bluuebunny/crossref_metadata_2025 huggingface dataset:
TIMEOUT AS A REINFORCER FOR ERRORS IN A SERIAL POSITION TASK
Authors: Redd William H. , Sidman Murray , Fletcher F. Garth
Published: March 2006

After learning to press keys in a predetermined serial position sequence, with timeouts scheduled as a consequence of errors, monkeys developed stereotyped errors. As soon as a new trial started, the animals would make an error. On trial after trial, they pressed the same incorrect key at the first member of the sequence, even though they had previously learned the sequence. First‐member errors occurred even when sequences of fully bright keys marking correct choices were presented. When timeout was eliminated as a consequence of one first‐member error, subjects switched to an error that did produce the timeout. When all first‐member errors failed to produce timeout the monkeys ceased responding. Both prefeeding and reduction in reinforcement density resulted in stereotyped errors occurring earlier in the session.
EFFECTS OF RESPONSE‐PRODUCED STIMULI UPON CONDITIONAL DISCRIMINATION PERFORMANCE1
Authors: Lydersen Tore , Perkins David
Published: March 2006

In zero‐delay matching procedures the performance of three groups of pigeons was examined when exteroceptive stimuli, response‐produced stimuli associated with the completion of either of two fixed ratios, or a compound of exteroceptive and response‐produced stimuli were available as samples. Exteroceptive samples were found to control a higher level of matching accuracy than response‐produced samples, while compound samples controlled a higher level of accuracy than did exteroceptive samples alone. When all subjects were placed on a transfer procedure, during which the previously used red and green samples were replaced by horizontal and vertical lines, the availability of sample‐specific fixed‐ratios facilitated acquisition of the task.
PREFERENCE FOR FIXED‐INTERVAL SCHEDULES: EFFECTS OF INITIAL‐LINK LENGTH1
Authors: Wardlaw G. R. , Davison M. C.
Published: March 2006

Six homing pigeons were trained on a variety of concurrent‐chains schedules in which the initial links were equal variable‐interval schedules and the terminal links were fixed‐interval schedules. Both terminal‐link and initial‐link schedules were systematically varied. The results showed that preference for a particular terminal‐link schedule combination was greater, the shorter the initial‐link schedules. The data closely matched predictions from the model of choice suggested by Davison and Temple (1973), but did not match predictions from two other models. An alternative method for analyzing concurrent‐chains performance by assuming that the schedule consists of both chained schedules and successive, discriminated components that comprise multiple schedules, was suggested.
AUTOSHAPING AND AUTOMAINTENANCE OF A KEY‐PRESS RESPONSE IN SQUIRREL MONKEYS
Authors: Gamzu Elkan , Schwam Elias
Published: March 2006

Following exposure for a minimum of 500 to 600 trials, three of four naive squirrel monkeys eventually pressed a response key, illumination of which always preceded delivery of a food pellet. Three other naive monkeys did not press the key when the pellets were delivered randomly with respect to key illumination. Despite some similarities to autoshaping using pigeons, the data indicate many points of difference when squirrel monkeys are used as subjects. Although key‐food pairings were shown to be important in the acquisition of the key‐press response, they were ineffective in maintaining the response when either a negative response‐reinforcer dependency was introduced, or when there was no scheduled response‐reinforcer dependency (fixed trial). Not all demonstrations of autoshaping can be considered to be under the control of those processes that are primarily responsible for the phenomena obtained in pigeons.
SCHEDULES OF RESPONSE‐INDEPENDENT CONDITIONED REINFORCEMENT1
Authors: Marr M. Jackson , Zeiler Michael D.
Published: March 2006

Rates and patterns of responding of pigeons under response‐independent and response‐dependent schedules of brief‐stimulus presentation were compared by superimposing 3‐min brief‐stimulus schedules on a 15‐min fixed‐interval schedule of food presentation. The brief‐stimulus schedules were fixed time, fixed interval, variable time, and variable interval. When the brief stimulus was paired with food presentation, its effects depended upon the schedule and ongoing rates. Fixed‐ and variable‐interval brief‐stimulus schedules enhanced the low rates normally occurring early in the 15‐min interval, whereas fixed‐ and variable‐time schedules suppressed these rates. Although the overall rates later in the interval were not affected to any great extent, the fixed brief‐stimulus schedules generated patterns of positively accelerated responding between stimulus presentations. These patterns appeared less frequently under the variable brief‐stimulus schedules. Initially, when not paired with food delivery, presentations of the brief stimulus produced relatively little effect on either response rate or patterning. However, once the stimulus had accompanied food presentation, the original performance under the non‐paired condition was not recovered. The effects were more like those occurring when the stimulus was paired with food.
INTERCURRENT AND REINFORCED BEHAVIOR UNDER MULTIPLE SPACED‐RESPONDING SCHEDULES1
Authors: Smith James B. , Clark Fogle C.
Published: March 2006

