An analysis of the solution of PAN ambiguous-cue problems by rhesus monkeys

Twenty-four monkeys were given 2-choice discrimination problems composed of three planometric plaque stimuli: P, the rewarded stimulus; N, the nonrewarded stimulus; and A, the ambiguous stimulus which was negative when paired with P, but positive when paired with N. When both pair of stimuli, PA and NA, were presented within a given session S was forced either to approach or to avoid the A plaque depending upon the stimulus with which it was paired. The results corroborated previous reports for plaque stimuli by showing PA performance to be superior to NA. The data also revealed that when plaque stimuli with distinctive cues were employed, NA performance exceeded PA as previously reported for stereometric object stimuli. Pretraining Ss with plaque stimuli possessing distinctive cues, then switching to plaques with less distinctive cues, also resulted in superior NA performance. These findings are discussed in the context of an interference-cue theory.     

Effects of a pre-aversive stimulus upon oddity performance in monkeys

Two monkeys (Macaca mulatta) were trained to perform an oddity discrimination using automatically projected patterned stimuli. After criteria for both response and discrimination stability were met, a tone followed by shock was superimposed upon the ongoing behavior. Each 60-sec tone was terminated with the onset of a 0.3-sec, 1 to 1.5-ma electric shock. During the tone, baseline responding was partially suppressed but discrimination performance was little altered from the pre-tone period. When shock was raised to 2 to 3 ma, responding was further suppressed, but discrimination performance was again essentially unaltered.     

Sequential transfer to related oddity problems by nursery school children

The initial learning and subsequent transfer of an oddity principle by children between 4 and 5 years of age were studied. The initial standard oddity problem was learned quickly by most of the children. A high level of performance was maintained on both transfer sets. The results were related to limitations placed on the oddity solutions learned by 4-year-olds by particular aspects of the original learning context.     

Serial order effects in auditory discrimination by oddity and matching to sample

The oddity method and several matching-to-sample procedures were used for frequency and intensity discrimination by adult Ss. For all sequence tasks involving three choices, the Ss employed a decision strategy which resulted in a pattern of correctness that differed from the pattern of discriminability among the choice sounds. It was concluded that the use of signal detection theory for analysis of results had added an important dimension to the study, and it was recommended that this method of analysis be used in further attempts to relate sequential processes to various forms of verbal impairment.     

The optimum decision rules for the oddity task

This paper presents the optimum decision rule for an m-interval oddity task in whichm-1 intervals contain the same signal and one is different or odd. The optimum decision rule depends on the degree of correlation among observations. The present approach unifies the different strategies that occur with “roved” or “fixed” experiments (Macmillan & Creelman, 1991, p. 147). It is shown that the commonly used decision rule for anm-interval oddity task corresponds to the special case of highly correlated observations. However, as is also true for thesame-different paradigm, there exists a different optimum decision rule when the observations are independent. The relation between the probability of a correct response andd’ is derived for the three-interval oddity task. Tables are presented of this relation for the three-, four-, and five-interval oddity task. Finally, an experimental method is proposed that allows one to determine the decision rule used by the observer in an oddity experiment.     

The effects of punishment intensity on squirrel monkeys

Responses of squirrel monkeys were maintained by a variable-interval schedule of food reinforcement. Concurrently, punishment consisting of a brief electric shock followed each response. As has been found for pigeons and rats, punishment did not produce extreme, all-or-none reactions. By gradually increasing the punishment intensity it was possible to produce response rates intermediate to no suppression and complete suppression. Similarly, the moment-to-moment response rate was free of extreme fluctuations. A “warm-up” effect occurred in which the punished responses were especially suppressed during the initial part of a session. The pre-punishment performance was negatively accelerated within a session, and punishment reduced the degree of negative acceleration. When punishment was discontinued, responding recovered immediately except when suppression had been complete or prolonged. When the punishment intensity was decreased gradually, more suppression resulted at a given intensity than when intensity was increased gradually. This suggests a “behavioral inertia” effect wherein behavior at a new punishment intensity is biased toward the behavior at the previous value. A corollary generalization is that the larger the change in intensity, the less the behavior at the new value will be biased toward the behavior at the previous value.