Response stability and variability induced in humans by different feedback contingencies

Abstract

In a fairly large number of studies, researchers have examined the effects of extinctionon conditionedresponding in classical and operant conditioningprocedures. Neuringer, Kornell, and Olufs (2001) found evidence in this literature, which will not be reviewed here again, of two opposing effects: response stability and response variability. An example of each of these effects can be found in the experiments reported by Neuringer et al. (2001). In their first experiment, rats were food-reinforced for emitting variable sequencesof responses, using one, two, or three of three different operanda: two levers (L and R) and a key (K). Each response sequence that could be reinforced consisted of three responses. There are a total of 27 possible threeresponse sequences involvingone, two, or three operand(a) (e.g., LLL, LLR, or LRK). Reinforcement was given for a sequence only if its relative frequency was less than or equal to .05. The purpose of this reinforcement schedule was to induce behavioral variability, and the question of major interest was whether, and how, response variability would change in a subsequent phase without reinforcement (extinction). The authors found evidence of behavioral stability, in that the ordering of the probabilities of the 27 possible sequences during extinction did not differ much from the ordering observed during reinforcement. The most preferred sequences during reinforcement were still preferred the most during extinction; the same was true for the least preferred sequences. However, interestingly, at the same time, the relative frequencies, expressed as a ratio that was computed by dividing the probability during extinction by the probability during reinforcement, of the least preferred sequences increased. This is indicative of increased response variability. This mix of stability and variability was also obtained in two further experiments in which extinctionwas preceded either by responseindependentnoncontingentreinforcement or by consistent reinforcement of only one single sequence. Neuringer et al. (2001) argued that the mix of stability and variability makes sense from an evolutionary perspective. On the one hand, stability implies continuationof behavior that was successful in the past; on the other hand, variability ensures the occurrence of (relatively) new behavior that, potentially, may be more successful than previous behavior.The aim of the present experiments was to evaluate the balance between response stability and variability in humans, rather than in rats, and to examine more than one type of contingency change. As will be outlined below, the type of contingency transition may be expected to be important with respect to the extent of behavioral stability and variability. More generally, data on the conditions that are or are not conducive to the occurrence of behavioral stability and variability (adaptive or not) may be relevant to applied settings, such as educational and therapeutic contexts.In the present experiments, I used a task that was modeled after that em...

Varied but not necessarily random: Human performance under variability contingencies is affected by instructions

“…Autocorrelations To evaluate higher-order patterns in the emission of sequences, lag 1 to 27 autocorrelations were computed (see also Maes, 2003). Lag 1 autocorrelations refer to correlations between the sequence emitted in trial n and the sequence emitted in trial n -1; lag 2 autocorrelations indicate correlations between trials n and n -2; and so on.…”

“…Furthermore, when requested to describe their performance, most participants reported using this strategy. Maes (2003) also observed systematic responding under a variability contingency. College students were asked to type sequences of three digits and received feedback for their performance.…”

“…We were also interested in evaluating whether these differential patterns of responding (i.e., systematic and random) would affect the probability of meeting the variability contingency (MetVar), the uncertainty in the emission of response sequences (U value)-traditional measures of response variability-and also the rate of responding. Previous studies (e.g., Maes, 2003) have not found a correlation between systematic and random response patterns and differential rates of reinforcement or uncertainty in the emission of sequences. We expected to replicate these findings.…”

“…The first three measures allowed for the identification of variation at the level of response units, whereas autocorrelations indicated whether the current sequence was influenced by previous sequences (sequence dependency), and therefore pointed out the use of responding strategies. Maes (2003) found that variability-dependent reinforcement engendered higher MetVar and U values and also a more even sequence distribution than did no reinforcement or variability-independent reinforcement. This increase in variable responding, however, was also accompanied by an increase in the tendency to respond systematically or strategically, such that high autocorrelations were obtained.…”

“…The studies by Schwartz (1982), Stokes andHarrison (2002), andMaes (2003) demonstrated that under variability contingencies, humans tend to develop a systematic strategy in emitting sequences of responses, although a random-like pattern would also be functional. Moreover, Maes suggested that self-rules induced by the experimenter-given instructions might be one of the factors that alters the probabilities of adopting systematic or random strategies to satisfy a variability contingency.…”