Lever pressing in rats was reinforced with food under a multiple spaced‐responding schedule. A lever, food cup, and drinking tube were mounted in a running wheel so that lever pressing, running, and licking could be recorded. Running and licking had no scheduled consequences. Lever pressing was reinforced under a multiple schedule with three spaced‐responding components and an extinction component. Each component was associated with a different auditory stimulus. Spaced‐responding components reinforced only lever presses terminating interresponse times equal to or greater than 10, 20, or 60 sec, respectively. Rates of lever pressing, reinforcement, and licking all decreased as schedule parameter increased. Efficiency of spaced responding, as measured by reinforcements per response, also decreased. Rate of wheel running either increased or increased and then decreased with increasing schedule parameter. Individual running rates differed substantially. Neither licking nor running rate correlated with individual differences in efficiency. Analysis of conditional probabilities among the several response classes showed that, as the schedule requirement increased, the probability of running after a lever press increased and the probability of licking after a lever press decreased. After reinforcement, one subject always pressed the lever next. In the other subjects, the conditional probability of lever pressing, given reinforcement, increased while the probability of licking, given reinforcement, decreased with increasing schedule requirement. Results are discussed in relation to the concepts of schedule‐induced and mediating behavior.
EFFECTS OF LICK‐CONTINGENT TIMEOUT ON SCHEDULE‐INDUCED POLYDIPSIA1
Authors: Flory Randall K. , Lickfett Gary G.
Published: March 2006

Rats bar pressing on a 1‐min fixed‐interval schedule for 45‐mg food pellets became Polydipsic when water was concurrently available. They were then exposed to conditions in which each lick on the drinking tube produced a timeout period during which the food‐schedule lever was retracted and the fixed‐interval timer either did or did not continue to operate. Licks occurring within a timeout period extended its duration. As the duration of the lick‐initiated timeout period was increased logarithmically through four values from 10 sec to 80 sec, lick rates as well as water intake rates generally decreased for all three subjects. As timeout duration was progressively increased, the rate of licks occurring in the absense of, but producing, timeouts decreased for all three rats, whereas the rate of licks occurring in the presence of timeout periods remained essentially constant. Water‐intake rates and, with one exception, lick rates were suppressed more by timeout periods during which the fixed‐interval timer did not continue to operate. These results indicate that lick‐contingent timeout from positive reinforcement reduces schedule‐induced drinking, and this suppressive effect is greater when the timeout period necessarily increases the interreinforcement interval beyond its minimum duration than when it does not.
IMPULSE CONTROL IN PIGEONS1
Authors: Ainslie G. W.
Published: March 2006

Pigeons were given a small, immediate food reinforcement for pecking a key, and a larger, delayed reinforcement for not pecking this key. Most subjects pecked the key on more than 95% of trials. However, when pecking a differently colored key at an earlier time prevented this option from becoming available, three of 10 subjects consistently pecked it, thereby forcing themselves to wait for the larger reward. They did not peck the earlier key when it did not prevent this option. This is an experimental example of psychological impulse and a learnable device to control it. Although only a minority of the subjects learned it, the fact that such learning is possible at all argues for a theory of delayed reward that can predict change of preference as a function of elapsing time.
TIME ALLOCATION AND RESPONSE RATE1
Authors: Shimp Charles P.
Published: March 2006

Food reinforcement for key pecking by three pigeons was arranged by a variable‐interval schedule and a device that assigned each reinforcement to one of 10 component response rates corresponding to 10 classes of equally reinforced interresponse times ranging from 1.0 to 6.0 sec in 0.5‐sec classes. The overall number of reinforcements per hour was varied from one to more than 60. Overall response rate was a monotonically increasing, negatively accelerated function of the overall number of reinforcements per hour. This function was decomposed into two time‐allocation functions: (1) the time allocated to all of the reinforced component response rates as a function of the total reinforcement rate, and, (2) the time allocated to a particular reinforced component response rate as a function of the reinforcement rate for that component. Asymptotic response rate was predicted by combining the asymptotes of the two separate time‐allocation functions: virtually all of the time was spent responding, and the percentage of the time spent responding that was allocated to a particular reinforced component response rate roughly equalled the relative reinforcements per hour for that component.
INHIBITORY STIMULUS CONTROL AND THE MAGNITUDE OF DELAYED REINFORCEMENT1
Authors: Richards Ralph W.
Published: March 2006

The key pecking of pigeons was reinforced according to a variable‐interval 1‐min schedule during each of two successively presented stimuli. When the key was illuminated by a black line on a white background, reinforcement was delayed for 10 sec. When the key was illuminated by a plain white light, reinforcement was not delayed. For half of the subjects, the delayed reinforcer was 4.0‐sec access to mixed grain, and for the remaining subjects it was 1.5‐sec access. The immediate reinforcer was 1.5‐sec access for all subjects. All subjects responded at a lower rate during the presentation of the black line; no between‐group difference in terms of terminal response rate during the presentation of the line was found. However, subjects that received 4.0 sec of delayed reinforcement responded at a lower terminal rate during presentation of the plain white light than subjects that received 1.5 sec of delayed reinforcement. A subsequent generalization test along the line‐orientation dimension produced flatter U‐shaped gradients for subjects that received 4.0‐sec of delayed reinforcement.
TOPOGRAPHY OF THE FOOD‐REINFORCED KEY PECK AND THE SOURCE OF 30‐MILLISECOND INTERRESPONSE TIMES1
Authors: Smith Richard F.
Published: March 2006

