The role of modeling in prevention and extinction of phobic behaviour in cynomolgus monkeys (Macaca Fascicularis)

In previous studies surrogate reared cynomolgus monkeys have been shown to become phobic of an unprepared harmless object. In the present study an attempt was made to prevent the development of phobic behaviour in young monkeys and to extinguish avoidance behaviour in phobic monkeys. In the first experiment subjects were exposed to the object in company of their (surrogate) mothers which approached the object. In the second experiment phobic subjects were exposed to the object in company of non-phobic conspecifics which approached the object. The results of the first experiment show that modeling was unsuccessful in preventing the acquisition of phobia in the surrogate-reared monkeys but seemed successful in accelerating approach in the mother-reared subjects. The results of the second experiment show that during the modeling treatment the phobic subjects followed the model and approached the object. However, in post treatment tests all subjects but one relapsed into avoidance. The effect of modeling during treatment is interpreted in terms of coaclive facilitation.     

Responses to novelty in phobic and non-phobic cynomolgus monkeys: The role of subject characteristics and object features

In two previous studies it has been shown that most surrogate-reared cynomolgus monkeys became phobic of a harmless object (a big paper bag) while most mother-reared monkeys approached that object. Results of the first study seemed to indicate that the phobic reaction was restricted to the bag. Barnett and Cowan (Interdisciplinary Science Review, 1, 43–62, 1976) and Suomi (Anxiety disorder in childhood, pp. 1–23, 1986), however, reported that subjects (respectively rats and monkeys) that avoided a first novel object also avoided subsequent novel objects. In the present study we exposed phobic (bag-avoiding) and non-phobic (bag-approaching) monkeys from the study by Röder, Timmermans and Vossen (Behaviour Research and Therapy, 27, 221–231, 1989) to several big and small novel objects. Our results show that, irrespective of their rearing conditions, subjects that were phobic also avoided big novel objects while subjects that were non-phobic approached big novel objects. The reaction to small novel objects was independent of the previous reaction to the bag.     

The role of the cs and avoidance period duration in discriminated avoidance conditioning

In an experiment investigating the effect of CS duration on discriminated bar-press conditioning, subjects were assigned to one warning period duration (1.5, 5.0 or 15.0 sec.) on the first day of avoidance training, and to one of the three durations on the second day of training. On each day avoidance behaviour was greatly influenced by the duration of the CS (warning) period, but the duration on day I had no effect on the second day's avoidance performance. Groups receiving no CS during training, although provided an avoidance contingency, showed little conditioning, but produced highly significant amounts of intertrial responding. In a second experiment, subjects receiving CS on day I were shifted to no CS on day II. Avoidance performance on day II was not significantly different from the day II performance of subjects in Experiment I having two training sessions with the CS present or absent on both days.     

Case Study: A Quantitative Report of Early Attention,Fear, Disgust,and Avoidance in Specific Phobia for Buttons

Specific phobia is characterized by elevated early attention to the phobic object, negative emotion, and avoidance. Typically, phobic objects are biologically relevant, such as potentially threatening snakes or spiders, or potentially contaminating needles or rodents. It is unclear whether the same early attention, emotion, and avoidance responses can be observed in phobia for uncommon, nonbiologically relevant objects, such as buttons (koumpounophobia). In an experimental case study, we measured early attention (detection rates to briefly presented images before a backward mask), emotion, and avoidance to clothing buttons in a button-phobic participant. We compared these responses to nonphobic objects (zippers), and to well-matched control participants. We observed elevated early attention, fear, and disgust to buttons, which did not generalize to nonphobic emotional stimuli. In addition, we observed elevated avoidance of buttons, which did generalize to normatively fearful and disgusting pictures. If replicated, our results indicate that nonbiologically prepared phobic objects elicit similar elevated early attention, emotion, and avoidance as biologically prepared phobic objects. The finding that avoidance was the only response that generalized to nonphobic objects may have treatment implications—namely, that therapeutic attempts to reduce avoidance might consider including a variety of objects, not just the phobic object.     

