Conditioned stimulus intensity and acquired alimentary aversions in the rat.

Studied 188 male Long-Evans hooded rats. Three groups were made ill following the ingestion of 1 of 3 intensities of salt taste and then were tested several times for aversions to each of the 3 intensities after this single training trial, yielding a 3 by 3 factorial design. ANOVA from this design revealed a significant positive effect on degree of aversion of both training intensity and testing intensity, and a significant interaction between these 2 intensity variables. The interaction was further analyzed into a component implying a multiplicative relationship between training intensity and testing intensity in determining strength of aversion, and into a component interpreted as indicating a decrement of the aversion when tested with intensities other than the training intensity. Results suggest a lawfulness of stimulus–response relationships comparable to those found in studies employing more typical conditioned responses. Previous conditioning studies, however, have demonstrated only the effect of conditioned stimulus intensity on "performance" (testing intensity effect), not on "learning" (training intensity effect). (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Variations in intensity, interstimulus interval, and interval between preconditioning CS exposures and conditioning with rats.

Investigated the relationship between preconditioning exposure to a stimulus later employed in conditioning as a CS and suppression of a licking response in the presence of that stimulus, in 2 experiments with a total of 216 male albino Sprague-Dawley rats. In Exp. I, a direct relationship was found between intensity of preconditioning stimulus and magnitude of suppression reduction. There was also evidence for the effects of stimulus intensity during conditioning and the operation of generalization decrement when conditioning and test stimulus intensities were not the same. Exp. II showed that preconditioning CS exposure reduced suppression to the test CS on the 1st test trial, regardless of interval between preconditioning exposures or preexposure and conditioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exposure and affect: Overview and meta-analysis of research, 1968–1987.

A review and meta-analysis of methodological and subject variables influencing the exposure–affect relationship was performed on studies of the mere exposure effect published in the 20 years following R. B. Zajonc's (see record 1968-12019-001) seminal monograph. Stimulus type, stimulus complexity, presentation sequence, exposure duration, stimulus recognition, age of subject, delay between exposure and ratings, and maximum number of stimulus presentations all influence the magnitude of the exposure effect. Implications of these findings are discussed in the context of previous reviews of the literature on exposure effects and with respect to prevailing theoretical models of the exposure–affect relationship. Modifications of the 2-factor model of exposure effects that increase the heuristic value of the model are described. A possible evolutionary basis of the exposure effect is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stimulus intensity dynamism.

The literature on the relationship between conditioned stimulus intensity and conditioned response magnitude—generally known by its Hullian name of "stimulus intensity dynamism" (Hull, 1949)—is reviewed. In contrast to the agreement found in the Russian literature as to the reality of this phenomenon, the results of Western research have often been negative or inconclusive. Possible reasons for these failures to obtain positive results are discussed, including the use of data obtained under conditions of extinction, choice of the GSR as the conditioned response, use of a restricted range of stimulus intensities, and failure to ensure that S discriminates the conditioned stimulus from other background stimuli. Also discussed is Perkins' (1953) hypothesis that stimulus intensity dynamism is due to generalization of inhibition from an unreinforced zero-intensity stimulus. (2 p. ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of stimulus intensity on the lateralized readiness potential.

Information-processing models differ about whether stimulus intensity affects the speed of motor processes involved in response activation and execution. Previous studies of intensity are reviewed, but they are not decisive on this point because they have used indirect approaches requiring strong assumptions. Two experiments examined the effects of stimulus intensity on the lateralized readiness potential (LRP), a measure of hand-specific response activation. In Experiment 1, visual stimulus intensity influenced the time from stimulus onset to LRP onset but not the time from LRP onset to the keypress response. In Experiment 2, auditory stimulus intensity did not influence either of these time intervals, although it did influence the time from stimulus onset to the N100 and P300 components of the evoked potential. The results indicate that stimulus intensity does not influence the duration of motor processes in choice reaction time tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An analysis of blocking in odorant mixtures: An increase but not a decrease in intensity of reinforcement produces unblocking.

