A comparison of several procedures for eliminating behavior

Explosive Detection Dogs: A Perspective from the Personality Profile, Selection, Training Methods, Employment, and Performance to Mitigate a Real Threat

Terrorist organizations have compelled security authorities of every nation to make an increasingly significant commitment toward mitigating the risk of mass casualties and severe financial and property damages. As a result, various security measures have been implemented, including the use of advanced equipment and an uptick in intelligence activities. One of the most effective tools that has yielded outstanding results is the use of explosive detection dogs (EDDs). The nature of EDDs demands a high level of sensitivity given the inherent danger and severity of real threat situations that may involve the risk of explosion. Moreover, the operating procedures for EDDs are unique and distinguishable from other forms of detection. We conducted a review to ensure a comprehensive understanding of the subject, highlighting the EDDs' personality profile, selection, training methods, performance, and employment, incorporating insights from diverse fields, conducting an analysis, and presenting a perspective on using EDDs to prevent explosion threats.

Is superstitious responding a matter of detectability? A replication of Killeen (1978)

Organisms may sometimes behave as if a contingency exists between behavior and consequences, even if this is not actually the case. Killeen (1978) suggested that such superstition occurs because of factors that bias subjects to behave "superstitiously" rather than because of failures of discrimination. We systematically replicated Killeen's experiment and compared contingency discrimination between different consequences. Six pigeons responded in a matching-to-sample procedure in which a response-independent or response-dependent stimulus change, food delivery, or blackout occurred. The pigeons reported whether the consequence was response dependent or response independent by choosing between two side keys. Discrimination was strongest after stimulus changes, weaker after blackouts, and weakest after food deliveries. These differences persisted even after additional training, suggesting asymmetries that may reflect differences in the disruptive effects of different consequences on remembering and/or behavioral mnemonics. Importantly, the pigeons were not biased to report response-dependent consequences unless that response was consistent with locational biases; that is, they behaved "superstitiously" when there was a reason to be biased to do so. These findings corroborate Killeen's and demonstrate that behavior may deviate from contingencies not necessarily because subjects cannot discriminate those contingencies but because they are biased to behave otherwise.

Effects of repeated exposure to escalating versus constant punishment intensity on response allocation

The present experiment investigated the effects of 1) repeated exposures to escalating punishment intensities and 2) repeated exposure to punishment after periods of vacation on response allocation between punished and unpunished responding in three groups of rats. The first group (intensity + vacation) experienced repeated exposures to escalating punishment intensities after a period of vacation (i.e., return to baseline) from punishment. The second group (intensity-only) experienced repeated exposures to escalating punishment intensities without vacation from punishment. The third group (vacation-only) experienced repeated exposures to a constant punishment intensity after a period of vacation from punishment. Results showed that superimposition of punishment on one of two concurrently available responses decreased allocation toward the punished response and increased allocation toward the unpunished response. Furthermore, greater changes in allocation were observed with the introduction of a moderate constant intensity than with the introduction of a low intensity that increased across sessions. Reexposure to punishment had different effects between the groups. Although there was evidence that high shock intensities can enhance the efficacy of lower intensities to shift allocation away from the punished response and toward the unpunished response, there was little evidence of changes in response allocation with reintroduction of punishment after a period of vacation.

Validation of a method to assess ADHD-related impulsivity in animal models

BACKGROUND

Response inhibition capacity (RIC), the ability to withhold instrumentally reinforced responses, is compromised in ADHD. Most standard methods for assessing RIC in rodents potentially confound motivational, motor, learning, and inhibitory processes, lack sensitivity to pharmacological treatment, and have unknown reliability.

NEW METHOD

The fixed minimum interval (FMI) schedule of reinforcement and its associated analytical techniques are designed to dissociate inhibitory processes from incentive-motivational and timing processes. This study is aimed at validating the FMI as a method for assessing RIC in animal models. FMI performance was compared across different withholding requirements (0.5, 3, 6 and 21s), deprivation levels, reinforcement rates, and reinforcer magnitudes.

RESULTS AND COMPARISON WITH EXISTING METHODS

Motivational manipulations differentially affected estimates of incentive motivation but not the FMI-derived index of RIC, θ. Changes in the withholding requirement influenced timed IRTs in a manner consistent with extant timing theories. Individual estimates of RIC were resilient to prolonged changes in motivation but not to changes in FMI schedule. Results indicate that the FMI schedule is not vulnerable to the same limitations associated with existing methods for assessing RIC.

