bluuebunny/crossref_metadata_2025 huggingface dataset:
VERBAL SELF‐REPORTS ABOUT MATCHING TO SAMPLE: EFFECTS OF THE NUMBER OF ELEMENTS IN A COMPOUND SAMPLE STIMULUS
Authors: Critchfield Thomas S. , Perone Michael
Published: March 2006

Adults' self‐reports about their choices in a delayed matching‐to‐sample task were studied as a function of the number of elements (one, two, or three) in a compound sample stimulus. Signal‐detection analyses were used to examine control of self‐reports by the number of sample elements, by the speed and accuracy of choices reported about, and by several events contingent on self‐reports. On each matching‐to‐sample trial, a sample element appeared as one of two comparison stimuli. Choice of the matching element, if made within 500 ms of the onset of the comparison stimuli, produced points worth money or chances in a drawing for money, depending on the subject. After each choice, subjects pressed either a “yes” or “no” button to answer a computer‐generated query about whether the choice met the point contingency. The number of sample elements in the matching‐to‐sample task varied across trials, and events contingent on self‐reports varied across experimental conditions. In Experiment 1, the conditions were defined by different combinations of feedback messages and point consequences contingent on self‐reports, but self‐reports were systematically influenced only by the sample‐stimulus manipulation. Self‐report errors increased with the number of sample elements. False alarms (inaccurate reports of success) were far more common than misses (inaccurate reports of failure), and false alarms were especially likely after choices that were correct but too slow to meet the point contingency. Sensitivity (A′) of self‐reports decreased as the number of sample elements increased. In addition, self‐reports were more sensitive to choice accuracy than to choice speed. All subjects showed a pronounced bias (B'H) for reporting successful responses, although the bias was reduced as the number of sample elements increased and successful choices became less frequent. Experiment 2 demonstrated that the failure of point contingencies to influence self‐reports in the first experiment was not due to a general ineffectiveness of the point consequences. Rates of inaccurate self‐reports decreased when they resulted in point losses and increased when they resulted in point gains.
TESTS FOR CONTROL BY EXCLUSION AND NEGATIVE STIMULUS RELATIONS OF ARBITRARY MATCHING TO SAMPLE IN A “SYMMETRY‐EMERGENT” CHIMPANZEE
Authors: Tomonaga Masaki
Published: March 2006

In the present experiments, controlling relations in arbitrary matching‐to‐sample performance were tested in a 9‐year‐old female chimpanzee who showed statistically significant emergence of symmetry in previous two‐choice conditional discrimination experiments. In Experiment 1, a novel (undefined) sample stimulus was followed by a pair of trained (defined) and undefined comparison stimuli to assess the control by exclusion in arbitrary matching. The chimpanzee selected the undefined shape comparison, excluding the defined one, in color‐sample‐to‐shape‐comparison probe trials, although stimulus preferences were relatively stronger than control by exclusion in shape‐sample trials. An additional test for control by relations of the sample to the positive comparison (S+ control) showed that her behavior was also under the control of relations of the sample to the positive comparison. In Experiment 2, a defined sample was followed by a pair of negatively defined and undefined comparisons to test control by the relations of the sample to the negative comparison. (S‐ control). The subject selected undefined comparisons in both color‐shape and shape‐color test trials. These results clearly indicate that the conditional discrimination behavior of this “symmetry‐emergent” chimpanzee was under both S+ and S‐ control. Furthermore, her performance was also under control by exclusion in color‐shape arbitrary matching, unlike other chimpanzees who showed no evidence of symmetry but only S+ control of arbitrary matching.
RESPONSE‐REINFORCER INDEPENDENCE AND THE ECONOMIC CONTINUUM: A PRELIMINARY ANALYSIS
Authors: Imam Abdulrazaq A.
Published: March 2006

Three pigeons were exposed to 1‐hr and 4‐hr sessions during which they earned food under a fixed‐ratio 50 schedule of reinforcement while obtaining additional food according to either a variable‐interval or a variable‐time schedule. Postsession food was provided after the 1‐hr sessions. The frequency of the variable‐interval and variable‐time food presentations was varied under the two session durations. The various combinations of within‐session earned and unearned food, as well as the postsession food, defined conditions on the open‐to‐closed economy continuum. Key pecks tended to increase as the frequency of either variable‐interval or variable‐time food decreased. An economic‐continuum analysis based on an independence quotient as a measure of response‐reinforcer independence is presented to account for the effects.
PERFORMANCES ON RATIO AND INTERVAL SCHEDULES OF REINFORCEMENT: DATA AND THEORY
Authors: Baum William M.
Published: March 2006

