Is suggestion the source of reported visual sensations in perceptual isolation?

The hypothesis that expectation or suggestion is responsible for the reports of visual sensations in perceptual isolation was tested using a control group and 3 additional groups incorporating increasing amounts of verbal and placebo suggestion. Ss were 58 male undergraduates. Prior knowledge and expectations were unrelated to reports of visual sensations. Only the least structured and meaningful type of reported visual sensations was found to increase with suggestion. Other reactions to isolation were unrelated to suggestion. Although the role of direct suggestion in perceptual isolation has been overestimated, the continuous reporting method may be influential in eliciting reports of visual sensations. (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A "pure" measure of perceptual defense uncontaminated by response suppression.

"Using a tachistoscopic recognition technique, an experiment was designed that provided measures both of 'perceptual defense' and of response suppression. The 'perceptual defense' measure could be corrected by the response suppression measure to yield a 'pure' perceptual defense measure. With this method, it was found that Ss scoring high on the Hy scale of the MMPI demonstrate a significant perceptual defense effect over and above a response suppression effect, when confronted by words preselected so as to be emotional for each S individually. It is therefore concluded that perceptual defense effects cannot be accounted for entirely on the basis of response suppression." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A further study of the relationship between response bias and perceptual defense.

Ss were exposed to tachistoscopically-presented pairs of words and asked to report whether a particular word was on the left or right of a fixation point. A non-statistically-significant trend showed that Ss tended to demonstrate a response bias in terms of reporting anxiety or neutral words on one or the other side whether or not they were in fact on the stated side of the point. A 2nd phase of the experiment presented S with blank stimulus fields although S was expecting words. A response bias was not demonstrated. "… it is suggested that the use of a forced-choice spatial indicator of perception may undermine the motivational basis for perceptual defense." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reaction time as a measure of perceptual vigilance.

Reviews the use made of reaction time as an index of performance deterioration in monitoring tasks, with special reference to the hypothesis that reaction time and detection rate are correlated indices of perceptual vigilance. It is concluded that this is the case, and a theoretical model relating the 2 indices to changes in vigilance occurring with time on task is proposed. (2 p. ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Denial of threat and emotional response to impending painful stimulation.

Significant negative correlations were obtained between scores on Byrne's Repression-Sensitization (R-S) scale and several indices of electrodermal activity in a paradigm in which Ss anticipated the presentation of strong electric shock. These results support the hypothesis that Ss who receive low scores on the R-S scale (repressers) exhibit greater disturbance than do those who receive high scores (sensitizers). Repressers reported a stronger tendency to avoid thinking about impending shock (suppression) than did sensitizers. This reported tendency to use suppression techniques was directly and significantly related to basal skin conductance, non-specific GSR activity, magnitude of anticipatory GSR activity, and the number of sec. by which this activity preceded shock. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Structural analysis of dreams: Clues to perceptual style.

"… persons who show differences in the perceptual attitude of flexibility-rigidity as estimated from the Rorschach test also differ predictably along this dimension in the perceptual response pattern of their dreams… . Results confirmed the experimental hypothesis." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conceptual and perceptual priming and dissociation in chronic posttraumatic stress disorder.

Cognitive models of posttraumatic stress disorder (PTSD) assert that memory processes play a significant role in PTSD (see e.g., Ehlers & Clark, 2000). Intrusive reexperiencing in PTSD has been linked to perceptual processing of trauma-related material with a corresponding hypothesized lack of conceptual processing. In an experimental study that included clinical participants with and without PTSD (N = 50), perceptual priming and conceptual priming for trauma-related, general threat, and neutral words were investigated in a population with chronic trauma-induced complaints as a result of the Troubles in Northern Ireland. The study used a new version of the word-stem completion task (Michael, Ehlers, & Halligan, 2005) and a word-cue association task. It also assessed the role of dissociation in threat processing. Further evidence of enhanced perceptual priming in PTSD for trauma stimuli was found, along with evidence of lack of conceptual priming for such stimuli. Furthermore, this pattern of priming for trauma-related words was associated with PTSD severity, and state dissociation and PTSD group made significant contributions to predicting perceptual priming for trauma words. The findings shed light on the importance of state dissociation in trauma-related information processing and posttraumatic symptoms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conflicts during response selection affect response programming: Reactions toward the source of stimulation.

