Concurrent Schedules Of Reinforcement Research Articles

The Effects of Varying Quality and Duration of Reinforcement on Mands to Work, Mands for Break, and Problem Behavior

Research on the effects of concurrent schedules of reinforcement during treatment of problem behavior has shown that response allocation can be biased in favor of adaptive responses by providing increased reinforcement for these responses. However, this research has focused on the effects of only two concurrently available response options. In applied situations, it is likely that more than two concurrently available response options exist. The purpose of this study was to evaluate the effects of varying qualities and durations of reinforcement on problem behavior, mands for breaks, and mands to work. Participants were 5 to 12 years old, had disabilities, and displayed escape-motivated problem behavior. Results showed that all participants' responding was sensitive to changes in quality and duration of reinforcement. That is, participants allocated responding to the response that produced the highest quality and longest duration of reinforcement. These results are consistent with previous literature on choice when two concurrent schedules of reinforcement were in effect. Implications for practice are discussed, as well as future research that could expand the findings.

A COMPUTATIONAL THEORY OF SELECTION BY CONSEQUENCES APPLIED TO CONCURRENT SCHEDULES

Virtual organisms animated by a computational theory of selection by consequences responded on symmetrical and asymmetrical concurrent schedules of reinforcement. The theory instantiated Darwinian principles of selection, reproduction, and mutation such that a population of potential behaviors evolved under the selection pressure exerted by reinforcement from the environment. The virtual organisms' steady-state behavior was well described by the power function matching equation, and the parameters of the equation behaved in ways that were consistent with findings from experiments with live organisms. Together with previous research on single-alternative schedules (McDowell, 2004; McDowell & Caron, 2007) these results indicate that the equations of matching theory are emergent properties of the evolutionary dynamics of selection by consequences.

Distinct subsets of nucleus accumbens neurons encode operant responding for ethanol versus water

Subsets of nucleus accumbens (NAc) neurons process information about operant responses for drugs as well as natural rewards (food and water) by excitations and inhibitions in firing rate time-locked to the operant response. The degree to which ensembles of neurons exhibit similar firing patterns when encoding cues and operant responses across different reinforcer conditions will provide critical information regarding the functional organization of this nucleus. The present experiment evaluated the relative contribution of subsets of accumbens neurons that encode distinct features of lever press responding for ethanol vs. water. Electrophysiological recordings (n = 153 neurons) were made in the accumbens of rats trained on concurrent reinforcement schedules for ethanol and water throughout a self-administration session. During operant responding, 52% of neurons exhibited patterned discharges characterized by significant increases or decreases in firing rate of +/- 1 s relative to lever presses for ethanol and/or water. Of these phasic cells, 85% discriminated between presses for ethanol and water (i.e. exhibited firing patterns unique to one reinforcer type), while 15% exhibited identical firing patterns relative to lever presses for both reinforcers. Notably, the data revealed that both high ethanol preference and spatially distinct lever positions contributed to the reinforcer specificity. Together, these data demonstrate that subsets of NAc neurons encode conditioned and instrumental aspects of ethanol vs. water reinforcement in well-trained rats, and that reinforcer preference and spatial cues are important components of this differential information processing.

Effects of acute and chronic aripiprazole treatment on choice between cocaine self-administration and food under a concurrent schedule of reinforcement in rats

Dopamine D2-like partial agonists such as aripiprazole have received some attention as potential pharmacotherapies for the treatment of psychostimulant addiction. However, the preclinical evaluations so far have focused on acute effects of aripiprazole. We tested the hypothesis that aripiprazole, both as acute and as chronic treatment, would preferentially decrease cocaine self-administration while sparing behavior maintained by a natural reinforcer, resulting in a shift in the allocation of behavior from cocaine-taking towards the alternative reinforcer. Rats were trained to self-administer intravenous cocaine in a concurrent choice procedure, with a palatable food as the competing reinforcer, under a fixed ratio (FR) 1 FR 5 chain schedule. Aripiprazole was then administered as continuous infusion by osmotic minipumps for 5 days, during which performance in the choice procedure was assessed daily. An intermediate dose of aripiprazole decreased cocaine self-administration and shifted the cocaine choice curve to the right as an acute treatment. However, as a chronic treatment, aripiprazole failed to decrease cocaine self-administration or cocaine choice, despite a dose-dependent decrease in overall response rates and food-maintained behavior. Our results confirm and extend earlier findings and indicate that acute administration of aripiprazole can decrease cocaine self-administration. However, based on the present data, chronic treatment with aripiprazole does not show much promise as a potential pharmacotherapy for cocaine addiction. Both acute and chronic treatment data are in agreement with published clinical findings, suggesting that the concurrent choice procedure in rats has predictive validity of efficacy in humans.