Studies of blocking between elements from the same stimulus modality elucidate how animals analyze such mixtures. Proboscis-extension conditioning of honey bees was used to examine the role of unconditioned stimulus (UCS) intensity in blocking in odorant mixtures. Several predictions from theoretical accounts of blocking were tested. One-trial blocking was found when Ss were pretrained with a high but not a low UCS concentration. Increases in UCS intensity produced unblocking, but decreases did not. Furthermore, an equivalent level of unblocking was observed when the increase occurred on the 1st or 2nd mixture-phase trials. These results are consistent with studies of vertebrates in which UCS intensity is altered to produce unblocking. Extension of these studies to include variation in other UCS parameters and to intramodal blocking in vertebrates will be necessary to determine whether this correspondence to vertebrate blocking is robust. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Verbal communication level and anxiety in psychotherapeutic groups.

Hypothesized a linear relationship in psychotherapeutic groups between verbal behavior (defined as the level of communication) and experienced anxiety. However, trained judges' ratings of 6 2-hr tape-recorded group sessions revealed a curvilinear relationship between these 2 variables. The maximum level of anxiety occurred on the border of communication of private and unknown-self material. When communication increased above these levels, the anxiety tended to decrease. This is explained in terms of S. Epstein's 1967 finding that bodily arousal and experienced anxiety increase progressively to a certain stimulus intensity level. Then, with still increasing stimulus intensity, the bodily arousal and physiological anxiety will continue to increase while the experienced anxiety will tend to decrease because of the intervention of certain inhibitory mechanisms. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of stimulus duration and intensity on simple reaction time and response force.

Previous research indicates that response force increases with stimulus intensity in simple reaction time (SRT) tasks. This result contradicts the common view that the perceptual system activates the motor system via a punctate go signal of fixed size. An elaborated view assumes that the size of the go signal depends on stimulus intensity so that more intense stimuli yield more forceful responses. In order to examine the latter hypothesis, the present experiments manipulated stimulus duration as well as intensity. Response force increased with duration even beyond a critical value of about 60 ms at which stimulus duration no longer affected SRT. In addition, increasing the duration of a stimulus also increased the duration of force output. These findings argue against models with punctate transmission of activation to the motor system. Certain continuous models and variable output models with prolonged go signals provide acceptable accounts of these effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implicit misattribution as a mechanism underlying evaluative conditioning.

Evaluative conditioning (EC) refers to the formation or change of an attitude toward an object, following that object’s pairing with positively or negatively valenced stimuli. The authors provide evidence that EC can occur through an implicit misattribution mechanism in which an evaluative response evoked by a valenced stimulus is incorrectly and implicitly attributed to another stimulus, forming or changing an attitude toward this other stimulus. In 5 studies, the authors measured or manipulated variables related to the potential for the misattribution of an evaluation, or source confusability. Greater EC was observed when participants’ eye gaze shifted frequently between a valenced and a neutral stimulus (Studies 1 & 2), when the 2 stimuli appeared in close spatial proximity (Study 3), and when the neutral stimulus was made more perceptually salient than was the valenced stimulus, due to the larger size of the neutral stimulus (Study 4). In other words, conditions conducive to source confusability increased EC. Study 5 provided evidence for multiple mechanisms of EC by comparing the effects of mildly evocative valenced stimuli (those evoking responses that might more easily be misattributed to another object) with more strongly evocative stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychosocial factors, immunologic mediation, and human susceptibility to infectious diseases: How much do we know?

Recent evidence from animal models of stress suggests that stress can impair immunologic competence, rendering the host more vulnerable to infection and neoplasm. The present authors review studies on the relationship between psychosocial factors and human immunologic functioning, focusing on studies bearing on the relationship of psychosocial factors to altered susceptibility to infectious diseases and those bearing on the relationship of such factors to specific aspects of the human immune response. Findings indicate that a variety of psychosocial variables, disease states, and aspects of both humoral and cell-mediated immune responses have been investigated, and evidence favors the view that psychosocial variables may play a role in modulating the human immune response. More research is needed before it can be definitively concluded that the relationship between stress and human susceptibility to infectious diseases is a psychoimmunologic nexus. Relationships between the endocrine and immune systems are also discussed. (5 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of context salience on heart rate orienting and habituation in preweanling and periadolescent rats.

