Psychophysiological responses during analogue systematic desensitization and non-relaxation control procedures

This investigation tested the hypotheses than an analogue systematic desensitization procedure (SD) would be both more effective and more efficient than a comparable non-relaxation control procedure (NRC) with respect to subjective report, behavioral and psychophysiological variables. Phobic subjects responded to slides depicting a feared aversive stimulus. The SD procedure resulted in significantly less reported fear, fewer trials to a criterion level of decrease in subjective fear, and significantly greater decreases in ANS baseline measures. However, measures of behavioral avoidance and measures of decrease in psychophysiological responsivity to the aversive stimuli revealed significant changes within both SD and NRC groups, and no significant differences between the groups, whether or not the groups were equated for number of stimulus presentations. The results, indicating equivalent efficacy and efficiency for the SD and NRC procedures, suggested a limited role for relaxation in systematic desensitization. An extinction or habituation hypothesis was supported at the expense of a counterconditioning hypothesis.     

Sensation seeking and stimulus intensity as modulators of cortical,cardiovascular, and electrodermal response: A cross-modality study

Previous studies have related the trait of sensation seeking to augmenting of the evoked potential (EP) in both visual and auditory modalities and to electrodermal and heart rate (HR) orienting and defensive reactions. The present study examined all of these phenomena in the same sample of subjects in order to replicate previous findings, and investigate cross-modality consistency and relationships between cortical and peripheral responses. Fifty-four male subjects, scoring high or low on the Disinhibition Sensation Seeking Scale, were exposed to 4 intensities of auditory stimuli (tones) on one occasion and visual stimuli (light flash) on another. Two interstimulus (ISIs) intervals were used for each set of stimuli: first a 17 sec series, and then a 2 sec series. High disinhibitors showed EP augmenting and lows reducing on 3 of the 4 series; differences were significant on two of them. High disinhibitors showed stronger orienting (deceleratory) HR responses to visual and auditory stimuli while lows showed stronger defensive (acceleratory) HR responses. HR responses were significantly correlated across stimulus modalities. Auditory and visual EP slope measures were correlated only for the long ISI series.     

Emotional responsivity to nonveridical heart rate feedback as a function of anxiety

The purpose of the present investigation was to examine the effects of nonveridical heart rate feedback and anxiety on electrodermal responses and verbal reports to emotionally laden stimuli. Forty-eight female subjects were divided into high and low anxious groups on the basis of their Taylor Manifest Anxiety Scale scores and resting level electrodermal activity. All subjects viewed 10 autopsy slides while hearing continuous auditory tones supposedly representing their own heartbeats. Twenty-four subjects heard the tones increase in rate with slide onset. The other 24 subjects heard no change in rate with slide onset. The high resting autonomic activity group responded with significantly larger electrodermal responses to the heart rate feedback-slide combination than the low resting level autonomic activity group. The high autonomic activity group also reported that the slides were significantly more unpleasant than the low autonomic activity group, particularly those slides accompanied by an increase in heart rate feedback. Implications of these findings for a cognitive-visceral model of emotion are discussed.     

Teaching children with autism spectrum disorder to tact auditory stimuli

Studies on teaching tacts to individuals with autism spectrum disorder (ASD) have primarily focused on visual stimuli, despite published clinical recommendations to teach tacts of stimuli in other sensory domains as well. In the current study, two children with ASD were taught to tact auditory stimuli under two stimulus‐presentation arrangements: isolated (auditory stimuli presented without visual cues) and compound (auditory stimuli presented with visual cues). Results indicate that compound stimulus presentation was a more effective teaching procedure, but that it interfered with prior object‐name tacts. A modified compound arrangement in which object‐name tact trials were interspersed with auditory‐stimulus trials mitigated this interference.     

