Frequency Of Reinforcement Research Articles

Comparing the Effectiveness of Restricted-Operant and Free-Operant Teaching Arrangements on Measures of Acquisition and Fluency Outcomes

Discrete-trial teaching (DTT), a restricted-operant teaching arrangement, and frequency-building instruction (FBI), a free-operant teaching arrangement, represent two instructional strategies derived from operant conditioning. Researchers and practicing behavior analysts have used both to establish and firm up novel stimulus-behavior relations. Despite the effectiveness of both procedures, few studies have compared the two techniques and assessed the effects on the emergence of fluent responding. The current study extends the research to typically developing college students to directly compare DTT and FBI. We taught participants the numerals 0-10 in unknown foreign languages (i.e., Mandarin, Arabic, and Hindi) using both procedures. Under both conditions, we held constant the number of practice trials and frequency of reinforcement. Results found quicker acquisition under restricted-operant conditions for all participants, though none of the participants met the desired frequency aim prior to the end of the study. We discuss the results of the study in the context of planning for learning across three stages of learning.

Study of the Physiological Characteristics of Drivers Facing Apparent Changes in Highway Tunnel Structures

The increasing frequency of structural damage and reinforcement repairs in long-term highway tunnels necessitates an understanding of their effects on drivers. This study examines drivers’ physiological responses to visible structural changes in highway tunnels. Using a vehicle static in-the-loop platform, we created various models of apparent tunnel structure changes for simulated driving experiments. These experiments enabled a detailed analysis of the effects of such changes on driver safety, utilizing metrics such as eye movements, regions of interest, heart rate, and vehicle speed. The results show that visible alterations in tunnel structures significantly affect drivers’ physiological responses. Structural spalling and fire residues within tunnel structures notably increased drivers’ vigilance and psychological stress, resulting in a 14.7% increase in the average number of fixations, a 26.35% increase in the average duration of fixations, and a 36.05% increase in heart rate variability. Additionally, tunnel spalling tends to cause drivers to accelerate or exceed the speed limit, with maximum speeds reaching 17.87% above the designed speed. In contrast, repairs involving cover arch erection had minimal impact on drivers, with eye movement and heart rate data similar to those in ordinary tunnels. However, reinforcement with steel strips and corrugated steel in tunnels has attracted significant attention, with the area of interest exceeding 50% of the tunnel area, potentially leading to distracted driving. This study clarifies the extent of the influence of visible tunnel structure changes on drivers, providing a reference for damage assessment, reinforcement, and repair measures for long-term operated tunnels.

Validation of a Behavioral Activation Model Including Self-Compassion: A Longitudinal Study at Three Time Points

Introduction: Depression is highly prevalent among university students. While behavioral activation has been shown to be an effective psychotherapy for depression, there is a lack of research regarding the behavioral activation mechanism. Furthermore, although self-compassion seems to be a factor in promoting behavioral activation, no studies have attempted to validate a behavioral activation model that includes positive self-compassion. In addition, mechanistic studies have lacked consideration in longitudinal studies of behavioral activation. Thus, in this longitudinal study, we constructed and validated an exploratory model of behavioral activation. Methods: A total of 300 undergraduate students completed online surveys in 2019, 2020, and 2021. We examined the longitudinal effects of five factors (value-based behavior, goal-oriented and scheduled activities, positive reinforcement, self-compassion, and depressive symptoms) using structural equation modeling based on maximum likelihood estimation using bootstrapping. Results: The exploratory model was found to be valid and to have a good fit with the data. The results indicate that value-based behaviors increase the frequency of goal-oriented and scheduled activities, which in turn increases the frequency of positive reinforcement in everyday life. Additionally, when self-compassion, value-based behavior, goal-oriented and scheduled activities, and positive reinforcement are considered together, self-compassion may be indirectly related to activation via value-based behavior. Conclusion: From the perspective of preventing depressive symptoms, it is important to increase the frequency of value-based activities. Furthermore, adding self-compassion is effective in behavioral activation to increase value-based activities. However, to address the limitations of this study, future studies should investigate the relationship among behavioral characteristics during interventions.