Danger expectancies, self-efficacy and insight in spider phobia

In the current edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV; American Psychiatric Association, (1994) Diagnostic and statistical manual of mental disorders (4th ed.) Washington, DC: author) phobic adults and adolescents are said to "recognize that the phobia is excessive or unreasonable" given the actual danger posed by the feared situation. The present study examined perceptions of danger in 15 spider phobic subjects and a matched set of controls before, during and after a spider-avoidance test. When detached from the phobic stimulus, phobic subjects: (1) gave higher estimates of the probability of being bitten than controls did; (2) gave higher estimates of the injuries that would result from being bitten and (3) in line with these first two findings, believed their high levels of anticipated anxiety were more reasonable and appropriate to the demands of the situation than controls did. These findings are inconsistent with the prevailing notion that when detached from the phobic situation patients can accurately evaluate the danger of potential phobic encounters. Instead, the findings suggest that phobic individuals, whether detached or in the presence of the feared object, have relatively limited insight into the irrationality of their fears. In examining the mediation of phobic phenomena, both self-efficacy and danger estimates remained significantly related to the anxiety and avoidance experienced in the spider-avoidance task. Further research designed to experimentally establish the likely causal roles of these two constructs is warranted.     

The effects of ethanol intoxication on phobic anxiety

Behavioral conceptions of alcohol abuse often include the hypothesis that drinking behavior is a negatively reinforced operant, with ethanol intoxication viewed as alleviating aversive environmental and internal states. This hypothesis has not been confirmed or refuted by previous studies which employed mild stressors and limited assessment methodology. In the present experiment, 22 patients with severe phobias approached their phobic animal under two consecutive conditions—first while sober and second after drinking either a placebo or an intoxicating dose of ethanol. The severe anxiety induced was assessed behaviorally, physiologically and by the patient's self-report of fear. The intoxicated patients did not experience decreased anxiety, tachycardia or avoidance, compared to the placebo group. These results have clinical implications and suggest the need to reconsider tension-reduction theories of alcohol abuse.     

Placebo effects in spider phobia: an eye-tracking experiment

ABSTRACT

Several eye-tracking studies have revealed that spider phobic patients show a typical hypervigilance-avoidance pattern when confronted with images of spiders. The present experiment investigated if this pattern can be changed via placebo treatment. We conducted an eye-tracking experiment with 37 women with spider phobia. They looked at picture pairs (a spider paired with a neutral picture) for 7?s each in a retest design: once with and once without a placebo pill presented along with the verbal suggestion that it can reduce phobic symptoms. The placebo was labelled as Propranolol, a beta-blocker that has been successfully used to treat spider phobia. In the placebo condition, both the fixation count and the dwell time on the spider pictures increased, especially in the second half of the presentation time. This was associated with a slight decrease in self-reported symptom severity. In summary, we were able to show that a placebo was able to positively influence visual avoidance in spider phobia. This effect might help to overcome apprehension about engaging in exposure therapy, which is present in many phobic patients.     

Effects of various hippocampal lesions on monkey plasma cortisol levels in two experimental conditions

The plasma cortisol levels of Rhesus monkeys with anterior, posterior, or near-total hippocampal lesions were compared to controls during two separate stressful conditions. In the first condition, each monkey was placed for the first time in a primate restraint chair for 72 h. In the second condition each monkey performed a complex behavioral task (titrating shock avoidance) to control the intensity of frequent footshock for a 24-h period. Control subjects had either no surgical operation or else surgical exposure of the hippocampus with no hippocampal lesion. They manifested lower plasma cortisol levels during shock avoidance compared with during the chair condition. Subjects with posterior hippocampal lesions manifested the same pattern but near-totally hippocampectomized subjects showed an opposite pattern with cortisol levels higher in the shock avoidance condition compared with the chair condition. Subjects with anterior hippocampal lesions had similar cortisol levels in both conditions. Thus hippocampal modulation of corticosteroid levels may depend on the specific condition under which such levels are measured, and may be relatively more subserved by anterior compared with posterior hippocampus in the monkey.     