Two differences between ratio and interval performance are well known: (a) Higher rates occur on ratio schedules, and (b) ratio schedules are unable to maintain responding at low rates of reinforcement (ratio “strain”). A third phenomenon, a downturn in response rate at the highest rates of reinforcement, is well documented for ratio schedules and is predicted for interval schedules. Pigeons were exposed to multiple variable‐ratio variable‐interval schedules in which the intervals generated in the variable‐ratio component were programmed in the variable‐interval component, thereby “yoking” or approximately matching reinforcement in the two components. The full range of ratio performances was studied, from strained to continuous reinforcement. In addition to the expected phenomena, a new phenomenon was observed: an upturn in variable‐interval response rate in the midrange of rates of reinforcement that brought response rates on the two schedules to equality before the downturn at the highest rates of reinforcement. When the average response rate was corrected by eliminating pausing after reinforcement, the downturn in response rate vanished, leaving a strictly monotonic performance curve. This apparent functional independence of the postreinforcement pause and the qualitative shift in response implied by the upturn in variable‐interval response rate suggest that theoretical accounts will require thinking of behavior as partitioned among at least three categories, and probably four: postreinforcement activity, other unprogrammed activity, ratio‐typical operant behavior, and interval‐typical operant behavior.
SHORT‐TERM AND LONG‐TERM EFFECTS OF REINFORCERS ON CHOICE
Authors: Buckner Randy L. , Green Leonard , Myerson Joel
Published: March 2006

The relation between molar and molecular aspects of time allocation was studied in pigeons on concurrent variable‐time variable‐time schedules of reinforcement. Fifteen‐minute reinforcer‐free periods were inserted in the middle of every third session. Generalized molar matching of time ratios to reinforcer ratios was observed during concurrent reinforcement. Contrary to melioration theory, preference was unchanged during the reinforcer‐free periods as well as in extinction. In addition to this long‐term effect of reinforcement, short‐term effects were observed: Reinforcers increased the duration of the stays during which they were delivered but had little consistent effect either on the immediately following stay in the same schedule or on the immediately following stay in the alternative schedule. Thus, an orderly effect of reinforcer delivery on molecular aspects of time allocation was observed, but because of its short‐term nature, this effect cannot account for the matching observed at the molar leve.
SELECTIVE ASSOCIATIONS PRODUCED SOLELY WITH APPETITIVE CONTINGENCIES: THE STIMULUS‐REINFORCER INTERACTION REVISITED
Authors: Weiss Stanley J. , Panlilio Leigh V. , Schindler Charles W.
Published: March 2006

In studies reporting stimulus‐reinforcer interactions in traditional conditioning paradigms, when a tone‐light compound was associated with food the light gained stimulus control, but when the compound was paired with shock avoidance the tone gained control. However, the physical nature of the reinforcerrelated events (food vs. shock) presented in the presence of the tone‐light compound was always confounded with the conditioned hedonic value of the compound's presence relative to its absence. When the compound was paired with shock, its presence was negative relative to its absence (which was shock‐free). In contrast, when the compound was paired with food, its presence was positive relative to its absence (which was food‐free). The present experiment dealt with this confounding effect by conditioning a tone‐light compound to be positive or negative, relative to its absence, solely with food reinforcement. One group of rats received food for responding in the presence of the tone‐light compound and no food in its absence. The other group also responded in the presence of the compound, but received food only in its absence. These rats were trained on a chained schedule in which responding in the presence of the tone‐light compound produced a terminal link signaled by the absence of the compound; responding ceased in the terminal link because it delayed food delivery. In a test session to assess stimulus control by the elements of the compound, tone and light were presented separately under extinction conditions. Rats that had been exposed to a positive correlation between food and the compound emitted almost double the responses in the presence of the light as in the presence of the tone. In comparison, rats that had been exposed to a negative correlation emitted only two thirds as many responses in the presence of the light as in the presence of the tone. Because this selective association was produced using only food, it appears that the contingencies under which a reinforcer is presented, rather than (or as well as) its physical properties, can generate the selective associations previously attributed to “stimulus‐reinforcer interactions.” This could mean that regardless of the class of reinforcer that ultimately maintains responding (appetitive or aversive), the contingency‐generated hedonic value of the compound stimulus may influence the dominant modality of stimulus control.
EFFECTS OF FIXED AND VARIABLE RATIOS ON HUMAN BEHAVIORAL VARIABILITY
Authors: Tatham Thomas A. , Wanchisen Barbara A. , Hineline Philip N.
Published: March 2006

The effect that ratio schedules of reinforcement had upon variability of responding was investigated in college students. Subjects were paid $0.02 contingent upon completion of eight presses, distributed in any combination across two push buttons; 256 different sequences were possible. Sequence emission was reinforced according to fixed‐ and variable‐ratio schedules. Ratio requirements of 1, 2, 4 and 8 were presented in alternate components of a multiple schedule. The variability engendered by variable‐ratio schedules was also compared to that engendered by fixed ratios. Variability increased with ratio size, irrespective of whether the schedule requirement was fixed or variable. The data demonstrate the similarity between the determinants of human and nonhuman variability, and they illustrate the role of ratio size in determining variability in operant behavior.
CHOICE AND DELAY OF REINFORCEMENT: EFFECTS OF TERMINAL‐LINK STIMULUS AND RESPONSE CONDITIONS
Authors: Omino Takashi , Ito Masato
Published: March 2006