Cue-induced reinstatement of alcohol-seeking behavior is associated with increased ERK 1/2 phosphorylation in specific limbic brain regions: Blockade by the mGluR5 antagonist MPEP

Relapse to alcohol use after periods of abstinence is a hallmark behavioral pathology of alcoholism and a major clinical problem. Emerging evidence indicates that metabotropic glutamate receptor 5 (mGluR5) antagonists attenuate relapse to alcohol-seeking behavior but the molecular mechanisms of this potential therapeutic effect remain unexplored. The extracellular signal-regulated kinase (ERK 1/2) pathway is downstream of mGluR5 and has been implicated in addiction. We sought to determine if cue-induced reinstatement of alcohol-seeking behavior, and its reduction by an mGluR5 antagonist, is associated with changes in ERK 1/2 activation in reward-related limbic brain regions. Selectively-bred alcohol-preferring (P) rats were trained to lever press on a concurrent schedule of alcohol (15% v/v) vs. water reinforcement. Following 9 days of extinction, rats were given an additional extinction trial or injected with the mGluR5 antagonist MPEP (0, 1, 3, or 10 mg/kg) and tested for cue-induced reinstatement. Brains were removed 90-min later from the rats in the extinction and MPEP (0 or 10 mg/kg) conditions for analysis of p-ERK 1/2, total ERK 1/2, and p-ERK 5 immunoreactivity (IR). Cue-induced reinstatement of alcohol-seeking behavior was associated with a three to five-fold increase in p-ERK 1/2 IR in the basolateral amygdala and nucleus accumbens shell. MPEP administration blocked both the relapse-like behavior and increase in p-ERK 1/2 IR. p-ERK 1/2 IR in the central amygdala and NAcb core was dissociated with the relapse-like behavior and the pharmacological effect of mGluR5 blockade. No changes in total ERK or p-ERK 5 were observed. These results suggest that exposure to cues previously associated with alcohol self-administration is sufficient to produce concomitant increases in relapse-like behavior and ERK 1/2 activation in specific limbic brain regions. Pharmacological compounds, such as mGluR5 antagonists, that reduce cue-induced ERK 1/2 activation may be useful for treatment of relapse in alcoholics that is triggered by exposure to environmental events.

Relationship between response rates and measures of reinforcing strength using a choice procedure in monkeys

Concurrent schedules of reinforcement are increasingly being used to investigate the reinforcing strength of abused drugs. A purported advantage of concurrent schedules is that the primary dependent measure, percentage of responses emitted on the drug-associated manipulandum, is independent of the rate-altering effects of drugs. Data supporting this hypothesis are, however, rarely presented, which was one goal of this study. In addition, we tested the hypothesis that drug-induced decreases in response rates provides an additional index to characterize abuse liability of drugs. This study examined the relationship between response rate and response allocation (i.e. drug choice) when 3,4-methylenedioxymethamphetamine (MDMA, 0.03-0.3 mg/kg/inj) or cocaine (0.003-0.1 mg/kg/inj) was the alternative to food under concurrent fixed-ratio reinforcement schedules in rhesus (n=4) and cynomolgus (n=16) monkeys, respectively. Increasing doses of MDMA or cocaine resulted in increased drug choice and dose-dependent decreases in overall response rates. For both drugs, response rates on the drug-associated lever were not affected by dose and were not different from saline. Furthermore, at most doses, rates of responding on the food-associated lever were significantly higher than response rates on the drug-associated lever. Finally, MDMA but not cocaine decreased food-reinforced responding, providing evidence for potential differences between the drugs. These results demonstrate that under concurrent food-drug reinforcement schedules, response rates on the drug-associated lever are independent of measures of reinforcement, whereas disruptions in food-maintained responding may be inversely related to abuse liability.

