Effects of sucrose concentrations on single alternation runway responding in rats

Rats received runway training under alternating reward and nonreward in which rewarded (R) trials provided 32 or 4% sucrose concentration from a drinking tube and nonrewarded (N) trials provided a dry tube or, for half of the rats in the 32% condition, plain water. Both 32 and 4% concentrations yielded faster running on R trials than on N trials; but this effect was reliable only for the 32% condition. Compared to 4% sucrose, 32% sucrose yielded reliably slower running on N trials and unreliably faster running on R trials.     

An examination of vicarious reinforcement processes in children

The primary purpose of the present investigation was to examine vicarious reinforcement processes in children. More specifically, the effects on one child of observing another same-sex child receive direct reinforcement were explored across three different age levels. Subjects were 216 children, randomly assigned to experimental or control conditions. For the control condition, neither child in the same-sex, same-age dyad received reinforcement for performance on the experimental task. For the experimental condition, one child in each dyad received direct social reinforcement for performance, while the other child received no social reinforcement for similar performance. Although children who observed other children receive direct social reinforcement initially increased performance (as predicted by vicarious reinforcement hypotheses), their performance soon decreased and was characterized by verbal and nonverbal responses which appeared to interfere with task performance (e.g., “Hey, I can do them too”, “Look at mine”, “There's no use in trying”). It appeared as if these observing children were being punished for their performance. Such effects were more pronounced for older than younger children; however, they were observed equally in boys and girls. Results were discussed in terms of vicarious reinforcement and “implicit punishment” hypotheses. Implications for applied settings were also addressed.     

Stimulus probability and prediction outcome as determinants of choice reaction time: Some procedural considerations

Effects of stimulus probability and prediction outcome on two-choice reaction speed (CRS) were determined when a frequency imbalance was reversed half-way through 300 samples of a 70/30 stimulus distribution and when the same 70/30 distribution was sampled for 1200 trials. Prior to each presentation Ss made a prediction; following each presentation Ss identified the stimulus by pressing a right-hand or left-hand trigger. CRS was faster to correctly predicted stimuli, and faster to the more probable stimulus. Ss who were informed of the frequency imbalance reacted significantly faster than Ss who were not. Both practice and boredom effects were demonstrated by using the extended number of trials. CRS was faster during the second session of 300 trials than during the first; after two sessions, CRS was slower during the second half of two additional sessions.     

Trait anxiety,stress, and learning a test of Saltz's hypothesis

Behavioral predictions from Saltz's, Spence's, and Spielberger's interpretations of trait anxiety were tested in a complex verbal learning task. Fifty-three high-anxious and 52 low-anxious male college students were randomly distributed to test conditions of failure-stress, pain-stress, or neutral instructions. The learning data revealed that high-anxious-failure and low-anxious-pain Ss were disrupted and supported Saltz's hypothesis; self-reported anxiety (A-State scale, STAI) was observed only in high-anxious-failure Ss and supported Spielberger's theory of the arousal of state anxiety as a function of trait anxiety. However, the contradiction between self-reported anxiety and learning behavior in low-anxious-pain Ss indicated that the verbal report of these Ss was an inaccurate or insensitive index of arousal.     

Similarity of attitudes and constructs in children's friendships

Sex prejudice in children's friendships has frequently been noted. This study examined the role of similarity of attitudes and personal construct ratings in this effect. Subjects were two classes of school children, aged 7–8 and 9–10 years. There were 29 children in each class. Subjects completed an attitude scale, construct rating scale, and sociometric questionnaire. Similarity effects were primarily in the younger children. Boys were more similar to each other in attitudes than were girls, and girls were more similar to each other in construct ratings than were boys (p < .001); there was greater similarity of attitudes and construct ratings in friendship rather than nonfriendship comparison dyads (p < .01). The sociometric data, when compared with sociometric data collected 6 months earlier, showed that these results could not be due to sex differences in the stability of friendships but rather suggested age and sex differences in the informational bases of friendships in middle childhood.     

American and Danish police “dropout” rates: Denmark's force as a case study in high job satisfaction,low stress,and low turnover

An excessive “dropout” rate among police officers—quitting prior to normal retirement—wastes resources and may result in a low level of experience. Denmark's police force appears to be a case study in low turnover and may provide valuable insights. A primarily qualitative analysis contends that factors related to Danish culture and police practices produce relatively low stress and high “need fulfillment” for Danish officers in comparison with their counterparts in typical U.S. police departments—variables previously found related to low turnover. Results of a mail questionnaire show rates of early leaving (prior to retirement) notably lower for the Danish police than for a U.S. national sample of 87 police departments in large cities, and a special subsample of 39 small-city departments in California. Qualifications and implications are discussed.     

Stimulus-reinforcer and response-reinforcer relations in the control of conditioned appetitive headpoking (“goal tracking”) in rats

Experiment 1 studied the effect of several Pavlovian appetitive conditioning procedures on rats' headpoking into a food tray (goal tracking). The procedures included forward delay conditioning, CS-alone extinction, differential conditioning, and simultaneous compound conditioned inhibition training. In general, the headpoke behaved in all of these treatments much like a Pavlovian CR; however, one could also say that the headpoke behaved like an adventitiously reinforced operant for which the CS was an S^D. Experiment 2, therefore, used the differential-nondifferential technique (E. Gamzu & D. R. Williams, Science, 1971, 171, 923–925), and Experiment 3 used an omission technique (F. D. Sheffield, in W. F. Prokasy, Ed., Classical conditioning, New York: Appleton-Century-Crofts, 1965; D. R. Williams & H. Williams, Journal of the Experimental Analysis of Behavior, 1969, 12, 511–520), to try to separate the role of stimulus-reinforcer and response-reinforcer relations in controlling the headpoke. These techniques proved inadequate. The results of Experiment 2 could be given either operant or Pavlovian interpretations. Those of Experiment 3 showed that headpoking is dominated by response-reinforcer, rather than by stimulus-reinforcer, relations when the two compete but forced no conclusion about which dominates when the two act together as in acquisition. Implications for pigeon autoshaping are discussed.     

Feature selection and classification: A developmental study

Two hundred and thirteen children between the ages of 4 and 16 sorted 30 complex objects freely into groups. These were either schematic faces, schematic imaginary animals, or histoform patterns and were constructed from 9 independently and continuously varying features, each with 10 levels. The three sets were equivalent in terms of underlying numerical structure. A new method of analysis of the groups formed yielded the following direct measures of subjective organization in the sorting of each child: the number of features used in sorting, the accuracy of sorting, and the number of independent dimensions of classification. Both the material and the analysis of sorting were devised on the assumption that only some of the component features of complex objects are used for classification, while others are ignored. Sorting performance differed markedly both with age and with different types of material. The improvement in sorting ability with age, except for the youngest children, could be attributed to an increase in the number of features used rather than an improvement in the accuracy of use. In contrast, the poor sorting of histoform patterns as opposed to faces and animals was due to a low level of sorting accuracy. The basic results on the development of classification confirmed previous studies, and hence suggest that it is valid to consider feature selection as a basic component of classification.