CONCLUSIONS

These results support the use of the FMI schedule and associated analytic techniques as tools for assessing RIC in animal models.

Suppressive and facilitative effects of shock intensity and interresponse times followed by shock

Although response-dependent shock often suppresses responding, response facilitation can occur. In two experiments, we examined the suppressive and facilitative effects of shock by manipulating shock intensity and the interresponse times that produced shock. Rats' lever presses were reinforced on a variable-interval 40-s schedule of food presentation. Shock followed either long or short interresponse times. Shock intensity was raised from 0.05 mA to 0.4 mA or 0.8 mA. Overall, shock contingent on long interresponse times punished long interresponse times and increased response rates. Shock contingent on short interresponse times punished short interresponse times and decreased response rates. In Experiment 1, raising the range of interresponse times that produced shock enhanced these effects. In Experiment 2, the effects of shock intensity depended on the interresponse times that produced shock. When long interresponse times produced shock, low intensities increased response rates. High intensities decreased response rates. When short interresponse times produced shock, high shock intensities punished short interresponse times and decreased response rates more than low intensities. The results may explain why punishment procedures occasionally facilitate responding and establish parameters for future studies of punishment.

Effects of timeout on spaced responding in pigeons

Three pigeons were trained under a differential-reinforcement-of-low-rate schedule of 20 sec, and then exposed to a schedule under which responses terminating interresponse times less than 20 sec produced timeout and responses terminating interresponse times greater than 20 sec produced reinforcement. Response-produced timeouts selectively decreased the probability of short interresponse times and thereby produced a higher frequency of reinforcement. The suppressive effect of timeout was independent of timeout duration, with timeouts of 5, 10, or 20 sec. Similar effects were found when the minimum interresponse time that could be terminated by response-produced reinforcement was increased to 30 sec. The suppressive effects of timeout on responding maintained by these schedules were similar to previous reports in which responding was punished with electric shock.

An interresponse time analysis of variable-ratio punishment

An interresponse time analysis was used to study the effects of variable-ratio punishment schedules on the temporal pattern of reinforced responding. Twelve pigeons responded on a baseline variable-interval schedule of food reinforcement. A variable-ratio ten schedule of electric shock punishment was then introduced. The shock intensity was systematically increased to the highest intensity at which responding could be maintained. At this intensity, the mean variable-ratio value was increased and then decreased. Variable-ratio punishment resulted in an increased relative frequency of very short unreinforced interresponse times (response bursting). Increased response bursting accounted for instances of response rate facilitation. In addition, shock was followed by interresponse times of decreasing mean length over the first several responses after shock.

Selective punishment of interresponse times

Lever pressing by two squirrel monkeys was maintained under a variable-interval 60-second schedule of food presentation. When response-dependent electric shock was made contingent on comparatively long interresponse times, response rate increased, and further increases were obtained when the minimum interresponse-time requirement was decreased. When an equal proportion of responses produced shock without regard to interresponse time, rates decreased. Thus, shock contingent on long interresponse times selectively decreased the relative frequency of those interresponse times, and increased the relative frequency of shorter interresponse times, whereas shock delivered independent of interresponse times decreased the relative frequency of shorter interresponse times while increasing the frequency of longer ones. The results provide preliminary evidence that interresponse times may be differentiated by punishment, further supporting the notion that interresponse times may be considered functional units of behavior.

The role of reinforcement in controlling sequential IRT dependencies

Sequential dependencies were investigated with two rats in a mixed and in a tandem differential-reinforcement-of-low-rate-responding schedule. In each schedule, 5-sec and 15-sec components were presented in fixed alternation. In the mixed schedule, a 5-sec interresponse time followed a 15-sec interresponse time and a 15-sec interresponse time followed a 5-sec interresponse time in predictable sequence. The correlation between prior and subsequent interresponse times, however, existed only when the prior interresponse time resulted in reinforcement. In the tandem schedule, an interresponse time greater than 5 sec in the differential-reinforcement-of-low-rate 5-sec component was not associated directly with reinforcement. One subject demonstrated sequential response patterns similar to those noted in the mixed schedule, even though the prior 5-sec interresponse time was not reinforced in the tandem schedule. The results indicate that the prior interresponse time length alone is not sufficient to influence the subsequent interresponse time length. Implications are, however, that a temporal response pattern arises when an interresponse interacts with schedule contingencies to control the interreinforcement interval.

