The effect of aversive stimuli on reaction time in schizophrenia.

"… the experiment was to assess the motivational role of aversive stimuli in modifying the performance of normal and… schizophrenic… males… [on] a visual reaction time task… . During… [one] series Ss responded under… experimental conditions… [part of which] involved the use of intense noise as an aversive stimulus. None of the experimental conditions appreciably altered the performance of normal Ss. However, schizophrenic Ss performing under… [conditions involving noise] displayed greater improvement than control Ss." 22 refs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Expectancy, alcohol, and sex guilt as determinants of interest in and reaction to sexual stimuli.

Selected 72 male undergraduate social drinkers from high, moderate, and low scorers on the Sex Guilt subscale of the Mosher Forced-Choice Guilt Scale. Ss were assigned to 1 of 4 conditions in a balanced-placebo design utilized to control for psychological as well as physiological factors determining the effects of drinking on behavior. After consuming beverages, Ss viewed and evaluated photographic slides of erotic content and then reported on their sexual arousal. The time Ss spent viewing each slide was unobtrusively recorded. Overall, greater sexual arousal was indicated by Ss who thought they had received alcoholic beverages, regardless of actual drink content. In all conditions except the high sex guilt/expect tonic groups, viewing times increased as a positive linear function of pornography ratings of the slides. Results demonstrate that psychological aspects of individual differences can mediate expectancy effects in research on alcohol and social behavior. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predisposition to fantasy and situational variations as determinants of attention in reaction time tasks.

Predicted the effects of procedural changes and embellished directions on performance in a RT task on the basis of 200 undergraduates' predisposition toward fantasy activity. Ss who had given more Human Movement (M) responses to an inkblot test were found to be more responsive than Ss who had given less M responses to changes in procedures and directions which altered the interest value of the task. However, this effect was primarily found for the female sample. Interpretations regarding the likelihood of task-relevant and task-irrelevant cognitive activity as mediators of the obtained changes in performance and cautions regarding sex differences in attention and fantasy processes are offered. (23 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simple reaction time to cutaneous temperature stimuli.

Describes an apparatus that permits the measurement of simple RT to temperatures applied to the skin. 3 above-normal temperatures and 3 below-normal skin temperatures were used. The RT to touch was also obtained. Ss were 6 male and 6 female undergraduates. RT to cold was significantly faster at each temperature than RT to warm. The relevance of these results to contemporary theory of thermal sensitivity is discussed. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychophysically principled models of visual simple reaction time.

Visual psychophysics has shown that the perceptual representation of a stimulus has complex time-varying properties that depend on the response characteristics of the channel on which it is encoded. A fundamental expression of these properties is the distinction between sustained and transient processing channels. A theoretical and mathematical framework is introduced that allows such properties to be incorporated into fully stochastic models of simple reaction time (RT). These models, the multichannel leaky stochastic integrators, combine a linear filter model of stimulus encoding with an accumulative decision process and yield a stimulus representation described by a time-inhomogeneous Ornstein-Uhlenbeck diffusion process. Methods for obtaining RT distributions for these models are described, together with comparative fits to luminance-increment data obtained under conditions of channel pooling and channel independence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of irregular preparatory intervals on reaction time in schizophrenia.

2 experiments attempted to (a) confirm previous observations that the slope of the negative relationship between reaction time (RT) and the length of the preparatory interval (PI) was steeper in schizophrenic than in normal Ss, and (b) investigate the effects of the PI on one trial on RT to the subsequent trial (PPI). The results show that the curves relating the PI with RT are significantly steeper for the patients even when differences in "baseline" RT level are controlled. Also, the detrimental effects of long PPIs are much greater for the schizophrenics. The data suggest that instead of establishing a generalized preparatory set, the schizophrenic Ss simplify the task by basing their pattern of preparation largely on the just preceding trial. (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Head position and spinal position as determinants of perceived emotional state

A sample of 60 first-year psychology students judged the emotional state of 21 drawn figures and completed the Adjective Checklist and a mood questionnaire. The judgments were affected by the interaction between head position and spinal position of the figure. Each figure was associated with a unique pattern of emotions, and the judgments given were not influenced by the subjects' own emotional state.     