High‐speed photography of key pecking revealed that the arc described by the upper bill as a pigeon closes its beak is capable of operating a Lehigh Valley pigeon key set at 8 to 14 g. Arc‐produced switch closure follows initial switch closure in less than 50 msec. When birds were trained on ratio schedules, the probability of interresponse times (IRTs) shorter than 50 msec exceeded 0.30. Interval‐trained birds produced a much lower probability of short‐IRTs. When the schedules were reversed, there was only weak evidence of a reversal in the probability of short IRTs. A temporal analysis of topographic features observed in the original photographs failed to reveal differences between ratio and interval pecking topography. It appeared that only the point of contact with the key differed between subjects trained on the two schedules. It was concluded that only the locus, but not the topography, of the food‐reinforced key peck was modified by the schedule of reinforcement.
CHANGES IN PROGRESSIVE‐RATIO PERFORMANCE UNDER INCREASED PRESSURES OF AIR1
Authors: Thomas John R.
Published: March 2006

Rats performed on progressive‐ratio schedules that required an increasing number of responses for each successive reinforcement. The number of responses required increased until the subjects failed to complete the next ratio in the sequence within 15 min. Response‐ratio increments of two responses, five responses, and 20 responses were investigated. The size of the final completed ratio generally increased with increases in the progressive‐ratio step size. Increased pressures of air in a hyperbaric chamber led to both increases and decreases in terminal ratio size, with the differential effects depending on both air pressure and on the size of the progressive‐ratio increment. Changes in the number of responses in the final ratio were related to increased pressures of nitrogen, as similar pressures of helium produced few effects.
DEVELOPMENT AND MAINTENANCE OF ATTACK IN PIGEONS DURING VARIABLE‐INTERVAL REINFORCEMENT OF KEY PECKING1
Authors: Dove L. Duane , Rashotte Michael E. , Katz Harold N.
Published: March 2006

Key‐peck responses of two pigeons were maintained on variable‐interval schedules of food reinforcement in the presence of a stuffed pigeon to study the characteristics of attack induced by that schedule. The mean interval of the schedule was increased from 15 sec to 600 sec in eight steps before an intermediate interval was reintroduced. The principal characteristics of attack were: (1) substantial attack first occurred on a variable‐interval schedule of 90 sec in one pigeon and at 180 sec in the other, (2) the highest attack rates occurred on variable‐interval schedules of 300 sec and 600 sec, (3) attack rate generally increased to a maximum and then decreased to a lower level across sessions at each schedule, (4) attacks developed a postreinforcement locus across the initial sessions on all schedules and, except on variable‐interval schedules of 300 and 600 sec, occurred primarily in the postreinforcement period during extended training, (5) attack rates and key‐peck rates were not recovered when the intermediate‐length schedules were reintroduced, and (6) attack rate and key‐peck rates were negatively correlated. Except for the fact that the maximum attack rates occurred at interfood intervals of 300 and 600 sec, and that attack and key‐peck rates were negatively correlated, these findings have counterparts in experiments with other reinforcement schedules.
CONDITIONED SUPPRESSION, PUNISHMENT, AND AVERSION1
Authors: Orme‐Johnson David W. , Yarczower Matthew
Published: March 2006

Three experiments were conducted to assess the aversive properties of a visual stimulus in the presence of which one group of birds received response‐contingent shock (discriminated punishment) while a yoked group of birds received non‐contingent shocks (conditioned suppression). In Experiment 1, presentation of the visual stimulus contingent on key pecking reduced the response rate (conditioned punishment effect) for birds under the conditioned suppression procedure but did not reduce the response rate of birds under the discriminative punishment procedure. Non‐contingent shocks also produced greater suppression of responding maintained by positive reinforcement in the presence of a visual stimulus than did response‐contingent shocks. In Experiment 2, a greater shock intensity (2 mA) was used. All the differences between the two groups found in Experiment 1 were also found in Experiment 2. Experiment 3 demonstrated that response‐contingent shock did not result in a conditioned punishment effect even when positive reinforcers were unavailable during the discriminative punishment schedule. The exteroceptive stimulus that was paired with shock in the conditioned suppression procedure acquired the ability to punish behavior. The exteroceptive stimulus in the discriminative punishment schedule did not acquire this ability.
PICTORIAL TARGET CONTROL OF SCHEDULE‐INDUCED ATTACK IN WHITE CARNEAUX PIGEONS1
Authors: Looney Thomas A. , Cohen Perrin S.
Published: March 2006

Three pigeons with a history of attacking a mirror target, and two of six pigeons with no prior exposure to targets, attacked a colored photograph of a conspecific during exposure to intermittent schedules of reinforcement for key pecking. Rate of attack on the photograph decreased when the reinforcement schedule was removed. The topography, temporal pattern, and locus of attack on the picture were comparable to schedule‐induced attack on live, stuffed, and mirror targets. When silhouette, outline, and plain paper targets were used, schedule‐induced attack was more sensitive to a change in target characteristics with a concurrent target‐preference procedure than with an analogous successive‐testing procedure. The combined results of the two testing procedures indicated that an “upright” white‐on‐black silhouette of a pigeon with or without an eye was more effective in controlling attack than was a comparable “inverted” silhouette, an outline of a pigeon, or a piece of colored paper.
CONCURRENT PERFORMANCES: STIMULUS‐CONTROL GRADIENTS DURING SCHEDULES OF SIGNALLED AND UNSIGNALLED CONCURRENT REINFORCEMENT1
Authors: Catania A. Charles , Silverman Philip J. , Stubbs D. Alan
Published: March 2006

