Effects of matches and mismatches in agoraphobic and neutral situations

An experiment was conducted to investigate the generalizability of Rachman's match/mismatch model and to explore if environmental conditions affect the consequences of an underprediction. Twenty subjects walked around in agoraphobic, and 15 did so in neutral, situations. Both groups carried a walkman and 7 aversive human screams were administered to them at random times. The results gave strong support to previous investigations on matches and mismatches, but no differences were shown between agoraphobic and neutral situations. Possible explanations are discussed.     

Modification of muscle activation patterns during fast goal-directed arm movements

The motor programming of fast goal-directed arm movements was studied in a tracking task. A target jumped once or twice randomly to the left or right direction with an interstimulus interval (ISI) in a range between 50 and 125 msec. Double step stimuli were either two steps in the same direction (C-trial) or in opposite direction (R-trial). Tracking results show that at the beginning average EMG-activity is the same for responses to single step trials, R-trials and C-trials. Differences set in after some time equal to or somewhat shorter than ISI. It was concluded that muscle activation patterns of fast goal-directed movements are not preprogrammed but that they can be modified during the movement. The time interval between second target step and the moment when EMG activity of the double step response deviates from the EMG activity of a single step (RT2) could be smaller than the time interval between first target displacement and EMG onset. (RT1). If modification of the muscle activation pattern required a longer or larger activation of the active muscle, RT2 tended to be smaller than RT1, whereas RT2 was about equal to RT1 if the new muscle activation required a termination of the ongoing muscle activation pattern and the activation of another muscle.     

Strategic factors in a lexical-decision task: Evidence for automatic and attention-driven processes

The present study examined strategic factors in a semantic-priming, lexical-decision task. The first experiment demonstrated that the greater the proportion of related word-word pairs to unrelated word-word pairs, the greater the amount of facilitation, a result which is consistent with others reported in the literature. The second experiment demonstrated that this strategic factor apparently requires that sufficient time (at least several hundred milliseconds) be available for the processing of the priming word, and thus is probably caused by attention-driven processes. The third experiment replicated and extended the results of the first two studies by demonstrating that prime-target stimulus onset asynchrony is an important limiting factor in determining whether such proportion-induced strategic factors are involved in word-recognition processes, even when no other aspect or variable of the procedure changes. The results are discussed in the context of Posner and Snyder’s (1975a) two-process model of word recognition.     

Agoraphobia and Locus of Control

This study investigated whether external locus of control, as measured with the Rotter Internal-External Locus of Control Scale, is a specific feature of agoraphobia or whether it characterizes neurosis in general. Forty agoraphobic patients, 81 nonagoraphobic neurotic controls, and 49 normal controls completed the Dutch version of the Rotter Internal-External Locus of Control Scale. Agoraphobic patients were found to have a more external orientation as compared to the normal controls, but as a group, they could not be identified as being different from neurotic controls.This study was supported in part by a grant from the Dutch Organization for Fundamental Research (ZWO/Psychon 560-268-001).     

Are prepared fears less severe, but more resistant to treatment?

In order to investigate the relationship between the extent to which clinical fears are prepared and clinically relevant characteristics of these fears (i.e. severity, age of onset and treatment outcome). the records of 63 obsessional and phobic patients were examined. Four independent raters scored the usable records (N = 55) on preparedness. The preparedness scores were combined and related to objective indices of severity (patients' scores on the Fear Survey Schedule, the Zung Depression Scale and the Maudsley Obsessional-Compulsive Inventory, as well as the treatment duration), onset ages and treatment outcomes (pre-treatment minus post-treatment MOCI scores, for a subsample of obsessional patients only). In contrast to earlier studies, it was found that product-moment correlations among preparedness ratings were relatively low and that prepared fears did not make up a majority in the sample. Indices of severity either did not correlate at all or correlated negatively with preparedness ratings. The positive correlation between preparedness and onset ages reached borderline significance. Evidence suggestive of a resistance to treatment of prepared fears was obtained.     

A test of symmetry and transitivity in the conditional discrimination performances of pigeons

In a matching-to-sample context, pigeons were taught two conditional discriminations according to one of three equivalence paradigms: train if A, then select B and if B, then select C; train if B, then A and if B, then C; or train if A, then B and if C, then B. Test trials without reinforcement revealed that the conditional relations did not satisfy the symmetrical and transitive properties of an equivalence relation. Apparently, only specific if... then relations were learned. Contrary to Kendall's (1983) findings, and probably as a consequence of procedural differences, none of the pigeons in the present experiment were observed to emit mediating behavior during the transitivity probe trials. The absence of symmetry and transitivity may be related to the individual stimuli not being reflexive. Behavioral techniques other than the commonly used matching-to-sample technique might better succeed in avoiding unintended stimulus control in the study of the formation of stimulus classes.     

Some properties of two measures of multivariate association

Two kinds of measures of multivariate association, based on Wilks' and the Bartlett-Nanda-Pillai trace criterionV, respectively, are compared in terms of properties of the univariateR ² which they generalize. A unified set of derivations of the properties is provided which are self-contained and not restricted to decompositions in canonical variates. One conclusion is that asymmetric index based on allows generalization of the multiplicative decomposition ofR ² in terms of squared partial correlations, but not the additive decomposition in terms of squared semipartial correlations, while the reverse is true for anasymmetric index based onV.We are indebted to Jos M. F. ten Berge for some fruitful discussions.     

Psychophysiological and subjective reactions of social phobics and normals to facial stimuli

Nine social phobics and 9 normal control subjects were exposed to slides of angry faces, happy faces, and neutral objects (i.e. flowers or mushrooms). Skin conductance responses (SCRs) to the stimuli and eyeblink rate (EBR) during stimulus exposure were recorded. In addition, subjects were asked to rate the stimuli in terms of pleasantness. While angry face stimuli elicited greater SCRs, stronger inhibition of EBR, and were evaluated more negatively than the other stimuli, there were no differences between social phobics and normals in these respects. Thus, the findings lend no support to the idea that social phobics are particularly sensitive to facial cues in general or to negative facial cues in particular.     

Observations on Chiang’s “new” theory of geometrical illusions

Several observations are reported which conflict with predictions derived from a recent theory of illusions presented by Chiang. It was concluded that Chiang’s analysis of the processes underlying contour formation is inadequate to explain a number of illusions such as the Poggendorff and the Muller-Lyer.