Lump detection in simulated human breasts

Sixteen observers palpated silicone models of human breasts containing lumps 1.6-12.1 mm in diameter. Detectability depended on the size of the lump, producing a systematic psychometric function. In eight observers who participated in three or more sessions, performance improved with practice, with most improvement occurring within one or two 26-trial sessions. Three-week retention measures disclosed no appreciable decrease in performance, but a significant correlation was found between the number of lumps detected and duration of trial (p < .01). There was no difference in performance between four observers who used their preferred hands and four observers who used their nonpreferred hands. These data establish that examination of breast models for the detection of lumps simulating cancer is a task amenable to experimental analysis.     

Fitting Rasch model using appropriateness measure statistics

In this paper, the distributional properties and power rates of the Lz, Eci2z, and Eci4z statistics when they are used as item fit statistics were explored. The results were compared to t-transformation of Outfit and Infit mean square. Four sample sizes were selected: 100, 250, 500, and 1000 examinees. The abilities were uniform and normal with mean 0 and standard deviation 1, and uniform and normal with mean -1 and standard deviation 1. The pseudo-guessing parameter was fixed at .25. Two ranges of difficulty parameters were selected: +/- 1 logits and +/- 2 logits. Two test lengths were selected: 15 and 30 items. The results showed important differences between the T-infit, T-outfit, Lz, Eci2z, and Eci4z statistics. The T-oufit, T-infit, and Lz statistics showed poor standardization with estimated parameters because their distributional properties were not close to the expected values. However, the Eci2z and Eci4z statistics showed satisfactory standardization on all conditions. Further, the power rates of Eci2z and Eci4z were 5% to 10% higher than the power rates of Lz, T-outfit, and T-infit to detect items that do not fit Rasch model.     

The object of my aggression: Sexual objectification increases physical aggression toward women

Objectification involves reducing someone to a sexual object, rather than seeing them as a full person. Despite numerous theoretical claims that people are more aggressive toward the objectified, and empirical evidence that objectification is linked to high willingness to aggress, rape proclivity, and aggressive attitudes, no research has examined a causal link between objectification and physical aggression, particularly in the context of provocation. In two experiments, we examined this predicted link. In Experiment 1, using a 2 (objectification: no/yes) × 2 (provocation: no/yes) factorial between‐subjects design, we investigated the effects of objectification, induced via body focus during a face‐to‐face interaction, and provocation on physical aggression toward a female confederate. Our results revealed a significant main effect of provocation, a marginal main effect of objectification, and a significant interaction between these variables. In the absence of a provocation, focusing on a woman's body increased aggression toward her. Experiment 2 replicated Experiment 1 using a video of a target woman instead of a face‐to‐face interaction. Again, our results showed a significant two‐way interaction between objectification and provocation, wherein objectification increased aggression in the absence of provocation. Overall, this research indicates that objectification can lead to heightened physical aggression toward objectified women.

     

Cross-Ethnic Measurement Equivalence of the RCMAS in Latino and White Youth With Anxiety Disorders

In normal vision, the various “gestalt-free” combinations which form early in a percept, are repressed by the emergence of the veridical composite perception; but in schizophrenic vision, with its inadequate repressive powers, the early combinations emerge as the completed composite. This completed composite, if at all veridical, is so only partially. Rorschach studies support the idea of a range of perceptual abortions among schizophrenics, varying directly with the process-reactive range.     

Some recommended statistical analytic practices when reliability generalization studies are conducted

Precursors of the reliability generalization (RG) meta‐analytic approach have not established a single preferred analytic method. By means of five real RG examples, we examine how using different statistical methods to integrate coefficients alpha can influence results in RG studies. Specifically, we compare thirteen different statistical models for averaging reliability coefficients and searching for moderator variables that differ in terms of: (a) whether to transform or not the coefficients alpha, and (b) the statistical model assumed, distinguishing between ordinary least squares methods, the fixed‐effect (FE) model, the varying coefficient (VC) model, and several versions of the random‐effects (RE) model. The results obtained with the different methods exhibited important discrepancies, especially regarding moderator analyses. The main criterion for the model choice should be the extent to which the meta‐analyst intends to generalize the results. RE models are the most appropriate when the meta‐analyst aims to generalize to a hypothetical population of past or future studies, while FE and VC models are the most appropriate when the interest focuses on generalizing the results to a population of studies identical to those included in the meta‐analysis. Finally, some guidelines are proposed for selecting the statistical model when conducting an RG study.     

Self-inhibiting effects of reinforcement

The reinforcers produced by one response reduce the rate of other, concurrently reinforced responses. An analysis of the logical and empirical implications of the relation indicates that one reinforcer must have this effect on responses maintained by other reinforcers even when all reinforcers are produced by the same class of responses. A quantitative expression of the relation leads to a formulation, mathematically equivalent to Herrnstein's (1970), in which the rate of a reinforced response is a joint function of (1) an excitatory effect of the reinforcers produced by that class of responses, and (2) an inhibitory effect of the total reinforcers produced both by that class and by other classes of responses.     

A quantitative analysis of the responding maintained by interval schedules of reinforcement

Interval schedules of reinforcement maintained pigeons' key-pecking in six experiments. Each schedule was specified in terms of mean interval, which determined the maximum rate of reinforcement possible, and distribution of intervals, which ranged from many-valued (variable-interval) to single-valued (fixed-interval). In Exp. 1, the relative durations of a sequence of intervals from an arithmetic progression were held constant while the mean interval was varied. Rate of responding was a monotonically increasing, negatively accelerated function of rate of reinforcement over a range from 8.4 to 300 reinforcements per hour. The rate of responding also increased as time passed within the individual intervals of a given schedule. In Exp. 2 and 3, several variable-interval schedules made up of different sequences of intervals were examined. In each schedule, the rate of responding at a particular time within an interval was shown to depend at least in part on the local rate of reinforcement at that time, derived from a measure of the probability of reinforcement at that time and the proximity of potential reinforcements at other times. The functional relationship between rate of responding and rate of reinforcement at different times within the intervals of a single schedule was similar to that obtained across different schedules in Exp. 1. Experiments 4, 5, and 6 examined fixed-interval and two-valued (mixed fixed-interval fixed-interval) schedules, and demonstrated that reinforcement at one time in an interval had substantial effects on responding maintained at other times. It was concluded that the rate of responding maintained by a given interval schedule depends not on the overall rate of reinforcement provided but rather on the summation of different local effects of reinforcement at different times within intervals.