On one key, pigeons' pecks were reinforced according to a variable‐interval schedule in the presence of vertical lines, and were not reinforced in the presence of oblique lines. On a second key, pecks were reinforced according to a variable‐interval schedule in the presence of blue, according to a signalled variable‐interval schedule in the presence of red, and were not reinforced in the presence of white. Subsequently, during extinction, stimulus‐control gradients were obtained by presenting eight different line orientations on the first key concurrent with each of the three colors on the second key. On the first key, line‐orientation gradients tended to be lower, narrower, and less shifted in peak or area when the second‐key stimulus was blue or red, the stimuli respectively correlated with unsignalled and signalled reinforcement, than when it was white, the stimulus correlated with extinction. Thus, the effect on first‐key line‐orientation gradients depended on second‐key stimuli correlated with concurrent reinforcement, whether or not these stimuli were also correlated with concurrent responding. As a function of first‐key line orientation, an inverted gradient was obtained on the second key during blue; during both red and white, rates of pecking on the second key were near zero.
THE EFFECTS OF NUMBER OF RESPONSES ON PAUSE LENGTH WITH TEMPORAL VARIABLES CONTROLLED1
Authors: Crossman E. K. , Heaps R. Steven , Nunes Dennis L. , Alferink Larry A.
Published: March 2006

A change in the size of a fixed‐ratio schedule involves a simultaneous change in number of responses, in time to complete the ratio (work time), and in the interval between successive reinforcements (interreinforcement interval). Previous studies have suggested the importance of work time and the interreinforcement interval in controlling the length of the post‐reinforcement pause. The present study sought to determine whether number of responses is also a significant factor. Pigeons were trained on a multiple fixed‐ratio x fixed‐ratio 2 plus timeout schedule in which the size of the fixed‐ratio x was manipulated. When the work times (Experiment I) or interreinforcement intervals (Experiment II) were equated for the two components, the pause before the fixed‐ratio x was longer than the pause before the fixed‐ratio 2 plus timeout. As fixed‐ratio x size increased, the relative difference in the lengths of the two types of pauses also increased. Because the fixed‐ratio x component contained a larger number of responses than the fixed‐ratio 2 plus timeout component, the relatively longer pause preceding the fixed‐ratio x indicates that number of responses played a significant role in determining the length of the post‐reinforcement pause.
CONTROL OF KEY PECKING BY THE DURATION OF A VISUAL STIMULUS
Authors: Périkel J. J. , Richelle M. , Maurissen J.
Published: March 2006

Pigeons' key pecks were brought under the control of the duration of a visual stimulus in one‐key and two‐key procedures. In the one‐key procedure, pecks were reinforced after presentations of a long‐duration stimulus but not after presentations of a short‐duration stimulus. In the two‐key procedure, left‐key pecks were reinforced after the long‐duration stimulus and right‐key pecks after the short‐duration stimulus. In both procedures, the long‐duration stimulus was 10 sec, and the short‐duration stimulus was increased from 1 to 8 sec in 1‐sec steps. Discriminative control developed with both procedures, but with greater accuracy in the two‐key procedure, in which a difference threshold was obtained at short‐duration values between 7 and 8 sec, or about 2.5 sec shorter than the long‐duration stimulus.
PATTERNING WITH FIXED‐TIME SCHEDULES OF RESPONSE‐INDEPENDENT REINFORCEMENT1
Authors: Alleman Harold D. , Zeiler Michael D.
Published: March 2006

Pigeons were first exposed to a schedule providing food when the time between successive key pecks (the interresponse time) exceeded a specified duration. When food then was presented at regular intervals independent of responding (fixed‐time schedule), responses typically occurred at a steady rate in the periods between successive food presentations. Once the birds had been exposed to a fixed‐ratio schedule, however, response rate under fixed‐time schedules was positively accelerated. Variations in the sequence of conditions given different subjects indicated that the changes in patterning were due to the fixed‐ratio schedule, rather than to the number of transitions from a response‐dependent to the response‐independent fixed‐time schedule, to changed parameter values, or to prolonged experience with the fixed‐time schedule. The effects of fixed‐time schedules on patterning depended upon experimental history.
ON THE NATURE OF NON‐RESPONDING IN DISCRIMINATION LEARNING WITH AND WITHOUT ERRORS1
Authors: Terrace H. S.
Published: March 2006

In human subjects, discrimination learning with errors results in active responding incompatible with the reinforced response. The direction of such incompatible behavior is opposite to that of the reinforced response. Responding occurs only during the stimulus correlated with extinction. The frequency of active non‐responding is maximal shortly after the start of discrimination training (the time at which the frequency of errors decreases most rapidly) and approaches zero as discrimination training continues. The magnitude of behavioral contrast is not related systematically to the number of errors. Instead it is related directly to the frequency of active non‐responding. Active non‐responding appears to be motivated by the aversiveness of self‐produced frustration, in the sense that active non‐responding allows the subject to avoid the aversiveness of non‐reinforced responding.
DISCRIMINATIVE EFFECTS OF MASSED EXTINCTION1
Authors: Yarczower Matthew
Published: March 2006

