Stimulus intrusion on fixed-interval responding in the rat: The effects of electric shock intensity,temporal location,and response contingency

After a scalloped lever-press response pattern had developed under a fixed-interval food reinforcement schedule, a 15-sec electric shock was intruded for different groups of rats in the first, second, third, or fourth quarter of each inter-reinforcement interval. Shock intensity was systematically increased for individual rats over 70 sessions, from 0.05 to 1.6 mA. Additional between-groups comparisons involved response-dependent versus clock-dependent fixed-interval schedules, and response-dependent versus response-independent electric shock intrusion. Response rates within each fixed interval prior to, during, and following electric shock intrusion showed regular and reproducible increases and decreases under systematic application of the experimental variables. These results provide further evidence that the functions of a stimulus are determined in part by the parameters of intensity, response contingency, and temporal location with respect to reinforcement.     

Dimensions of threshold work experience for high school graduates and dropouts: A factor analysis

Data on 19 threshold work experience variables were obtained by interview from 183 high school graduates and 90 dropouts $\text{1}\text{1}\text{2}$ years after leaving school. Factor analyses of these data showed strikingly similar factor structures for both groups. Seven variables were found to represent the factor dimensions adequately: Number of Jobs Held; Average Tenure in Weeks, Past Jobs; Average Number of Weeks to Find Jobs; Average Hours Worked Weekly; Average Weekly Pay, Past Jobs; Supervisor Rating, Present Level of Performance; and Employment Status. These variables, representing “objective success” were found to correlate only slightly with job satisfaction variables (Average Job Satisfaction, Past Jobs; Job Satisfaction, Present Job), thereby supporting the conceptualization of job satisfactoriness and job satisfaction as relatively independent sets of variables.     

Empirical derivation of SVIB-Holland scales: A brief report

The Strong Vocational Interest Blank responses of 93 students were used to construct six empirical scales similar to the scales of Holland's Vocational Preference Inventory. Scores on the empirical scales were correlated with actual VPI scores. The resulting correlations were compared to coefficients obtained from correlating the intuitive scales designed by Campbell with actual VPI scores. It was concluded that (1) meaningful estimates of VPI profiles can be obtained by scoring selected items from the SVIB and (2) further work with the empirical scales is needed prior to settling on a SVIB scoring procedure for estimating VPI profiles.     

Anomie and vocational-technical education

Graduates from a public, postsecondary vocational-technical school are compared with a control group of individuals without such education in order to assess differences in level of anomie (via Srole Scale).While differences in some cases were minimal, vocational-technical graduates generally revealed a more positive attitude about the present and future. It is suggested that since their education is more job-centered, and they have already experienced some occupational “success”, they are more likely to have internalized and reflect traditional societal norms. The control group, while possessing similar demographic backgrounds, still are in transition-attending college, looking for work, etc.     

Paradoxical preference for more frequently occurring negative stimuli and for less frequently occurring positive stimuli as a function of amount of training in simultaneous discrimination learning

Development of a preference for more frequently occurring negative stimuli was found in a within-subject design. In this experiment, pigeons learned two simultaneous problems with an unequal number of training trials. At various stages in training, for example, the more-trained negative stimulus was paired with the less-trained negative stimulus for a single preference trial. These probe trials pointed to a swing in stimulus function in negative stimuli which also occurred at an earlier stage in positive (reward-correlated) stimuli. The paradoxical preference for less-trained positive over more-trained positive stimuli was found in this study, confirming the earlier reported phenomenon. The paradoxical preference for more-trained negative stimuli was discussed in terms of a frustration analysis. A symmetrical, albeit positive, emotional factor was discussed with regard to the paradoxical findings with positive probe trials.     

Infants' intermodal perception of events

Four-month-old infants viewed two sound motion picture films of simple, natural events. The films were projected side by side, as one of the two sound tracks was played through a centrally placed speaker. Infants' visual attention to the films was consistently influenced by what they heard: They looked primarily at the event specified by the sound track. The experiment demonstrates that infants are able to perceive relations between sights and sounds in the absence of spatial cues. They respond to a perceived intermodal invariance with increased attention to the event reaching them over two modalities.     

Cardiac deceleration in newborns: habituation, dishabituation, and offset responses.

Twenty healthy, 1–4 day-old infants were selected from a sample of 135 neonates on the basis of alertness during testing. The infants were presented mild intensity colored light with gradual onset and offset while heart rate was monitored. Half the infants received six exposures to blue light followed by two exposures to blue-green light, whereas remaining subjects received colors in reverse order. Stimulus duration was 20 sec and variable periods between stimuli averaged 30 sec. Results of trend analysis of variance of the second-by-second cardiac data indicated that for infants older than the median age, the decelerative responses to both stimulus onset and offset were significant. Further, these subjects' onset decelerations significantly habituated within the six stimulus repetitions and significantly dishabituated with change in the stimulus color. Offset decelerations incremented over habituation trials and decremented with change in stimulus color. Responses of younger subjects were more variable which probably reflects their less complete recovery from the effects of maternal medication and the birth process.     

A developmental and cross-cultural study of the influences of rule structure and problem composition on the learning of conceptual classifications

Five experiments were conducted permitting direct comparisons in the way Ss of different ages and cultures solved conceptual problems. One group of problems (Traditional) could be solved using a reference rule of conjunction or disjunction. Another group of problems (Intradimensional) could be solved either by one of the reference rules, or by a structurally simpler rule. Analysis of American performance confirmed that older Ss not only solved using the simpler rule more often than younger Ss, but when they did so they solved faster. For both American age groups, solution using the simpler rule led to no difference in performance between conjunctive and disjunctive Intradimensional problems. Conjunction proved easier than disjunction only for the Traditional problems. Unlike Americans, the Kpelle of Liberia did not solve using the simpler rule, and found conjunction easier than disjunction for both Traditional and Intradimensional problems. When a memory aid was provided the Kpelle showed a pattern of performance exactly like Americans.