AVOIDANCE CONDITIONING OE SKIN POTENTIAL RESPONSES

Avoidance of electric shock was used to manipulate skin potential changes elicited by a simple visual stimulus. Experimental and control Ss were matched on habituation trials and yoked for 40 acquisition and 10 extinction trials. During acquisition the avoidance Ss differentiated between stimulus and non-stimulus periods more reliably than the controls. During extinction the avoidance group produced significantly more criterion electrodermal responses, with greater magnitude of positive wave components, than the control group. Some of the problems of appropriate control procedures inherent in this design are examined in relation to these results.     

REM Sleep Interruption: Experimental Shortening of REM Period Duration

This experiment concerns itself with the extent to which psychological factors can influence normal sleep patterns. After 4 baseline nights of uninterrupted sleep, each of 4 Ss was awakened in the course of 2 nights during every REM period about 10 min following each REM onset. Ss, however, were not REM deprived. The interruption nights were followed by a recovery night of uninterrupted sleep. All nights were consecutive. The results show that during recovery nights all Ss continued to have significantly shorter than normal REM periods by going into NREM sleep at about the time they would have been awakened during the interruption nights. These shortened REM periods occurred even during early morning hours, when REM periods normally become longer. Arguments are advanced that this finding may best be explained in terms of a conditioned avoidance response.     

ABILITY OF ACTORS TO CONTROL THEIR GSRS AND EXPRESS EMOTIONS

Ability to control GSRs through the use of ideational stimulation was studied in 26 professional actors. During one 10-min period, “Respond,”Ss had to make as many GSRs as possible; during the other period, “Rest,”Ss were instructed to inhibit their GSRs. All Ss received continuous visual feedback of their responses during both periods. No relationship was found between ability to control GSRs and emotional expression as measured by the ratings of directors. However, as predicted, method actors performed at a significantly higher level than non-method actors. An additional finding was that those actors who normally experience sweating as their primary response to stress performed at a higher level than non-sweaters.     

The orienting response to brief auditory stimuli in preweanling and adult rats

The cardiac orienting response to brief auditory stimuli was measured in preweanling and adult rats. The eliciting stimulus varied in duration (2 or 10 s) and complexity (continuous or pulsing). Stimulus complexity affected response magnitude with the pulsing stimulus eliciting a larger response than the continuous stimulus. Stimulus duration affected response persistence but only when a pulsing stimulus was used. In contrast to recent research with stimuli of much longer duration, age did not significantly affect any aspect of the cardiac response to the novel auditory stimuli in the present study. These results are discussed in terms of (1) the effects of stimulus duration on the heart-rate component of the orienting response and (2) two-stage models of attention.© 1994 John Wiley & Sons, Inc.     

GALVANIC SKIN RESPONSE DURING AVOIDANCE LEARNING

Relations between galvanic skin response (GSR) and other variables during learning of a shock-avoidance task were observed. Ss operated a four-position switch as cued by visual stimuli: one always shocked, one never shocked, and two associated with switch positions which avoided the shock. Forty-eight Ss formed successive subgroups which exhibited: (1) progressively better avoidance learning with increased awareness instruction and (2) significantly decreased GSR when the correct avoidance had been learned. Analyses were made to differentiate autonomic responding due to reinforcement (i.e. number of shocks received) from that due to expectancy (anticipation of avoidance).     

Analysis of the effects of operant conditioning on cortical unit response patterns

Patterns of response to visual stimuli were studied in cells in cat visual cortex. Changes in these patterns were measured during an operant conditioning paradigm in which reinforcement (rewarding brain stimulation) was presented contingent upon the occurrence of a specific change in a cell's pattern of response. For half of the cells studied, frequency of reinforcement increased significantly during the conditioning procedure: in 26% of the cells, the increase was due to increased firing confined to the time segment specified by the contingency of reinforcement. Cells studied during a control procedure, in which reinforcement was delivered randomly, did not exhibit changes in response pattern. Statistical properties of each cell's preconditioning or baseline pattern of response, as reflected in peristimulus time histograms compiled on line, were analyzed. Modifiability of a cell's response pattern was significantly correlated with spontaneous discharge rate and also with the overall strength of the changes initially evoked in the cell's activity by the visual stimulus. Cells that exhibited specific conditioned changes had higher spontaneous rates and more complicated response patterns than cells that did not.     

To What Does the Terminal Orienting Response Respond?