Prior studies have reported that generalization gradients are not steepened if periods of non‐reinforcement in S— follow and are not interspersed with periods of reinforcement in S+. Sharper gradients are produced by this massed‐extinction procedure if it is preceded by prior discriminative training on a dimension orthogonal to the S+, S— dimension. The present study, using pigeons, found that generalization gradients along the wavelength dimension were steepened by massed‐extinction sessions in 570 nm that had been preceded by: (1) discriminative training in which the S+ was a 550‐nm light and the S— was a black vertical line superimposed on the 550‐nm light; Final Acceptance (2) non‐differential reinforcement training with a 550‐nm light and a black vertical line superimposed on the 550‐nm light; Final Acceptance (3) reinforcement training with only the 550‐nm light. Massed‐extinction sessions were administered until the response rate in the presence of the 570‐nm stimulus was one‐tenth of the mean response rate in the presence of the 550‐nm stimulus during prior reinforcement training. Prior studies have used a time‐dependent criterion, rather than a response‐rate criterion of extinction, and this difference may be responsible for the differences in the effects of massed extinction on stimulus control.
CONCURRENT PERFORMANCES: REINFORCEMENT BY DIFFERENT DOSES OF INTRAVENOUS COCAINE IN RHESUS MONKEYS1
Authors: Iglauer Carol , Woods James H.
Published: March 2006

Different doses of intravenous cocaine reinforced the lever pressing of rhesus monkeys under two‐lever concurrent or concurrent‐chain schedules. Under the concurrent procedure, responding produced drug reinforcers arranged according to independent variable‐interval 1‐min schedules. Under the concurrent‐chain procedure, responding in the variable‐interval link led to one of two mutually exclusive, equal‐valued, fixed‐ratio links; Final Acceptance completion of the ratio produced a drug reinforcer. Under both procedures, responding on one lever produced a constant dose of 0.05 or 0.1 mg/kg/injection, while on the other lever, dose was systematically varied within a range of 0.013 to 0.8 mg/kg/injection. Preference, indicated by relative response frequency on the variable‐dose lever during the variable‐interval link, was always for the larger of the doses. Relative response frequencies on the variable‐dose lever roughly matched relative drug intake (mg/kg of drug obtained on variable lever divided by mg/kg of drug obtained on both levers). For many dose comparisons, responding occurred and reinforcers were obtained almost exclusively on the preferred lever. Overall variable‐interval rates generally were lower than with other reinforcers, and these low rates, under the experimental conditions, may have occasioned the exclusive preferences.
INDUCED ATTACK DURING MULTIPLE FIXED‐RATIO, VARIABLE‐RATIO SCHEDULES OF REINFORCEMENT1
Authors: Webbe Frank M. , DeWeese Jo , Malagodi E. F.
Published: March 2006

Two pigeons were exposed to a multiple schedule of reinforcement: in the presence of one discriminative stimulus, key pecks produced grain according to a fixed‐ratio schedule; Final Acceptance in the presence of a second discriminative stimulus, key pecks produced grain according to a variable‐ratio schedule. The key‐peck requirements in the two components were increased in successive stages from 50 to 125 responses. Live target pigeons were restrained at the rear of the chamber. Attacks against the targets were automatically recorded, and a variety of measures of attack behavior were taken. Attacks, when they occurred, always followed grain presentation. All measures revealed higher levels of attack during the fixed‐ratio component at all parameter values. All measures generally increased with increases in fixed‐ratio values with both birds, and with increases in variable‐ratio values with one bird. With the other bird, only the per cent of reinforcements followed by attack increased with increases in variable‐ratio value; Final Acceptance all other measures first increased and then decreased. Both increasing and bitonic functions relating induced attack to schedule parameters have been reported in experiments usually employing a single measure of attack. The measures have varied widely among these experiments. It is suggested that further studies of induced attack examine a wider range of schedule parameters and that relationships among measures be studied.
KEY PECKING AS A FUNCTION OF RESPONSE‐SHOCK AND SHOCK‐SHOCK INTERVALS IN UNSIGNALLED AVOIDANCE1
Authors: Todorov João Claudio , Ferrari Elenice A. M. , de Souza Deisy G.
Published: March 2006

Five pigeons were exposed to an unsignalled avoidance procedure where key pecks were maintained through shock postponement. Functions obtained showed an inverse relationship between rate of responding and length of the response‐shock interval, while changes in the shock‐shock interval had no systematic effect on response rates. The rate of shocks delivered generally decreased with increases in length of both response‐shock and shock‐shock intervals. Results show that key pecking in pigeons, maintained through an unsignalled avoidance procedure, was affected by changes in response‐shock and shock‐shock intervals in the same manner as other responses in pigeons and in rats.
FREE‐OPERANT ESCAPE‐AVOIDANCE OF NOISE BY RATS1
Authors: Knutson John F. , Bailey Margaret I.
Published: March 2006