The influence of reinforcement’s congestion to the strength of centrally compressed concrete members with GFRP reinforcement

The article presents the results of the computational analysis of compressed concrete columns of a water tank with GFRP reinforcement. It is analytically proved that with an increase in the confinement reinforcement ratio and the magnitude of the relative lateral pressure coefficient due to an increase in the congestion of the longitudinal and transverse reinforcement, the strength of the effectively compressed core increases linearly. The strength of the effectively confined concrete core in GFRP reinforced specimens is somewhat less compared to similar specimens reinforced with steel reinforcement. The coefficient of strengthening of columns (in relation to a pure concrete specimen without reinforcement) increases with increasing frequency of transverse reinforcement. At the same time, the calculated strength of columns with GFRP reinforcement is only 10% less than that of similar columns with steel reinforcement.

Divided stimulus control depends on differential and nondifferential reinforcement: Testing a quantitative model.

We investigated the effects of differential and nondifferential reinforcers on divided control by compound-stimulus dimensions. Six pigeons responded in a delayed matching-to-sample procedure in which a blue or yellow sample stimulus flashed on/off at a fast or slow rate, and subjects reported its color or alternation frequency. The dimension to report was unsignaled (Phase 1) or signaled (Phase 2). Correct responses were reinforced with a probability of .70, and the probability of reinforcers for errors varied across conditions. Comparison choice depended on reinforcer ratios for correct and incorrect responding; as the frequency of error reinforcers according to a dimension increased, control (measured by log d) by that dimension decreased and control by the other dimension increased. Davison and Nevin's (1999) model described data when the dimension to report was unsignaled, whereas model fits were poorer when it was signaled, perhaps due to carryover between conditions. We are the first to test this quantitative model of divided control with reinforcers for errors and when the dimension to report is signaled; hence, further research is needed to establish the model's generality. We question whether divided stimulus control is dimensional and suggest it may instead reflect joint control by compound stimuli and reinforcer ratios.

Instrumental learning and behavioral persistence in children with attention-deficit/hyperactivity-disorder: does reinforcement frequency matter?

Prominent theoretical accounts of attention-deficit/hyperactivity-disorder (ADHD) hypothesize that reinforcement learning deficits underlie symptoms of ADHD. The Dynamic Developmental Theory and the Dopamine Transfer Deficit hypothesis assume impairments in both the acquisition and extinction of behavior, especially when learning occurs under partial (non-continuous) reinforcement, and subsequently the Partial Reinforcement Extinction Effect (PREE). Few studies have evaluated instrumental learning in ADHD and the results are inconsistent. The current study investigates instrumental learning under partial and continuous reinforcement schedules and subsequent behavioral persistence when reinforcement is withheld (extinction) in children with and without ADHD. Large well-defined samples of children with ADHD (n = 93) and typically developing (TD) children (n = 73) completed a simple instrumental learning task. The children completed acquisition under continuous (100%) or partial (20%) reinforcement, followed by a 4-min extinction phase. Two-way (diagnosis by condition) ANOVAs evaluated responses needed to reach the learning criterion during acquisition, and target and total responses during extinction. Children with ADHD required more trials to reach criterion compared to TD children under both continuous and partial reinforcement. After partial reinforcement, children with ADHD executed fewer target responses during extinction than TD children. Children with ADHD executed more responses than TD children during extinction, irrespective of learning condition. The findings demonstrate general difficulties in instrumental learning in ADHD, that is, slower learning irrespective of reinforcement schedule. They also show faster extinction following learning under partial reinforcement in those with ADHD, that is, a diminished PREE. Children with ADHD executed more responses during extinction. Results are theoretically important, with clinical implications for understanding and managing learning difficulties in those with ADHD, as they suggest poorer reinforcement learning and lower behavioral persistence.

Effects of acute and chronic nicotine administration on probability discounting.