Additional-delay schedules: A continuum of temporal contingencies by varying food delay

Pigeons performed on discrete-trial, temporally defined schedules in which the food delay (D) was adjusted according to the latency of the key peck (X) and two schedule parameters (t and A). The schedule function was D = A(t - X), where D is the experienced delay between a response and a reinforcer. The schedule parameter t is the maximum value below which the present contingencies occur. A is the additional delay to reinforcement for each second the response latency is shorter than the t value. When A = 0 s, the schedule is a continuous reinforcement schedule with immediate reinforcement. When A = 1 s, the schedule is a conjunctive fixed-ratio 1 fixed-time t-s schedule. When A approaches infinity, the schedule becomes a differential reinforcement of long latency schedule. The latencies for subjects with t = 10 s and t = 30 s were observed with the present schedules having seven values for A between 0 s and 11 s. In addition, the latencies for subjects for which t = 30 s were observed at an A value of 31 s to 41 s. As the A value increased, the latencies approached the t value for subjects for which t = 10 s. The latencies for 30-s-t subjects did not approach t, even when the A value was 41 s. The latencies for 10-s-t subjects at 11-s A value were longer than those under yoked conditions having exactly the same delays/interreinforcement intervals. These results demonstrated a continuum of latency related to the schedule continuum (value of A) at a small t value.

Punishment of autoshaped key-peck responses of pigeons

The effects of different voltages of response-dependent and response-independent electric shock on the frequency of key-peck responses engendered by an autoshaping procedure were studied. In Experiments I and II, each response produced a brief electric shock, and response frequency generally decreased more with higher-voltage shock. Preshock frequencies of responding were generally recovered across successive sessions of relatively low-voltage shock delivery but not at higher shock voltages. The effects of response-dependent and response-independent shock were compared in Experiment III by using a yoked-control procedure in which each pigeon received each type of shock delivery at different times. Response-dependent shock generally produced greater decreases in response frequency. In the final experiment, one response-independent shock per autoshaping trial was scheduled. The number of autoshaped responses per trial was related to shock voltages. These results suggest that response-dependent and response-independent electric shock effectively decrease frequency of autoshaped responses.

Two-component schedules of differential-reinforcement-of-low-rate

Two-component schedules of differential-reinforcement-of-low-rate were presented, where the contingencies specified separately two minimum interresponse times, t(1) and t(2), required for reinforcement, depending on whether the interresponse time was initiated by, in one case, a reinforced response (t(1)) or, in the other, a nonreinforced response (t(2)). A distinctive pattern of responding developed on each of the two contingencies. Duration of an interresponse time approximated t(1) when the t(1) contingency was in effect, and t(2) when the t(2) contingency was in effect. This relationship persisted even when t(2) was shorter than t(1), and responding at a higher rate on the t(1) contingency would have greatly increased the rate of reinforcement. Increasing the value of t(2) resulted in both longer interresponse times on the t(1) contingency, and a higher probability of a response-burst on those occasions when the contingency switched from t(1) to t(2). The results indicated that both reinforced and nonreinforced responses functioned as discriminative events in determining the duration of following interresponse times.

Stereotypy I: a review of behavioral assessment and treatment

In this paper, we review definitional issues related to stereotypy, behavioral interpretations of stereotypy, procedures for determining operant function(s) of stereotypy, and behavioral interventions for stereotypy. In general, a preponderance of the assessment literature suggests that most forms of stereotypy are maintained by automatic reinforcement. Review of the treatment literature suggests that antecedent (e.g., environmental enrichment) and consequent (e.g., differential reinforcement of alternative behavior) interventions produce at least short-term reductions in stereotypy. Suggestions for further assessment and treatment of stereotypy are provided.

