Stability criteria

Three approaches to the determination of behavioral stability were examined. In the first, a learning curve was fit to acquisition data (from Cumming and Schoenfeld, 1960), and the “experiment” stopped when the data approached sufficiently close to the theoretical asymptote. In the second, the data were analyzed for variability and linear and quadratic trend. In the third, the experiment was stopped when the magnitude of the daily changes in the data fell below a criterion. Accuracy was measured as deviation between the average value of the dependent variable when the experiment was stopped, and the average value over the last 100 sessions. The first approach was most accurate, but at the cost of requiring the most sessions and being the most difficult to apply. Both the second and third approaches provided acceptable criteria with a reasonable cost-accuracy tradeoff. The second approach permits a continuous adjustment of the criteria to accommodate the variability intrinsic in the experimental paradigm. The third, nomothetic, approach also takes into account the decreasing marginal utility of extended training sessions.     

Warmup in avoidance as a function of time since prior training

On avoidance procedures, rats and pigeons typically show warmup effects, characterized by improving performance within sessions and loss of the improvement (“warmup decrement”) between sessions. Between-session losses were examined by varying the time between periods of avoidance training. In one experiment, rats lived fulltime in conditioning chambers while intermission intervals were varied. In a second experiment, the animals lived in home cages between sessions; timeout intervals were introduced at midession, producing recurrence of warmup in the second half-session. In both experiments, the warmup decrements increased substantially as the timeout or intersession intervals were increased from zero to 30 minutes. With intervals of 60 or 120 minutes, the decrements approached or exceeded those obtained with intervals of a day or more. When avoidance was interposed between appetitive sessions, the appetitive responding was disrupted, but this seemed unrelated to the warmup or to the proficiency of avoidance. The warmup in avoidance shares characteristics with transient punishment effects, with the Kamin effect, and with habituation phenomena, but it is premature to assume that they reflect common processes.     

Sleep and memory: reproduction of syntactic structures previously evoked within REM sleep-related reports.

7 subjects, aged 19 to 25 yr., who evoked syntactic verbal material in the report made after awakening during REM sleep, were asked to reproduce it a few minutes later. No big differences had been obsered between the two recalls; all recalled verbal materials, many sentences and kernel-sentences reappeared. These results indicate a good consolidation of the material obtained after awakening during REM sleep.     

DESIGNING INCENTIVE PLANS FOR UNIONIZED EMPLOYEES: A COMPARISON OF CONTINUOUS AND VARIABLE RATIO REINFORCEMENT SCHEDULES1

The relative effectiveness of incentive plans administered on continuous and VR-4 schedules of reinforcement was investigated with unionized employees using a within subjects design. Mountain beaver trappers working side by side were randomly assigned to one of two groups. In group A the trappers received $1.00 for every rat they trapped. At the end of four weeks, they were switched to a VR-4 schedule in which they received $4.00 contingent upon trapping a rat and correctly guessing the color of one of four marbles prior to drawing it from a bag held by the supervisor. In group B the order of the schedules was reversed. The results were analyzed in terms of cost-related, behavioral, and reaction criteria. The study increased employee productivity and decreased costs for the company. Inexperienced workers had higher productivity on the continuous reinforcement than on the VR-4 schedule; experienced workers had higher productivity on the VR-4 schedule than on the continuous schedule. Both the experienced and the inexperienced employees preferred the VR-4 schedule over the continuous schedule.     

Nasality and precision of articulation

Two reading passages, one with nasal consonants and one without, were tape-recorded for 72 subjects: 34 selected as having precise articulation and 38 selected as having imprecise articulation. These speech samples were evaluated for degree of precision and also for degree of nasality by the psychological scaling method of equal-appearing intervals employing a 7-point scale. Analysis indicated a relationship between degree of precision and degree of unpleasant nasality, that is, a tendency for decreases in precision to be accompanied by increased nasality and a tendency for males to be more imprecise in articulation and more nasal than females.