This study was designed to evaluate the effect of breast examination training with silicone models on the detection of lesions in natural breast tissue. Six women with a total of 13 benign breast lumps were examined by 20 trainees before and after a 20--30 minute training session or a period of unrelated activity. Following the training, percentage of correct detections, duration of examination, and reports of false positives increased. Confidence in correct detections and false positives also increased, although confidence in correct detections was greater than confidence in false positives. The results indicate the effectiveness of the training and suggest a need for a more complex model for training discrimination between normal nodularity and breast lesions.

Five adult humans palpated silicone breast models in a lump-detection task. The effects on detection of several lump and model characteristics were studied in three phases, using both discrete trial (restricted search procedure) and "free response" (free search procedure) psychophysical methods. Size and depth of fixed steel lumps were varied in Phase 1. Depth and hardness of uniformly sized, fixed lumps were varied in Phase 2. The presence and depth of simulated breast nodularity were also studied in Phases 1 and 2. In Phase 3, all breast models were uniformly nodular and lumps varied along dimensions of size, depth, hardness, and fixation. In Phase I, lump detection was greatest with maximum lump size and minimum depth within the model. Neither lump hardness nor depth differentially influenced detection of the fixed lumps in Phase 2. When breast lumps were mobile, in Phase 3, size and hardness were major stimulus dimensions determining detection. These results suggest physical parameters for realistic breast models and lumps to be used in training effective breast self-examination and breast lump detection. 251Breast cancer is the leading cause of cancer death in women. In 1980, approximately 36,000 women were expected to die of breast cancer

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. The potential effectiveness of breast selfexamination (BSE) as a screening procedure for early detection of breast cancer depends on the effectiveness of manual palpation. The external location of the breast, coupled with the softness of the tissue and the hardness of its backing, makes it an ideal organ for physical examination. In addition, 940/0 of all cancerous lesions of the breast are potentially palpable; the remaining 6% are considered to be poor candidates for early detection by manual palpation alone (Haagensen, 1971). There is general agreement that the earlier a breast cancer is detected, diagnosed, and treated, the greater are chances for survival

In dim illumination, adult human pupil area becomes asymptotic at about 51 mm2 whereas the dolphin pupil achieves an area of about 70 mm2 under equivalent conditions. At moderate illumination levels (greater than 100 lx), the dolphin pupil becomes a horizontally oriented ellipse and develops a pronounced central constriction with additional light. The relative relationship between pupil area and illumination copmares closely with published human data. Rates of pupil response to step increments in illumination are very similar for the two species. Although the pupil has been proposed as a mechanism for correction of the dolphins' high aerial myopia, correlation of the laboratory findings on static and kinetic pupil properties with visually controlled aerial behaviors disclosed no special interdependence.

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