Nicotine use is a continuing public health concern. Smokers are more likely to make risky or maladaptive decisions compared to nonsmokers, so the relation between nicotine and risky choice warrants further investigation. Risky choice can be operationally defined as the choice for a larger, uncertain reinforcer over a smaller, certain reinforcer and can be assessed through a probability-discounting procedure. Acute nicotine administration has been shown to alter risky choice, but because the everyday smoker uses nicotine repeatedly, more research on chronic administration is needed and would allow for assessment of tolerance or sensitization of any effects. The present study examined effects of acute and repeated nicotine administration on probability discounting. Sprague-Dawley rats were used as subjects and the probability-discounting task involved discrete-trial choices between a small, certain reinforcer and a larger, uncertain reinforcer. The probability of larger-reinforcer delivery decreased across blocks within each session. Acute nicotine (0.1-1.0 mg/kg) administration dose-dependently increased risky choice, increased lose-stay ratios (a measure of response perseveration), and decreased reinforcement frequency. Tolerance to nicotine's effects on larger-reinforcer choice was observed after repeated 1.0 mg/kg nicotine administration. The results of the present study add to the existing literature that acute nicotine administration increases risky choice and demonstrates that tolerance to this effect develops after chronic exposure to the drug. Possible behavioral mechanisms behind this effect are discussed, as are suggestions for future research on nicotine and risky choice.

A test of the evolutionary theory's account of punishment superimposed on single-alternative schedules.

A test of the evolutionary theory was conducted by replicating Bradshaw et al.'s (1977, 1978, 1979) experiments in which human participants worked on single-alternative variable-interval (VI) schedules of reinforcement under three punishment conditions: no punishment, superimposed VI punishment, and superimposed variable-ratio (VR) punishment. Artificial organisms (AOs) animated by the theory worked in the same environments. Four principal findings were reported for the human participants: (1) their behavior was well described by an hyperbola in all conditions, (2) the asymptote of the hyperbola under VI punishment was equal to the asymptote in the absence of punishment, but the asymptote under VR punishment was lower than the asymptote in the absence of punishment, (3) the parameter in the denominator of the hyperbola was larger under both VI and VR punishment than in the absence of punishment, and (4) response suppression under punishment was greater at lower than at higher reinforcement frequencies. These four outcomes were also observed in the behavior of the AOs working in the same environments, thereby confirming the theory's first-order predictions about the effects of punishment on single-alternative responding.

Nondrug reinforcers contingent on alternative behavior or abstinence increase resistance to extinction and reinstatement of ethanol-maintained behavior.

The effects of delivering nondrug alternative reinforcement on resistance to extinction and reinstatement of rats' ethanol-maintained lever pressing were evaluated in two experiments. In both, rats self-administered ethanol by lever pressing in a two-component multiple schedule during baseline. In the Rich component, alternative food reinforcement was made available for performing an alternative response (Experiment 1) or according to a differential-reinforcement-of-other-behavior schedule for lever pressing (Experiment 2). In the Lean component, only ethanol was available. Moreover, the frequency of alternative reinforcement was manipulated across conditions in Experiment 1. Following baseline, lever pressing was extinguished in both components by suspending ethanol reinforcement, and alternative food reinforcers were discontinued. Finally, to test for reinstatement, ethanol reinforcers were delivered independently of lever pressing in both components. In both experiments, proportion-of-baseline response rates were higher during extinction and reinstatement testing in the Rich component than in the Lean component (although differentiation was not observed at the lowest frequency of alternative reinforcement in Experiment 1). Thus, alternative nondrug reinforcers increased resistance to extinction and reinstatement of rats' ethanol-maintained lever pressing, even when those reinforcers were delivered contingently on an alternative response or on abstinence from lever pressing.