Concurrent schedules of positive and negative reinforcement: differential-impact and differential-outcomes hypotheses.

Considerable evidence from outside of operant psychology suggests that aversive events exert greater influence over behavior than equal-sized positive-reinforcement events. Operant theory is largely moot on this point, and most operant research is uninformative because of a scaling problem that prevents aversive events and those based on positive reinforcement from being directly compared. In the present investigation, humans' mouse-click responses were maintained on similarly structured, concurrent schedules of positive (money gain) and negative (avoidance of money loss) reinforcement. Because gains and losses were of equal magnitude, according to the analytical conventions of the generalized matching law, bias (log b (double dagger) 0) would indicate differential impact by one type of consequence; however, no systematic bias was observed. Further research is needed to reconcile this outcome with apparently robust findings in other literatures of superior behavior control by aversive events. In an incidental finding, the linear function relating log behavior ratio and log reinforcement ratio was steeper for concurrent negative and positive reinforcement than for control conditions involving concurrent positive reinforcement. This may represent the first empirical confirmation of a free-operant differential-outcomes effect predicted by contingency-discriminability theories of choice.

Random-ratio schedules of reinforcement: The role of early wins and unreinforced trials

The distribution of rewards in both variable-ratio and random-ratio schedules is examined with specific reference to gambling behaviour. In particular, it is the number of early wins and unreinforced trials that is suggested to be of importance in these schedules, rather than the often-reported average frequency of wins. Gaming machine data are provided to demonstrate the importance of early wins and unreinforced trials. Additionally, the implication of these distributional properties for betting strategies and the gambler's fallacy is discussed. Finally, the role of early wins and unreinforced trials is considered for gambling research that utilises simulated gaming machines and research that compares concurrent schedules of reinforcement.

Effect on subsequent fixed-interval schedule performance of prior exposure to ratio and interval schedules of reinforcement

In three experiments, we examined the effect on the patterns of responding noted on fixed interval (FI) schedules of prior exposure to a range of interval and ratio schedules. Rats leverpressed for food reinforcement on random ratio (RR), random interval (RI), or variable interval (VI) schedules prior to transfer to FI schedules. In Experiment 1, prior exposure to an RR schedule retarded the development of typical FI patterns of responding. Exposure to a yoked RI schedule produced even greater retardation of typical FI performance. This effect was replicated in Experiment 2, using a within-subjects design. Rats responded on a multiple RR-RI schedule prior to a multiple FI-FI schedule. Typical FI performance emerged more slowly in the component previously associated with the RI than with that associated with the RR. In Experiment 3, exposure to an RR schedule retarded the development of FI performance to a greater extent than did exposure to a VR schedule. The latter schedule was programmed to allow the possibility that inhibitory control would develop after reinforcement. These results confirm that ratio schedules independently result in the disruption of FI responding. This effect was not long lasting and cannot be used plausibly to explain species differences in responding to FI schedules. However, it does suggest that temporal control--as manifested by the transfer of inhibitory control from one schedule to another--could facilitate movement between interval schedules.

Effect of contingent auditory stimuli on concurrent schedule performance: An alternative punisher to electric shock

This study explored whether load auditory stimuli could be used as functional punishing stimuli in place of electric shock. Three experiments examined the effect of a loud auditory stimulus on rats' responding maintained by a concurrent reinforcement schedule. In Experiment 1, overall response rate decreased when a concurrent 1.5 s tone presentation schedule was superimposed on the concurrent variable interval (VI) 180-s, VI 180-s reinforcement schedule. On the contrary, response rate increased when a click presentation schedule was added. In Experiment 2, the extent of the response suppression with a 1.5 s tone presentation varied as a function of the frequency of the reinforcement schedule maintaining responses; the leaner the schedule employed, the greater the response suppression. In Experiment 3, response suppression was observed to be inversely related to the duration of the tone; response facilitation was observed when a 3.0-s tone was used. In Experiments 1 and 2, a preference shift towards the alternative with richer reinforcement was observed when the tone schedule was added. In contrast, the preference shifted towards the leaner alternative when the click or longer duration stimulus was used. These results imply that both the type and duration of a loud auditory stimulus, as well as the reinforcement schedule maintaining responses, have a critical role in determining the effect of the stimuli on responding. They also suggest that a loud auditory stimulus can be used as a positive punisher in a choice situation for rats, when the duration of the tone is brief, and the reinforcement schedule maintaining responses is lean.