Previous authors suggested that the electrodermal orienting response to stimulus onset (OR) reflects cognitive processes related to the content of a stimulus while responses to stimulus offset (TOR) reflect processes related to stimulus duration. Experiment 1 tested the hypothesis that the OR and TOR are special cases of Ss responding to whatever part of the stimulus contains information necessary to make the requested judgment. The results clearly supported this alternative hypothesis. The Ss responded to stimulus onset when asked to judge the pitch (content) of a constant tone and to stimulus offset when asked to judge the terminal pitch of a varying tone. They responded to both the onset and offset of a stimulus when asked to compare the onset and offset pitch and when asked to judge stimulus duration. Experiment 2 partially replicated Experiment 1 in an attempt to assess the OR-TOR phenomenon in a second sensory modality (vision) and with a second dependent measure. The patterns of both electrodermal and heart rate responses were similar to those of Experiment 1 and to those observed by other authors.     

Race Differences and Experimenter Race Effect in Galvanic Skin Response

The present study was designed to ascertain whether racial differences exist in the several components of the skin resistance response and to assess the importance of the role of the experimenter's race in determining the subject's responsiveness. Basal measures, GSR magnitude, and spontaneous GSR activity of 12 Negro and 12 Caucasian Ss were recorded by 2 Negro and 2 Caucasian experimental assistants matched for age, physical stature, and dress. Following a 15 min resting phase, all Ss received 14 1-sec bursts of 75 dB white noise. Variable stimulus intervals were employed. Significant subject-race effects, but no experimenter-race effects, were found for base level measures. Negro Ss evidenced significantly higher basal resistance levels. Conversely, experimenter-race effects, but no subject-race effects, were apparent in the GSR magnitude data. White Ss showed a significantly slower rate of response magnitude decrease over trials when paired with black Es. A significant decrease in spontaneous activity over time was observed for all Ss.     

AVERAGE EVOKED RESPONSE AND VERBAL CORRELATES OF UNCONSCIOUS MENTAL PROCESSES

Two methods for identifying visual average evoked response components—one based on sequence, the other on peak amplitude—resulted in significant discriminations between subliminal visual stimuli, thus supporting and extending previous findings dealing with the investigation of unconscious mental processes. In addition, verbal effects of a subliminal stimulus, detected by a free association procedure, were found, which correlated with different AER characteristics. Verbal effects which were conceptually and veridically related to the stimulus correlated with an AER amplitude component (90–260 msec post-stimulus), while homophonic, unveridical verbal effects were related to the incidence of alpha bursts approximately 1 1/2 sec post-stimulus. Ss were 12 pairs of twins, ranging in age from 13–22. For older Ss (17–20) the sequence and peak amplitude components coincided; for younger Ss (12–16), they were different. Younger Ss also had significantly larger amplitudes than older Ss for both subliminal and supraliminal conditions (peak amplitude method) and for the supraliminal condition (sequence method).     

The Effect of Predictability on Evoked Response Enhancement in Intramodal Selective Attention

We investigated the relationship between the attention enhancement of the visual average evoked response (AER) and the S's ability to predict the presentation of the attended stimulus. Twelve students were presented with sequences of two distinct visual stimuli while DC EEG and electro-oculogram (EOG) were simultaneously recorded. Stimuli were either regularly alternated (predictable) or randomly intermixed (nonpredictable). Verbal instructions directed S's attention and push button response to either one or both of the two stimuli. Interstimulus interval was held constant to permit computer averaging of the AER and the contingent negative variation. Selective attention enhanced the late positive component of the AER equally in the two conditions of predictability. Thus, it seems that the AER enhancement with intramodal selective attention does not depend on the S's ability to predict the presentation of the attended stimulus or to differentially arouse prior to its presentation. In the high predictability condition, the baseline EEG potential fluctuated with attention such that the AERs to the attended stimuli were negative relative to those to the ignored stimuli.     