A series of experiments was conducted to establish free‐operant escape‐avoidance responding in rats using noise as the stimulus. Naive rats did not acquire a bar‐press response on an escape‐avoidance of noise schedule. Similarly, free‐operant responding established using escape‐avoidance of shock was not maintained when noise was substituted for shock. Noise stimuli of 110 dB did maintain responding, but at a lower level than during training, when the noise stimuli had first been paired with shock. Noise stimuli of 97 dB and 87 dB were not effective under those same conditions. Additional rats were trained on a free‐operant escape‐avoidance schedule of shock and then exposed to a delayed conditioning procedure in which noise was the conditioned stimulus and shock was the unconditioned stimulus. When these subjects were then tested with noise alone, two of the three subjects conditioned and tested with 105‐dB noise displayed escape‐avoidance of noise, but none of the rats conditioned and tested at 97 dB displayed escape‐avoidance of noise. The results suggest that free‐operant escape‐avoidance of noise can be demonstrated; Final Acceptance however, only higher intensity noise stimuli that have been paired with shock are effective.
THE EVALUATION AND CONTROL OF ACOUSTICAL STANDING WAVES1
Authors: Krasnegor Norman A. , Hodos William
Published: March 2006

Calibration of a standard pigeon box subsequently modified for use as an acoustical chamber in a frequency discrimination experiment revealed that the enclosure was not acoustically “flat”. Standing waves were detected at each of the six frequencies measured. To ascertain whether the maximum standing waves recorded (3.0 dB) could serve as an added or alternative cue for pigeons tested in the chamber on a frequency discrimination problem, pure‐tone intensity difference thresholds were determined for two pigeons at 1.0, 2.0, and 3.0 KHz. The results of the experiment indicated that the smallest intensity difference detectable was 10.0 dB, a value that was 7.0 dB above the maximum standing wave measured in the box. These data suggest that the modified pigeon chamber is suitable to test pure‐tone frequency discriminations in pigeons in the range of 1.0 to 3.0 KHz.
TRANSFER OF CONTROL OF THE PIGEON'S KEY PECK FROM FOOD REINFORCEMENT TO AVOIDANCE OF SHOCK
Authors: Foree Donald D. , Lolordo Vincent M.
Published: March 2006

Eight pigeons were initially trained to peck a white key for food under a variable‐interval 1‐min schedule of reinforcement. Then, a shock‐avoidance schedule was initiated and food was no longer available in the experimental situation. Under the avoidance schedule, each peck on the key postponed shock for 40 sec. A warning signal, consisting of tone and red houselights, was presented after 30 sec without a response. If no response occurred, a shock was delivered 10 sec after warning‐signal onset. Shocks were delivered every 10 sec in the presence of the warning signal until a response was made. The warning signal was terminated only by a response. Key pecking of all eight pigeons came under control of the avoidance schedule and responding continued throughout the 20‐day avoidance training period.
ACQUISITION OF MATCHING TO SAMPLE VIA MEDIATED TRANSFER1
Authors: Sidman Murray , Cresson Osborne , Willson‐Morris Martha
Published: March 2006

Two severely retarded Down's‐syndrome boys learned a matching‐to‐sample performance through mediated transfer. The transfer paradigm involved three sets of stimuli, one auditory set (A) and two visual sets (B and C). The subjects were taught directly to do B‐A and C‐B matching, but experienced no direct association between C and A. They acquired the ability to do C‐A matching without having been taught that performance directly. They also learned indirectly to name some of the visual stimuli, but naming was apparently not the mediator in the emergent C‐A matching. The use of words and letters as stimuli highlighted the possible relevance of mediated associations in the indirect acquisition of elementary reading comprehension and oral reading. The acquisition of matching via mediated transfer also raised some new considerations concerning the role of coding responses in arbitrary matching to sample.
DIFFERENTIATION OF PRESS DURATIONS WITH UPPER AND LOWER LIMITS ON REINFORCED VALUES
Authors: Kuch Dennis O.
Published: March 2006

Rats received food following lever‐press durations between t and t + t′ sec where t was 2, 4, or 8 sec and t′ was 0.25t, 0.50t, or 1.00t sec. Modal press durations were greater than t but less than t + t′ in all cases. Distributions of press durations were lower and broader for larger values of t. Lower t′/t ratios produced lower median press durations and relatively narrower press‐duration distributions. Median press duration was a power function of t within a t′/t ratio condition, corresponding to previous results for latency, interresponse time, and response durations.
TIME LIMITS FOR COMPLETING FIXED RATIOS. III. STIMULUS VARIABLES1
Authors: Decasper Anthony J. , Zeiler Michael D.
Published: March 2006

Pigeons received food only if they took longer than a specified time to begin and complete a fixed ratio. In Experiment 1, ratios with shorter durations had no stimulus consequence; in Experiment 2, these ratios ended with a stimulus change. In both studies, the mean time to complete the ratio exceeded requirements of less than 30 sec, approximately matched requirements of 30 sec, and fell progressively short of matching thereafter. Variability increased together with the means. The various effects resembled those of temporal differentiation experiments involving single responses. Although both number of ratios and time separating successive food presentations increased along with ratio duration, control experiments showed that differential reinforcement of duration, rather than either form or reinforcer intermittency, accounted for the performance. Experiment 2 also studied the effects of adding a stimulus that signalled when the required time had elapsed. The stimulus produced durations that matched even the most stringent requirements. This precision was not maintained when the stimulus was removed. Temporal differentiation schedules seem to have similar effects regardless of the response class and temporal property involved.
AN APPRAISAL OF PREFERENCE FOR MULTIPLE versus MIXED SCHEDULES1
Authors: Hursh Steven R. , Fantino Edmund
Published: March 2006

