Event-Related Brain Potentials during Identification of Tachistoscopically Presented Pictures

In the present study in 20 healthy subjects, event-related potentials (ERPs) were used to investigate the identification of picture stimuli. Each of 36 landscape pictures and 36 scrambled pictures was presented by a tachistoscope repeatedly until the subject made an identification response. Presentation of one picture was finished after 12 exposures. On the average, landscapes were identified after 5.8 ± 0.4 exposures; identification responses to scrambles were always wrong and occurred after 11.8 ± 0.1 exposures. Latencies and amplitude measures were assessed for P2, P3, N400, and the slow wave (SW). Changes in P2 across stimulus presentations did not differ between landscapes and scrambles excluding this component from being indicative for the processing of stimulus meaning. Amplitude of P3 generally declined across presentations, but increased prior to identification for landscape pictures. N400 rapidly declined across presentations of landscapes, but less rapidly for scrambles. The SW increased across stimulus presentations. This increase was more pronounced for landscape than scrambled pictures. The pattern of ERP changes can be interpreted in a framework of a stepwise inhibition of spreading activation within semantic memory with progressing picture identification.     

ACQUISITION AND GENERALIZATION OF COMPLIANCE WITH COMPLEX FIVE-COMPONENT INSTRUCTIONS1

A 7-yr-old bilingual boy of normal intelligence, judged by his school to be deficient in carrying out complex requests, was trained to comply with five-component instructions, e.g., “Give me/the chip/behind/the block/on blue”. Three interchangeable words or phrases were used for each component. Training proceeded in stages. First, the child was trained to identify all individual objects and actions; then to carry out requests involving only the first component, then the first two, then three, etc. On every trial, the visual setting permitted every possible response in the set. A test for generalization to nonreinforced instructions was given at each stage by giving no feedback for all instructions that included one preselected phrase. The phrase selected at each stage was one of the three that was introduced at that stage. As a further test for generalization, nonreinforced instructions were also given that included one additional component: the next to be trained (Probes Ahead). As a test for generalization across settings and instructions, several five-component instructions were presented each session in an unused classroom. These instructions used phrases, most of which were different from those being trained, and which referred to familiar classroom objects. Results showed: acquisition occurred for each stage of training, including the full five-component instruction; almost complete generalization of responding occurred to the subset of nonreinforced instructions; little or no generalization occurred to the Probes Ahead, where an additional untrained component was included; and little or no generalization was seen to the five-component classroom instructions, until training began on the five-component instructions in the training sessions. Performance was also examined for each component. Results showed that when a new component was introduced, correct performance to previously trained components declined, and was little if any superior to performance on the new component. In summary, transfer was found to untrained sentences of the same form as those being trained, even in another setting, where most of the components were different; but poor transfer was found to more complex sentences, and performance declined for previously trained components during training of a more complex sentence. Some features of the training procedure that may have affected the degree and form of transfer were discussed: the necessity for prior training in an appropriate response to the component phrases, the importance of intermixing of reinforced and nonreinforced trials, and the effects of the abruptness with which more complex sentence forms were introduced.     

A method of factor analysis by means of which all coordinates of the factor matrix are given simultaneously

In general, the methods of factor analysis developed during the past five years are based on the reduction of the correlational matrix by successive steps. The first factor loadings are determined and eliminated from the correlational matrix, giving a residual matrix. This process is continued for successive factor loadings until the elements of the last obtained residual matrix may be regarded as due to chance. The method outlined in this paper assumes the maximum number of factorsm in the correlational matrix. Them factor vectors are solved for simultaneously. Once them factor vectors are found, any vectors having only negligible factor loadings may be discarded.     

A non-graphical method for transforming an arbitrary factor matrix into a simple structure factor matrix

The most commonly used method of factoring a matrix of intercorrelations is the centroid method developed by L. L. Thurstone. It is, however, necessary to transform the centroid matrix of factor loadings into a simple structure matrix in order to facilitate the interpretation of the factor loadings. Current methods for effecting this transformation are chiefly graphical and require considerable experience and personal judgment. This paper presents a new method for transforming an arbitrary factor matrix into a simple structure matrix by methods almost completely objective. The theory underlying the method is developed and approximation procedures are derived. The method is applied to a matrix of factor loadings previously analyzed by Thurstone.     