Contextual dependencies in predictive learning

Two experiments assessed contextual dependencies in a predictive-learning task. Subjects learned to associate each of four pictorial stimuli with the occurrence or non-occurrence of a specific outcome. Each of these stimuli, the intentional stimuli, was presented against one of two different visual (Experiment 1) or auditory (Experiment 2) context stimuli. These context stimuli were incidental: subjects were not explicitly instructed to pay any attention to them and each of them in isolation was not predictive of the outcome. During acquisition and testing, subjects expressed the expected relationship between intentional stimulus and outcome by an appropriate key press. At test, intentional stimuli were presented either with the same contextual stimulus as also present during acquisition (same trials), or with the other one (switched trials). The response latency was slower on switched trials than on same trials in each experiment, a result extending previous findings on the effect of environmental contextual stimuli on task performance. Results are discussed in the framework of contextual occasion setting and habituation to contextual stimuli.     

Contextual dependencies in predictive learning

Two experiments assessed contextual dependencies in a predictive-learning task. Subjects learned to associate each of four pictorial stimuli with the occurrence or non-occurrence of a specific outcome. Each of these stimuli, the intentional stimuli, was presented against one of two different visual (Experiment 1) or auditory (Experiment 2) context stimuli. These context stimuli were incidental: subjects were not explicitly instructed to pay any attention to them and each of them in isolation was not predictive of the outcome. During acquisition and testing, subjects expressed the expected relationship between intentional stimulus and outcome by an appropriate key press. At test, intentional stimuli were presented either with the same contextual stimulus as also present during acquisition (same trials), or with the other one (switched trials). The response latency was slower on switched trials than on same trials in each experiment, a result extending previous findings on the effect of environmental contextual stimuli on task performance. Results are discussed in the framework of contextual occasion setting and habituation to contextual stimuli.     

Simultaneous auditory discrimination.

Stimuli in many visual stimulus control studies typically are presented simultaneously; in contrast the stimuli in auditory discrimination studies are presented successively. Many everyday auditory stimuli that control responding occur simultaneously. This suggests that simultaneous auditory discriminations should be readily acquired. The purpose of the present experiment was to train rats in a simultaneous auditory discrimination. The apparatus consisted of a cage with two response levers mounted on one wall and a speaker mounted adjacent to each lever. A feeder was mounted on the opposite wall. In a go-right/go-left procedure, two stimuli were presented on each trial, a wide-band noise burst through one speaker and a 2-kHz complex signal through the other. The stimuli alternated randomly from side to side across trials, and the stimulus correlated with reinforcement for presses varied across subjects. The rats acquired the discrimination in 400 to 700 trials, and no response position preference developed during acquisition. The ease with which the simultaneous discrimination was acquired suggests that procedures, such as matching to sample, that require simultaneous presentation of stimuli can be used with auditory stimuli in animals having poor vision.     

Visual dominance in the pigeon

In Experiment 1, three pigeons were trained to obtain grain by depressing one foot treadle in the presence of a 746-Hertz tone stimulus and by depressing a second foot treadle in the presence of a red light stimulus. Intertrial stimuli included white light and the absence of tone. The latencies to respond on auditory element trials were as fast, or faster, than on visual element trials, but pigeons always responded on the visual treadle when presented with a compound stimulus composed of the auditory and visual elements. In Experiment 2, pigeons were trained on the auditory-visual discrimination task using as trial stimuli increases in the intensity of auditory or visual intertrial stimuli. Again, pigeons showed visual dominance on subsequent compound stimulus test trials. In Experiment 3, on compound test trials, the onset of the visual stimulus was delayed relative to the onset of the auditory stimulus. Visual treadle responses generally occurred with delay intervals of less than 500 milliseconds, and auditory treadle responses generally occurred with delay intervals of greater than 500 milliseconds. The results are discussed in terms of Posner, Nissen, and Klein's (1976) theory of visual dominance in humans.     