Individual response differences in spider phobia: comparing phobic and non-phobic women of different reactivity levels

In contrast to previous stress research, studies concerning phobic disorders have never systematically investigated individual response differences between phobic participants integrating numerous different response measures. The aim of this article is to clarify the existence of significant individual response differences in psychophysiological responses (e.g., heart rate, skin conductance responses (SCR), corrugator, cortisol), subjective ratings (e.g., valence, arousal), and avoidance behavior in 46 spider phobic and 44 non-phobic women when exposed to 20 phobic and 20 neutral pictures. Previous studies that did not attend to individual response differences showed that, during phobic stimulation, phobic individuals have increased psychophysiological responses (heart rate, SCR, and corrugator responses), more negative valence rating, and more subjective arousal than non-phobic individuals. These results were confirmed by our data. With regard to individual response uniqueness, 1/3-2/3 of spider-phobic women with low responsiveness in heart rate, cortisol, and avoidance behavior were indistinguishable from non-phobic women during phobic stimulation. With SCR, corrugator EMG, and subjective ratings, no individual response uniqueness was found. Based on the findings, exposure therapy might be improved by tailoring interventions to individuals with a therapeutic focus on those psychophysiological measures that show the highest individual responsivity.     

A comparison of escape and avoidance conditioning in wild and domesticated rats

In the first of two experiments, three cotton rats (Sigmodon hispidus) and three albino rats were exposed to instrumental escape, unsignaled avoidance, and signaled avoidance, in that order. All subjects learned the escape procedure quickly, with the albino rats having generally shorter latencies, higher response rates, and requiring fewer sessions to reach the criterion. When the avoidance contingency was introduced, the cotton rats continued to respond almost entirely in the presence of the shock, whereas the albino rats responded in its absence, thus displaying effective avoidance behavior. Introduction of a pre-aversive stimulus did not improve the performance of the cotton rats. In the second experiment, five cotton rats and four albino rats were exposed to a free-operant (Sidman) avoidance procedure with a shock-shock interval of 3 sec and a response-shock interval of 20 sec. The cotton rats initiated responding at lower shock intensities than the albino rats, but their asymptotic avoidance responding was far less effective.     

Individual response differences in spider phobia: Comparing phobic and non-phobic women of different reactivity levels

Abstract

In contrast to previous stress research, studies concerning phobic disorders have never systematically investigated individual response differences between phobic participants integrating numerous different response measures. The aim of this article is to clarify the existence of significant individual response differences in psychophysiological responses (e.g., heart rate, skin conductance responses (SCR), corrugator, cortisol), subjective ratings (e.g., valence, arousal), and avoidance behavior in 46 spider phobic and 44 non-phobic women when exposed to 20 phobic and 20 neutral pictures. Previous studies that did not attend to individual response differences showed that, during phobic stimulation, phobic individuals have increased psychophysiological responses (heart rate, SCR, and corrugator responses), more negative valence rating, and more subjective arousal than non-phobic individuals. These results were confirmed by our data. With regard to individual response uniqueness, 1/3–2/3 of spider-phobic women with low responsiveness in heart rate, cortisol, and avoidance behavior were indistinguishable from non-phobic women during phobic stimulation. With SCR, corrugator EMG, and subjective ratings, no individual response uniqueness was found. Based on the findings, exposure therapy might be improved by tailoring interventions to individuals with a therapeutic focus on those psychophysiological measures that show the highest individual responsivity.     

