Human Ss Research Articles

Acculturation as a Factor in TraditionalVersusAtraditional two-Trial Learning Sets

Summary The present study hypothesized that acculturation of human Ss affects learning performance of such Ss, but doesn't affect that of infrahuman primates. If this is so, then differences as a function of age should be manifest in human Ss. Ss were 24 college students, aged 19; 24 parochial school students, aged 12; and 24 such students, aged 7. Sex representation was equal in each group. The Ss, using the median test, showed a significant decrease in errors as a function of age on two-trial response perseveration learning set to reinforced cues combined with two-trial response shift learning set to reinforced cues (x = 6.0000, df = 2, p & .05). No significant differences as a function of age were manifest on two-trial response perseveration learning set to nonreinforced cues combined with two-trial response shift learning set to nonreinforced cues (X = 4.6664, df = 2, p > :05). It was concluded that such findings may be attributed to acculturation.

Hemispheric factors and scanning dynamics in the processing of briefly exposed stimuli by human subjects: bibliography.

268 journal articles on hemispheric factors and scanning dynamics involved in the encoding of briefly exposed stimuli by human Ss are grouped into the categories of experiments with normal Ss, experiments with various types of patients, and review and theoretical articles.

Interhemispheric transfer of figural information in right- and non-right-handed subjects

The capacity of normal human Ss to match abstract shapes across the cerebral hemispheres was studied as a function of exposure duration. A general right hemisphere superiority was found, and in the conditions where one stimulus was presented to each hemisphere, the order of stimuli (to the right or left hemisphere first) did not affect performance. Decreasing stimulus exposure was shown to interact with hemisphere differences. An overall superiority of non-right-handed subjects was found, although their pattern of results did not differ from right-handed Ss, and it is argued that this supports the hypothesis that the cerebral organisation of the non-right-hander is more diffuse in its general organisational structure.

The paradoxical effect of brief CS exposure on analogue phobic subjects

In formulating a theory of anxiety incubation, Eysenck (1968) has cited evidence from infrahuman and human aversive conditioning studies to suggest that nonreinforced CS exposure may, under certain conditions, lead to increases in fear. In several studies, repeated or prolonged exposure to symbolic representations of feared stimuli has been found to elicit unexpected increases in autonomic responses, whether these stimuli were visual (Borkovec and Glasgow, 1973), verbal descriptions (Boulougouris, Marks and Marset, 1971), or self-induced thoughts (Rankin et al., 1964; Bresnitz, 1967). While these studies support the existence of an incubation process, recent studies suggest that duration of CS exposure may be an important variable in producing this effect. Rohrbaugh and Riccio (1970) and Rohrbaugh, Riccio, and Arthur (1972) investigated the effect of varying the temporal parameters of extinction following Pavlovian fear conditioning and conditioned suppression, respectively. In both studies, short duration exposure to the CS subsequent to conditioning resulted in greater fear relative to zero or long exposure conditions. Furthermore, in support of an incubation effect, the latter study found increases in fear over post-conditioning base levels among brief exposure Ss. Miller and Levis (1971) using a procedure analogous to Rohrbaugh and Riccio (1970) obtained similar results with human Ss. Subjects who refused to touch a live snake were assigned either 0. 15, 30 or 45 min exposure to the snake. Consistent with analogue outcome research employing pre-posttest design. all groups showed greater approach scores on posttest. However, the approach of the 15 min exposure group was significantly less than that of the zero exposure group, while the 45 min condition did not differ from zero exposure. Miller and Levis (1971) suggested that the paradoxical enhancement of fear (Rohrbaugh and Riccio, 1970) exhibited by their brief exposure Ss relative to both zero and long exposure Ss was a function of the failure of redintegrated fear-eliciting cues to extinguish. In contrast, Staub (1968) has suggested that the reduced efficacy of brief exposure may be attributed to a failure to complete a cognitive re-evaluation of the probability of adverse consequences. The primary purpose of the present study was to replicate and extend the Miller and Levis study. Analogue phobic Ss were exposed to a snake for 0, 15 or 45 min. To assess whether fear enhancement suggested by Miller and Levis (1971) or fear re-evaluation offered by Staub (1968) might mitigate the paradoxical enhancement phenomenon, Ss in the brief (15 min) exposure condition were divided into three groups. During the 30 min subsequent to 15 min phobic stimulus exposure, Ss in one group were directed to write an essay concerning the most terrifying experience imaginable involving a snake. Ss in a second group were directed to identify and evaluate the logic of assumptions underlying their fear of snakes (similar to Meichenbaum, 1972). Ss in a control condition engaged in activities unrelated to fear or snakes. Of secondary interest was the relationship of subject characteristics to the occurrence of paradoxical enhancement. Eysenck has suggested that incubation is more likely to occur in Ss scoring high on anxiety/emotionality indices. Consequently, snake phobic Ss in each treatment group were divided on the basis of Mandler. Mandler, and Uviller's (1958) Autonomic Perception Questionnaire into high and low perceivers to represent high and low emotionality groups.

