Choosing between fixed time and variable time shock

Two experiments are reported dealing with choice of fixed or variable time shock schedules with and without signals. Response independent shock was presented on either a fixed-time or a variable-time schedule and subjects could change from one condition to the other for short periods after which the initial condition was automatically reinstated. In the first experiment shocks for both schedules were either unsignalled (6 subjects) or signalled (3 subjects) and all subjects changed from a schedule of variable-time shock to a fixed-time one. Subjects that were given the opportunity to change in the reverse direction did not do so. Opposite findings were obtained in the second experiment (7 subjects) comparing unsignalled fixed-time shock with signalled variable-time shock. Six of the seven subjects changed from the fixed-time schedule to the signalled variable-time one but not the reverse. The data were considered consistent with an analysis of choice based on the reinforcing value of discriminable shock-free periods.     

Oral overcorrection: side effects and extended applications.

Experiment 1: In a specialized daycare program the use of oral overcorrection (contingent toothbrushing with an oral antiseptic) to suppress one child's thumbsucking at Language Time was found to suppress the behavior of another child who was not treated but who witnessed the target child's treatment. Experiment 2: The main effects of oral overcorrection were replicated. Contingent overcorrection threats (warnings), used independently, were then shown to suppress thumbsucking behavior that had returned to its baseline level. These effects were maintained one month after the threats were discontinued, but they did not generalize to other activity periods, particularly Nap Time. Experiment 3: Contingent threats were found to suppress the persistent nap-time thumbsucking of the child from Expt 2. Increments in certain other (nonoral) inappropriate behaviors were correlated with the suppression of thumbsucking. Threats to use oral overcorrection contingent upon nonoral misbehaviors at Nap Time were not effective. However, the actual use of oral overcorrection for these categories of nonoral misbehavior served to suppress these behaviors. Experimental controls combined treatment reversal and multiple baseline single-subject designs.     

Noticing and responding in a discrimination based on a distinguishing element

In learning a successive go/no-go discrimination between a positive display consisting of the elements A and B, and negative display consisting of A-alone, pigeons first trained to peck A shift to pecking the distinguishing B element. In order to learn whether or not the shift to B is facilitated by B's function as a signal of the reinforcer, apart from the direct reinforcement of B responses, six arrangements of the elements with respect to the food reinforcer were used. Discrete trials were terminated by a single peck or after 4 sec. The A and B elements were dots of different color. The most critical comparison was between two groups, both of which received no reinforcement for a response directed to B. In one case, B signaled the reinforcer: An A response was reinforced when B was present but not when A appeared alone. In the other, B signaled the absence of a reinforcer: An A response was nonreinforced when B was present, while the response to A-alone was reinforced. During training and in extinction many more reponses were made to B when it signaled the reinforcer than when it signaled its absence. It is concluded that in a discrimination between AB positive and A negative the shift from pecking A to pecking B is facilitated by B's role as a signal for the reinforcer even on trials in which the peck is not made to B. Results from certain other groups showed that, unless pecks shifted to B within the positive display, pecks to A continued on the negative, A-alone trials as well as on the positive AB trials.     

The effects of parent-presented models and praise on the vocal behavior of their children

The combined and separate effects of parent-presented models and praise on specific vocalizations of three children (15, 17, and 20 months old) were investigated. The frequency of a specific vocalization was higher when parents modeled and praised it than when they did not. In addition, modeling and praise, when used in combination, had a greater effect on the frequency of specific vocalizations than when used separately. Three additional parents were asked to attempt, by any means they wished, to increase the frequency of a specific vocalization by their children. These parents used modeling almost, exclusively, and the children did not exhibit the specific vocalizations as frequently as did the children whose parents were instructed both to model and praise specific vocalizations.     

Free recall and retrieval speed of categorized items by kindergarten children

Kindergarten Ss were presented with 16 pictorial items in four category sets or a partially random ordem with one item from each category composing the four presentation sets. The pictures were presented either on conceptually related background pictures or on white backgrounds. The categorically grouped presentation facilitated free recall performance, both in terms of number of items recalled and the speed with which the items were recalled, and increased the amount of clustering in recall. Categorical clustering in recall was associated with shorter within- than between-category intervals and for those Ss who recalled items from each of four categories successively, the over-all temporal pattern in recall closely approximated that found with adults. No background effects were found.     

Sex differences in the occupational choices of second graders

A questionnaire was administered to 61 second graders. Sexual differences in occupational choices were apparent. Boys chose twice as many occupations as girls. Of 29 occupations selected as “most desirable,” only one was mentioned by both boys and girls. Of 37 occupations selected as “least desirable,” only two were mentioned by both sexes. More boys than girls knew their father's occupation. Although 76% of the girls knew their father's occupation, they did not select that occupation for themselves. A series of hypotheses based on the above data was generated.     

The child's memory for actional, locational, and serial scenes

Three-, four-, and six-year-old children (N = 180) were tested for recall of a toy missing from a previously seen display of four toys. Toys were displayed initially as a series (StoS), as a unit (UtoU), or moved from a series to a unit as S watched (StoU). There was a significant increase in memory for the missing toy with age. In addition, children viewing StoU displays remembered significantly more toys than did children viewing the other displays, independent of age. Twenty-five percent of the 6-year-olds rehearsed spontaneously while viewing the displays. Results indicated that the nature of a memory unit does not change with age, that memory improves with age, and that separate visual and verbal memories are operative in Ss in this age range.