Warmup in avoidance as a function of time since prior training

On avoidance procedures, rats and pigeons typically show warmup effects, characterized by improving performance within sessions and loss of the improvement (“warmup decrement”) between sessions. Between-session losses were examined by varying the time between periods of avoidance training. In one experiment, rats lived fulltime in conditioning chambers while intermission intervals were varied. In a second experiment, the animals lived in home cages between sessions; timeout intervals were introduced at midession, producing recurrence of warmup in the second half-session. In both experiments, the warmup decrements increased substantially as the timeout or intersession intervals were increased from zero to 30 minutes. With intervals of 60 or 120 minutes, the decrements approached or exceeded those obtained with intervals of a day or more. When avoidance was interposed between appetitive sessions, the appetitive responding was disrupted, but this seemed unrelated to the warmup or to the proficiency of avoidance. The warmup in avoidance shares characteristics with transient punishment effects, with the Kamin effect, and with habituation phenomena, but it is premature to assume that they reflect common processes.     

Self-observation versus flooding in the treatment of agoraphobia

The effects on agoraphobia of (1) self-observation with a minimum of therapeutic intervention. (2) flooding, (3) a combination of flooding and self-observation, and (4) no-treatment control were compared. Assessments were made at the beginning of treatment, during and at the end of treatment and at the follow-up three months later. They were carried out by the therapist (in vivo) measurement; phobic anxiety and phobic avoidance scale) by an independent observer (phobic anxiety scale and phobic avoidance scale) and by the client (phobic anxiety scale; phobic avoidance scale: FSS; social anxiety scale; SDS and I-E scale).Self-observation, flooding and flooding/self-observation resulted in significant improvement on several variables, whereas the no-treatment control group did not improve. No difference in effectiveness was found between the self-observation and flooding treatments. In addition, the results suggest that a combined flooding/self-observation treatment is more effective than each of the individual treatments.     

The degree of control exerted by phobic and non-phobic verbal stimuli over the recognition behaviour of phobic and non-phobic subjects

Four groups of subjects comprised of one control group, two analogue phobic groups and one clinical phobic group were exposed to a dichotic listening experiment in which they were required both to shadow one message to the exclusion of the other and recognize the occurrence of target words appearing in both the attended and rejected messages. Target words were either phobic-relevant or neutral. It was found that the clinical phobic group recognized significantly more target words than any of the other groups. This difference was due to their superior recognition of phobic-relevant targets from the rejected message. The results were interpreted within a combined framework of Staats's (1968, 1975) social behaviour theory and the Rescorla and Wagner (1972) model of classical conditioning.     

Tool-use learning in Tonkean macaques (Macaca tonkeana)

The transmission of tool use is a rare event in monkeys. Such an event arose in a group of semi-free-ranging Tonkean macaques (Macaca tonkeana) in which leaning a pole against the parks fence (branch leaning) appeared and spread to several males. This prompted us to test individual and social learning of this behavior in seven young males. In the first experiment, three males learned individually to obtain a food reward using a wooden pole as a climbing tool. They began using the pole to retrieve the reward only when they could alternatively experience acting on the object and reaching the target. In a second experiment, we first tested whether four other subjects could learn branch leaning after having observed a group-mate performing the task. Despite repeated opportunities to observe the demonstrator, they did not learn to use the pole as a tool. Hence we exposed the latter subjects to individual learning trials and they succeeded in the task. Tool use was not transmitted in the experimental situation, which contrasts with observations in the park. We can conclude that the subjects were not able to recognize the target as such. It is possible that they recognized it and learned the task individually when we alternated the opportunity to act upon the object and to reach the reward. This suggests that these macaques could then have associated the action they exercised upon the pole and the use of the pole as a means to reach the reward.     

The effect of perceived motion-in-depth on time perception

The present study examined the effect of perceived motion-in-depth on temporal interval perception. We required subjects to estimate the length of a short empty interval starting from the offset of a first marker and ending with the onset of a second marker. The size of the markers was manipulated so that the subjects perceived a visual object as approaching or receding. We demonstrated that the empty intervals between markers was perceived as taking shorter to view when the object was perceived as approaching than when it was perceived as receding. We found in addition that the motion-in-depth effect disappeared when the shape continuity between the first and second marker was broken or when the object approached but missed the face. We conclude that anticipated collision of an approaching object altered perception of an empty interval.     

