The sampling distribution ofd′

The distribution of sample $\hat d's$ , although mathematically intractable, can be tabulated readily by computer. Such tabulations reveal a number of interesting properties of this distribution, including: (1) sample $\hat d's$ are biased, with an expected value that can be higher or lower than the true value, depending on the sample size, the true value itself, and the convention adopted for handling cases in which the sample $\hat d'$ is undefined; (2) the variance of $\hat d'$ also depends on the convention adopted for handling cases in which the sample $\hat d'$ is undefined and is in some cases poorly approximated by the standard approximation formula, (3) the standard formula for a confidence interval for $\hat d'$ is quite accurate with at least 50–100 trials per condition, but more accurate intervals can be obtained by direct computation with smaller samples.     

Reinforcing effects of prerecorded words and delayed speech feedback on the verbal behavior of a neologistic schizophrenic

The possibility of using prerecorded words and 2-sec. delayed speech feedback as reinforcement in the reconditioning of intelligible verbal responses in a chronic, neologistic schizophrenic patient was investigated. A test situation was devised which involved daily presentation of 100 stimulus word-picture cards to elicit verbal responses. The results indicated that both singly presented prerecorded words and delayed speech feedback apparently strengthened correct and intelligible verbal responding.     

A method for simulating non-normal distributions

A method of introducing a controlled degree of skew and kurtosis for Monte Carlo studies was derived. The form of such a transformation on normal deviates [X N(0, 1)] isY =a +bX +cX ² +dX ³. Analytic and empirical validation of the method is demonstrated.This work was done while the author was at the University of Illinois at Champaign-Urbana.     

The relative effectiveness of alternative job sources

Vocational research has focused on the occupational choice process and the individual's adjustment to work. Very little research has examined the job search process in which the individual must engage in order to implement occupational choices. This study examines one dimension of the job search process: the relationship between job source and subsequent work experiences. The data reveal that when the respondents initially entered the labor market, those relying on formal job sources tended to work in higher-level occupations and in jobs more closely related to their training than their counterparts who used other job sources. In the longer run, the labor market advantages associated with the use of formal job sources dissipated for the engineering majors but tended to persist for the business alumni.     

Adult age differences in letter-level and word-level processing

Older and young adults' letter detection and lexical decision performance were examined as word frequency varied to determine whether there were age differences in word recognition. Allen and Madden (1989) found that older adults' pattern of reaction time (RT) across word frequency categories was different from young adults' pattern for a letter detection task. In this study, for both letter detection and lexical decision tasks, older adults exhibited a monotonically decreasing RT function as word frequency increased. However, young adults exhibited a nonmonotonic RT function across word frequency for the letter detection task but a monotonically decreasing RT function as word frequency increased for the lexical decision task. An expanded parallel input serial analysis model of word processing was hypothesized.     

RITALIN VS. RESPONSE COST IN THE CONTROL OF HYPERACTIVE CHILDREN: A WITHIN-SUBJECT COMPARISON

A within-subject comparison was made of the effects of methylphenidate (Ritalin) and response cost in reducing the off-task behavior of two boys, 7 and 8 years of age, who had been diagnosed as having an attentional deficit disorder with hyperactivity. Several dosages of Ritalin (5 to 20 mg/day) were evaluated with the results indicating varying effects of the drug for both children. Response cost (with free-time as the reinforcer) was superior to Ritalin in raising levels of on-task behavior and in improving academic performance.     

The self-serving attributional bias: Beyond self-presentation

An experiment was conducted to provide empirical support for the notion that asymmetrical causal attributions for favorable and unfavorable outcomes result from a self-serving attributional bias that occurs independently of self-presentational concerns. Subjects did either well or poorly on an ego-involving test for which their performance, attributions, and evaluations of the test were either public or private. A pattern of self-serving responses for subjects' attributions and evaluations of the test was found in the private conditions, thus providing evidence of the influence of outcome favorability on individuals' perceptions of causality. Theoretical and practical implications of these finding are discussed and suggestions for future research are offered.     

Strategies in cross-modality matching

Subjects were tested on cross-and within-modality matching conditions with either a 5-sec or a 20-sec delay imposed between standard and comparison stimuli. Half the subjects were informed before the trial of what the comparison modality would be, while the others were not. There was a strong effect of instructions on the cross-modality conditions, but little on the within-modality conditions. The informed subjects showed better performance in the haptic-visual condition, while for the uninformed subjects, visual-haptic performance was better. The results suggest the importance of subjects’ processing strategies in cross-modality performance.     

Counting eliminates the repetition effect in judgments of temporal duration.

College student subjects estimated the duration of time intervals (8–54 sec) by counting or not (N=35 per group). Counting eliminated the repetition effect (a decline in the magnitude of estimations across trials), and resulted in a truncation of the psychophysical function. The former result was interpreted as contrary to Treisman's (1963) model. The latter result was attributed to the effortfulness of counting, which was established in a subsequent experiment.