Attention to auditory and peripheral visual stimuli: effects of arousal and predictability

Changes in the distribution of attention among auditory and peripheral visual stimuli were examined in a choice reaction time paradigm. Two variables were manipulated: predictability of stimulus locations and arousal state of subjects. The arousal level of some subjects was raised by occasionally exposing them to brief, mild electric shocks. On most trials either a tone or a light was presented alone (single-stimulus trials). However, on 20% of the trials both a tone and light were presented simultaneously (dual trials). Two dependent variables were used to assess dominance of attention: reaction time (on all trials) and percentage of time each modality was chosen on dual trials. Neither modality was dominant when subjects were in a nonaroused state and stimulus locations were unpredictable. However, peripheral vision dominated when stimulus locations were predictable or when the subjects' level of arousal was raised. The results are discussed with reference to previous research on sensory dominance and on the facilitating or inhibiting effects of auditory stimuli on reaction time.     

Autoshaping in the rat: The effects of localizable visual and auditory signals for food

Two experiments investigated autoshaping in rats to localizable visual and auditory conditioned stimuli predicting response-independent food. In Experiment 1 considerable conditioned-stimulus approach behavior was generated by a localizable visual conditioned stimulus that was situated approximately 35 cm from the food tray. Using the same apparatus in Experiment 2 we found that the conditioned-stimulus approach was generated only to a visual conditioned stimulus and not to a localizable auditory conditioned stimulus even though subjects (1) could discriminate presentations of the auditory conditioned stimulus, (2) had associated it with food, (3) could localize it, and (4) would approach the auditory stimulus if this behavior constituted an instrumental response to food. The predominant conditioned responses to the auditory stimuli were goal tracking (entering the food tray) and orienting towards the food-paired conditioned stimulus by head turning and rearing and turning. These results imply that rats do not invariably approach a localizable appetitive Pavlovian conditioned stimulus but that stimulus-approach responses depend on the nature and modality of the conditioned stimulus.     

Electrodermal orienting responses to verbal and geometrical visual stimuli projected to the left or right retinal half-fields: sex differences

Using the visual half-field technique, verbal and geometrical slides were repeatedly projected to either the left or right visual field in an electrodermal orienting paradigm. Bilateral skin conductance response-magnitudes were recorded continuously over trials. Half the subjects (8 males and 8 females) had a verbal and a geometrical slide repeatedly presented to the right of a central fixation-point, (i.e. initial left hemisphere input) and the other half had the same kinds of stimuli presented to the left (i.e. initial right hemisphere input). There were 32 presentations of each stimulus, i.e. a total of 64 trials. The intertrial interval (ITI) varied between 25 to 40 sec. Results showed significantly larger response-magnitudes in the female group having the stimuli presented in the left visual field and especially to the geometrical slide. The same trend in data was also found for the male subgroup having the stimuli presented in the left visual field. No significant differences between the bilateral left and right hand recordings were foundin the main analysis. However, a closer inspection of the data indicated the left hand recording to be more sensitive than the right hand recording.     

Flexibility of working memory encoding in a sentence–picture–sound verification task

Dual-process accounts of working memory have suggested distinct encoding processes for verbal and visual information in working memory, but encoding for nonspeech sounds (e.g., tones) is not well understood. This experiment modified the sentence–picture verification task to include nonspeech sounds with a complete factorial examination of all possible stimulus pairings. Participants studied simple stimuli–pictures, sentences, or sounds–and encoded the stimuli verbally, as visual images, or as auditory images. Participants then compared their encoded representations to verification stimuli–again pictures, sentences, or sounds–in a two-choice reaction time task. With some caveats, the encoding strategy appeared to be as important or more important than the external format of the initial stimulus in determining the speed of verification decisions. Findings suggested that: (1) auditory imagery may be distinct from verbal and visuospatial processing in working memory; (2) visual perception but not visual imagery may automatically activate concurrent verbal codes; and (3) the effects of hearing a sound may linger for some time despite recoding in working memory. We discuss the role of auditory imagery in dual-process theories of working memory.     