In two experiments, pigeons were exposed to concurrent‐chains schedules in which a single initial‐link variable‐interval schedule led to access to terminal links composed of fixed‐interval or fixed‐delay schedules. In Experiment 1, an 8‐s (or 16‐s) delay to reinforcement was associated with the standard key, while reinforcer delay values associated with the experimental key were varied from 4 to 32 s. The results of Experiment 1 showed undermatching of response ratios to delay ratios with terminallink fixed‐delay schedules, whereas in some pigeons matching or overmatching was evident with the fixed‐interval schedules. In Experiment 2, one pair of reinforcer delay values, either 8 versus 16 s or 16 versus 32 s, was used. In the first condition of Experiment 2, different delays were associated with different keylight stimuli (cued condition). In the second condition, different terminal‐link delays were associated with the same stimulus, either a blackout (uncued‐blackout condition) or a white key (uncued‐white condition). To examine the role of responses emitted during delays, the keys were retracted during a delay (key‐absent condition) in the third condition and responses were required by a fixed‐interval schedule in the fourth condition. Experiment 2 demonstrated that the choice proportions for the shorter delay were more extreme in the cued condition than in the uncued‐blackout condition, and that the response requirement imposed by the fixed‐interval schedules did not affect choice of the shorter delay, nor did the key‐absent and key‐present conditions. These results indicate that the keylight‐stimulus conditions affected preference for the shorter of two delays and that the findings obtained in Experiment 1 depended mainly on the keylight‐stimulus conditions of the terminal links (i.e., the conditioned reinforcing value of the terminal‐link stimuli).
STOCK OPTIMIZING: MAXIMIZING REINFORCERS PER SESSION ON A VARIABLE‐INTERVAL SCHEDULE
Authors: Silberberg Alan , Bauman Richard , Hursh Steven
Published: March 2006

In Experiment 1, 2 monkeys earned their daily food ration by pressing a key that delivered food according to a variable‐interval 3‐min schedule. In Phases 1 and 4, sessions ended after 3 hr. In Phases 2 and 3, sessions ended after a fixed number of responses that reduced food intake and body weights from levels during Phases 1 and 4. Monkeys responded at higher rates and emitted more responses per food delivery when the food earned in a session was reduced. In Experiment 2, monkeys earned their daily food ration by depositing tokens into the response panel. Deposits delivered food according to a variable‐interval 3‐min schedule. When the token supply was unlimited (Phases 1, 3, and 5), sessions ended after 3 hr. In Phases 2 and 4, sessions ended after 150 tokens were deposited, resulting in a decrease in food intake and body weight. Both monkeys responded at lower rates and emitted fewer responses per food delivery when the food earned in a session was reduced. Experiment 1's results are consistent with a strength account, according to which the phases that reduced body weights increased food's value and therefore increased subjects' response rates. The results of Experiment 2 are consistent with an optimizing strategy, because lowering response rates when food is restricted defends body weight on variable‐interval schedules. These contrasting results may be attributed to the discriminability of the contingency between response number and the end of a session being greater in Experiment 2 than in Experiment 1. In consequence, subjects lowered their response rates in order to increase the number of reinforcers per session (stock optimizing).
THE BEHAVIORAL THEORY OF TIMING: TRANSITION ANALYSES
Authors: Killeen Peter R. , Fetterman J. Gregor
Published: March 2006

Gibbon and Church (1990, 1992) have recently confirmed an important, parameter‐free prediction of the behavioral theory of timing (Killeen & Fetterman, 1988): The times of exiting from a bout of activity are positively correlated with the times of entrance to it. The correlations were slightly less than predicted, however, and the correlations between the start of an activity and the time spent engaged in that activity were negative, rather than zero. We adapted their serial model as an augmented (one‐parameter) version of the behavioral theory, positing a lag between the receipt of a pulse from the pacemaker and transition into the next class of responses. The augmented version of the behavioral theory further improved the correspondence between the theory and the correlational data reported by Gibbon and Church. It also accounts for previously unpublished data from our laboratory derived from a new timing technique, the “peak choice” procedure. We show that the measured variance of movement times from one key to another closely approximates the estimated variance of transition times recovered from fits of the augmented model to the data. Such correspondence both attests to the correct identification of this source of variance and suggests ways to remove it, both from behavior and from our models of behavior.
ACQUISITION OF MATCHING‐TO‐SAMPLE PERFORMANCE IN RATS USING VISUAL STIMULI ON NOSE KEYS
Authors: Iversen Iver H.
Published: March 2006

Steady and blinking white lights were projected on three nose keys arranged horizontally on one wall. The procedure was a conditional discrimination with a sample stimulus presented on the middle key and comparison stimuli on the side keys. Three rats acquired simultaneous “identity matching.” Accuracy reached 80% in about 25 sessions and 90% or higher after about 50 sessions. Acquisition progressed through several stages of repeated errors, alternation between comparison keys from trial to trial, preference of specific keys or stimuli, and a gradual lengthening of strings of consecutive trials with correct responses. An analysis of the acquisition curves for individual trial configurations indicated that the matching‐to‐sample performance possibly consisted of separate discriminations.
PIGEONS' WAIT‐TIME RESPONSES TO TRANSITIONS IN INTERFOOD‐INTERVAL DURATION: ANOTHER LOOK AT CYCLIC SCHEDULE PERFORMANCE
Authors: Higa Jennifer J. , Thaw Jean M. , Staddon John E. R.
Published: March 2006