A classically conditionable skeletal response can be acquired with a discriminated punishment contingency

Human Ss were exposed to a discriminated punishment contingency with the aversive stimulus being an air puff to the cornea. In most Ss there was an increase in response probability (an eyelid reflex) across trials and an application of the two-phase model showed that the increases, though not great, were reliable. An analysis of the estimated parameter values showed that for only 5 of the 26 Ss did the pattern of parameter values conform to what would be expected on the basis of either two-factor or relative reinforcement theory. The results were, however, consistent with what might have been expected from giving Ss a low ratio intermittent reinforcement schedule in a more traditional classical conditioning arrangement.

Heightened Sexual Interest and Sleep Disturbance

The study demonstrates a behavioral effect of selective sleep disturbance in normal human Ss. Ten male Ss were selectively REM-deprived for two nights by awakening them at the onset of REM sleep. In addition, there were baseline and non-REM awakening conditions. Heightened sexual interest was defined by the number of film frames (using a Mackworth camera) in which Ss fixated on parts of the female figure in photographs. The largest mean difference in sexual interest was found between baseline and REM-deprivation. Both the non-REM awakenings and REM-sleep deprivation enhanced sexual interest. The failure to demonstrate a significant difference between REM-deprivation and non-REM awakenings may be due to the fact that Ss were REM-sleep-deprived in both conditions. It is suggested that REM-sleep loss may lead to increased selective attention and preoccupation with any cues which are usually interesting.

Effect of emotions on visual evoked potentials.

The effects of anxiety and anger on the visual evoked potentials generated by exposure to visual stimuli (circle or square as compared to blank card) did not for 80 human Ss modify the latencies or the amplitude of P1, P2, N1 and N2 peaks. Anxiety and anger modified, however, in a statistically significant manner P3 and the following waves. The P3 – N4 wave complex seemed to relate to cognitive processes. The results suggest that the effects of cognitive processes related to anxiety and rage differ, at least in part.

The effectiveness of visual and gustatory conditioned stimuli in human classical aversive conditioning with electric shock

Thirty-six undergraduate volunteers, divided into three equal groups, were given electric shock while sipping a colored, unflavored solution (Group I): a flavored, colorless solution (Group 2); or a colored, flavored solution (Group 3), in order to determine whether human Ss respond differentially to visual and gustatory cues when the UCS is aversive electric shock. Using a standard classical discrimination procedure, the CS + was blue water for Group 1, citric acid solution for Group 2, and blue citric acid solution for Group 3. For all groups the CS- was plain water, which was never paired with electric shock. The dependent variables were derived from Staats' A-R-D theory: attitudinal change (A) and a performance measure of sip-size taken during conditioning trials (D) both confirmed the hypothesis that taste can be an effective CS when the UCS is shock, in contrast to results typically obtained with rats where visual but not taste cues are effective with a shock UCS.

Transfer of Training on Location of a Fault: Effects of Trainer's Observation, Prompting, and Achievement Level

Four training conditions were investigated with human Ss differentiated according to high achievement and low achievement academic histories. Trainer's presence or absence was paired with conditions of trial and error and prompting in a complete factorial. It was hypothesized based on a Hull-Spence interpretation of social facilitation that trainer's presence with prompting during training would lead to superior transfer over conditions of trainer's absence and prompting, while the lowest transfer was expected with the combined condition of trainer's presence and trial and error. It was further assumed that high achievers would learn the task readily and be relatively unaffected by the four training conditions. On the transfer task for both fault-misses and response time trial and error for the low achievers was superior to prompting. Trainer's presence was insignificant, while achievement level was influential. The results suggested that active learning involving the task-activity of trial and error was more arousing than the social factor of the trainer's presence, particularly in view of the fact that the trainer lacked significant evaluative ability for the trainee- Ss in the laboratory setting.