Second-order conditioning with diffuse auditory reinforcers in the pigeon

Pigeon subjects were used in five experiments investigating second-order conditioning with visual second-order and diffuse auditory first-order stimuli. Experiment 1 used a discriminative conditioning procedure to demonstrate reliable and substantial second-order conditioning with these stimuli. In Experiments 2 and 3, extinction of the auditory first-order stimulus after second-order conditioning had little effect upon responding to the second-order stimulus, when compared to a stimulus whose reinforcer was maintained. Experiment 4 compared directly the susceptibility of second-order responding to extinction of the first-order reinforcing stimulus as a function of the modality of that reinforcer. When a visual second-order stimulus was paired with a visual reinforcer, and the response to the latter was extinguished, then second-order responding was greatly reduced relative to control levels. In contrast, when that reinforcer was an auditory stimulus, second-order responding was not affected by the current value of the first-order stimulus after conditioning. Finally, in Experiment 5 the auditory stimulus was established as a reinforcer through discriminative-operant training. Following second-order conditioning, extinction of responding to this stimulus again had little impact upon responding to the second-order stimulus with which it had been paired. These results are discussed in terms of previous work on second-order conditioning with rat and pigeon subjects.     

Effects of awareness and motor involvement on autonomic conditioning in chronic schizophrenics

Chronic schizophrenics under neuroleptic medication were compared with normals, matched for age and education, in two conditioning experiments. Both experiments employed a differential paradigm with long conditional stimulus-unconditional stimulus (CS-UCS) intervals. Skin resistance (SR) and finger pulse or heart rate (HR) were recorded. In Experiment 1, half of the subjects were trained in categorizing the to-be conditional stimuli. In a further step, half of the subjects were informed about the CS-UCS contingency. The UCS was an electric shock. Information improved discrimination of SR responses only of normals, and discrimination training had no effect at all on autonomic responses. In Experiment 2, only electrodermal responders were included. Each subject was tested in two sessions, using a loud tone as UCS in one, and a reaction time signal in the other. Again, half of the subjects were informed about the contingency. Information improved discrimination of SR responses of both diagnostic groups. Decelerations of HR following CS onset showed informed schizophrenics to discriminate better with the loud tone UCS than with the reaction time signal. General autonomic responsivity seems to determine not only discriminative conditioning of schizophrenic patients but also the reports of awareness and the effects of manipulations of awareness. However, when subjects are matched for electrodermal responsivity and are equivalent in terms of SR response conditioning, patients react to information about the contingency with enhanced HR deceleration to the CSs, possibly reflecting a heightened sensitivity of the cardiovascular system.     

The nature of control by spoken words over visual stimulus selection.

Eight retarded adolescents were trained to select one (a trained S+) of two visual stimuli in response to a spoken word (a trained word). Two different visual stimuli alternated randomly as the S-. To determine if the spoken work was merely a temporal discriminative stimulus for when to respond, or if it also specified which visual stimulus to select, the subjects were given intermittent presentations of untrained (novel) spoken words. All subjects consistently selected the trained S+ in response to the trained spoken word and selected the previous S- in response to the untrained spoken words. It was hypothesized that the subjects were responding away from the trained S+ in response to untrained spoken words, and control by untrained spoken words would not be observed when the trained S+ was not present. The two visual S- stimuli selected on trials of untrained spoken words were presented simultaneously. The untrained spoken words presented on these trials no longer controlled stimulus selections for seven subjects. The results supported the hypothesis that previous control by spoken words was due to responding away from the trained S+ in response to untrained spoken words.     

‘Preparedness’ and ‘arousability’ as determinants of electrodermal conditioning

‘Arousability’, as defined through spontaneous electrodermal responses, has been empirically linked to anxiety, phobic symptoms and outcome of systematic desensitization. Previous data from our laboratory indicate that ‘preparedness’, as defined through potentially phobic vs. fear-irrelevant or ‘neutral’ conditioned stimuh, is an important determinant of electrodermal conditioning. The present experiment compared groups selected to be high or low in spontaneous responding during differential conditioning to potentially phobic or neutral stimuh. It was found that the effects of these two factors were essentially additive, i.e. conditioning and resistance to extinction were better for phobic stimuli and for high-arousal groups. The high-aroused group with phobic stimuh showed diffuse responding during acquisition, not differentiating between reinforced and unreinforced cues. However, it was the only group that failed to extinguish during 20 trials, which indicates that high arousal gives superior resistance to extinction particularly for phobic stimuli.     

