same”-“different”) task. Mean “same” reaction time increased monotonically with increases in disparity between the two stimuli on the irrelevant dimension. Experiment 3 also revealed a monotonie increase in “same” RT as a function of irrelevant disparity in a successive-comparison task. These results were discussed in terms of a normalization model proposed by Dixon and Just (1978) in which it is assumed that a subject equates the two stimuli on the irrelevant dimension before deciding that they are the same along the relevant dimension. It was concluded that: (1) although subjects can efficiently filter out irrelevant disparity in a speeded-classification task, interference due to irrelevant disparity is obtained in the comparison tasks, (2) a common process such as normalization does not necessarily underlie performance in the speeded-classification and comparison tasks, (3) the ability to attend selectively to a stimulus dimension may be task determined as well as stimulus determined, and (4) contrary to the Dixon and Just proposal, normalization of irrelevant disparity occurs in a comparison task, even when the relevant dimension is represented as a separate encoding feature.     

Common items and reliability in personality measurement

Most psychological tests and inventories, particularly in personality and attitude measurement, contain common items, that is, various subscales of the test or inventory may share one or more items in common. Surprisingly, the role of common items in such a fundamental personality test attribute as reliability is not known. The present report specifically considered common-item contributions to test internal consistency reliability using extant data from the California Psychological Inventory. No negative contribution of item overlap was found. To the contrary, it was concluded that the use of common items is an economical technique for increasing the total number of items in the scales, thus increasing scale internal reliabilities without increasing the overall number of items in the inventory.     

Verbal and nonverbal recognition memory in aphasic and nonaphasic stroke patients

The ability to retain lists of verbal and nonverbalizable items across recurrent recognition tasks was tested in three groups: (1) stroke patients with a left-brain lesion and aphasia, (2) stroke patients with a right-brain lesion and left hemiplegia, and (3) nonneurologically impaired outpatients. As determined with signal detection measures, aphasics were deficient in discriminating words that were to be remembered from those that were not; their recognition of nonverbal visual (geometric art) or auditory (bird calls) patterns, however, was unimpaired. Left hemiplegics showed the opposite pattern. After a long-term interval (<10 min), correct recognition of words was diminished in all groups whereas recognition of visual patterns increased. Both groups of stroke patients adopted material-specific decision criteria which in part accounted for the dissociation of verbal and nonverbal recognition memory by laterality of lesion. Item analysis indicated that aphasics' verbal memory difficulties were affected by acoustic-semantic confusion of list words.     

Self-instructions: Effects of cognitive level and active rehearsal

This research examined the effects of a self-instruction intervention on the relationship between cognitive level and conceptual tempo. Preoperational and concrete operational children received the Matching Familiar Figures Test prior to and after serving in either a no training control group, a content only control group, or a self-instruction group. Children in the content only control group received the same set of self-guiding strategy statements as those in the self-instruction group but without overt rehearsal of the statements. Cognitive level and conceptual tempo were strongly related; preoperational children tended to be classified as impulsive, concrete operational chidlren, as reflective. Although cognitive level predicted overall performance, with concrete operational children being more successful and more reflective than preoperational children, the influence of training was similar for both groups. On posttest, children in the self-instruction groups made more correct responses and were more reflective than children in the other two training groups.     

Evaluation of the relative effectiveness of methylphenidate and cognitive behavior modification in the treatment of kindergarten-aged hyperactive children

This study of kindergarten-aged hyperactive children evaluated the effects of three modes of treatment in relation to an untreated control group. The treatments were administered over a 3-month period and included cognitive behavior modification, methylphenidate, and the two treatments combined. A follow-up assessment was done approximately 1 year later at the end of the first grade. Analyses of psychological, rating scale observational, and interview data showed that hyperactive children became less symptomatic over time;the data did not provide evidence indicating that any of the treatments studied was more effective than any other or than no treatment at all.This research was supported by grants from the Ontario Mental Health Foundation (Grant No. 701-76/78) and The Hospital for Sick Children Foundation (Grant No. 77-22). The authors wish to thank Mr. Syl Sauro, of the Etobicoke Board of Education, and Mrs. M. Stijovic, of the Etobicoke Community Health Department, for their cooperation.     

A procedural theory of eye movements in doing arithmetic

A procedural theory of eye movement that accounts for main features of the stochastic behavior of eye-fixation durations and direction of movement of saccades in the process of solving arithmetic exercises of addition and subtraction is presented. The best-fitting distribution of fixation durations with a relatively simple theoretical justification consists of a mixture of an exponential distribution and the convolution of two exponential distributions. The eye movements themselves were found to approximate a random walk that fits rather closely in both adult and juvenile subjects the motion postulated by the normative algorithm ordinarily taught in schools. Certain structural features of addition and subtraction exercises, such as the number of columns, the presence or absence of a carry or a borrow, are well known to affect their difficulty. In this study, regressions on such structural variables were found to account for only a relatively small part of the variation in eye-fixation durations.     

The effects of distributed training on retention of operant conditioning in human infants

Long-term retention of operant footkicking acquired in the mobile conjugate reinforcement paradigm was assessed as a function of the distribution of training time. In the first study, 3-month-old infants were trained for either one 18-min session or for two 9-min or three 6-min sessions separated by 24-hr intervals. All infants exhibited retention during a test administered immediately after training, but only those trained in a single session continued to perform the conditioned response during cued-recall tests 7 or 14 days later. Infants trained in three sessions showed no evidence of remembering the contingency even after a week. A warm-up decrement, seen in the day-to-day performance of infants in the distributed conditions, was eliminated in the second study by the interpolation of a nonreinforcement period at the outset of daily sessions. This procedure also enhanced long-term retention such that infants trained in three 6-min session now remembered the contingency for 14 days and did not differ from infants who had received a single 18-min session. Whether distributed training facilitates or impairs long-term retention appears to depend on the opportunity for infants to acquire a sufficient number (or kind) of effective retrieval cues during original learning.     

Spatial representations of young children: the role of self- versus adult-directed movement and viewing

The influence of the control of movement and viewing while exploring a novel large-scale environment was assessed. Forty kindergarteners and forty second grade children served in four activity conditions that represented the factorial combination of movement (self vs adult directed) and viewing (self vs adult directed). A significant grade level X movement X viewing interaction revealed that when kindergarteners directed their own movement, estimates of interlocation distances were equivalent whether viewing was self or adult directed. If movement was directed by an adult, kindergarteners estimated interlocation distances more accurately if the adult also directed their viewing than if the children directed their own viewing. Second grade children performed comparably across all four experimental conditions.