Temporal lobe epilepsy and schizophrenia: Comparison of reaction time deficits.

Current theory suggests that temporal–limbic dysfunction is responsible for schizophrenic symtomatology. Such theory dovetails with many reports of a higher frequency of schizophreniform psychoses in temporal lobe epilepsy (TLE) than is found with other forms of seizure activity. To explore the possibility of a common neurological substrate for the 2 disorders, a variable foreperiod reaction-time task, on which early crossover has been found to be characteristic of many schizophrenics, was administered to 11 schizophrenics, 12 TLE patients, 9 generalized seizure patients, and 10 normal controls. Results show that only TLE and schizophrenic Ss showed an early crossover of regular and irregular preparatory interval gradients. Discussion focuses on the status of crossover as a marker variable, and relevant animal and human lesion literature is reviewed. (45 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cortical and subcortical visual evoked potential correlates of reaction time in monkeys.

Investigated the relationships between reaction time (RT) and evoked potentials in 3 monkeys ( Macaca nemestrina ) during the performance of a simultaneous brightness discrimination task. Evoked potentials from the lateral geniculate, medial and inferior pulvinar, midbrain reticular formation, hippocampus, and striate and prestriate cortex were recorded concurrently with RT in response to the discriminative stimuli. An early component of the geniculate response and a late positive wave in striate cortex were found to be related systematically to RT. These components were largest for short RTs and diminished progressively in amplitude as RT lengthened. The statistical significance of these relationships is supported by a detailed analysis of single trials. The increases in amplitude of evoked potentials associated with short RTs are attributed to increased arousal level and are discussed in terms of reticular formation modulation of central excitability levels. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Autonomic correlates of chronic schizophrenia: A reaction time paradigm.

Assessed basal, tonic, and 2 phasic measures of heart rate and skin conductance among 16 drug-free, chronic, process, nonparanoid schizophrenics, and 2 groups of control Ss (hospital staff and prison inmates). Of particular interest were changes in autonomic activity that attended manipulation of "go" signal intensity within a reaction time paradigm. Among control Ss, increased signal intensity produced increases in tonic levels and amplitude of anticipatory responding. Among schizophrenics, however, the reverse occurred: Increased signal intensity resulted in decreased tonic levels and inhibition of anticipatory responding. Schizophrenic responses occurred in the absence of basal level differences between groups. Results are interpreted as indicating the presence of a learned anticipatory set that serves to reduce the impact of stimulus intensity. This inhibitory set would also appear to reduce receptivity to the cue component of stimuli. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cardiac and visual responses to stimuli presented both foveally and peripherally as a function of moving stimuli.

Measured heart rate (HR) and visual fixation responses as indices of attention getting (AG) and attention holding (AH) in 17 15-wk-old infants. The stimulus situation was one in which a brief central stimulus was followed by either a brief peripheral stimulus (AG trials) or a prolonged peripheral stimulus (AH trials). The stimuli for both central and peripheral presentations were moving black and white bar patterns. The speed for the central stimulus was constant over trials and groups (at 6.6°/sec), whereas the peripheral stimuli were either 6.6 or 26°/sec. Results suggest that much of the observed HR change can be accounted for by the AG phase, whereas the AH phase was reflected in the time it took for the cardiac responses to return to prestimulus baseline values. Stimulus speed also affected both attention behaviors; the faster speed produced the greatest HR change. Latency of 1st fixation and duration of looking measures did not show any discrimination between stimuli of different speeds. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive controls of attention deployment as determinants of visual illusions.