Classical conditioning and information processing: Different mechanism for prepared and unprepared stimuli?

Although learning without awareness conflicts with recent theories of classical human Pavlovian conditioning, there is at least one type of conditioning in which CS-US contingency is processed without awareness—the so-called prepared conditioning. Therefore, presenting a secondary reaction time probe to measure the amount of information processing capacity required should produce interference with the secondary task in unprepared, but not in prepared conditioning, since in the latter information should be processed in parallel. In a previous study, the authors could not find differences between both types of conditioning, neither in reaction time nor in electrodermal indicators of information processing. The present study was conducted to replicate and extend these findings, using a differential autonomic conditioning paradigm. One half of 42 subjects received spider and snake slides as prepared stimuli, while the other half received flower slides as unprepared stimuli. Both kinds of stimuli were used as CS+ and as CS-. An electric shock served as unconditioned stimulus. During 24 acquisition and 24 extinction trials, electrodermal and heart rate responses, as well as reaction times to a probe stimulus, were recorded. The results revealed significant conditioning effects in terms of CS-/CS+ differences. However, no differences were found between prepared and unprepared stimuli, neither in autonomic measures nor in reaction time. Again, our results are in favor of serial information processing in both prepared and unprepared stimuli, suggesting that the so-called prepared conditioning may be treated as a subclass of classical autonomic conditioning instead of forming a specific class of learning.     

Reliability of electrodermal habituation measures under two conditions of stimulus intensity

The present study investigated test-retest reliability of habituation of the evoked skin conductance response. Subjects received 20 presentations of a 1000-Hz, 3-sec tone at the same time of day on two separate occasions, separated by an interval of 97–160 days. Thirteen subjects received stimuli of 90 dB, while for 24 subjects, stimulus intensity was 70 dB. Interstimulus interval was 21 sec for both groups. Both absolute rate of habituation and trials to criterion displayed moderate reliability, and the relationships between habituation measures and other aspects of electrodermal activity were in agreement with previous findings.     

“Enacted” auditory images are ambiguous; “pure” auditory images are not

Previous research indicates that visual images are inherently unambiguous. The present study extends this argument to auditory imagery. In Experiment 1, subjects were able to reinterpret an imaged ambiguous auditory figure, but covert subvocalization apparently aided this reinterpretation. When subvocalization was blocked, reinterpretations were eliminated. Experiments 2 and 3 generalize this finding to different procedures and stimuli. Experiment 4 explores further the role of subvocalization, by showing that the likelihood of reinterpreting an imaged stimulus is directly proportional to the degree of enactment allowed. We argue that subvocalization or enactment provides an internal stimulus that is subject to reinterpretation. Without enactment, the “pure” auditory image is as unambiguous as a visual image. Thus, in both visual and auditory modalities, images come into being as representations and so are inherently meaningful.     

Associative modulation of the orienting response: distinct effects revealed by hippocampal lesions

The ability of auditory stimuli to modulate rats' tendency to orient to visual targets was assessed. In Experiment 1, trials where an auditory stimulus (A) signaled one visual array (X) were intermixed with unsignaled presentations of a second array (Y). Comparison of the orienting responses (ORs) to X and Y revealed that A produced a transient (unconditioned) and an emerging (conditioned) disruptive influence on the OR to X. In Experiments 2 and 3, trials where A signaled X were intermixed with others where another auditory stimulus (B) signaled Y. Stimulus A's ability to modulate the OR to X was then assessed by presenting A prior to test arrays containing both X and Y. Control rats were more likely to orient to Y than X (Experiments 2 and 3) and rats with excitotoxic lesions of the hippocampus were more likely to orient to X than Y (Experiment 3). These results show that auditory stimuli exert distinct modulatory influences on the OR to visual stimuli with which they are associated.