Recent developments reveal that animals can rapidly learn about intervals of time. We studied the nature of this fast‐acting process in two experiments. In Experiment 1 pigeons were exposed to a modified fixed‐time schedule, in which the time between food rewards (interfood interval) changed at an unpredictable point in each session, either decreasing from 15 to 5 s (step‐down) or increasing from 15 to 45 s (step‐up). The birds were able to track under both conditions by producing postreinforcement wait times proportional to the preceding interfood‐interval duration. However, the time course of responding differed: Tracking was apparently more gradual in the step‐up condition. Experiment 2 studied the effect of having both kinds of transitions within the same session by exposing pigeons to a repeating (cyclic) sequence of the interfood‐interval values used in Experiment 1. Pigeons detected changes in the input sequence of interfood intervals, but only for a few sessions—discrimination worsened with further training. The dynamic effects we observed do not support a linear waiting process of time discrimination, but instead point to a timing mechanism based on the frequency and recency of prior interfood intervals and not the preceding interfood interval alone.
LOW‐RESPONSE‐RATE CONDITIONING HISTORY AND FIXED‐INTERVAL RESPONDING IN RATS
Authors: Lefrancois Janet R. , Metzger Barbara
Published: March 2006

Bar presses by one group of rats were conditioned under a differential‐reinforcement‐of‐low‐rate reinforcement schedule immediately prior to conditioning under a fixed‐interval schedule. In a second group of rats, bar presses were conditioned first under a differential‐reinforcement‐of‐low‐rate schedule and then under a fixed‐ratio schedule prior to conditioning under a fixed‐interval schedule. Low response rates occurred under the fixed‐interval schedule only when it was immediately preceded by low‐rate conditioning. Otherwise, fixed‐interval responding was similar to responding under the fixed‐ratio schedule. This finding suggests that responses of laboratory animals are sensitive to immediate history, and, unlike human responses, are relatively insensitive to a history of low‐rate conditioning when it is followed by high‐rate conditioning.
RESPONSE DEPRIVATION, REINFORCEMENT, AND ECONOMICS
Authors: Allison James
Published: March 2006

Reinforcement of an instrumental response results not from a special kind of response consequence known as a reinforcer, but from a special kind of schedule known as a response‐deprivation schedule. Under the requirements of a response‐deprivation schedule, the baseline rate of the instrumental response permits less than the baseline rate of the contingent response. Because reinforcement occurs only if the schedule deprives the organism of the contingent response, reinforcement cannot result from any intrinsic property of the contingent response or any property relative to the instrumental response. Two typical effects of response‐deprivation schedules—facilitation of the instrumental response and suppression of the contingent response—are discussed in terms of economic concepts and models of instrumental performance. It is suggested that response deprivation makes the contingent response function as an economic good, the instrumental response as currency.
THE SUBSTITUTABILITY OF REINFORCERS
Authors: Green Leonard , Freed Debra E.
Published: March 2006

Substitutability is a construct borrowed from microeconomics that describes a continuum of possible interactions among the reinforcers in a given situation. Highly substitutable reinforcers, which occupy one end of the continuum, are readily traded for each other due to their functional similarity. Complementary reinforcers, at the other end of the continuum, tend to be consumed jointly in fairly rigid proportion, and therefore cannot be traded for one another except to achieve that proportion. At the center of the continuum are reinforcers that are independent with respect to each other; consumption of one has no influence on consumption of another. Psychological research and analyses in terms of substitutability employ standard operant conditioning paradigms in which humans and nonhumans choose between alternative reinforcers. The range of reinforcer interactions found in these studies is more readily accommodated and predicted when behavior‐analytic models of choice consider issues of substitutability. New insights are gained into such areas as eating and drinking, electrical brain stimulation, temporal separation of choice alternatives, behavior therapy, drug use, and addictions. Moreover, the generalized matching law (Baum, 1974) gains greater explanatory power and comprehensiveness when measures of substitutability are included.
DELAY REDUCTION: CURRENT STATUS
Authors: Fantino Edmund , Preston Ray A. , Dunn Roger
Published: March 2006

Delay‐reduction theory states that the effectiveness of a stimulus as a conditioned reinforcer may be predicted most accurately by the reduction in time to primary reinforcement correlated with its onset. We review support for the theory and then discuss two new types of experiments that assess it. One compares models of choice in situations wherein the less preferred outcome is made more accessible; the other investigates whether frequency of conditioned reinforcement affects choice beyond the effect exerted by frequency of primary reinforcement.
RESPONSE ACQUISITION UNDER TARGETED PERCENTILE SCHEDULES: A CONTINUING QUANDARY FOR MOLAR MODELS OF OPERANT BEHAVIOR
Authors: Galbicka Gregory , Kautz Mary A. , Jagers Traci
Published: March 2006