This study represents a continuation of efforts to relate hypotheses drawn from psychoanalytic theory to psychological theory and, in particular, ego psychology to cognitive functioning. The capacity to deploy attention selectively was measured on 8 perceptual tasks, including such problems as Embedded figures, rod and frame, and various measures of illusion. Performance on all 8 tasks was intercorrelated and the matrix factor analyzed. The result was 3 factors, viz., a "field articulation factor" involving "individual consistencies in the capacity to achieve differential response to relevant vs, irrelevant cues," a "scanning factor," and a factor which represents "individual differences in proneness to satiation effects." The results are discussed from the pont of view of their contribution towards cognitive function and the individual's "cognitive style," and are related to several theoretical frames of reference. From Psyc Abstracts 36:01:3BD20G. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Irrelevant peripheral visual stimuli impair manual reaction times in Parkinson's disease

In three experiments, the effects of irrelevant visual information on the time to initiate and to complete a simple movement of the hand in response to a visual signal were studied in patients with a diagnosis of Parkinson's disease, and in age-matched normal controls. Subjects gazed at the centre of a TV monitor and were instructed to move their preferred hand from one metal plate to another as soon as a blue disc appeared in the centre of the screen. This control condition was compared with other conditions in which the surrounding area of the screen was simultaneously filled with fields of irrelevant discs, which in Experiment 1 were either stationary, or streamed out from or in towards the centre of the screen. Reaction times, but not movement times, were significantly slowed in the patients (but not the controls) by the irrelevant disc fields. When the irrelevant dots were continuously present (between as well as within trials--Experiment 2), they had no effect on RT. When they were present between trials, but turned off as the movement signal was turned on, RT was again slowed in patients. The results are discussed in relation to the akinesia ("freezing") experienced by some patients in confined spaces (such as doorways), and to possible abnormalities of visual cortical and striato-nigro-collicular activity.     

Common and distinctive features of verbal and pictorial stimuli as determinants of psychophysiological responsivity.

The present study focuses on the relation between stimulus features and psychophysiological responsivity by using a modified version of the information detection paradigm. Compound pictorial and verbal stimuli were used as the relevant stimuli that Ss were instructed to memorize. Skin conductance responses were measured during the subsequent presentation of a sequence of test stimuli. We hypothesized that the electrodermal responsivity to the critical stimulus would reflect the degree it matches the relevant one. The results indicated that when the critical stimulus was identical to the relevant stimulus, responsivity was maximal. Neutral stimuli produced minimal responsivity, and critical stimuli that only partially matched the relevant one produced intermediate levels of responsivity (in spite of the subjects' awareness of the differences between the critical and the relevant stimuli). Comparison of the geometric and contrast models for similarity showed that the pattern of responsivity violated the minimality and symmetry assumptions of the geometric model. The relation between cognitive processes and psychophysiological responsivity is discussed, as are implications for the application of the guilty knowledge technique for detecting information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Manual and saccadic reaction time with constant and variable preparatory intervals in schizophrenia.

Saccadic reaction time (RT) has been shown to be unimpaired in schizophrenia. Could this be due to its not requiring controlled information processing? The authors gave 49 schizophrenia patients and 34 controls manual and saccadic RT tasks with preparatory intervals of 1, 3, and 5 s given in regular and irregular sequences. If saccades require mainly automatic processes, they should not be affected by variations in the preparatory interval that are mediated by controlled processing. The manual task showed typical slower RT and larger preparatory interval effects in patients than in controls. Although the saccadic task showed significant effects of both the preparatory interval and the preparatory interval on the preceding trial similar in kind to those in manual RT, there were no group differences in these or in RT. The results are attributed to greater stimulus-response compatibility in the saccadic task, which puts fewer demands on working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The location of noisy visual stimuli.

