Post-processual archaeology developed largely independently among the archaeological community in the United States . As such its primary influence was critical theory, as opposed to the French Marxist anthropology which had been the primary influence upon their British counterparts. Many American archaeologists had begun to recognise issues of bias within the scientific community, and within the processual movement itself which attempted to be scientific. They also began to notice elements of ethnic prejudice within archaeology, particularly in regards to Native American peoples, who had commonly not had a chance to participate in their own heritage management up until the 1990s.  Many American archaeologists also began to take note of a gender bias in the archaeological interpretation and in the discipline as a whole, as women had been largely marginalised. The 1980s saw archaeological studies finally being published that dealt with this issue, namely through Joan Gero 's paper on "Gender bias in archaeology: a cross-cultural perspective" (1983)  and Margaret Conkey and Janet Spector's paper on "Archaeology and the Study of Gender" (1984).  Among the post-processualists, less emphasis was put on correcting class biases in the American archaeological record than had been put into studying gender and ethnic differences. Instead, it was mostly among historical archaeologists (those who study the archaeology of the historic, or literate period of the past), that such investigation into marginalised classes such as workers and slaves took place.