The number of responses rats made in a “run” of consecutive left‐lever presses, prior to a trial‐ending right‐lever press, was differentiated using a targeted percentile procedure. Under the nondifferential baseline, reinforcement was provided with a probability of .33 at the end of a trial, irrespective of the run on that trial. Most of the 30 subjects made short runs under these conditions, with the mean for the group around three. A targeted percentile schedule was next used to differentiate run length around the target value of 12. The current run was reinforced if it was nearer the target than 67% of those runs in the last 24 trials that were on the same side of the target as the current run. Programming reinforcement in this way held overall reinforcement probability per trial constant at .33 while providing reinforcement differentially with respect to runs more closely approximating the target of 12. The mean run for the group under this procedure increased to approximately 10. Runs approaching the target length were acquired even though differentiated responding produced the same probability of reinforcement per trial, decreased the probability of reinforcement per response, did not increase overall reinforcement rate, and generally substantially reduced it (i.e., in only a few instances did response rate increase sufficiently to compensate for the increase in the number of responses per trial). Models of behavior predicated solely on molar reinforcement contingencies all predict that runs should remain short throughout this experiment, because such runs promote both the most frequent reinforcement and the greatest reinforcement per press. To the contrary, 29 of 30 subjects emitted runs in the vicinity of the target, driving down reinforcement rate while greatly increasing the number of presses per pellet. These results illustrate the powerful effects of local reinforcement contingencies in changing behavior, and in doing so underscore a need for more dynamic quantitative formulations of operant behavior to supplement or supplant the currently prevalent static ones.
VIOLATIONS OF TRANSITIVITY: IMPLICATIONS FOR A THEORY OF CONTEXTUAL CHOICE
Authors: Grace Randolph C.
Published: March 2006

Violations of strong stochastic transitivity in concurrent‐chains choice were first reported by Navarick and Fantino. In a series of articles, Navarick and Fantino concluded that neither a unidimensional model capable of predicting exact choice probabilities nor a fixed‐variable equivalence rule was possible for the concurrent‐chains procedure. I show that when choice is modeled contextually (i.e., when preference for a schedule is affected by factors other than the schedule itself, e.g., aspects of the alternative schedule), a unidimensional, exact‐choice probability model is possible that both predicts the intransitivities reported by Navarick and Fantino and provides a fixed‐variable equivalence rule for the concurrent‐chains procedure. The contextual model is an extension of the generalized matching law and violates a key assumption underlying traditional choice models—simple scalability—because of (a) schedule interdependence and (b) bias from procedural contingencies. Therefore, strong stochastic transitivity cannot be expected to hold. Contextual scalability is analyzed to reveal a hierarchy of context effects in choice. Navarick and Fantino's intransitivities can be satisfactorily explained by bias. If attribute sensitivity is context dependent, however, and if there are similarity structures among choice alternatives, the contextual model is shown to be able to predict violations of ordinal preference. Therefore, it may be possible to formulate a deterministic, general psychophysical model of choice as a behavioral alternative to probabilistic, multidimensional choice theories.
TECHNIQUES FOR ESTABLISHING SCHEDULES WITH WHEEL RUNNING AS REINFORCEMENT IN RATS
Authors: Iversen Iver H.
Published: March 2006

In three experiments, access to wheel running was contingent on lever pressing. In each experiment, the duration of access to running was reduced gradually to 4, 5, or 6 s, and the schedule parameters were expanded gradually. The sessions lasted 2 hr. In Experiment 1, a fixed‐ratio 20 schedule controlled a typical break‐and‐run pattern of lever pressing that was maintained throughout the session for 3 rats. In Experiment 2, a fixed‐interval schedule of 6 min maintained lever pressing throughout the session for 3 rats, and for 1 rat, the rate of lever pressing was positively accelerated between reinforcements. In Experiment 3, a variable‐ratio schedule of 20 or 35 was in effect and maintained lever pressing at a very stable pace throughout the session for 2 of 3 rats; for 1 rat, lever pressing was maintained at an irregular rate. When the session duration was extended to successive 24‐hr periods, with food and water accessible in Experiment 3, lever pressing settled into a periodic pattern occurring at a high rate at approximately the same time each day. In each experiment, the rats that developed the highest local rates of running during wheel access also maintained the most stable and highest rates of lever pressing.
FIXED‐INTERVAL PERFORMANCE AND SELF‐CONTROL IN INFANTS
Authors: Darcheville J. C. , Rivière V. , Wearden J. H.
Published: March 2006

Twenty‐six infants, 3 to 23 months old, were trained on fixed‐interval schedules ranging from 10 s to 80 s. The operant response was touching an illuminated location on a touch‐sensitive screen, and 20 s of cartoon presentation was the reinforcer. The subjects were also trained in a six‐phase self‐control procedure in which the critical phases involved choice between 20 s of cartoon available after a 0.5‐s delay (impulsive choice) and 40 s of cartoon delayed for 40 s (self‐controlled choice). All the youngest children (3 to 5 months) showed long postreinforcement pauses on the fixed‐interval schedule, with most intervals involving the emission of a single, reinforced, response, and all made self‐controlled choices. Older subjects (9 to 23 months) either produced the same pattern as the younger ones on the fixed‐interval schedule (classified as pause‐sensitive subjects) or produced short pauses and higher steady response rates (classified as pause‐insensitive subjects). All pause‐sensitive subjects made self‐controlled choices in the self‐control condition, and all pause‐insensitive subjects made impulsive ones.
TESTS OF BEHAVIOR MOMENTUM IN SIMPLE AND MULTIPLE SCHEDULES WITH RATS AND PIGEONS
Authors: Cohen Steven L. , Riley Deborah S. , Weigle Pat A.
Published: March 2006

