See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/6972694 Second-order schedules of token reinforcement: Effects of varying the schedule of food presentation Article in Journal of the Experimental Analysis of Behavior · October 1975 DOI: 10.1901/jeab.1975.24-173 · Source: PubMed CITATIONS READS 18 64 3 authors , including: Frank M Webbe Florida Institute of Technology 73 PUBLICATIONS 1,435 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Novel methods for objective assessment of mild traumatic brain injury View project Validity Factors in Baseline Concussion Assessment View project All content following this page was uploaded by Frank M Webbe on 17 May 2014. The user has requested enhancement of the downloaded file.
NUMBER 2 (SEPTEMBER) 1975, 24, 173-181 JOURNAL OF THE EXPERIMENTAL ANALYSIS OF BEHAVIOR SECOND-ORDER SCHEDULES OF TOKEN REINFORCEMENT: EFFECTS OF VARYING THE SCHEDULE OF FOOD PRESENTATION' E. F. MALAGODI, FRANK M. WEBBE, AND THOMAS R. WADDELL UNIVERSITY OF FLORIDA In the initial link of a complex schedule, one discriminative stimulus was presented and lever pressing produced tokens on fixed-ratio schedules. In the terminal link, signalled by a second discriminative stimulus, deposits of the tokens produced food. With two rats, the terminal link was presented after each sixth component schedule of token reinforcement was completed. With the other two rats, the terminal link was presented following the first component schedule completed after a fixed interval. During the terminal link, each token deposit initially produced food. The schedule of food presentation was subsequently in- creased such that an increasing number of token deposits in the terminal link was required for each food presentation. Rates of lever pressing in the initial link were inversely related to the schedule of food presentation in the terminal link. These results are similar to those of experiments that have varied schedules of food presentation in chained schedules. Rates and patterns of responding controlled throughout the initial link were more similar to those ordinarily controlled by second-order brief-stimulus schedules than to those con- trolled by comparable extended chained schedules. Key words: second-order schedules, chained schedules, token reinforcement, reinforce- ment probability, lever press, rats Second-order schedules involving brief-stim- and exchange schedules. In general, the re- ulus and chaining procedures have been widely sults reflected the contribution of both types studied 1969; of schedules in controlling characteristic pat- (cf., Kelleher, 1966; Marr, Stubbs, 1971). A third form of second-order terns of responding throughout sequences of schedule, involving delivery of tokens, has re- components terminating in token reinforce- ceived less attention. This procedure may be ment. In those experiments, and in the early described in terms of the three types of sched- studies of Wolfe (1936) and Cowles (1937), the ules inherent within the paradigm. The first is deposit of each token (in the presence of the the schedule of token reinforcement: the sched- appropriate discriminative stimulus) produced ule according to which a response (e.g., lever food delivery. pressing) produces delivery of tokens (objects The present experiment followed Kelleher's such as poker chips or marbles). The second is (1956) suggestion that it would be interesting the exchange schedule: the schedule for pre- to determine the effects of "inflating the coin senting a discriminative stimulus in the pres- of the realm" in the token-reinforcement para- ence of which the tokens may be exchanged for digm by increasing the number of token de- food. The third is the schedule of food rein- posits required for delivery of each food rein- forcement: the schedule according to which forcer. The effects of this manipulation were token deposits produce food. of interest for two reasons. First, of the three Previous experiments studying token rein- types of schedules inherent within the para- forcement with chimpanzees (Kelleher, 1956; digmn, it is the only one that has not been stud- 1957a, b, c; 1958) and with rats (Malagodi, ied experimentally. Second, experiments with 1966; 1967a, b, c; Waddell, Leander, Webbe, chained schedules have shown that the schedule and Malagodi, 1972) have examined lever of food presentation in the terminal link is a pressing (or panel pushing) under several com- powerful determinant of responding in ante- binations of schedules of token reinforcement cedent links (cf., Kelleher, 1966; Kelleher and Gollub, 1962, Marr, 1969). The effects of vary- "This research was supported by grant MH 15901 ing the schedule of food presentation would from the National Institute of Mental Health. Reprints thus bear upon the analysis of the token-rein- may be obtained from E. F. Malagodi, Department of forcement paradigm as a form of extended Psychology, University of Florida, Gainesville, Florida chained schedule (Kelleher, 1966; Kelleher and 32611. 173
