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To validate the supposition that thin malignant melanomas (less than 0.76 mm thick) of ordinarily low risk but with areas of regression may paradoxically metastasize, we observed 121 thin malignant melanomas over a six year period. Of these, 23 displayed readily apparent areas of regression, of which five (21.7%) metastasized. The incidence of metastases in their 98 counterparts without regression was 2.0% (2/98). The difference between the two is statistically significant (p = less than .01). Of the entire group of the two is statistically significant (p = less than .01). Of the entire group of thin melanomas, those with regression represented 19.0% (23/121) yet accounted for a disproportionate 71.4% (5/7) of all metastases. We conclude that regression is a relatively poor prognostic sign, whose occurrence within an otherwise thin melanoma represents a significant caveat to the current histologic staging system that equates thinness with low risk. We thus submit that patients whose malignant melanomas display regression be followed rigorously for evidence of metastases irrespective of the tumor's actual measured thickness or level of invasion.

Experimental subjects were exposed to prism-induced visual displacement of a target whose location was correctly given by proprioceptive-kinesthetic information. Control subjects were exposed alternately to visual displacement or proprioceptive-kinesthetic location information. During the adaptation period, experimental subjects in the visual attention condition performed a localization task that directed them to attend selectively to the visual modality; experimental subjects in the proprioceptive attention condition attended selectively to the proprioceptive modaltiy; control subjects performed the task on the basis of the available modality. Measures of adaptation and aftereffect were secured separately in each of the two modalities. These confirmed the predictions that the shifts in the experimental conditions would be confirmed to localization tests dependent on the unattended modality and that control subjects would not exhibit adaptation. We proposed that allocation of attention determines situational dominance and that dominance determines the locus of adaptation. The findings were compared to those reported by Canon (1970) and were applied to a reassessment of the "visual capture" phenomenon.

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