Four experiments examined the relationship between rate of reinforcement and resistance to change in rats' and pigeons' responses under simple and multiple schedules of reinforcement. In Experiment 1, 28 rats responded under either simple fixed‐ratio, variable‐ratio, fixed‐interval, or variable‐interval schedules; in Experiment 2, 3 pigeons responded under simple fixed‐ratio schedules. Under each schedule, rate of reinforcement varied across four successive conditions. In Experiment 3, 14 rats responded under either a multiple fixed‐ratio schedule or a multiple fixed‐interval schedule, each with two components that differed in rate of reinforcement. In Experiment 4, 7 pigeons responded under either a multiple fixed‐ratio or a multiple fixed‐interval schedule, each with three components that also differed in rate of reinforcement. Under each condition of each experiment, resistance to change was studied by measuring schedule‐controlled performance under conditions with prefeeding, response‐independent food during the schedule or during timeouts that separated components of the multiple schedules, and by measuring behavior under extinction. There were no consistent differences between rats and pigeons. There was no direct relationship between rates of reinforcement and resistance to change when rates of reinforcement varied across successive conditions in the simple schedules. By comparison, in the multiple schedules there was a direct relationship between rates of reinforcement and resistance to change during most tests of resistance to change. The major exception was delivering response‐independent food during the schedule; this disrupted responding, but there was no direct relationship between rates of reinforcement and resistance to change in simple‐ or multiple‐schedule contexts. The data suggest that rate of reinforcement determines resistance to change in multiple schedules, but that this relationship does not hold under simple schedules.
TEMPORAL CONTROL ON INTERVAL SCHEDULES: WHAT DETERMINES THE POSTREINFORCEMENT PAUSE?
Authors: Innis Nancy K. , Mitchell Stephen K. , Staddon J. E. R.
Published: March 2006

On fixed‐interval or response‐initiated delay schedules of reinforcement, the average pause following food presentation is proportional to the interfood interval. Moreover, when a number of intervals of different durations occur in a programmed cyclic series, postreinforcement pauses track the changes in interval value. What controls the duration of postreinforcement pauses under these conditions? Staddon, Wynne, and Higa (1991), in their linear waiting model, propose control by the preceding interfood interval. Another possibility is that delay to reinforcement, signaled by a key peck and/or stimulus change, determines the subsequent pause. The experiments reported here examined the role of these two possible time markers by studying the performance of pigeons under a chained cyclic fixed‐interval procedure. The data support the linear waiting model, but suggest that more than the immediately preceding interfood interval plays a role in temporal control.
ADAPTATION, TELEOLOGY, AND SELECTION BY CONSEQUENCES
Authors: Ringen Jon D.
Published: March 2006

This paper presents and defends the view that reinforcement and natural selection are selection processes, that selection processes are neither mechanistic nor teleological, and that mentalistic and vitalistic processes are teleological but not mechanistic. The differences between these types of processes are described and used in discussing the conceptual and methodological significance of “selection type theories” and B. F. Skinner's radical behaviorist view that “operant behavior is the field of intention, purpose, and expectation. It deals with that field precisely as the theory of evolution has dealt with another kind of purpose” (1986, p. 716). The antimentalism of radical behaviorism emerges as a post‐Darwinian extension of Francis Bacon's (and Galileo's) influential view that “[the introduction of final causes] rather corrupts than advances the sciences” (Bacon, 1905, p. 302).
CONTEXT SPECIFICITY OF OPERANT DISCRIMINATIVE PERFORMANCE IN PIGEONS: II NECESSARY AND SUFFICIENT CONDITIONS
Authors: Thomas David R. , Empedocles Stephen , Morrison Spencer K. , Bing Mark Nathaniel
Published: March 2006

Six experiments were performed to explore the necessary and sufficient conditions for producing context specificity of discriminative operant performance in pigeons. In Experiment 1, pigeons learned a successive discrimination (red S+/blue S–) in two chambers that had a particular odor present and between which they were frequently switched. The birds subsequently learned the reversal (blue S+/red S–) in one of these chambers with a different odor present. When switched to the alternative chamber, although the odor and the reinforcement contingency were still appropriate to the reversal, performance appropriate to the original discrimination recurred in subjects for which the houselights were on during training and testing but not for those for which the houselights were off. This indicated the importance of visual contextual cues in producing context specificity. Experiment 2 showed that the frequent switching between boxes in initial training was of no consequence, presumably because the apparatus cues were highly salient to the subjects. Experiment 3 showed significantly less context specificity when odor cues were omitted. Experiment 4 showed that simply using a different reinforced stimulus in each phase of training was ineffective in producing context specificity. Experiment 5 showed that the generalization test procedure used in Experiment 4 was sensitive to context specificity when discrimination‐reversal training was used with different odors in the two training phases. Experiment 6 replicated the results of Experiment 4, but then showed that when different odors accompanied the two training phases, context specificity was obtained with the single‐stimulus paradigm. Thus in both single‐stimulus and discrimination‐reversal paradigms, redundant odor cues potentiated learning about apparatus cues.
BEHAVIORAL CONTRAST FOR KEY PECKING AS A FUNCTION OF COMPONENT DURATION WHEN ONLY ONE COMPONENT VARIES
Authors: McSweeney Frances K. , Melville Cam L.
Published: March 2006