Human eye movement response to z-axis linear acceleration: the effect of varying the phase relationships between visual and vestibular inputs

We investigated the effect of systematically varying the phase relationship between 0.5-Hz sinusoidal z-axis optokinetic (OKN) and linear acceleration stimuli upon the resulting vertical eye movement responses of five humans. Subjects lay supine on a linear sled which accelerated them sinusoidally along their z-axis at 0.4 g peak acceleration (peak velocity 1.25 m/s). A high-contrast, striped z-axis OKN stimulus moving sinusoidally at 0.5 Hz, 70°/s peak velocity was presented either concurrently or with the acceleration stimulus or alone. Subjects' vertical eye movements were recorded using scleral search coils. When stimuli were paired in the naturally occurring relationship (e.g., visual stripes moving upward paired with downward physical acceleration), the response was enhanced over the response to the visual stimulus presented alone. When the stimuli were opposed (e.g., visual stripes moving upward during upward physical acceleration, a combination that does not occur naturally), the response was not significantly different from the response to the visual stimulus presented alone. Enhancement was maximized when the velocities of the visual and motion stimuli were in their normal phase relationship, while the response took intermediate values for other phase relationships. The phase of the response depended upon the phase difference between the two inputs. We suggest that linear self-motion processing looks at agreement between the two stimuli — a sensory conflict model.     

Effects of Long Term Exposure to Tone Pulse Noise on Human Sleep

Electrophysiological and self-report data were obtained from 10 and 20 Ss, respectively, during 15 days of baseline, 30 days of 24-hr per day exposure to a 660 msec, 3.5K Hz tone pulse with a 22 sec interstimulus interval (10 days each at 80, 85, and 90 dB), and during a 10-day post-exposure period. A self-reported increase in difficulty falling asleep was not substantiated by objective sleep latency measures. Changes in total hours of sleep, number of awakenings, and percent time for sleep stages were of small magnitude and not consistently related to stimulus intensity. All 10 monitored Ss gave clear EEG and autonomic responses to the stimulus, with no evidence of response extinction over the 30-day exposure period. There was no change in average all-night heart rate. Total number of body movements during the night did not change. However, the movements that did occur, tended to be triggered by the stimulus, with most movements closely following the tone pulse. The youth and good health of the Ss, and the 24-hr per day exposure, favoring rapid adaptation to the stimulus, are suggested to account for the lack of disruption of sleep.     

Developmental constraints on the expression of behavioral and heart-rate orienting responses: I. The role of cardiosomatic coupling

The ontogeny of behavioral and heart-rate orienting responses to a novel olfactory stimulus was examined in three experiments. The results of Experiment 1 demonstrated that behavioral responses to the olfactory stimulus were observed as early as Day 1, although heart-rate deceleration in response to the stimulus was not observed until Day 9. In Experiment 2, bradycardia was observed in 6-day-old pups if stimulus-elicited motor activity was reduced with haloperidol. Thus, the developmental asynchrony in the expression of behavioral and heart-rate orienting responses was due, at least in part, to cardiosomatic coupling in the very young animal. The results of Experiment 3 demonstrated that although cardiosomatic coupling interferes with the expression of the heart-rate orienting response very early in development, it has increasingly less impact over the course of the preweaning period.     

Heart rate control under conditions of augmented sensory feedback

Five human Ss were presented with a high frequency tone on the emission of each short inter-heartbeat interval and a low frequency tone on the emission of each long inter-heartbeat interval. Under these conditions, all Ss learned within a short period of time to produce significantly lower heart rates in the presence of one visual stimulus than in the presence of another. On the basis of this finding, it is suggested that an important determinant of where a given response falls on the voluntary/involuntary continuum is the availability of specific feedback from the response in question.     

THE USE OF ELECTRO-OCULOGRAPHY FOR IDENTIFYING PHASES OF COGNITIVE PROCESS

The present investigators were partly concerned with possible uses of electro-oculography for studying the cognitive process in decision-making situations involving nonneutral visual stimuli. S was faced with receiving an electric shock if on critical trials he correctly reported (manually) the identity of the visual stimulus, or with escaping shock by incorrect reporting. Electrooculogram responses were ascertained to identify eye movements. The first study employed slit geometric figures as critical stimuli and nonslit figures as noncritical stimuli. The second study differed only in using blanks as critical and nonblanks (figures) as noncritical stimuli. The 80 males in the first study showed longer ocular latency, then greater ocular avoidance (narrower excursions) but longer stimulus viewing, then longer poststimulus viewing on critical compared to noncritical trials. The 25 males in the second study showed relatively greater ocular latency, then greater ocular avoidance and briefer stimulus viewing, then briefer poststimulus viewing on critical trials. Discrepancies between the two studies were discussed. The results clearly indicate the applicability of electrooculography for identifying phases of cognitive process.     

The impact of two different reinforcers on conditioned operant heart-rate acceleration and deceleration.