Effects of mGlu1-receptor blockade on ethanol self-administration in inbred alcohol-preferring rats

The Group I family of metabotropic glutamate receptors includes subtype 1 (mGlu1) and subtype 5 (mGlu5) receptors. This family of receptors has generated interest as potential targets for different areas of therapeutic development, including intervention for alcohol and drug abuse. Most of this interest is driven by findings showing involvement of mGlu5 receptors in the regulation of drug self-administration; however, studies examining the role of mGlu1 receptors in drug self-administration are limited. The purpose of this work was to examine the role of mGlu1-receptor antagonism in the maintenance of ethanol self-administration and the self-administration of an alternate nondrug reward, sucrose. Male alcohol-preferring inbred rats were trained to self-administer ethanol (15% vol/vol) versus water on a concurrent schedule of reinforcement, and the effect of the mGlu1-receptor antagonist JNJ16259685 (0.1–1.0 mg/kg intraperitoneal [IP]) was evaluated on self-administration. The rats were then trained to self-administer sucrose (0.4% wt/vol) versus water, and the same dose range of JNJ16259685 was tested. Locomotor activity was tested in a separate assessment to evaluate potential nonspecific motor effects of the antagonist. Ethanol self-administration was dose dependently reduced by JNJ16259685. This reduction was likely due to a motor impairment as the lowest effective dose (0.1 mg/kg) significantly reduced locomotor behavior. Sucrose self-administration was reduced by the highest JNJ16259685 dose (1.0 mg/kg), and this reduction was also likely due to a motor impairment. Interestingly, ethanol self-administration was more sensitive to mGlu1-receptor antagonism than sucrose self-administration as lower JNJ16259685 doses reduced ethanol-reinforced responding and motor behavior. Together, these results suggest that mGlu1 receptors do not play a specific role in modulating ethanol self-administration or the self-administration of an alternate nondrug reward (i.e., sucrose).

Matching by fixing and sampling: A local model based on internality

Undermatching and overmatching in concurrent schedules of reinforcement have been traditionally described as changes in the slope of the Generalized Matching Law function. More recently, it has been suggested that deviations from strict matching may be better described as following a policy of mostly fixing on the preferred schedule, and occasionally sampling the alternative schedule. So far, no model of local performance predicts the global outcome of this policy. We describe one such model; it assumes immediate and long-term effects of reinforcement on local performance. The model assumes long-term effects as changes in the internal state of the organism. Formally, the model is analogous to the Axiom of Repeated Choice [Lefebvre, V.A., 2004. Bipolarity, choice, and entro-field. In: Proceedings of the Eighth World Multi-Conference on Systemics, Cybernetics and Informatics, vol. IV, pp. 95-99].

Contingência e contigüidade no responder de ratos submetidos a esquemas de razão, intervalo e tempo variáveis

No presente estudo, foram investigados os efeitos produzidos pela introdução de atraso do reforço sobre a taxa e a distribuição de freqüência das respostas de pressão à barra emitidas por oito ratos expostos a esquemas de intervalo, razão e tempo variáveis (VI, VR e VT, respectivamente). A partir de condições de linha de base sob reforçamento imediato, aplicou-se o atraso do reforço não sinalizado e non-resetting pelo tempo fixo de 5 s a cada um dos esquemas. Os resultados mostraram que, com a introdução do atraso do reforço, houve diminuição nas taxas de respostas de todos os sujeitos, em todos os três esquemas, mais acentuadamente sob VT, VI e VR, nesta ordem. A análise molecular dos dados revelou que, para os sujeitos sob VI, os valores efetivamente registrados de atrasos concentraram-se proximamente ao atraso programado de 5 s, enquanto que, para os sujeitos expostos a VR, os intervalos assumiram valores menores. Esses resultados demonstram, portanto, que os efeitos do atraso do reforço sobre o responder operante variam em função do esquema de reforçamento vigente. No presente estudo, o uso de VI e VR, cujos controles pelo tempo e pelo número de respostas caracterizam, respectivamente, cada um desses esquemas, foi acompanhado por efeitos diferenciados tanto nas taxas de resposta quanto na distribuição do responder no tempo.Palavras-chave: contingência; contigüidade; atraso do reforço; esquemas de reforçamento; ratos.

