Some shortcomings of past and current approaches for modeling human visual search and target acquisition (STA) are discussed. The effects of complex pattern perception, visual attention, learning, and cognition on STA performance are particularly emphasized. The importance of these processes is explained and approaches are suggested for modeling them. Guidelines are also provided for testing and validating models of visual STA. These guidelines take into account the roles of pattern perception, visual attention, learning, and cognition in STA performance. We also present and compare alternative approaches to field testing for the purpose of model validation.