E. F. MALAGODI, F. M. WEBBE, and T. R. WADDELL 174 Gollub, 1962). The forms of the schedules of TOKEN schedules turned off the red light and token reinforcement and exchange schedules turned on the white light and a clicker (FR 6: used in the present experiment were similar to EXCHANGE). Initially, in the presence of the those used previously in second-order brief- white light and clicker, the deposit of each stimulus schedules. These aspects of the pro- token into the receptacle produced a single food pellet (FR: 1 FOOD). The white liglht and cedure enabled relating the results to sugges- tions that the token-reinforcement paradigm clicker terminated 0.75 sec after the last token also resembles brief-stimulus procedures was deposited, at which time the red light and (Marr, 1969; Waddell et al., 1972). corresponding schedule were re-instated. The red-light sequence is referred to as the initial link, the white-light/clicker sequence as the METHOD terminal link. The successive FR 20: TOKEN Subjects schedules during the initial link are referred to Four adult male Long-Evans hooded rats as component schedules. The initial condition were maintained at 80% of their adjusted free- was the same with Rat T-23, except that an FR feeding weights; their 80% deprivation values 15: TOKEN schedule was used. were calculated weekly on the basis of the Rats W-33 and W-35 were exposed to similar mean weights of free-feeding male littermates. conditions, except that the exchange schedule They had free access to water in their home was fixed interval rather than fixed ratio. The cages. Rats T-22 and T-23 were experimentally schedule of token reinforcement for both rats naive, and Rats W-33 and W-35 had served in was FR 20: TOKEN, and the first component a previous token-reinforcement experiment schedule completed after a fixed period of time (Waddell et al., 1972). in the initial link resulted in presentation of the terminal link. The fixed-interval parame- Apparatus ter of the exchange schedule was 4.5 min with The experimental chamber contained a Ger- Rat W-33 (Fl 4.5: EXCHANGE), and 9.0 min brand's rat lever, a hopper into which dark with Rat W-35 (FI 9.0: EXCHANGE). These clear-glass marbles (tokens) were dispensed, a fixed-interval parameters were selected as those receptacle into which the rats deposited the that produced comparable baseline perform- marbles, and a hopper into which 45-mg Noyes ance for the two rats. standard-formula food pellets were dispensed. The baseline conditions remained in effect A red light (6-W, 115-V ac) was located directly until both lever pressing and token depositing above the lever and a similar white light was were stable. Stability was defined as the ab- located inside the receptacle. The chamber was sence of any systematic trends in overall rates housed within a ventilated, sound-attenuating of level pressing and in rates within individual exterior chamber. A one-way window allowed components for 10 consecutive sessions. In ad- for observation of the rats, and an exhaust fan, dition, medians and ranges of overall rates for air-conditioner, and white-noise generator pro- the last five sessions had to be equivalent to vided masking background noise. Standard those from the previous five sessions before electromechanical scheduling and recording conditions were changed. After stability had equipment was located in an adjacent room. been obtained, the initial-link schedules were A detailed description of the experimental held constant while the schedule of food pre- chamber and early training procedures has sentation in the terminal link was systemati- been presented elsewhere (Malagodi, 1967a). cally varied. The schedule of food presentation was increased for all rats to FR 2: FOOD-de- Procedure livery of one food pellet followed deposit of The initial condition for Rat T-22 illus- every second token. Thus, with Rats T-22 and trates the basic procedure, notation system, T-23, the second, fourth, and sixth deposits and use of descriptive terms such as "links" during each presentation of the terminal link and "components". In the presence of the red produced food. Because Rats W-33 and W-35 light, each 20 lever presses produced delivery responded under Fl t: EXCHANGE schedules, of a single token (FR 20: TOKEN), each de- the number of tokens available for deposit var- livery being accompanied by a 0.75-sec, 1000- ied in presentations of the terminal link, de- Hz tone. Completion of six successive FR 20: pending upon the number of component FR
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