Contour Completion And Relative Depth: Petter's Rule and Support Ratio

The ability to see complete objects despite occlusion is critical to humans' visual success. Human vision can amodally complete visual objects that are partially occluded, and modally complete visual objects that occlude other objects. Previous experiments showed that the perceived strength of a completed contour depends on its support ratio: the ratio of the length of the physically specified contour to the total length of the contour. Other experiments showed that human vision prefers to make modal completions as short as possible, an effect known as Petter's rule. The experiment reported here examined the relationship between Petter's rule and support ratio, showing that both affect modal completion in figures of homogeneous color, but that when they compete Petter's rule dominates. Finally, our results confirm that Petter's rule is an effect of relative gap lengths and not of relative size.     

Dialectical behavior therapy--family skills training

Over the past three decades, family interventions have become important components of treatment for a number of psychiatric disorders. To date, however, there has been no family treatment designed specifically for borderline personality disorder patients and their relatives. This article describes one short-term family intervention called Dialectical Behavior Therapy-Family Skills Training. Based on Linehan's Dialectical Behavior Therapy (DBT), borderline patients' behavioral patterns are thought to result from a lifelong transaction between emotional vulnerability and invalidating features of the social and familial environment. Individual DBT focuses on reducing individual emotion dysregulation and vulnerability and enhancing individual stability. The complementary family interventions proposed in this article aim to: 1) provide all family members an understanding of borderline behavioral patterns in a clear, nonjudgmental way; 2) enhance the contributions of all family members to a mutually validating environment; and 3) address all family members' emotion regulation and interpersonal skills deficits.     

Discrimination of second-formant-like frequency transitions

Discrimination of two types of simulated single-second-formant: frequency transitions was studied, transitions where members of a stimulus set shared the same onset frequency and transitions where stimuli of a set shared the same offset frequency. Experiment 1 employed an adaptive procedure to measure just-noticeable differences for transitions that increased in frequency. Experiment 2 obtained complete psychometric functions, based on a three-interval,forced choice procedure,for transitions that either increased or decreased in frequency. In both experiments, better discrimination occurred for longer stimuli, measured in hertz/millisecond, and for transitions that shared the same onset frequency. There were no differences, in Experiment 2, between discrimination of rising and falling transitions. Results are considered from several theoretical perspectives.     

The role of small changes in the acoustic environment in modifying the startle reflex.

When either the intensity or frequency spectrum of an approximately 70-db. SPL narrow-band noise was abruptly changed by a small amount, the rat's response to a startle stimulus presented 64 msec later was inhibited. When similar small frequency changes preceded the startle stimulus by ony 5 msec, the latency of the startle response was reduced, but even relatively large changes in intensity of the antecedent stimulus had no effect on response latency. These findings provide added support for the generalization that the neural processes associated with startle are engaged by small changes in the auditory environment. They also point to a measure of separation between the processes responsible for inhibition and those responsible for latency shift.     

Temporal and spatial characteristics of selective encoding from visual displays

The time required for Ss to voice a target letter in a visual display was studied as a function of the spatial proximity of two kinds of noise elements (letters or disks) to the target and as a function of when the noise elements were presented following the onset of the target letter. The results were not consistent with a focusing model of attention or selective encoding. Instead, there appears to be a small area in the visual field (about 1 deg of angle) in which all stimuli are processed in detail.     

Some characteristics of selective attention in visual perception determined by vocal reaction time

Previous research had found that the accuracy with which an S could report an indicated letter or target in a briefly exposed multiletter display decreased as the number of irrelevant letters increased, and accuracy increased if the position of the target letter was indicated 150 msec before the display was presented. Iii the present experiment, these variables were reinvestigated using vocal reaction time as the dependent variable. An interpretation of the accuracy measures in terms of differential processing times was supported. The results of the two experiments were discussed in terms of a model of attentional selectivity.     

Overt activity during conditioned suppression: a search for punishment artifacts

Pigeons, previously trained to peck a key (using food as the reinforcer), were permitted unlimited access to food and, concurrently, key pecking was allowed to go unreinforced until all pecking ceased. A tone ending with electrical shock was then repeatedly presented in an effort to establish the tone as a potentially suppressing stimulus. When key pecking was later reestablished, tone presentation (without shock) sharply reduced the rate of pecks. At selected points throughout the experiment, special observation procedures supplemented the recordings of key pecks and provided detailed fine-grain protocols of the birds' overt movements during the periods before, during, and after tone presentations. Results indicated that neither punishment of key pecks nor punishment of other overt movements was a necessary precursor to the conditioned suppression observed in the final stage. As such, the findings support interpretations of conditioned suppression that characterize the phenomenon as reflecting a conditioned emotional reaction that either directly or indirectly inhibits overt activity.