Pigeons' choice responses on either of two keys occasionally produced entry into a terminal link associated with that key. During the terminal links, responses produced access to grain according to mixed‐ or multiple‐interval schedules. The multiple schedules provided stimuli correlated with the interval of time preceding reinforcement whereas the mixed schedules did not. The two subjects reliably preferred the multiple schedules to the mixed schedules throughout a series of replications. Preference for the multiple schedule was much smaller than suggested by earlier work comparing multiple and mixed schedules that had much higher rates of entry into the terminal links. Preference for the multiple schedule was greatly increased in this study when the rate of entry into the terminal schedules was increased. As in previous studies, these high preferences may have been the result of a sharp increase in the number of reinforcements on the multiple (as opposed to the mixed) schedule. The reliable but smaller preferences for the multiple schedule found with lower rates of entry into the terminal links were unconfounded by differences in the number of reinforcements obtained in the two terminal links.
COMBINING STIMULI SIGNALLING RESPONSE‐DEPENDENT FOOD AND SHOCK1
Authors: Wiltz Robert A.
Published: March 2006

Three rats were exposed to a multiple schedule in which separate presentations of light and tone alternated with periods during which light and tone were absent. In Phase 1, light and tone each signalled identical variable‐interval schedules of food delivery. In Phase 2, light and tone signalled separate but concurrent variable‐interval schedules of food and shock delivery. In both phases, the absence of light and tone was associated with the differential reinforcement of other behavior. Test presentations of light, tone, and a light‐plus‐tone combination indicated that in both phases, light‐plus‐tone controlled higher response rates than either light or tone alone. The combination continued to control enhanced responding even when the test stimuli signalled variable‐interval schedules of food and fixed‐ratio schedules of shock. In these latter sessions, enhanced control by the combination increased shock frequency with no corresponding change in food frequency. Apparently, the level of behavior controlled by the absence of two single stimuli may be more important than the consequences of responding in determining the effects of combined‐stimulus presentations.
SIGNALLED REINFORCEMENT IN DIFFERENTIAL‐REINFORCEMENT‐OF‐LOW‐RATE SCHEDULES1
Authors: Marcucella Henry
Published: March 2006

At several fixed and variable minimum reinforced interresponse times, a stimulus was added to differential‐reinforcement‐of‐low‐rate schedules to signal the availability or nonavailability of reinforcement. As the minimum reinforced interresponse time increased, the rate of unreinforced responding decreased. Changing from fixed to variable minimum interresponse time in the basic differential‐reinforcement‐of‐low‐rate schedule further decreased the rate of unreinforced responding. Both effects were to some degree reversible. For fixed minimum reinforced interresponse times of 30 sec or shorter, most unreinforced responses terminated interresponse times just short of that required for reinforcement. The minimum reinforced interresponse time and the number of short response latencies (≤0.5 sec) to the onset of the signal were negatively correlated. Both of these analyses suggested that at values of 30 sec or shorter, the subjects discriminated the availability of the reinforcer more on the basis of time than on the basis of presence or absence of the signal.
THE EFFECTS OF TOTAL DARKNESS ON SCHEDULE CONTROL
Authors: Robinson Paul W. , Shelley Monte F.
Published: March 2006

The study investigated the effect of total darkness on the key pecking of pigeons under fixed‐ratio, variable‐ratio, fixed‐interval, and variable‐interval schedules of food reinforcement. Eight pigeons were divided into groups of two, with each group conditioned to peck under one of the four schedules of reinforcement. Under an ABAB procedure, all pigeons experienced alternating light and dark conditions. The house‐ and keylights were (a) maintained at full intensity for the first 30 one‐hour sessions, (b) faded out and disconnected over Sessions 31 through 50, (c) totally illuminated for Sessions 51 to 60, and (d) disconnected again for the final 10 sessions. Responding under the ratio schedules increased from 20% to 108% in the dark and responding under the interval schedules in the dark decreased by 37% to 93%.
AVERAGE UNCERTAINTY AS A DETERMINANT OF OBSERVING BEHAVIOR1
Authors: Mcmillan John C.
Published: March 2006

After discrimination training on a multiple variable‐interval extinction schedule of food reinforcement, pigeons were placed on the uncued or mixed version of the same schedule and allowed to make an optional “observing response” that converted the uncued schedule to the corresponding cued schedule by providing a 20‐sec exposure to the appropriate discriminative stimulus. The schedule consisted of one hundred 40‐sec components, and the probability that any one of them would be a variable‐interval component was systematically varied between 0.00 and 1.00. The results showed that the amount of observing behavior was an inverted “U” function of the probability of the variable‐interval component. Few observing responses occurred at probabilities of 0.00 or 1.00, and maximum responding occurred at a value less than 0.50.
THE MEASUREMENT OF RESPONSE FORCE DURING A LEVER‐PRESS SHOCK‐ESCAPE PROCEDURE IN RATS1
Authors: Davis Hank , Burton Jo‐Ann
Published: March 2006