Differential conditioning and contrast effects in humans

The present study investigated discrimination S+ contrast effects as a function of the magnitude of reward in S- while attempting to alleviate ceiling effect and decision time problems present in previous animal and human simultaneous contrast studies. In the study, three groups of human Ss recrived differential reward conditioning for accurately tracing numbered-nonnumbered star patterns, whereas a control group received only large reward in both discriminanda. The results replicated the findings of a previous animal study which also attempted to control for ceiling and decision time variables in that a positive S+ contrast effect was found. Also, the positive S+ contrast effect increased as the magnitude of reward in S- decreased. The results seem to support a perceptual analysis of contrast effects.

Human Responding on a Temporally Defined Schedule of Point-Loss Avoidance

Two experiments extended the investigation of temporally defined avoidance schedules to human Ss responding on a schedule of point-loss avoidance. Experiment I found that superimposition of a td-correlated added stimulus had no effect on response rate or distribution, while response-cost contingency of 1 point per response produced a decrease in response rate and an increase in failures to avoid 10-point losses. Discriminated responding was produced only by combination of the added stimulus and the response-cost contingency. Experiment II found that a high-effort response mani-pulandum was functionally equivalent to the response-cost contingency in behavioral effects. The results are consistent with Weiner’s explanation for apparent insensitivity of human responding to nonresponse contingency events and support the generic use of the term “cost” in exchange theories.

Corners, receptive fields, and visually evoked cortical potentials

Alternating stimuli with herringbone patterns were used to obtain visually evoked cortical potentials (VECPs) from three human Ss. Two sets of stimulus patterns were used, one with sharp corners and one with the corners rounded off. Each set ranged in angularity from 180 to 45 deg in 45-deg steps. Results showed that: (a)VECP response amplitude was greatest for the 90-deg-corner pattern, (b) response amplitude was greater for the 45-deg-corner pattern than for the 135-deg-corner pattern, and (c) cornered and rounded patterns evoked responses of greater amplitude than those evoked by the straight (180-deg) patterns. Also, the peak latency of responses to cornered patterns was shorter than that of responses to rounded and straight patterns.

Trace and delay differential classical eyelid conditioning in human adults

Experiment I compared trace and delay differential classical eyelid conditioning in adult human Ss at three ISIs (800, 1,100, 1,400 msec). Pure-tone CSs were used, with the trace CS having a duration of 50 msec and the delay CS terminating with the UCS. There was no significant trace deficit at any ISI, which indicates that the recognition or identification response involved in the differential classical conditioning of adult humans is maintained during long trace-stimulus offset to UCS-onset intervals. Experiment II compared trace and delay differential conditioning at 300-, 500-, and 800-msec ISIs. Again there was no trace conditioning deficit. Differential conditioning was significantly poorer at a 500- than at an 800-msec ISI, and no differential conditioning was found with a 300-msec ISI. The level of conditioning of the 300-msec group was much below that of the other groups and that expected for single-cue conditioning at the same ISI.

Human sensory dominance

Human Ss matched an auditory and a visual stimulus for subjective magnitude. Then each stimulus was used as a cue in a reaction time task. On occasions when both stimuli were presented simultaneously, Ss’ responding was seen to be dominated by the visual stimulus. Of further interest was the finding that on some occasions of simultaneous light-tone presentation Ss were unaware that the tone had been presented. This apparent prepotency of the visual over the auditory stimulus was seen to persist across a variety of experimental conditions, which included giving Ss verbal instructions to respond to the tone when both stimuli were presented simultaneously.

