Forced fusion and fatigue

Recall from Section 6.4 that our perceptual systems integrate cues from different sources, across different sensing modalities, to obtain a coherent perceptual interpretation. In the case of minor discrepancies between the cues, the resulting interpretation can be considered as forced fusion [121], in which the perceptual systems appear to work harder to form a match in spite of errors. The situation is similar in engineering systems that perform sensor fusion or visual scene interpretation; the optimization or search for possible interpretations may be much larger in the presence of more noise or incomplete information. Forced fusion appears to lead directly to fatigue and eyestrain. By analogy to computation, it may be not unlike a CPU or GPU heating up as computations intensify for a more difficult problem. Thus, human bodies are forced to work harder as they learn to interpret virtual worlds in spite of engineering flaws. Fortunately, repeated exposure leads to learning or adaptation, which might ultimately reduce fatigue.