Three albino rats were given extensive exposure to an escape procedure in which shocks were scheduled to occur 30 sec apart. The amount of downward force exerted on the lever was continuously recorded and compared with traditional discrete measurement in which only responses above an arbitrary force threshold were recorded. Subjects typically remained in contact with the lever throughout the shock‐free intertrial interval. Shock onset reliably occasioned a brief lurch from and return to the lever, which resulted in a lever‐press escape response being recorded. Lever contact, which occupied an average of 90% of session time, showed great stability in force after a brief (e.g., 5‐sec) period of instability after each shock terminated. In general, continuous measurement revealed considerably different results than discrete measurements of on‐lever behavior. For example, continuous lever contact fluctuating near response threshold was often recorded as discrete responding, and sustained lever contact occurring below response threshold was omitted from discrete measurement.
BEHAVIORAL INTERACTIONS IN MULTIPLE VARIABLE‐INTERVAL SCHEDULES1
Authors: Spealman Roger D. , Gollub Lewis R.
Published: March 2006

In Experiment I, two groups of four pigeons each were exposed to multiple schedules in which one component was always a variable‐interval schedule with a mean interreinforcement interval of 30 or 180 seconds. The other component was either an equal variable‐interval schedule or extinction. Response rates in the unchanged component always increased when reinforcement was no longer scheduled in the changed component, and decreased in seven of eight cases when the variable‐interval schedule was re‐introduced. The per cent rate change in the unchanged component was inversely related to the frequency of reinforcement and to the ongoing response rate in the unchanged component. Rate changes in the unchanged component were not consistently correlated with changes in any single feature of the relative‐frequency interresponse‐time distributions. In Experiment II, the same pigeons were exposed to variable‐interval schedules and multiple variable‐interval variable‐interval schedules with equal mean interreinforcement intervals. Response rates were similar under both conditions.
EFFECTS OF VARYING THE PERCENTAGE OF KEY ILLUMINATIONS PAIRED WITH FOOD IN A POSITIVE AUTOMAINTENANCE PROCEDURE1
Authors: Gonzalez Fernando A.
Published: March 2006

Three pigeons were exposed to a positive automaintenance procedure in which each trial began with a brief tone followed by the transillumination of a small central area of the response key for 10 sec. Key illumination was followed by food on 100%, 50%, 25%, 12.5%, and 0% of the trials. The effects depended on the dependent variable observed. The mean rate of responding during key illumination rapidly increased and then decreased slightly as the percentage of key illuminations paired with food increased. The number of key illuminations during which at least one response occurred increased as a negatively accelerating function of the percentage of key illuminations paired with food, and the mean latency to the first response during the key illuminations decreased as a negatively decelerating function of the percentage condition. The mean rate of sustained responding during key illumination was not systematically affected by changes in the percentage conditions.
LEVER‐CONTACT RESPONSES IN RATS: AUTOMAINTENANCE WITH AND WITHOUT A NEGATIVE RESPONSE‐REINFORCER DEPENDENCY1
Authors: Stiers Michael , Silberberg Alan
Published: March 2006

Pairing the presentations of one lever (cueing lever) with food led to the acquisition and persistence of lever contacts by rats. This behavior did not occur with a second lever, which was presented randomly with regard to food delivery. This finding obtained whether food delivery was independent of cueing‐lever contacts (positive automaintenance) or dependent on the absence of cueing‐lever contacts (negative automaintenance). The general findings were: (1) cueing‐lever contacts on the positive automaintenance procedure occurred on a higher proportion of trials and at higher rates when contacts occurred than on the negative automaintenance procedure; (2) instances of the cueing lever's failure to support responding were more frequent on the negative than the positive automaintenance procedure; and (3) the topography and median contact duration of positively automaintained responding differed from negatively automaintained responding. These findings agree substantially with the automaintenance literature on pigeons, suggesting that similar processes may characterize automaintained responding in both pigeons and rats.
TIMING OF AVOIDANCE RESPONSES BY RATS1
Authors: Libby Myrna E. , Church Russell M.
Published: March 2006

Three rats were trained on an unsignalled shuttlebox‐avoidance task under three response‐shock intervals (10, 20, and 40 sec). Under all conditions, subjects developed excellent temporal gradients of avoidance; that is, response rate was an increasing function of time since last response. Although the response rate at any given interval of time after the previous response was inversely related to the response‐shock interval, there was an underlying similarity in the temporal gradients for the three intervals. In all cases, response rate relative to the maximum response rate was approximately equal to the proportion of the interval that had elapsed. This suggests that rats in unsignalled avoidance are estimating time from response completion, and that the units of the estimate are proportional parts of the response‐shock interval.
ADDITIVE AND SUPPRESSIVE RESPONSE SUMMATION WITH A CHAIN SCHEDULE
Authors: Meltzer Donald , Niebuhr Bruce R.
Published: March 2006

Rats responded in a two‐segment (variable‐interval variable‐interval) chain schedule. In one experiment, three subjects had either clicker, light, or clicker plus light as terminal‐segment stimuli. All three responded at the highest rate when clicker plus light were present, thus showing additive summation. For three other subjects, initial‐segment stimuli were either clicker, light, or clicker plus light. Two subjects responded at the lowest rate when clicker plus light were present, thus showing suppressive summation. In a second experiment, three subjects had either clicker, light, or neither clicker nor light as terminal‐segment stimuli. None of these subjects showed reliable additive summation. Three other subjects had clicker, light, or neither as the initial‐segment stimulus, and all three showed suppressive summation. Additive and suppressive summation both can be demonstrated with chain schedules, but stimulus parameters may be major variables in producing the effect.