On the status of knowledge for using punishment implications for treating behavior disorders

In this paper, we review basic and applied findings on punishment and discuss the importance of conducting further research in this area. The characteristics of responding during punishment and numerous factors that interact with basic processes are delineated in conjunction with implications for the treatment of behavior disorders in clinical populations. We conclude that further understanding of punishment processes is needed to develop a highly systematic, effective technology of behavior change, including strategies for improving the efficacy of less intrusive procedures and for successfully fading treatment.

TEMPORALLY SPACED RESPONDING BY PIGEONS: DEVELOPMENT AND EFFECTS OF DEPRIVATION AND EXTINCTION

In the first five or six sessions on a DRL 20-sec schedule of reinforcement there developed a stable performance characterized by a relatively constant conditional probability of occurrence (IRTs/op) of interresponse times (IRTs) of durations greater than 5 or 6 sec. Extinction and the level of deprivation changed both the overall rate of responding and the form of the function relating the duration of an IRT to its value of IRTs/op. The value of IRTs/op decreased more rapidly for short than for longer IRTs, resulting in the emergence of a finer discrimination of IRT duration.

MOTIVATIONAL ASPECTS OF ESCAPE FROM PUNISHMENT

Punishment and escape were studied simultaneously by allowing a subject to escape from a stimulus situation in which responses were punished, into a stimulus situation in which responses were not punished. The frequency of the punished responses was found to be an inverse function of the intensity of punishment, whereas the frequency of the escape response was a direct function of the intensity of punishment. Both of these functions were obtained under three different schedules of food reinforcement. The strength of the escape behavior was evidenced by (1) the emergence of the escape response even when the frequency of food reinforcement decreased as a consequence of the escape response, (2) the maintenance of the escape response by fixed-interval and fixed-ratio schedules of escape reinforcement, and (3) the occurrence of escape responses at intensities of punishment that otherwise produced only mild suppression of the punished response when no escape was possible. This last finding indicates that a subject may be driven out of a situation involving punishment even though the punishment is relatively ineffective in suppressing the punished responses when no escape is possible.

Developing a technology for the use of operant extinction in clinical settings: an examination of basic and applied research

Extinction of operant behavior, which involves terminating the reinforcement contingency that maintains a response, is important to the development, generalization, and reduction of behavior in clinical settings. We review basic and applied research findings on variables that influence the direct and indirect effects of extinction and discuss the potential value of a general technology for the use of extinction. We suggest that current research findings are not sufficient for the development of a comprehensive, applied technology of extinction and provide extensive guidelines for further studies on factors that may affect the course of extinction in clinical settings.

Operant extinction in the treatment of severe maladaptive behavior: adapting research to practice

Operant extinction involves termination of reinforcement for a previously reinforced response. As a clinical intervention for severe maladaptive behavior operant extinction is often repudiated because of intensity of side effects, length of treatment time required, and implementation difficulties. This article discusses both theoretical and practical aspects of extinction, including components of the extinction process and the importance of functional assessment to its effective use. Potential strategies for increasing the effectiveness of extinction while diminishing intrusiveness are recommended. Based on recent research innovations, a technology is emerging for effective use of operant extinction in the treatment of severe maladaptive behavior.

Effects of self-generated rules on the development of schedule-controlled behavior

College students responded under a multiple differential-reinforcement-of-low-rate 5-s fixed-ratio 8 schedule, with components alternating every 2 min. After 40 programmed minutes of acquisition and 12 min of maintenance, without notice, both schedules changed to extinction for 28 min. During acquisition, between alternations of the multiple schedule, some subjects were asked to develop rules describing the schedule contingencies. Other subjects were given these same rules between alternations, and a third group neither received nor were asked to develop rules. By the end of the acquisition phase, self-generated-rule subjects were more likely to show schedule-typical behavior than were subjects not asked to generate rules. The behavior of those given rules was similar to those asked to generate rules at the end of acquisition, but yoked-rule subjects acquired schedule-typical behavior at a quicker rate. By the end of extinction, during the period corresponding to the previous fixed-ratio interval, all no-rule subjects who had earned points during acquisition and maintenance were responding at a rate of less than 30 responses per minute. Only 3 of the 9 self-generated-rule subjects and 2 of the 5 yoked-rule subjects were similarly responding at this low rate. Results suggest that asking subjects to develop self-rules facilitates acquisition, but can retard extinction. Results also suggest that self-generated rules function similarly to external rules.