КОМПЬЮТЕРИЗИРОВАННАЯ ДИНАМИЧЕСКАЯ ОЦЕНКА ОБУЧАЕМОСТИ СТУДЕНТОВ ВРЕМЕНАМ ГЛАГОЛОВ В АНГЛИЙСКОМ ЯЗЫКЕ

Statement of the problem. Computerized dynamic assessment of aptitude for learning foreign languages ​​is insufficiently represented in educational practice. The paper reveals new possibilities of using information technologies for solving a topical issue of diagnosing aptitude for learning a foreign language as an integral dynamic indicator for monitoring the quality of foreign language teaching. The instrumental basis for the computerized dynamic assessment of learning criteria is the dynamic computerized test simulators (DCTS) of educational activity. The purpose of the article is to study the potential of dynamic computer test simulators “English Language Tenses” as an instrument of dynamic assessment of students’ aptitude for learning the English language verbal tenses. Research methodology includes analysis of studies by Russian and international scientists on computerization of dynamic assessment of English language learning. The methods used in the computerization of dynamic learning assessment are based on the theory of development by J. Piaget, reinforcement learning, activity and environment approaches to the analysis of procedural characteristics of learning activities. Research results. We developed instrumental tools for diagnostics of learning aptitude – DCTS “English Language Tenses”. Experimentally, two groups of subjects were chosen so that they differed from each other in the dynamics of procedural characteristics of educational activity: the first group was characterized by a monotonous decrease in the number of errors with an increase in the number of the task being performed; the second group was characterized by a non-monotonous decrease in the number of errors, disturbed by an abrupt increase in the number of errors. The subjects of the first student group, as a rule, have a greater learning potential or learning aptitude, in comparison with the subjects of the second group. Approbation was carried out and recommendations were given for the use of the DCTS “English Language Tenses” for monitoring the process of teaching English. Conclusions. Analyzing the results of experimental testing of the DCTS “English Language Tenses” in the dynamic assessment of English learning, the authors come to the conclusion that it is advisable to use the procedural characteristics of learning activities: labor intensity, temporal pace, frequency of errors and reinforcement of learning activities as indicators for monitoring English language learning. The considered approach to the diagnostics of students’ aptitude for learning the tenses of the English language provides information about features of developing cognitive functions in students.

Long-term efficacy of contingency management treatment based on objective indicators of abstinence from illicit substance use up to 1 year following treatment: A meta-analysis.

Contingency management (CM) is often criticized for limited long-term impact. This meta-analysis focused on objective indices of drug use (i.e., urine toxicology) to examine the effects of CM on illicit substance use up to 1 year following treatment. Analyses included randomized trials (k = 23) of CM for stimulant, opioid, or polysubstance use disorders that reported outcomes up to 1 year after the incentive delivery had ended. Using random effects models, odds ratios (OR) were calculated for the likelihood of abstinence. Metaregressions and subgroup analyses explored how parameters of CM treatment, namely escalation, frequency, immediacy, and magnitude of reinforcers, moderated outcomes. The overall likelihood of abstinence at the long-term follow-up among participants who received CM versus a comparison treatment (nearly half of which were community-based comprehensive therapies or protocol-based specific therapies) was OR = 1.22, 95% confidence interval [1.01, 1.44], with low to moderate heterogeneity (I² = 36.68). Among 18 moderators, longer length of active treatment was found to significantly improve long-term abstinence. CM showed long-term benefit in reducing objective indices of drug use, above and beyond other active, evidence-based treatments (e.g., cognitive-behavioral therapy, 12-step facilitation) and community-based intensive outpatient treatment. These data suggest that policymakers and insurers should support and cover costs for CM, which is the focus of hundreds of studies demonstrating its short-term efficacy and, now, additional data supporting its long-term efficacy. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Remifentanil-food choice follows predictions of relative subjective value

BackgroundPreclinical studies into drug vs. nondrug choice have emerged to better model and investigate the neurobehavioral mechanisms underlying drug preference. Current literature has suggested that drugs of abuse have inherently low value, thus promoting food preference. Herein, we examined remifentanil vs. food choice to test both the relative value hypothesis and the ‘direct effects’ (pharmacological effects of drugs on alternative reinforcers) hypothesis of opioid preference. MethodsAdult male rats were trained under two choice procedures (controlled vs. uncontrolled reinforcer frequency) for remifentanil vs. food choice. Furthermore, a series of procedural manipulations known to affect drug reinforcement were tested under both choice procedures. Using remifentanil self-administration data, pharmacokinetic profiles were calculated and analyzed to determine if opioid intake was related to opioid preference. ResultsBoth choice procedures produced dose-dependent preference. Moreover, procedural manipulations produced comparable changes in remifentanil preference under both choice procedures. In addition, calculated pharmacokinetic data revealed that preference was dissociable from intake under the controlled reinforcer frequency choice procedure. ConclusionsWhen compared to the ‘direct effects’ hypothesis, remifentanil preference was better predicted by the relative value hypothesis, formalized in generalized matching. Use of a controlled reinforcer frequency schedule successfully removed the drug preference-intake confound found in most drug-choice procedures. Importantly, drug preference under the controlled reinforcer frequency schedule remained sensitive to procedural manipulations known to affect drug reinforcement. Thus, given that differential drug intake itself affects neurobiological measurements, future use of controlled reinforcer frequency schedules may help to better isolate the neurobehavioral mechanisms that mediate opioid preference.