Flexible attention deployment in threatening contexts: An instructed fear conditioning study

Factors leading humans to shift attention away from danger cues remain poorly understood. Two laboratory experiments reported here show that context interacts with learning experiences to shape attention avoidance of mild danger cues. The first experiment exposed 18 participants to contextual threat of electric shock. Attention allocation to mild danger cues was then assessed with the dot-probe task. Results showed that contextual threat caused subjects to avert attention from danger cues. In the second experiment, 36 participants were conditioned to the same contextual threat used in Experiment 1. These subjects then were randomly assigned to either an experimental group, trained to shift attention toward danger cues, or a placebo group exposed to the same stimuli without the training component. As in Experiment 1, contextual threat again caused attention allocation away from danger in the control group. However, this did not occur in the experimental group. These experiments show that acute contextual threat and learning experiences interact to shape the deployment of attention away from danger cues. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Effects of fornix transection upon associative memory in monkeys: Role of the hippocampus in learned action

Thirty-three monkeys took part in seven experiments designed to elucidate further the effect of fornix transection on learning and memory. In the first experiment the monkeys had to remember whether stimulus objects had previously been paired with reward or no reward, and they had to use this memory to guide choice between stimulus objects at retention tests according to an arbitrary rule which they had learned: to choose objects previously paired with no reward in preference to objects previously paired with reward. Fornix transection produced a severe and permanent impairment in this task. In the second experiment the monkeys also had to remember object-reward associations but the performance rule was more natural: to choose objects previously paired with reward. Here fornix transection had no effect. The third experiment required the monkeys to remember, given a stimulus object, which of two events of equal valence had previously been the outcome of displacing that object. The two events were either a peanut and a sultana or a black penny and a white penny of equal secondary reinforcing value. Performance was unimpaired by fornix transection. The fourth experiment also demonstrated, in a different paradigm, unimpaired recall of sensory events. The fifth experiment demonstrated an impairment following fornix transection in acquisition of simultaneous spatial-visual conditional discriminations; the sixth demonstrated normal learning by fornix-transected monkeys of a successive spatial-visual conditional discrimination and the seventh demonstrated unimpaired acquisition of a simultaneous auditory-visual conditional discrimination. These results, when considered in detail and together, are incompatible with existing hypotheses of hippocampal function. A new hypothesis is discussed.     

One-trial learning and superior resistance to extinction of autonomic responses conditioned to potentially phobic stimuli.

Human subjects were exposed to pictures of potentially phobic (snakes) and supposedly neutral (houses) objects as conditioned stimuli (CSs) in a Pavlovian conditioning experiment with shock as unconditioned stimulus (US), and skin conductance and finger pulse volume as dependent variables. The skin conductance responses conditioned to phobic stimuli were acquired after one CS-US pairing, and showed practically no extinction, whereas the responses to neutral stimuli showed very little resistance to extinction after both 1 and 5 reinforcements. The superior resistance to extinction of the phobic condition was interpreted to be a specific associative effect. In general, the skin conductance acquisition data showed tendencies similar to those during extinction. For finger pulse volume responses, however, there were very weak conditioning effects, and no effect of stimulus.     

Second-order avoidance behavior in monkeys

Two monkeys were trained on a three-component multiple schedule using discrete trials. In one component (food), a response terminated a red stimulus and produced food and S(Delta). In the second component (avoidance), a response terminated a green stimulus and avoided shock. In the third component (optional), a response terminated a blue stimulus and produced S(Delta). The consequence of not responding in the blue stimulus, however, was the production of either a food or an avoidance trial. Manipulation of these consequences showed that when food trials were available only a small percent of the time after optional trials, the subjects tended not to respond in the blue, even though this led to an increase in the total number of avoidance trials per day. If only avoidance trials followed as a consequence of not responding in the optional component, the animals terminated the blue stimulus and avoided the avoidance trials. Throughout the experiment both subjects maintained consistently low shock rates (about 10 per day) and these were not affected by the various manipulations. The data suggest that a stimulus associated with avoidance can be a conditioned aversive stimulus and will maintain a more remote avoidance response under certain conditions.