Temporally spaced responding for food in adult rats after undernutrition early in life

Rats were undernourished during the suckling and early post-weaning periods and were then fed a good quality diet ad libitum from 43 to 300 days when behavioural testing was begun. Male previously undernourished and control rats were tested on three operant conditioning schedules in which low rates of bar-pressing were rewarded with food (differential reinforcement of low rate or DRL schedules). These were DRL 5 sec, DRL 10 sec and DRL 30 sec. On each schedule the response rates of both groups of animals declined over several sessions and their efficiency at obtaining the food rewards increased. However, there were no significant differences between the two groups on either of these measures. This finding indicates that, despite being hyper-responsive in many situations, including some operant conditioning schedules, previously undernourished rats are as capable as controls of withholding responding when necessary.

Steady and transition states: effects of alternative activity on body-rocking in retarded children

Two experiments are reported in which steady and transition states were observed for two independent operants (body-rocking and ball-manipulandum). First, stable fixed-ratio response rates were successively obtained for body-rocking and ball-manipulandum responding. Second, transition states were obtained for the two operants simultaneously. The results showed that the independent operants under standardized experimental conditions showed moderately correlated and stable response rates. The method of simultaneous operants provided a valid technique for analysis of transition states, i.e., the functional separation of stereotyped acts (e.g., body-rocking) and alternative activity (ball-manipulandum). Finally, the effects of experimental manipulations were reversible.

Screening hallucinogenic drugs: systematic study of three behavioral tests

The effects of several hallucinogenic and non-hallucinogenic drugs have been studied on three behavioral tests proposed as useful indexes of hallucinogenic activity: "head-twitching" in mice, defecation in an open-field, and suppression of responding on a differential reinforcement of low rates (DRL) schedule of reinforcement. According to the original propositions, after administration of hallucinogenic agents the frequency of head-twitches would increase in mice, the defecation of rats in an open field would decrease without consistent change in ambulation, rearing and grooming, and the responding of rats on a DRL schedule would yield a typical cumulative record pattern. It was found that the head-twitch test was sensitive to mescaline and LSD-25, but not to delta9-THC or to myristicin and elemicin. Besides, the data on interobserver agreement suggested there is a high degree of subjectivity involved in assessing this response. In the open-field test, non-hallucinogenic drugs such as chlorpromazine and apomorphine fell into the hallucinogenic pattern proposed. In addition, the post-injection interval selected seemed to critically affect defecation scores. The DRL "hallucinogenic" pattern occurred nonspecifically after administration of hallucinogenic and non-hallucinogenic drugs. It was concluded that the three tests have limited value for screening purposes.

Bias functions and operating characteristics of rats discriminating auditory stimuli

Rats were trained to discriminate between two bursts of random noise that differed in intensity. In a two-lever, discrete-trial procedure, correct responses were reinforced with brain stimulation, and incorrect responses produced timeout. Responding was studied as a function of the decibel difference between the stimuli, the probabilities of presenting the stimuli, the relative duration of timeout consequent upon the two types of incorrect responses, and the absolute duration of timeout consequent upon incorrect responses. The results showed that the distribution of responses between the two levers depended upon the stimulus probabilities, but were independent of either the absolute or relative durations of timeout. When the stimulus probabilities were varied, the response probabilities did not match the stimulus probabilities; when the relative durations of timeout were varied, the animals did not obtain the maximum rate of reinforcement per unit time. Instead, the animals distributed their responses so as to obtain the maximum number of reinforcements at each level of discrimination. In addition, the level of discrimination increased as a function of the decibel difference between the stimuli.

Effects of chlorpromazine and pentobarbital on pattern and number of responses in extinction

In a series of experiments rats were trained and subsequently extinguished under different conditions of drug administration. High doses of chlorpromazine (5 mg/kg) or pentobarbital (20 mg/kg) were administered during the first extinction session and the dose was progressively reduced to zero over 10 successive sessions. Extinction was continued until all Ss had consistent near zero responding. When compared to saline control, chlorpromazine had no effect on total extinction responding, while pentobarbital significantly reduced total extinction responding. Ss receiving both drugs had erratic runs of responding in extinction, whereas Ss receiving saline showed a normal extinction pattern. Ss receiving pentobarbital during both training and extinction had more total extinction responding than Ss receiving only pentobarbital in extinction.