Event-related brain potentials and subjective probability in a learning task

In a paired associate learning task, subjects responded to each presentation of a nonsense syllable by typing both a three-letter associate and a rating of their confidence that this response was correct or incorrect. Average event-related potentials (ERPs) elicited by the subsequent presentation of the actual paired syllable varied with the interaction of confidence and trial outcome. A larger amplitude P300 was elicited by syllables that informed subjects that they were correct when they thought they were incorrect or that they were incorrect when they thought they were correct than by syllables that confirmed subjects expectations. That this average ERP result was indeed an effect on P300 amplitude, and not an artifact of single-trial variability in P30O latency, was confirmed with a trial-by-trial latency adjustment procedure. Consistent with findings from other tasks, P300 amplitude varied inversely with the subj ective probability of the ERP-eliciting events.     

Discrimination of visually perceived intervals of time

The discrimination of short intervals of time, demarcated by a foveally presented spatially distinct double pulse of light, was studied under several conditions of pulse intensity, angular diameter, and duration. We defined temporal acuity as a measure of discrimination capacity in terms of d′ values. It is shown that the acuity mechanism uses largely integrated information—in the spatial and temporal domain, up to at least 56′ and 32 msec, respectively. Acuity increases slightly with increasing integrated pulse energy, but seems quite independent of the presence of an adapting field of appreciable brightness. Studies on the effect of the foveal site aimed at by the pulses of light have shown that temporal projections lead to significantly poorer acuity values than nasal projections. Monoptic and dichoptic stimulation, however, are fully equivalent.     

Imposed and chosen monitoring and blunting strategies in the dental setting: Effects, self-efficacy, and coping preference

Abstract In the present study, 94 dental patients received either monitoring (i.e., paying attention) or blunting (i.e., distraction) coping instructions during treatment. Half of the patients were given the possibility of choice, whereas the other half were offered one of both strategies without choice. A majority of the patients (n=61) indicated that the intervention had resulted in a decrease of their anxiety. Some indications were found for the monitoring strategy to be more effective than the blunting strategy. More specifically, monitoring strategy subjects reported that they had experienced less distress during treatment than blunting strategy subjects. In agreement with this finding, self-efficacy ratings of monitoring strategy subjects were higher than those of blunting strategy subjects. Possibility of choice and coping preference had no substantial influence on effectiveness of the interventions.     

Optimal test length for maximum differential prediction

For the case of a single criterion a method is already available for determining the optimal distribution of testing time for a battery of predictors, assuming that intercorrelation, validity, and reliability data are available for predictors of arbitrary lengths. In this article a modification and generalization of the method is presented for the case of differential prediction involving a number of criterion variables. A numerical example is given to illustrate the method, after which the mathematical rationale is outlined.This research was carried out under Contract Nonr-477(08) between the University of Washington and the Office of Naval Research. Most of the computations were carried out by Robert Dear, Charlotte MacEwan, and Donald Mills. Much credit is due the typist, Elizabeth Cross. Supervision of both computational and editorial activities was provided by William Clemans. To each of these able contributors I am deeply grateful.     

Brauchen wir Richtlinien oder Leitlinien für psychotherapeutische Behandlungen?

In many countries, psychotherapy is increasingly influenced by standards of scientifically evaluated methods and disorder-specific approaches. Referring to the definitions of the Scientific Council for Psychotherapy in Germany (WBP) concerning the differentiation of modalities, methods and techniques, this article points out that clear distinctions between modalities and methods are increasingly vanishing; instead, the tendency, especially within behavior therapy, to integrate all scientifically based methods and techniques is prevailing. This trend runs parallel with a development away from ?disorder-specific“ to a ?disorder-oriented“ approach. Facing the fact that technical aspects explain a relatively small proportion of outcome variance in psychotherapy, research related to the quality of psychotherapists is recommended. In addition, ?empirically validated psychotherapists“ should receive guidelines instead of rules of action.