Regulation of Motivation to Self‐Administer Ethanol by mGluR5 in Alcohol‐Preferring (P) Rats

Emerging evidence indicates that Group I metabotropic glutamate receptors (mGluR1 and mGluR5) differentially regulates ethanol self-administration in several rodent behavioral models. The purpose of this work was to further characterize involvement of Group I mGluRs in the reinforcing effects of ethanol using a progressive ratio schedule of reinforcement. Alcohol-preferring (P) rats were trained to self-administer ethanol (15% v/v) versus water on a concurrent schedule of reinforcement, and the effects of the Group I mGluR antagonists were evaluated on progressive ratio performance. The rats were then trained to self-administer sucrose (0.4% w/v) versus water, and the effects of the antagonists were tested on progressive ratio performance. The mGluR1 antagonist, 3,4-dihydro-2H-pyrano[2,3]b quinolin-7-yl (cis-4-methoxycyclohexyl) methanone (JNJ 16259685; 0 to 1 mg/kg) and the mGluR5 antagonist, 6-methyl-2-(phenylethynyl) pyridine (MPEP; 0 to 10 mg/kg) dose-dependently reduced ethanol break point. In separate locomotor activity assessments, the lowest effective dose of JNJ 16259685 (0.3 mg/kg) produced a motor impairment, whereas the lowest effective dose of MPEP (3 mg/kg) did not. Thus, the reduction in ethanol break point by mGluR1 antagonism was probably a result of a motor impairment. JNJ 16259685 (0.3 mg/kg) and MPEP (10 mg/kg) reduced sucrose break point and produced motor impairments. Thus, the reductions in sucrose break point produced by both Group I antagonists were probably because of nonspecific effects on motor activity. Together, these results suggest that glutamate activity at mGluR5 regulates motivation to self-administer ethanol.

Discrete-trial vs. continuous free-operant procedures in assessing whether reinforcement context affects reinforcement value

Pigeons were trained to respond to two alternating concurrent reinforcement schedules. The reinforcement probabilities were .05 and .10 in one component, and .10 and .20 in the other. In one condition, the pigeons received training on a discrete-trial procedure in which the keylights remained illuminated for 5s or until a response occurred. In another condition, pigeons received training on a procedure in which the reinforcement contingencies were the same as in the discrete-trial procedure, but the stimuli were not turned off after 5s or after a response. Following training in each condition, probe tests were presented. In both conditions, the .20 alternative was, overall, preferred to the .05 alternative during probe tests. Following discrete-trial training, there was no reliable preference between the two .10 alternatives. However, when the stimuli remained illuminated during the intertrial interval periods during training, probe tests results showed preference for the .10 alternative that had been presented in the leaner context during training. The pattern of results is consistent with the notion that probe preference can be influenced both by the absolute reinforcement schedules associated with each alternative, as well as changeover behavior developed during training.

