Shape Coding Technique Effects on Tactical Point Symbol Perceptibility and Discriminability

This report examines the effects of pictorial, abstract, and arbitrary shape coding on symbol perception and discrimination. This investigation also explored effects of varied or double border, regular or reverse screen, and augmentation coding. Perceptibility was assessed by measuring the time to detect a symbols presence, recognize its coded affiliation, and identify its coded system type. Correct response times were analyzed with separate nested one-factor analyses of variance, and errors were analyzed with both confusion matrices and chi-square test. Discriminability was assessed by recording errors made while determining if sequentially presented symbols were identical. Errors were analyzed with both confusion matrixes and chi-square test. Correct detection and recognition times did not differ significantly identification times did, however. Matrix analyses of discrimination errors showed that confusions resulted from the same factors that caused both recognition and identification errors. Chi-square tests indicated the scheme coded with varied or double borders and abstract shapes had a significantly greater number of discrimination errors than the one coded with regular or reverse screening and pictorial shapes, which had more than the one coded with augmentations and arbitrary shapes. Exit survey results confirmed earlier findings.