Examined the results of experiments where Ss were required to detect the misalignment of 2 abutting dot clusters on a monitor screen. Thresholds varied with the square root of dot density and did not appear to be affected by changing the sampling strategy used to generate the random dot clusters. Comparison of the Ss' performance with that expected of 3 information processing strategies suggested that Ss accomplished the task by locating the edges of the dot clusters rather than by extracting measures of global scope or of central position. The efficiency with which edge information was extracted was approximately 50% for low-density stimuli and declined exponentially with increasing dot density. (French abstract) (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention and modality specific interference as determinants of short-term verbal and visual retention.

Conducted 2 experiments with a total of 210 undergraduates to investigate short-term retention of verbal and visual information as a function of interpolated activities, varying along the dimensions of attention and modality specific interference. Results show that retention losses due to competing attention demands were comparable in verbal and visual coding conditions, regardless of the modality of the interpolated activity. In addition, retention losses were larger when the same modality was involved in processing the memory and interpolated tasks. Results demonstrate a clear separation of short-term losses due to (a) attention diversion, and (b) modality specific interference, with attention diversion accounting for a larger part of total retention losses. It is proposed that the maintenance of information for short intervals relies on the availability of central attentional processes, with modality specific coding processes determining the most appropriate coding mode for a given stimulus situation. (French summary) (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal and content variations as determinants of infants' visual control of verbal stimulations.

20 93–119 day old infants were presented with utterances varying in content or temporal structure that were contingent on fixation on a visual target. Treatment A consisted of utterances of equal duration and continually varying content. Treatment B consisted of utterances of slightly variable duration (temporal runs) and continually varying content. Treatment C included utterances organized in temporal runs and was composed of partial content variations (content runs). For Group AB, each A trial alternated with a B trial 4 times. For Group AC, each A trial alternated with a C trial 4 times. Half of the Ss in each group received Treatment A as their 1st trial; half of the Ss in Group AB received Treatment B; and half of the Ss in Group AC received Treatment C as their 1st trial. Group AB Ss showed a longer total fixation time than those of Group AC, with a more homogeneous distribution of number of fixations across treatments. Mean length of fixations was longer for Treatment A than B in Group AB, whereas Group AC showed a longer mean length of fixation for Treatment C relative to Treatment A. Those with Treatment B or C as their 1st trial looked more frequently at the target, and their decrease in looking time over trials showed a linear trend, whereas Ss with Treatment A at first displayed irregular decreases. These differences between groups and presentation orders suggest that 3-mo-old infants are sensitive to differences in linguistic material. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Time allocated and time spent relative to time needed for learning as determinants of achievement.

171 Ss in Grades 4 and 5 who read at grade level were given 3 task presentations, each of which yielded a trials score (trials needed, trials spent, trials allocated) as well as a retention score. In addition to these scores, degree of learning or achievement scores were obtained. Degree of learning was the level of accuracy attained by the last learning trial of each task presentation. Achievement was set for 100% for the time-needed presentation; 91% of Ss reached this criterion. Degree of learning under the time-spent and time-allocated presentations varied from 30 to 100%. The trials-spent:trials-needed ratio scores were calculated for each S. Results show that spending and/or allocating insufficient learning time had a direct negative effect on achievement. Both degree of initial learning and 1-wk retention dropped significantly when Ss spent or were given fewer trials than needed to learn the experimental task. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sexual identity, physical attractiveness and seating position as determinants of influence in discussion groups.

Two experiments are reported which show the importance of sexual identity as a determinant of influence in heterosexual discussion groups. In one study a male confederate was more likely than a female to get an elegant solution to a problem accepted. In general, male subjects were more active and exerted more influence in the group than did females. In the second study the social context of the problems was changed to make them less male-oriented, but a female confederate was still largely unable to get the elegant solution accepted. The physical attractiveness of the confederate had no influence on her effectiveness. Male domination of the discussions continued as before. Finally, there was some indication that sitting at the head of a table in a discussion group makes a person a little more influential in the group. (PsycINFO Database Record (c) 2010 APA, all rights reserved)