The value assigned to six different rooting materials by growing pigs

According to EU legislation pigs must have access to rooting material, and the aim of the study was to quantify growing pigs’ preferences among six different rooting materials. The relative attractiveness of six rooting materials was assessed in an operant conditioning set-up using concurrent schedules of reinforcement. Twelve pigs were tested with all six combinations of the reference material (peat) and one of the six test materials in a balanced design. The cost of access (fixed ratio of presses per reward (FR)) to both reference material and test material was varied (reference/test: FR8/FR40, FR16/FR32, FR24/FR24, FR32/FR16, FR40/FR8). For each combination, demand functions for both materials were estimated as a function of the cost of the reference material leading to a cross point of the two demand functions. The intercept of the demand functions for the test materials differed (1.27, 0.97, 0.91, 0.64, 0.53, 0.48 (±0.14) for maize silage with straw, compost, spruce chips, seed grass hay, sisal rope and chopped straw, respectively; P<0.001). The slopes of the demand functions for the six test materials did not differ. Furthermore, the demand functions for the reference material were not affected by test material. The cross point of the two demand functions for each of the six combinations was calculated to assess the relative attractiveness of the six test materials using the reference material as a common scaling factor. The cross points (95% confidence interval in brackets) revealed the following ranking (the lower values are the most preferred): maize silage with straw (14.2 (9.5–18.5)), spruce chips (18.0 (13.8–21.9)), compost (18.2 (13.8–22.3)), sisal rope (25.5 (21.4–29.6)), seed grass hay (27.1 (22.7–31.8)), chopped straw (28.5 (24.5–32.8)). All the tested materials were valued as much as chopped straw, but maize silage with straw, spruce chips and compost were valued higher. The results confirm that pigs prefer more complex and compound rooting materials.

The effect of housing rats in a stimulus rich versus stimulus poor environment on preference measured by sigmoid double demand curves

The cross-point between double demand curves, obtained by concurrent schedules of reinforcement, provides a measure of resource preference. Studies using operant conditioning have shown that animals may work for unused rewards and work even when not reinforced, which indicates that pressing a lever may be rewarding in itself. Animals actively seek stimulation when given the opportunity. It is likely that pressing is particularly rewarding for animals housed under barren conditions, and that they will perform more pressing than animals from stimulating environments. This constitutes a methodological problem if the cross-point is affected. The present experiment investigated if the double demand curve method is sensitive to differences in housing conditions. We tested if rats performed more pressing when housed under barren compared to stimulating conditions, and if cross-points were ultimately affected. The experiment also aimed at inspecting the shape of double demand curves. Sixteen rats worked concurrently for distilled water on one lever and quinine water on another. When workload was high for distilled water it was low for quinine water and vice versa. The rats were subjected alternately to four housing treatments: non-enriched (NE), object enriched (OE), social enriched (SE), and object and social enriched (OSE). Results showed a significant interaction between housing treatment and type of water ( P = 0.04). The distilled water lever received significantly more pressing than the quinine water lever, and the amount of pressing at the distilled water lever differed significantly between housing treatments. Rats were expected to press most when NE and least when OSE housed, but they pressed most when SE and least when OE housed. The double demand curves were s-shaped, which confirms findings from a previous experiment. The cross-point was significantly higher for OSE than NE ( P < 0.05), i.e. preference for distilled water was higher when rats were OSE housed than when they were NE housed. Results indicate that housing conditions may exert some effect on both the amount of pressing performed and cross-points, but results on pressing and cross-points did not agree. In contrast to expectation, impoverished conditions did not cause rats to press more. Thus, more studies are needed before any final conclusions about sensitivity of the double demand curve method towards differences in housing conditions can be drawn.

Concurrent schedules of reinforcement as a method to quantify the relative attractiveness of two rooting materials

Operant conditioning techniques were applied to investigate pigs’ preference for peat and long straw using concurrent schedules of reinforcement. Ten pigs worked, by pressing one of two panels, for access to two different materials in daily 50 min test sessions. Workloads of the reference material and the test materials, respectively, were varied in random order over 5 days with combinations of fixed ratios (FR) of 8/40, 16/32, 24/24, 32/16, 40/8. The slopes, intercepts and cross points of curves describing the number of rewards obtained of the reference material (peat) and the two test materials (peat and long straw) as a function of increasing workload of the reference material were estimated. Finally, the pigs worked for access to only one of the two materials at a time and the relation between number of rewards as a function of work load was estimated for the two materials. The increase in number of rewards of the test material with increasing workload for the reference material was higher for peat than for long straw ( t 301 = −2.4, P = 0.01) and the cross point for peat/peat was slightly lower (FR 26.7; 95% confidence interval: FR 23.8 to FR 29.6) than the cross point of long straw/peat (FR 31.0; 95% confidence interval: FR 27.5 to FR 35.0), indicating a slight preference for peat over long straw. There was no difference between the reference curves. Thus long straw substituted for peat. The validity of comparing the material on the reference panel with materials presented on the test panel was questioned.