ФИБРОБЕТОН ДЛЯ 3-D АДДИТИВНЫХ ТЕХНОЛОГИЙ

fine-grained fiber concrete used in 3D printing is significantly different from conventional heavy concrete, which is determined by the increased consumption of cement, low water-cement ratio and the absence of large aggregates. The largest grain size of fine aggregate is selected taking into account the thickness of the section, the frequency and type of reinforcement, as well as the method of concrete placement. Despite the fact that the tensile strength of concrete on fine sand is more than 1.5 times higher than the strength of concrete on coarse sand, while there is a decrease in compressive strength. Due to the peculiarities of the technology of concrete manufacturing for layering, the use of coarse sands is impractical, and therefore it was decided to use quartz sand with a particle size module of 1.12 as a filler.

Effects of reward magnitude and training frequency on the learning rates and memory retention of the Port Jackson shark Heterodontus portusjacksoni.

The development of adaptive responses to novel situations via learning has been demonstrated in a wide variety of animal taxa. However, knowledge on the learning abilities of one of the oldest extant vertebrate groups, Chondrichthyes, remains limited. With the increasing interest in global wildlife tourism and shark feeding operations, it is important to understand the capacities of these animals to form associations between human activities and food. We used an operant conditioning regime with a simple spatial cognitive task to investigate the effects of reinforcement frequency and reward magnitude on the learning performance and memory retention of Port Jackson sharks (Heterodontus portusjacksoni). Twenty-four Port Jackson sharks were assigned one of four treatments differing in reward magnitude and reinforcement frequency (large magnitude-high frequency; large magnitude-low frequency; small magnitude-high frequency; small magnitude-low frequency). The sharks were trained over a 21-day period to compare the number of days that it took to learn to pass an assigned door to feed. Sharks trained at a high reinforcement frequency demonstrated faster learning rates and a higher number of passes through the correct door at the end of the trials, while reward magnitude had limited effects on learning rate. This suggests that a reduction in reinforcement frequency during tourism-related feeding operations is likely to be more effective in reducing the risk of sharks making associations with food than limiting the amount of food provided.

Pair housing, but not using a controlled reinforcer frequency procedure, attenuates the modulatory effect of probability presentation order on amphetamine-induced changes in risky choice

Probability discounting is often measured with independent schedules. Independent schedules have several limitations, such as confounding preference for one alternative with frequency of reward presentation and generating ceiling/floor effects at certain probabilities. To address this potential caveat, a controlled reinforcer frequency schedule can be used, in which the manipulandum that leads to reinforcement is pseudo-randomly determined before each trial. This schedule ensures subjects receive equal presentations of the small and large magnitude reinforcers across each block of trials. A total of 24 pair-housed and 11 individually housed female Sprague Dawley rats were tested in a controlled reinforcer frequency procedure. For half of the rats, the odds against (OA) receiving the large magnitude reinforcer increased across the session (ascending schedule); the OA decreased across the session for half of the rats (descending schedule). Following training, rats received treatments of amphetamine (AMPH; 0, 0.25, 0.5, 1.0 mg/kg; s.c.). For pair-housed rats, AMPH (0.5 mg/kg) increased risky choice, regardless of probability presentation order, whereas a higher dose of AMPH (1.0 mg/kg) decreased discriminability of reinforcer magnitude for rats trained on the descending schedule only. For individually housed rats, probability presentation order modulated the effects of AMPH on probability discounting, as AMPH (0.25 and 0.5 mg/kg) increased risky choice in rats trained on the ascending schedule but not on the descending schedule. These results show that pair-housing animals, but not using a controlled reinforcer frequency procedure, attenuates the modulatory effects of probability presentation order on drug effects on risky choice.

Decreasing Target Behavior in a Child Using Functional Behavior Assessment and Differential Reinforcement.

Techniques of behavior modification were employed to address the target behavior of functional excessive coughing-psychogenic cough in a 12-y-old boy referred by a pediatrician who found no identifiable medical reasons. To identify the purpose that maintains the behavior, functional behavior assessment was carried out and in order to reduce the frequency of target behavior, extinction and differential reinforcement of behavior analysis was incorporated. The management resulted in significant decrease of the target behavior of coughing without any medical intervention. Behavior modification is the most empirically supported intervention not only for children with developmental delays but for typical individuals as well.

