Fear reduction in rats through avoidance blocking

Rats trained to avoid an electric shock in an alley were divided into two groups depending on their behavior during 25 min of response blocking. Subjects demonstrating exploratory behavior while blocked were put in one group, while subjects demonstrating agitation, freezing or grooming were placed in another. Fear measures, when subsequently exposed to the CS. were taken on experimental subjects and compared to controls. The results confirmed the hypothesis that response blocking can lead to fear reduction and that the fear reduction is related to the behavior of the subject during blocking.     

The role of instrumental responding and contiguity of stimuli in the development of infant secondary reinforcement

Ten-month-old infants received contingent pairings of a tone (T+) and food reinforcer. Groups S^r and S^D received the food on an FI 23-sec schedule for target touching, the former group receiving T+ immediately after the response and 1.5 sec prior to food and the latter group receiving T+ at the end of the intertrial interval. Group SC received food reinforcers 1.5 sec after T+ with no response required. A second tone (Tⁿ) was heard by all groups once during each intertrial interval, at randomly determined points. All groups subsequently were given a spatial discrimination task, receiving T+ for one alternative and Tⁿ for the other. Group S^r gave significantly more responses for T+ than for Tⁿ, but neither of the other two groups produced a superiority for T+. Thus, both contiguity with a primary reinforcer and the presence of an operant during training appear to be necessary for a neutral signal to acquire the ability to enhance responding.     

Parent's report of stress and articulation oscillation as factors in a preschooler's dysfluencies

Recently, one focus of research on dysfluency and stuttering seems to be on the preschooler. One goal of such research should be to determine what factors in the child's language system and what factors in the social environment may put the child at risk for developing dysfluencies and stuttering. The following is a parent's account of the occurrence of dysfluencies in a preschooler. Emphasis is on a language phenomenon that might be labeled “articulation oscillation” and on apparent social environmental stress.     

Stimulus configuration and valence-enhanced pecking by neonatal chicks

Valence-enhanced pecking occurs when hatchling chicks preferentially peck at releasing stimuli that have been assigned increased releasing power or valence. Enhanced valence is assigned by another releasing stimulus—here a “pecking” arrow. Pecking movements by the arrow have two separate effects: the stimulation or release of pecking by chicks and releasing valence enhancement, that is, pecking directed to particular stimuli. Exposure of chicks to the moving arrow yields pecking significantly increased over that accruing to a stationary arrow. A distinctive stimulus placed on the floor at the tip of the arrow, or, most effective, attached to the tip of the moving arrow, produces enhanced valence: pecking by observing chicks that is selectively increased to matching stimuli.     

The optional shift performance of reflective and impulsive girls

The optional shift performance of 52 reflective and 50 impulsive second-grade girls was assessed under two response-consequence conditions: (a) reward for correct responses only, and (b) reward for correct responses and a penalty for incorrect responses. Reflection—impulsivity was defined on the basis of performance on the Matching Familiar Figures test. The reflectives showed a significantly greater percentage of reversal shifts than the impulsives. The impulsives showed more reversal shifts under the penalty condition than the reward alone condition whereas the performance of the reflectives was the same in both consequence conditions. A test of statistical association indicated that reflection—impulsivity may be as strongly related to reversal shift performance as age and perceptual pretraining. The results are interpreted as indicating that individual differences in perceptual search strategies may have an important influence on the problem-solving behavior of children.     

Saccadic eye movements during reading

Exposure duration and sequential redundancy are major determinants of report accuracy for textual displays. Increased emission of left-to-right saccades to both word strings and letter strings are associated with sequential redundancy. Such saccades are more frequent when words rather than pseudowords are viewed. The pattern of scanning is not simply left to right, and certain patterns of eye movements are associated positively with accuracy of report. These are a function of the sequential constraints of the display and are stronger for word strings than for letter strings. Presence of a word elicits more left-to-right saccades than does a pseudoword, even at exposures too short for a second fixation to be useful. In that case, there is no difference between redundant and nonredundant pseudowords. There is no redundancy effect at short exposures of pseudosentences.     

Structured personality test item characteristics and validity

Using the structured personality test item as the unit of analysis, the purpose of this research was to evaluate the relationship between validity and a variety of other test item parameters. Of particular interest was the relationship of test item criterion validity to negative keying and to negative wording. By drawing a distinction between negative keying and negative wording it was demonstrated that the use of balanced scales to control acquiescence need not result in a reduction in item criterion validity. Whereas the use of negative wording has in the past reduced validity, data demonstrated that positively worded, negatively keyed items did not. In addition, results indicated that clear, moderately short, relevant test items tended to be the most empirically valid.