The Foundations of Behavior: The Beliefs, Preferences, and Constraints Model

The rational actor model is a basic organizing principle in economic theory. As I shall explain below, biologists generally employ the same model in understanding the behavior of organisms, albeit with different connotations (Grafen 1999; Gintis 2004). By contrast, psychologists generally reject this model altogether. This theoretical discrepancy must be squarely faced if fruitful collaboration between psychologists and biologists is to emerge, especially in areas where behavior is concerned, including behavioral game theory, animal behavior, gene-culture coevolution, and neuroeconomics. I argue here that the rational actor model is justified by basic evolutionary theory and should be conserved in transdisciplinary research, though it is better expressed as the beliefs, preferences, and constraints model, as the term “rational” is laden with irrelevant and misleading connotations. To document the rejection of the rational actor model in standard psychological theory, note that cognitive psychology generally defines the brain as an “information-processing organ,” but in fact the brain is a decision-making mechanism, information processing simply being a necessary element thereof. For instance, a widely used text of graduatelevel readings in psychology (Sternberg and Wagner 1999) devotes the ninth of 11 chapters to “Reasoning, Judgment, and Decision Making,” offering two papers, the first of which shows that human subjects generally fail simple logical inference tasks, and the second shows that human subjects are irrationally swayed by the way a problem is verbally “framed” by the experimenter. A leading undergraduate text (Goldstein 2005) placed “Reasoning and Decision Making” the last of 12 chapters. This includes one paragraph describing the rational actor model, followed by many pages purporting to explain why it is wrong. Behavioral psychology generally avoids positing internal states, of which preferences and beliefs, and even constraints, are examples. Not surprisingly, when the rational actor model is mentioned, it is summarily rejected (Kahneman et al. 1982; Herrnstein et al 1997). Not surprisingly, in a leading behavioral psychology text (Mazur 2002), choice is covered in the last of 14 chapters and is limited to a review of the literature on choice between concurrent reinforcement schedules and the capacity to defer gratification. Summing up a quarter century of psychological research in 1995, Paul Slovic asserted, accurately I believe, that “it is now generally recognized among psychologists that utility maximization provides only limited insight into the processes by which decisions are made” (Slovic 1995: 365). “People are not logical,” psychologists are fond of saying, “they are psychological.” Economics and biology aside, the behavioral sciences have generally spurned the rational actor model. Sociology and anthropology, in addition to cognitive, behavioral, and social psychology, broadly reject this model. Yet, the evolutionary argument for the rational actor model is strong. The fitness of an organism depends on how effectively it makes decisions in an uncertain and varying environment. Effective decision making is a function of the organism’s state of knowledge, which consists of the information supplied by the sensory inputs that monitor the organism’s internal states and its external environment. The fact that the brain is an organ adapted for fitness-maximizing decision making follows from basic biological principles. The brain is a costly organ that evolved because it enhanced the fitness of its carriers, and hence is structured to make on balance fitness-enhancing decisions in the face of the various constellations of sensory inputs it commonly faces. For every such constellation, each decision taken by the organism generates a probability distribution over fitness outcomes, the expected value of which is the fitness value associated with that decision. Since fitness is a scalar variable, for each constellation of sensory inputs, each possible action the organism might take has a specific fitness value, and organisms whose decision mechanisms are optimized for this environment will choose the available action

Deviations from Matching in Consumer Choice

Previous research has demonstrated that the matching law can be successfully applied to consumers’ patterns of choice with substitutable products at both individual and aggregated (across a number of individuals) levels of analysis. This research aimed to clarify and generalize previous results found at an individual level using independent and complementary products. Aggregated results show that consumers behave according to the predictions of the matching law with qualitatively different reinforcers only when the data are considered on a weekly basis, i.e., as determined by a series of analogic FR schedules. For analogic VR schedules consumers showed matching independently of the degree of substitutability between the products. Further research is needed at an individual level for which the results were not conclusive, and with more extreme forms of complementarity between products.