Selective imitation of the passive construction through modeling

Six 4- to 5-yr-old subjects were exposed to five sessions in which an adult model used passive sentences to describe a set of modeling stimuli. Probe stimuli, which the subjects were asked to describe without benefit of modeling and without selective reinforcement were interspersed among modeling stimuli. A matched group of control subjects received probletrials but no modeling trials. Both groups of subjects were subsequently tested on their ability to comprehend active and passive sentence forms. Every subject in the experimental group produced passive sentences on probe trials even though there was considerable variability in the number of passives produced. No control subject produced passives. The modeling procedure increased the comprehension scores of the experimental group above those of the control group though the scores of both groups were above chance. The results were contrasted with earlier studies in which modeling was ineffective in producing passive usage and in which comprehension of the passive was not demonstrated by even older children.     

A developmental study of recognition of pictures and nouns

Children at four age levels (4, 6, 8, and 10 years) were given continuous recognition tasks using concrete noun, abstract noun, and pictorial stimuli in a 4 × 3 factorial design. Pictures were recognized significantly better than concrete and abstract nouns at the 4- and 6-year age levels and significantly better than abstract nouns at the 8- and 10-year age levels. This supported Paivio's contention that pictures are easier to remember than words because of a greater possibility of dual encoding, while Rohwer's contention that there is a shift in recognition memory development received no support. There were no significant differences between recognition of concrete and abstract nouns at any age level, which opposed the findings from adult studies and suggested that Paivio's theoretical orientation would have to be extended in order to account for developmental data. Recognition for both concrete and abstract nouns was found to be linear and increasing significantly with age, but no age trends for picture recognition were found.     

Instrumental and contingent saccharin licking in rats: Response deprivation and reinforcement

Instrumental licking of .4% saccharin solution was increased by the contingent opportunity to lick a less-preferred saccharin solution when the contingency schedule deprived the subject of the contingent response, but not otherwise. Schedules that imposed comparable amounts of response deprivation produced comparable increases in instrumental responding. The results support the hypothesis that instrumental responding will increase if and only if the contingency schedule deprives the subject of the contingent response. They also support the implication that the predicted increase will occur even if the contingent response has a lower operant level than the instrumental response.     

The importance of subject control in reinforcing brain stimulation

A comparison between the reinforcement strength of self-administered and externally imposed brain stimulation was undertaken. Rats performed on a chain schedule in order to receive brain stimulation, either selfadministered or imposed, during the second component of the chain. Response rates during the first component of the chain schedule indicated that self-stimulation was more reinforcing than imposed stimulation. In addition, contrast, both positive and negative, seemed to be present. It was concluded that reinforcement strength may be enhanced when the subject controls the presentation of reinforcement.     

The temporal course of the frustration effect

General activity subsequent to reward (R) and nonreward (N) was monitored at 5-sec intervals with a stabilimeter in the runway goal box. Activity of never-rewarded control Ss was also measured. In Expt 1 it was found that the frustration effect (difference between N- and R-trial activities) disappeared after about 40 sec of goal box confinement. This disappearance of the frustration effect was due to activity increase on R trials rather than activity decrease on N trials as a function of time. Comparison of N-trial activity with control group activity indicated that frustration does not dissipate within 60 sec. Expt 2 investigated activity following reward and nonreward as a function of reward magnitude. Evidence from these experiments suggests that the late R-trial activity increase results from frustration, possibly conditioned to apparatus cues on N trials.     

Conditions necessary for sand digging in laboratory rats

Continuous availability of a sand blocked tube elicited intense and persistent digging by laboratory rats. Neither training nor prior exposure to the apparatus were necessary for response initiation. Continuous presence of an open pile of sand would not elicit digging. No theoretical explanation is offered.     

The efficacy of “right” as a function of its relationship with reinforcement

The effects of the relationship between the presentation of a verbal stimulus (“right”) and an established reinforcer (M&Ms) on the reinforcement efficacy of the verbal stimulus was tested with three groups of retarded boys. Blocks of training and test trials alternated. During training of the Discriminative Group, “right” reliably preceded candy. For the Contiguous Group, “right” accompanied candy, and for the Random Group “right” and candy were programmed independently. “Right” promoted learning in the Discriminative Group but did not in the latter two groups. The results support Cairns' analysis of the often found failure of approval to be an effective reinforcer in laboratory tasks.     

Stereotypical thinking as a mediating factor in the association between exposure to terror and post-traumatic stress disorder symptoms among Israeli youth

Background and Objectives: The negative impact of exposure to terror on mental health, as well as on the perceptions of each side of the conflict toward the other, is well-documented. However, the association between stereotyping, concomitant with perceived threat, and anxiety, was rarely investigated. The current study examined information processing attributes and exposure to terror as predictors of PTSD symptoms among youth at inter-group conflict, with stereotypical thinking toward a threatening out-group as a possible mediator. Design: Cross-sectional, with exposure to terror, need for cognitive structure (NCS), efficacy at fulfilling the need for closure (EFNC) and self-esteem, predicting stereotypical thinking and PTSD symptoms. Method: Ninth graders (N?=?263) from two residential areas in Israel, varying in their degree of exposure to terror, responded to a self-report questionnaire tapping the above variables. Results: Stereotypical thinking was found to mediate the association between exposure to terror and PTSD symptoms, but not the association between the NCS and EFNC interaction and PTSD symptoms. Conclusions: The findings support terror management theory, so that a negative and rigid perception makes it difficult to construct coherent world-view, thus contributing to aggregation of existential anxiety and PTSD symptoms.     

Is there a spillover effect of a right turn on red permission for bicyclists?

A number of countries allow bicyclists to perform a right turn on red (RTOR) at some specific intersections to promote cycling by reducing the required physical effort and trip time. Implementation of a rule that allows a RTOR for bicyclists at some intersections could lead not only to local effects at those intersections where the rule actually applies, but also to supralocal effects. Using an experimental survey approach, this study explores whether a so-called ‘spillover effect’ of the rule can be expected. This effect would imply that allowing bicyclists to turn right on red at some intersections causes them to also turn right on red more often at intersections where RTOR for bicyclists is not allowed.The answers from 768 respondents indicate that respondents with a high awareness of the existence of a RTOR rule for bicyclists (experimental group) turn right on red significantly more often at intersections where RTOR for bicyclists is not permitted than respondents with a low awareness of the rule (control group). This indicates that implementation of the RTOR rule for bicyclists can indeed lead to an increase in red light running at other intersections. This might lead to safety issues at intersections where RTOR for bicyclists is not permitted, since road authorities could have decided not to allow RTOR for bicyclists at these intersections for safety reasons.The study also finds that men, young people and people who generally perform more risky cycling behaviours have a higher tendency to perform non-permitted RTOR. These findings are in line with existing literature.