Influence of order of occurrence of non-reward and large and small reward on acquisition and extinction.

Abstract

The 2X2 factorial design employed 48 rats in the runway. Manipulated were number of nonrewarded (N) trials preceding the rewarded trial (N-length, 3 vs. 1) and order of occurrence of the larger reward magnitude (.09 vs. .675 gm.), either before or after nonreward. The intertrial interval was IS min. Consistent with previous results under short intertrial intervals (ITI) (e.g., 30 sec.), but inconsistent with a previous finding under 15-min. ITI, resistance to extinction increased as N-length increased. Also found was that resistance to extinction was greater when large reward followed, rather than preceded, nonreward. The results were examined relative to several current hypotheses of the effects of partial reward at different ITIs.

Sequential effects of resistance to extinction at widely spaced trials.

“…Gonzalez and Bitterman suggest that massed-and spaced-trials phenomena may be controlled by different processes. The present experiments, however, along with a number of others (e.g., Capaldi & Kassover, 1970;Capaldi & Minkoff, 1969;Mellgren & Seybert, 1973), strongly indicate that at least some sequential variables may operate in experimental situations involving wide spacing of trials in much the same way as they do in massed-trials situations. Clearly, more re-search is needed to determine the parallels that exist between massed-and spaced-trials extinction phenomena, at which point presumably more definitive theoretical accounts will be forthcoming.…”

“…The results of the Capaldi and Kassover (1970), Capaldi and Minkoff (1969), and Mellgren and Seybert (1973) studies indicate that extinction performance at spaced trials may be controlled by sequential processes. If the boundary conditions of sequential theory are to be extended to include spaced-trials phenomena, as the data of these experiments suggest, additional massed-trials sequential phenomena need to be investigated using spaced-trials procedures.…”

“…Several investigators (e.g., Gonzalez & Bitterman, 1969) have stated that Capaldi's (1967) sequential explanation of the partial reinforcement effect is appropriate only under experimental conditions involving very short intertrial intervals (ITIs). The notion that sequential theory is appropriate only for data collected at massed trials has been supported in some experiments (Gonzalez & Bitterman, 1969;Surridge & Amsel, 1966); but others have supported a sequential explanation of spaced-trials data (Capaldi & Kassover, 1970;Capaldi & Minkoff, 1969;Mellgren & Seybert, 1973). Both the Gonzalez and Bitterman study and Surridge and Amsel study failed to find that one sequential variable, N lengthnumber of consecutive nonreward (N) trials followed by a reward (R) trial-had any effect on resistance to extinction at spaced trials.…”

A stimulus-sampling model of the partial reinforcement effect.

“…N-length. Capaldi (1964Capaldi ( , 1966, Capaldi, Hart, and Stanley (1963), Capaldi and Kassover (1970), Capaldi and Minkoff (1969), Capaldi and Spivey (1963), and Gonzalez and Bitterman (1964) have all shown that the length of run of successive nonreinforcements (N-length), number of different N-lengths, and number of occurrences of each N-length are all variables relevant to the magnitude of the increased resistance to extinction. These were also confounded with percentage of reinforcement in earlier studies.…”

Magnitude of partial reward, irregular reward schedules, and a 24-hour ITI: A test of several hypotheses.

“…Investigations attempting to determine the effects of magnitude of partial reward on resistance to extinction (R to E) have employed either a 24-hr, intertrial interval (ITI) and irregular reward schedules (Hulse, 1958;Wagner, 1961) or relatively Eiassed trials and regular reward schedules (Capaldi & Lynch, 1968;Capaldi & Minkoff, 1969;Leonard, 1969). Whether the results produced by these two "kinds" of investigations may be interpreted in terms of a single theory, and thus in terms of common variables, or whether they demand two entirely different sorts of explanation is at present an open question.…”