In the Simon effect, participants make a left or right keypress in response to a nonspatial attribute (e.g., color) that is presented on the left or right. Reaction times (RTs) increase when the response activated by the irrelevant stimulus location and the response retrieved by instruction are in conflict. The authors measured RTs and movement parameters (MPs) of pointing responses in a typical Simon task. Their results show that the trajectories veer toward the imperative stimulus. This bias decreased as RTs increased. The authors suggest that the time course of trajectory deviations reflects the resolution of the response conflict over time. Further, time pressure did not affect the size of the Simon effect in MPs or its time course, but strongly reduced the Simon effect in RTs. In contrast, response selection before the onset of a go signal on the left or right did not affect the Simon effect in RTs, but reduced the Simon effect in MPs and reversed the time course. The authors speculate about independent Simon effects associated with response selection and programming. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Growth of brain stimulation reward as a function of duration and stimulation strength.

The strength of a train of rewarding brain stimulation required to support a criterion level of operant performance declines hyperbolically as the duration is increased. This finding has been attributed to a process of leaky integration. However, the rate at which integration approaches asymptote has been shown to depend on stimulation strength, a finding that differs from the behavior of a simple leaky integrator. The authors replicate both findings and show that they are both well described by a new model that incorporates a hyperbolic strength-duration function, a logistic function mapping stimulation frequency onto reward intensity, and another logistic function mapping reward intensity onto performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The duration of movement components in a repetitive task as a function of the locus of a perceptual cue.

A simplified pins-into-holes assembly task was used to study the interrelation of perceptual processes and work movements, by varying the locus of a perceptual cue within a repetitive patterned motion. "First, it is apparent that a perceptually loaded component takes significantly longer than its counterpart which involves less perceptual load. Secondly, placing a perceptual cue in one part of a work cycle not only affects the duration of that part of the cycle, but also significantly affects the durations of certain other parts of the movement." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Avoidance learning of perceptual defense and vigilance.

Thirty-two undergraduates were randomly assigned to defense and vigilance training groups. "This study supports the view that perceptual defense and vigilance are learned reactions to anxiety arousing stimuli." A behavior theory analysis of the learning process is proposed. "According to this analysis, perceptual defense is learned when the perceptual response to a threatening stimulus is punished and competing perceptual responses are instrumental to anxiety reduction. Competing perceptual responses when reinforced are strengthened at the expense of the critical perceptual response. Perceptual vigilance is learned when the perceptual response to a threatening stimulus is reinforced by anxiety reduction and competing perceptual responses are punished." Learning for both groups "proceeded in the absence of awareness." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The affiliation motive and perceptual sensitivity to faces.

An attempt was made to predict from imaginative measures of the affiliation motive the frequency with which S selects human faces from similar but nonhuman figures in a perceptual task. The Ss were 93 male undergraduates who responded to pictures with imaginative stories scored for n Affiliation. A month later they were introduced to the perceptual task which required that they state which of 4 figures flashed on a screen was clearest, all stimuli being below the recognition threshold. On each trial 1 of the 4 stimuli was a face and the others were similar but affiliation-neutral. Ss high in n Affiliation recognized faces significantly more frequently than those low in n Affiliation. Thus, the predicted relationship between motivation and the perceptual selection of motive-relevant stimuli was supported. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Independence and resistance to perceptual field forces.

36 "independents" and 36 "yielders" were selected from the extremes of a distribution of 143 Ss scored on an inventory measure of conformity. While looking at a Necker reversible cube Ss were instructed to keep the perspective in the "up" phase. At random intervals Ss recorded the actual phase perceived. The "independents" had fewer reversals of perspective than the "yielders" (p     

Feature sampling in detection: Implications for the measurement of perceptual independence.

The article presents the feature sampling signal detection (FS-SDT) model, an extension of the multivariate signal detection (SDT) model. The FS-SDT model assumes that, because of attentional shifts, different subsets of features are sampled for different presentations of the same multidimensional stimulus. Contrary to the SDT model, the FS-SDT model enables the estimation of pure perceptual effects that are uncontaminated by strategic attention shifts. The consideration of feature sampling in detection and identification opens a new perspective on the problem of measuring, respectively, the separability and integrality of stimulus dimensions. Disregarding feature sampling as a component process in detection and identification usually results in biased estimations of perceptual independence concepts relevant for judgments of whether stimulus dimensions are processed independently. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of double stimulation: Temporary inhibition of response.