Voluntary Control of Heart Rate During Anxiety and Oxygen Deprivation

In Experiment I human Ss were biofeedback trained to accelerate and decelerate their heart rate (HR) to high and low frequency tones. An anxiety response of an acceleration in HR was then classically conditioned to a sequence of flashing lights paired with shock. During later testing Ss were still able to change their HR voluntarily to the tones when the flashing lights were presented. In Exp. II the bradycardia reflex, which involves a deceleration in HR, was found to vary as a function of oxygen deprivation, stimulation of the nasal passages with water, and S’s physical condition. In Exp. III a well-trained biofeedback S showed significant voluntary HR changes to the tones during bradycardia when his face was under water. Theoretical and clinical implications of biofeedback training in counteracting anxiety and psychological stress are discussed.

Campylobacter fetus Subspecies jejuni (Vibrio fetus) from Commercially Processed Poultry

Three isolates of the human and animal pathogen Campylobacter fetus ss. jejuni (Vibrio fetus) were obtained from 165 poultry meat samples purchased from local retail stores.

Human DRL performance, collateral behavior, and verbalization of the reinforcement contingency

Adult human Ss, reinforced for keypressing on a DRL 5-sec schedule of reinforcement, regularly verbalized hypotheses about the behavioral requirements necessary for obtaining reinforcement. High frequencies of overt collateral behavior accompanied response-based hypotheses and low or absent rates of overt collateral behavior accompanied time-based hypotheses. The findings support the conclusion that overt collateral responding can be functionally equivalent to mediative counting during temporally spaced responding.

Dual payoff band control of reaction time

The location of a S’s simple reaction time (RT) distribution can be controlled by differential reinforcement of RTs that fall within specified temporal limits called a payoff band. Both humans and monkeys can gradually shift the location of a single RT distribution over hundreds of milliseconds in accord with changing payoff band requirements. This study establishes that trained human Ss can also accurately shift theft response latencies back and forth between two different RT distributions when the payoff band is changed from trial to trial. On each trial, the color of the warning stimulus indicated which of two payoff bands would be in effect when the S reacted to a light flashed 1,500 msec later. The RT distributions produced under the condition of random trial-to-trial switching between two payoff bands were the same as the low-variability RT distributions produced when only one payoff band was in effect over a long series of trials.

GREATER REPETITION OF ERRORS UNDER PERFORMANCE COMPARED TO OBSERVATION IN MULTIPLE-CHOICE HUMAN LEARNING

This experiment was designed to determine whether human Ss repeat performance errors ( S makes his own response) more frequently than observation errors ( S watches the response of his partner) with immediate knowledge of results supplied in both conditions. Increased repetition of errors by performers in multiple-choice learning has been reported by Marx and Witter ( 1972 ). Method.Two groups of Ss, one of 13 women and the other of 14 men, were formed from students in an introductory psychology course, serving to satisfy course requirements. Each group was run in three sessions, 1 wk. aparL with different stimulus materials; al l stimuli were in the form of slides projected on a screen. In Session 1 were used 40 black-and-white facial photographs (20 of famous men, 20 of female models); in Session 2 color slides showed scenes from various locations around the world (14 categorized as urban, 14 as rural, 2 mixed); in Session 3 slides depicted 30 hand-drawn facial features (half male, half female). In each session Ss always performed on the same half of the stimuli and always observed on the other half; they worked in pairs and reversed roles after the first half of the stimuli were shown. Knowledge of results was supplied by means of a stylus-template device, the Rapid Rater, which allowed four possible answers and was operated by the performing S. The apparatus and general procedure are described in more detail in the previous report (Marx & Witter, 1972). Each slide was shown to the group for 5 sec. During this period the performer selected one of the four response alternatives (one of which had been arbitrarily selected as correct) and received knowledge of r,esults, which was also received by the observing S of the pair. The interstimulus interval was approximately 1 sec. Each training trial consisted of a single run through all of the stimuli, with each S alternately performing and observing. It was followed

Response variability for humans receiving continuous, intermittent, or no positive experimenter feedback

Undergraduates made an “x” on a series of blank sheets of paper in a study designated as an “acquisition of a manual skill.” Each mark was designated as “correct” or “incorrect” by the E, but according to a pre-fixed order rather than according to characteristics of the response. Variability in location of the mark on the page was lowest during trials in which each mark was “correct,” intermediate when an average of every third mark was “correct,” and highest when no marks were “correct.” Increased variability during these latter two conditions is attributable to trials following marks which were “incorrect.” Evidence demonstrating control of response variability for human Ss by the schedule of E feedback is thus provided.