Effects of stimulus control and deprivation upon discriminative responding

Discriminative responding in pigeons was studied under multiple variable-interval extinction schedules in which extinction was correlated with either a tone or a white keylight. The two procedures resulted in weak and strong stimulus control, respectively. In the first experiment, there was no interaction between schedule components when stimulus control was strong and reinforcement was omitted under the previously reinforced component. However, there was marked induction between components when stimulus control was weak and responding was extinguished under the previously reinforced component. In the second experiment, hours of food deprivation was varied under two levels of stimulus control. Deprivation mainly influenced response rates under the extinction stimulus, with greater absolute rate increases occurring the lower the existing level of stimulus control. Increases in responding during the extinction stimulus were four times as great from 24 to 72 hours of deprivation as from 24 to 48 hours under conditions of both high and low stimulus control.

Behavior modification of exessive noise in a young Basenji

Use of a bell contingent upon howling was mildly aversive to a young Basenji and led to decreased noise.

Effects of Punishing Different Bands of IRTS on DRL Responding

The present study compared the effects of punishing different bands of noncriterion IRTs during a DRL 20-sec. schedule on bursts of responding. Results indicated that punishing relatively short or long noncriterion IRTs was equally effective, as contrasted with a control group, in producing a significant decrease in the percentage of bursts. Findings were discussed in terms of a stimulus feedback interpretation of bursts.

Punishment and rate of positive reinforcement

This experiment investigated the effect of several punishment intensities on two responses maintained by contrasting rates of reinforcement. The responses were concurrently reinforced according to two different variable-interval schedules. Because these schedules were independent of one another and programmed different rates of reinforcement, the two responses occurred at dissimilar rates. When responses were simultaneously suppressed by punishment, both rates were reduced proportionately until suppression was virtually complete. In other words, the per cent suppression resulting from punishment was independent of the rate at which the response was reinforced. Phenomena found in single-response studies were duplicated here. Responding tended to increase both within and between punishment sessions at mild and moderate punishment intensities. Cessation of punishment led to a "compensatory" overshooting beyond the prepunished response rate.

A comparison of the punishing effects of response-produced shock and response-produced time out

Electric shock and time out were compared as punishers in the squirrel monkey. At the parameters investigated, both suppressed responding to about the same degree. Scheduling punishment intermittently or administering pentobarbital reduced the effectiveness of both punishers. The effects of the punishers were different in that responding suppressed by shock recovered more within a session than responding suppressed by time out. Responding was suppressed after some shock-punishment components, but less often after time-out-punishment components. The similarities of the two punishers were more striking than the differences.

A DRL schedule with temporal adjustment

Rats under 48-hr. water deprivation were placed on a DRL schedule that required IRTs of 30 sec. or 60 sec. for the first component and longer IRTs of 120 sec., 150 sec., 180 sec., 240 sec., or 300 sec. for the second component. Ss were switched back and forth between components on the basis of their IRTs. These two-component DRL schedules utilizing various time requirements quickly produced rates of response as low as 20 per hour and still maintained responding over a 4-hr. session. When Ss were changed from the initial two-component DRL schedules to another, shifts in response rates occurred during the first session after a change and remained steady over several additional sessions.

Conditioned acceleration and conditioned suppression in pigeons

Two experiments were performed to investigate the effects on pigeons' keypecking behavior of stimuli that signal different kinds of aversive events: time-out from positive reinforcement, electric shock, loud noise, and loud tone. Behavior maintained by a variable-interval schedule of reinforcement was suppressed by a stimulus before shock, was accelerated by a stimulus before time-out from positive reinforcement, and was unchanged by a stimulus before loud noise or a stimulus before loud tone. Conditioned acceleration with time-out from positive reinforcement and conditioned suppression with shock were obtained regardless of whether a response contingent or response-independent procedure was employed.

Self-control procedures in personal behavior problems

A rationale for the use of self-control procedures in counseling is presented, along with illustrative material from several case studies. Self-control, as used here, involves specification of the behavioral deficit or desired behaviors which are lacking, and having S himself set up or program the conditions which may produce the desired behavioral modification. The procedures selected are extensions from laboratory research in operant modification of behavior, and the counseling sessions may include training S in behavior analysis, with his own behaviors as the experimental data.