METHODS AND APPARATUSES FOR PRESENTING CHALLENGES TO TELL HUMANS AND COMPUTERS APART

Methods and apparatuses to tell humans and machines apart. In one embodiment, automated determination of whether a human or machine is at the other end of a communication channel is based on whether the correct response to a challenge/question is received from the other end of the communication channel. The challenge is provided in a non-image format, such as a text based questions or a sound clip, to prevent abuses of the communication system by computer software robots. The communication system may be primarily for text and/or voice communications, or be such that the rendering image-based challenges can cause significant disruption in normal flow of usage. In one example, the challenge includes deliberately generated random misspelling. In one example, the challenge is context sensitive, factual based, and/or instructive of an operation in a natural language to obtain a result.