Previous research indicates that target learning is facilitated in the presence of strong extraneous sensory cues (e.g., salient contextual cues) in infant, but not adult, rats (McKinzie & Spear, 1995). The present study assessed whether such facilitation of conditioning is due to age-related differences in the effect of a salient context on processing of the conditioned stimulus (tone in this case). Preweanling and periadolescent rats were presented with a tone in either the presence (salient context) or absence (plain context) of a potent odorant. Magnitude of the heart rate orienting response to the target stimulus and its subsequent rate of habituation served as dependent variables. The results revealed that preweanling, but not periadolescent, rats showed greater cardiac orienting to the auditory stimulus in the salient than in the plain context. The results suggest that a salient context may influence stimulus processing by increasing the perceived salience and, perhaps in terms of perceived intensity, of the target stimulus. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The relation of response length to the Holtzman Inkblot Technique.

2 studies are presented which explore the relationship between the mean number of words an S uses in his responses to inkblots and the score pattern he obtains. Significant relations between Response Length (RL) and Holtzman Inkblot Technique scores are demonstrated in samples of juvenile delinquents and college students. 1 experiment is described which indicates that RL is 1 of the factors which determines Movement scores. The role of RL as a variable mediating some of the observed relations between personality and situational variables and inkblot scores is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Unemployed individuals: Motives, job-search competencies, and job-search constraints as predictors of job seeking and reemployment.

This study investigated 3 broad classes of individual-differences variables (job-search motives, competencies, and constraints) as predictors of job-search intensity among 292 unemployed job seekers. Also assessed was the relationship between job-search intensity and reemployment success in a longitudinal context. Results show significant relationships between the predictors employment commitment, financial hardship, job-search self-efficacy, and motivation control and the outcome job-search intensity. Support was not found for a relationship between perceived job-search constraints and job-search intensity. Motivation control was highlighted as the only lagged predictor of job-search intensity over time for those who were continuously unemployed. Job-search intensity predicted Time 2 reemployment status for the sample as a whole, but not reemployment quality for those who found jobs over the study's duration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cross-modal equivalence in early infancy: Auditory–visual intensity matching.

To examine the hypothesis that young infants ignore differences between lights and sounds and instead respond to auditory and visual stimuli as more or less similar depending on their intensity, a cardiac habituation/dishabituation method with a test for stimulus generalization was employed. In 2 experiments, a total of 40 3-wk-old Ss were repeatedly presented with white-light followed by white-noise stimuli of different intensities. A U-shaped relationship between magnitude of cardiac response (CR) and loudness was found. In view of previous findings that without prior visual stimulation a monotonic increase in CR to the same range of auditory stimuli results, this finding of a significant quadratic relationship with loudness suggests that Ss were responding to the auditory stimuli in terms of their similarity to the previously presented visual stimulus. A separate group of 14 infants presented with a more intense visual stimulus exhibited a shift in the intensity at which a minimal CR occurred. Results of a study with 31 adults did not show any systematic relationship between CR and loudness, indicating that unlike infants, adults do not spontaneously make cross-modal matches of intensity. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The relationship between attentional blink and psychological refractory period.

This study examined the relationship between attentional blink (AB) and psychological refractory period (PRP) using a conventional AB procedure combined with a requirement of speeded responses to the second target (T2). Experiments 1 and 2 showed that, as with PRP, memory retrieval of targets is not a necessary condition for the occurrence of AB in terms of accuracy and that AB occurred in the speed data. Experiment 3 further indicated that the PRP-like speed data were not due to the first target serving as a warning signal that triggered preparation of responses to T2. Experiment 4 manipulated T2 stimulus intensity to be normal or low. Results showed an underadditive interaction between stimulus intensity and lag position in the speed data, whereas an overadditive interaction was found in the accuracy data, suggesting 2 sources of interference leading to AB: the single-channel bottleneck and resource-limited visual-processing capacity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrophysiological evidence for temporal overlap among contingent mental processes.