Fiber Concrete for 3-D Additive Technologies

Fine-grained fiber concrete used in 3D printing is significantly different from conventional heavy concrete, which is determined by the increased consumption of cement, low water-cement ratio and the absence of large aggregates. The largest grain size of fine aggregate is selected taking into account the thickness of the section, the frequency and type of reinforcement, as well as the method of concrete placement. Despite the fact that the tensile strength of concrete on fine sand is more than 1.5 times higher than the strength of concrete on coarse sand, while there is a decrease in compressive strength. Due to the peculiarities of the technology of concrete manufacturing for layering, the use of coarse sands is impractical, and therefore it was decided to use quartz sand with a particle size module of 1.12 as a filler.

Effectiveness of different modes of school dental health education on the oral health status of children - an interventional study with 2-year follow-up

ABSTRACTThe aim of the study was to compare the effectiveness of three modes of school dental health education (SDHE) and the two frequencies of reinforcements, on the oral health status of children. Three hundred and sixty school children aged 8 to 9 years participated in this study. Dental caries (dft/DMFT), oral hygiene (OHI-S) and oral health-related quality of life (OHRQoL) scores were recorded by a calibrated investigator. The interventions included three different modes of SDHE (drama, game and flashcards). One mode of SDHE was randomly allotted to each school. Children were randomly sub-divided based on the frequency of reinforcement provided (3 months and 6 months). Post-intervention data were collected after 2 years. There was a significant reduction in the dft [drama (p = 0.006), game (p = 0.001) and flashcards (p = 0.002)] and OHI-S scores [drama and game (p < 0.001) and flashcards (p = 0.01)] and significant improvement in the total OHRQoL scores [drama (p = 0.001), game (p = 0.016) and flashcards (p = 0.023)] in all the three modes. Children who received game mode SDHE every 3 months had a significantly higher number of filled primary teeth (p = 0.03) compared to children who received the reinforcement every 6 months. All three modes were effective in improving the oral health status of school children. Game mode had the highest impact followed by drama and flashcard modes. Reinforcements given every 3 months using the game mode had a positive influence on the oral health of these children. Health educators must focus on child-friendly modes to make the health information more retentive.

Cocaine-associated decision-making: Toward isolating preference

Ever-increasing evidence suggests that substance use disorder is mediated by decision-making processes, and as such, providing nondrug alternatives can shift maladaptive preferences away from drug reinforcers, such as cocaine. Of note, a recent hypothesis suggests that preference for cocaine is simply a byproduct of cocaine intake, such that the ‘direct’ effects of cocaine weaken the impact of non-drug alternatives while measuring choice. Conversely, existing quantitative theories of decision-making suggest preference is determined by various dimensions of concurrent reinforcers that in turn determine the relative value of available alternatives. Toward teasing apart the conflicting theories above, we developed a novel drug-choice procedure to control for reinforcer frequency and magnitude (two reinforcer dimensions well known to influence preference) that consequently controls for overall cocaine intake. As predicted by quantitative choice theory, results suggest that cocaine intake and preference are dissociable while measuring choice, with reinforcer frequency and magnitude having independent influence on the relative value of choice alternatives. Furthermore, we demonstrate that the choice procedure is sensitive to various manipulations known to alter cocaine reinforcement, all while keeping cocaine intake constant. Finally, the results point to the process of economic substitution as an important avenue of future neurobehavioral investigation toward the improvement of behavioral and pharmacological therapies for substance use disorders. Overall, the proposed choice procedure will allow for improved isolation of the neurobehavioral processes that mediate drug-associated decision-making in future studies.

Frequency and value both matter in the suboptimal choice procedure.

Pigeons chose between two options on a concurrent-chains task with a single response requirement in the initial link. The suboptimal option ended with food 20% of the time whereas the optimal option ended with food 80% of the time. During a Sig-Both condition, terminal-link stimuli on both options signaled whether or not food would occur. During a Sig-Sub condition, terminal-link stimuli on the suboptimal option provided differential signals, but stimuli on the optimal option did not differentially signal the food and no food outcomes. Initial-link choices revealed a clear preference for the optimal option in the Sig-Both condition, but preference shifted toward suboptimality in the Sig-Sub condition. These findings show that pigeon suboptimal choice is not singularly driven by signal value, as has been suggested, but also by reinforcer frequency.