Pigeons pecked keys for food reinforcers delivered by multiple variable‐interval 2‐min variable‐interval 2‐min schedules. Positive behavioral contrast was created by changing one component to extinction; negative contrast was achieved by changing one component to a variable‐interval 15‐s schedule. The duration of each component was varied independently of the other from 5 to 960 s. The size of positive contrast was greatest when the extinction component was 30 or 60 s long. It did not change significantly with changes in the duration of the variable‐interval 2‐min component. The absolute size of negative contrast decreased with increases in the duration of the variable‐interval 2‐min component. It did not change significantly with changes in the duration of the variable‐interval 15‐s component. These results show that the size of contrast is determined primarily by the duration of the component that provides the less favorable conditions of reinforcement. These results are not predicted by current theories.
DRL INTERRESPONSE‐TIME DISTRIBUTIONS: QUANTIFICATION BY PEAK DEVIATION ANALYSIS
Authors: Richards Jerry B. , Sabol Karen E. , Seiden Lewis S.
Published: March 2006

Peak deviation analysis is a quantitative technique for characterizing interresponse‐time distributions that result from training on differential‐reinforcement‐of‐low‐rate schedules of reinforcement. It compares each rat's obtained interresponse‐time distribution to the corresponding negative exponential distribution that would have occurred if the rat had emitted the same number of responses randomly in time, at the same rate. The comparison of the obtained distributions with corresponding negative exponential distributions provides the basis for computing three standardized metrics (burst ratio, peak location, and peak area) that quantitatively characterize the profile of the obtained interresponse‐time distributions. In Experiment 1 peak deviation analysis quantitatively described the difference between the interresponse‐time distributions of rats trained on variable‐interval 300‐s and differential‐reinforcement‐of‐low‐rate 72‐s schedules of reinforcement. In Experiment 2 peak deviation analysis differentiated between the effects of the psychomotor stimulant d‐amphetamine, the anxiolytic compound chlordiazepoxide, and the antidepressant desipramine. The results suggest that peak deviation analysis of interresponse‐time distributions may provide a useful behavioral assay system for characterizing the effects of drugs.
STIMULUS CONTROL AND RESPONSE BIAS IN AN ANALOGUE PREY‐DETECTION PROCEDURE
Authors: Voss Philip , McCarthy Dianne , Davison Michael
Published: March 2006

The present study compared the performance of 6 pigeons trained to detect luminance differences in two different signal‐detection procedures. Exposed to a three‐key array, the pigeons were trained to peck the left key when the brighter of two light intensities had been presented on the center key and to peck the right key when the dimmer of two light intensities had been presented on the center key. Procedure A was a standard signal‐detection procedure in which left/bright and right/dim responses produced food reinforcement and left/dim and right/bright responses produced periods of timeout. Procedure B was designed to simulate some of the contingencies operating in a prey‐detection situation. Left‐key responses produced reinforcement following the brighter center‐key stimulus and a period of timeout following the dimmer center‐key stimulus. Right‐key responses always produced a short period of timeout irrespective of the stimulus. Within each procedure, the duration of timeout arranged for false alarms (left/dim responses) was varied between 3 s and 120 s. Measures of accuracy and response bias were compared between the two procedures. The timeout manipulation produced systematic, but relatively small, changes in these measures when right/dim responses (i.e., correct rejections) produced reinforcement (Procedure A). Arranging timeout for right/dim responses in Procedure B produced greater variability in accuracy and response bias than did arranging reinforcement, but this variability was not related to timeout duration. Overall, discrimination accuracy was considerably higher when right/dim responses produced timeout than when they resulted in reinforcement, and accuracy was accompanied by a large bias toward the response associated with reinforcement. These results are consistent with a recently proposed model of signal detection.
SIGNAL‐DETECTION PROPERTIES OF VERBAL SELF‐REPORTS
Authors: Critchfield Thomas S.
Published: March 2006

