Manual Character Transmission by Presenting Trajectories of 7mm-high Letters in One Second

In this paper, we report a method of intuitively transmitting symbolic information to untrained users via only their hands without using any visual or auditory cues. Our simple concept is presenting three-dimensional letter trajectories to the user's hand via a stylus which is mechanically manipulated. By this simple method, in our experiments, participants were able to read 14 mm-high lower-case letters displayed at a rate of one letter per second with an accuracy rate of 71.9% in their first trials, which was improved to 91.3% after a five-minute training period. These results showed small individual differences among participants (standard deviation of 12.7% in the first trials and 6.7% after training). We also found that this accuracy was still retained to a high level (85.1% with SD of 8.2%) even when the letters were reduced to a height of 7 mm. Thus, we revealed that sighted adults potentially possess the ability to read small letters accurately at normal writing speed using their hands.