The effects of two types of reinforcers on operant heart-rate acceleration and deceleration conditioning were examined over a number of sessions. The initial use of monetary reinforcement facilitated discriminative pre-trial to trial heart-rate acceleration during sessions utilizing both monetary reinforcement and visual feedback. The initial use of visual feedback did not produce such discriminative control, but the subsequent use of monetary reinforcement resulted in increases in pre-trial and trial heart rate over sessions. No effects due to type of reinforcement were noted for heart-rate deceleration. Increases and decreases in cardiovascular functioning were imposed upon a background of increased skin responding. The cardiovascular responses that developed over sessions appeared to be relatively independent of changes in skin response.     

PERSONALITY, AWARENESS AND AUTONOMIC CONDITIONING

The relationship between extraversion and autonomic conditioning was examined in three response systems: skin resistance, pulse rate and pulse volume. A discrimination schedule was employed as suggested by Eysenck (1965), and also as a means of differentiating conditioning effects from pseudoconditioning. Ss were afterwards interviewed to assess whether or not they were aware of the CSUCS contingency. Most of the Ss (93 out of US) could verbalize the contingency, and evidence of conditioning was clearcut in this group and virtually non-existent in the unaware group. There were no significant correlations between conditioning and personality in any of the response systems, a finding considered in the light of the overwhelming effect of cognitive factors on the acquisition curve.     

Amplitude and Habituation of the Orienting Reflex as a Function of Stimulus Intensity

Two within-S experiments involving 20 Ss each and one between-S experiment employing 100 Ss were performed to examine effects of stimulus intensity on orienting response amplitude and habituation. Five intensities of a 1000 Hz tone were presented, ranging from 0 to 40 dB in Experiment I and from 0 to 80 dB in Experiments II and III. Response measures were skin conductance response (SCR) and heart rate (HR). Skin conductance response amplitude increased monotonically with stimulus intensity while HR deceleration was a generally decreasing function which tended to decrease, increase, and finally decrease again as intensity increased. Not only was deceleration greatest at 0 dB but it was more resistant to habituation. Several intensities of test stimulation were presented after habituating stimuli in the between-S experiment. Skin conductance response to test stimuli was facilitated by habituation at 0 dB and depressed by habituation at 80 dB. The results suggest a direct relationship between stimulus intensity and development of habituation.     

Some Limits on the Cognitive Control of Conditioned Autonomic Behavior

Because certain recently adopted doctrinaire cognitivist positions are just as undesirable as the doctrinaire behaviorist positions of the fifties, evidence is presented to indicate that there are some instances where cognitive factors do not appear to control autonomic conditioning. The first aspect of that evidence deals with tests of the applicability of the contingency position to Pavlovian autonomic conditioning, and the data indicate that conditioned autonomic responses like the GSR do not act like “contingency analysers” over CS-US intervals ranging from .75 to 8.0 sec. Moreover, measures of cognitive subjective contingency (SC), which could not be taken in the animal studies used previously to support the contingency analysis of Pavlovian conditioning, indicate that the human Ss are aware of the contingency differences considered important for autonomic conditioning by the contingency position. This lack of correspondence between the autonomic and cognitive dependent variables is also relevant to another form of the cognitive-control position, that knowledge of CS-US contingencies is related to autonomic conditioning. Such relations were not, in fact, observed between the extents of autonomic and cognitive (SC) discrimination. Finally, a more sensitive and continuous measure of SC is proposed which should yield more precise answers to the empirical and complex question of the limits of cognitive control of conditioned autonomic behavior.     

THE INFLUENCE OF SOME PSYCHOLOGICAL FACTORS ON LATENCY OF THE GALVANIC SKIN REFLEX

The purpose of this study was to examine the effect of differences in motivativation and in attention on latency of the endosomatic GSR. Using verbal instructions, two different levels of motivation were induced in a group of 37 Ss who performed a simple reaction task in which they pressed a button whenever a 250 cycle tone was presented. The same tone also served as a stimulus for eliciting the GSR. In a second experiment, 42 different Ss performed a similar reaction task, but in this case the stimulus was the 250 cycle tone or a 1,000 cycle tone of equal subjective intensity. Ss were asked to give a voluntary response to all tones irrespective of frequency and then, later on, to respond only when the 1,000 cycle tone was presented. Although voluntary reaction times were significantly shorter under conditions of high as compared with low motivation, latency of the GSR did not differ for the two conditions. In the second experiment, significantly shorter GSR latencies were recorded under the condition where Ss were required to pay closer attention to the stimulus.