The bias (B′H) and discriminability (A′) of college students' self‐reports about choices made in a delayed identity matching‐to‐sample task were studied as a function of characteristics of the response about which they reported. Each matching‐to‐sample trial consisted of two, three, or four simultaneously presented sample stimuli, a 1‐s retention interval, and two, three, or four comparison stimuli. One sample stimulus was always reproduced among the comparisons, and choice of the matching comparison in less than 800 ms produced points worth chances in a drawing for money. After each choice, subjects pressed either a “yes” or a “no” button to answer a computer‐generated query about whether the choice met the point contingency. The number of sample and comparison stimuli was manipulated across experimental conditions. Rates of successful matching‐to‐sample choices were negatively correlated with the number of matching‐to‐sample stimuli, regardless of whether samples or comparisons were manipulated. As in previous studies, subjects exhibited a pronounced bias for reporting successful responses. Self‐report bias tended to become less pronounced as matching‐to‐sample success became less frequent, an outcome consistent with signal‐frequency effects in psychophysical research. The bias was also resistant to change, suggesting influences other than signal frequency that remain to be identified. Self‐report discriminability tended to decrease with the number of sample stimuli and increase with the number of comparison stimuli, an effect not attributable to differential effects of the two manipulations on matching‐to‐sample performance. Overall, bias and discriminability indices revealed effects that were not evident in self‐report accuracy scores. The results indicate that analyses based on signal‐detection theory can improve the description of correspondence between self‐reports and their referents and thus contribute to the identification of environmental sources of control over verbal self‐reports.
COMPOUND STIMULI IN EMERGENT STIMULUS RELATIONS: EXTENDING THE SCOPE OF STIMULUS EQUIVALENCE
Authors: Markham Michael R. , Dougher Michael J.
Published: March 2006

Three experiments were conducted to investigate stimulus relations that might emerge when college students are taught relations between compound sample stimuli and unitary comparison stimuli using match‐to‐sample procedures. In Experiment 1, subjects were taught nine AB‐C stimulus relations, then tested for the emergence of 18 AC‐B and BC‐A relations. All subjects showed the emergence of all tested relations. Twelve subjects participated in Experiment 2. Six subjects were taught nine AB‐C relations and were then tested for symmetrical (C‐AB) relations. Six subjects were taught nine AB‐C and three C‐D relations and were then tested for nine AB‐D (transitive) relations. Five of 6 subjects demonstrated the emergence of symmetrical relations, and 6 subjects showed the emergence of transitivity. In Experiment 3, 5 college students were taught nine AB‐C and three C‐D relations and were then tested for nine equivalence (D‐AB) relations and 18 AD‐B and BD‐A relations. Three subjects demonstrated all tested relations. One subject demonstrated the AD‐B and BD‐A relations but not the D‐AB relations. One subject did not respond systematically during testing. The results of these experiments extend stimulus equivalence research to more complex cases.
THE NATURE OF SEXUAL REINFORCEMENT
Authors: Crawford Lawrence L. , Holloway Kevin S. , Domjan Michael
Published: March 2006

Sexual reinforcers are not part of a regulatory system involved in the maintenance of critical metabolic processes, they differ for males and females, they differ as a function of species and mating system, and they show ontogenetic and seasonal changes related to endocrine conditions. Exposure to a member of the opposite sex without copulation can be sufficient for sexual reinforcement. However, copulatory access is a stronger reinforcer, and copulatory opportunity can serve to enhance the reinforcing efficacy of stimulus features of a sexual partner. Conversely, under certain conditions, noncopulatory exposure serves to decrease reinforcer efficacy. Many common learning phenomena such as acquisition, extinction, discrimination learning, second‐order conditioning, and latent inhibition have been demonstrated in sexual conditioning. These observations extend the generality of findings obtained with more conventional reinforcers, but the mechanisms of these effects and their gender and species specificity remain to be explored.
THE BEHAVIORAL ECONOMICS OF PRODUCTION
Authors: Allison James , English Justin
Published: March 2006

In two experiments, thirsty rats licked an empty spout instrumentally for water delivered at a neighboring spout. Each such pair of spouts constituted a work station, and one, two, or three stations were available in the test enclosure. In 1‐hr sessions, the rats worked alone or in the company of 1 or 2 other rats, and performed either five, 10, or 40 licks at the empty spout for each water delivery. The total number of empty‐spout licks, summed across rats and stations, increased with the empty‐lick requirement and, with some exceptions, the number of rats in the enclosure and the number of work stations available. A Cobb—Douglas production function, with instrumental responding as an output and the three independent variables as inputs, accounted for a significant percentage of the variance. Contrary to that function, output failed to increase with additional rats (or work stations) when the number of work stations (or rats) was relatively small.
CONDITIONAL DISCRIMINATION IN MENTALLY RETARDED SUBJECTS: PROGRAMMING ACQUISITION AND LEARNING SET
Authors: Saunders Kathryn J. , Spradlin Joseph E.
Published: March 2006

In Experiment 1, 3 subjects with retardation were exposed to two visual‐visual arbitrary matching‐to‐sample problems each day. One conditional discrimination was presented under trial‐and‐error conditions, and the other was presented under a component training procedure. The latter began by establishing the comparison discrimination and its rapid reversal. The successive discrimination between the sample stimuli was established through differential naming. Then, sample naming was maintained in conditional discrimination sessions in which the same sample was presented in blocks of consecutive trials. Block size was decreased across sessions until sample presentation was randomized as in trial‐and‐error training (but with naming maintained). Two subjects initially learned only with component training. The performance of the 3rd subject was inconsistent across conditional discriminations. One of the successful subjects ultimately learned rapidly and consistently with trial‐and‐error procedures. Experiment 2 sought to demonstrate learning set in the other 2 subjects. Elements of the component training procedure were withdrawn over successive conditional discriminations. Ultimately, 1 subject nearly always learned under trial‐and‐error conditions, and the other learned under trial‐and‐error conditions combined with differential sample naming.