This paper deals primarily with findings in the area of reaction time, with a lesser focus on dichotic listening studies and stereoscopic perception. The generality of a temporary inhibition of response (TIR) phenomenon, given double stimulation in close temporal contiguity, is posited. 3 alternatives are offered: an S-centered (information and/or "filter" theory), an O-centered (the "expectancy" position), and an R-centered (a competing-response position) explanation. The latter is suggested as most adequately dealing with the data, although the alternatives are not seen as mutually exclusive. A method for the training of prepotent responses is suggested, along with an associated line of research into the TIR phenomenon. (38 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The motivating effects of exteroceptive stimulation.

The effects of perceptual deficit in infancy on the dog are considered insofar as they bear on motivational and emotional problems. "The animal reared in isolation is a permanent screwball at maturity: motivationally, socially, intellectually abnormal." Dog-rearing experiments indicate that "dogs reared in isolation showed none of the physical debility and susceptibility to infection that Spitz reported." Dogs whose patterns of exteroceptive stimulation were restricted were markedly atypical in a number of performances. A finding based on "brainwashing" by Chinese communists in the Korean War is that: "Without physical pain, without drugs, the personality can be badly deformed simply by modifying the perceptual environment." In an experiment with sensory isolation for the human there were hallucinations, disturbances in the selfpercept, impairment of intelligence test performance, changes in EEG, and marked visual disturbances on first emerging from isolation. "With the possible exception of the effects of propaganda, the changes were reversible, disappearing in a day or so." Making isolation more drastic produces motivational and emotional disturbances much more quickly. "Clearly man's motivation is a function of his exteroceptive stimulation." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence for response bias as a source of error variance in applied assessment.

After 100 years of discussion, response bias remains a controversial topic in psychological measurement. The use of bias indicators in applied assessment is predicated on the assumptions that (a) response bias suppresses or moderates the criterion-related validity of substantive psychological indicators and (b) bias indicators are capable of detecting the presence of response bias. To test these assumptions, we reviewed literature comprising investigations in which bias indicators were evaluated as suppressors or moderators of the validity of other indicators. This review yielded only 41 studies across the contexts of personality assessment, workplace variables, emotional disorders, eligibility for disability, and forensic populations. In the first two contexts, there were enough studies to conclude that support for the use of bias indicators was weak. Evidence suggesting that random or careless responding may represent a biasing influence was noted, but this conclusion was based on a small set of studies. Several possible causes for failure to support the overall hypothesis were suggested, including poor validity of bias indicators, the extreme base rate of bias, and the adequacy of the criteria. In the other settings, the yield was too small to afford viable conclusions. Although the absence of a consensus could be used to justify continued use of bias indicators in such settings, false positives have their costs, including wasted effort and adverse impact. Despite many years of research, a sufficient justification for the use of bias indicators in applied settings remains elusive. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The reliability of a response measure: Differential recognition-threshold scores.

In studies of perceptual defense where the dependent variable has been differential thresholds for emotionally toned vs. neutral stimulus materials, little attention has been given to the internal consistency of such measures. A study is reported which suggests that the internal consistency may be very low. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predictability of perceptual defense behavior.

As part of a larger study, 140 Ss were given a sentence-completion task with stems which were specially selected to elicit sex and hostility content. The sentence completions were judged by four clinical psychologists for indication of conflict and for the particular type of defense, repressive or sensitizing, used by the subject. When Ss were selected as using repressive or sensitizing mechanisms in particular conflict areas, it was found, as predicted, that sensitizers were significantly faster in perceiving conflict words than were repressers. 20 references. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Converging operations for perceptual defense.

Discusses some recent experimental attempts to provide converging operations for a concept of perceptual defense. For present purposes, perceptual defense is defined as a relative failure of perception per se due to the emotional character of the stimulus. Experiments are evaluated and discussed mainly in terms of their ability to eliminate as an explanation the response-bias hypothesis for differential accuracy between neutral and emotional words. In addition, following Blum, a stimulus-effect hypothesis is described and applied; all the experiments discussed require, if differences in accuracy of recognition are to be attributed to perceptual variation, converging operations to eliminate this hypothesis. It is argued as well that the search for converging operations for perceptual defense has implications for methodology in other areas of perception. (20 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)