A series of studies assessed perceptual-motor transmission of stimulus information by measuring lateralization of movement-related brain potentials in a choice reaction task with no-go trials. When stimuli varied in shape and size, lateralized potentials on no-go trials suggested that easily recognized shape information was used to initiate motor preparation and that this preparation was aborted when size analysis signified that the response should be withheld. This indicates that movement preparation can begin once partial perceptual information about a stimulus becomes available, contrary to an assumption of fully discrete models of information processing. By contrast, when stimuli varied only in size, no evidence for preliminary response preparation was obtained, contrary to an assumption of fully continuous models but consistent with asynchronous discrete coding models (J. Miller, 1982, 1988). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Habituation model of systematic desensitization.

Discusses the relevance of habituation as a model for response decrement in desensitization. A discussion of the relationship between habituation and extinction leads to the view that there are no sound reasons for explaining desensitization as an extinction rather than as a habituation phenomenon. The maximal habituation theory of desensitization proposed by M. H. Lader and A. M. Mathews (1968) is discussed and relevant evidence reviewed. Finally, a revised habituation theory of desensitization, based on the dual-process theory of habituation, is elaborated, and the role in desensitization of relaxation, stimulus intensity, stimulus lengths, and interstimulus interval lengths are discussed in the context of this theory. It is suggested that relaxation and an incremental stimulus hierarchy may reduce sensitization rather than facilitate habituation. (60 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Latency-probability functions as bases for evaluating competing accounts of the sensory decision process.

Analyzes certain properties in 4 different models of the sensory decision process and suggests that models with those properties cannot legitimately be evaluated on the basis of differing latency–probability functions. This strategy of evaluation has been recommended and adopted in a number of studies, the only criticism having come from S. Koppell (see record 1976-29070-001), whose criticism was directed more at a particular comparison than at the strategy as a whole. The present analysis indicates that the overall strategy defaults (a) because the theoretical variables that in each model determine response probability underdetermine response latency, and (b) because there is a lack of suitably powerful measurement of those variables that affect the former but not the latter. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychophysiology of P300.

The P300 component of the human average evoked potential has been associated with a host of stimulus and S variables, such as information delivery and stimulus salience. P300 is emitted by the brain in response to either attended events that are surprising or to unattended events that produce orienting. P300 does not appear to be a real-time index of signal (target) selection, since attended low-probability nonsignals also result in P300 and its latency is too long. P300 further appears to be independent of response selection; its latency therefore may or may not correlate with RT, depending on the experimental context. P300 latency does appear to index stimulus evaluation time in that it is not emitted until the stimulus has been cognitively evaluated. P300 amplitude appears sensitive to manipulations of perceptual limited capacity but not sensitive to manipulations of motor limited capacity. It has been proposed that P300's functional role in human information processing is the updating of neurocognitive models concerning future events, although other functions have also been proposed. (5 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Externalized self-perceptions, self-silencing, and the prediction of eating pathology.

Gender role socialization models posit that the greater prevalence of problematic eating patterns in girls and women is partly due to a socialization process whereby women are taught to view themselves in relation to others, to avoid confrontation, and to conform to societal ideals regarding thinness. This study explored the relationship of these factors to eating pathology. 236 undergraduate women (aged 18-24 years) completed measures related to body image (body dissatisfaction, weight status, perceived importance of shape and weight), relational variables shaped by differential gender role socialization (externalized self-perceptions, self-silencing behaviors and attitudes), and disturbed eating cognitions and behaviors. Perceived importance of shape and weight and externalized self-perceptions were found to predict maladaptive eating-related cognitions, and self-silencing predicted bulimic behaviors when body-related variables were controlled. Thus, it appears that externalized self-perceptions and self-silencing are indeed related to eating disturbances, although further research is needed to demonstrate a causal role for these variables in the development of eating disorders. (PsycINFO Database Record (c) 2010 APA, all rights reserved)