Objectives: In a further attempt to expand the planned behavior theory, we apply its general version (based on compound measures) that is less sensitive to incidental influences and more trait-like in its concepts' definition. Our primary goal was to test an extended model, in which anticipated guilt and shame feelings are included as additional determinants of intention. A secondary goal was to explore the differential nature of this expansion. So, depending on people's socio-cultural background, we expect them to differentially respond either to guilt or to shame threats. While individualists are expected to be more sensitive to anticipated guilt, collectivists are predicted to respond to anticipated shame. Theoretical Background: While guilt feelings and anticipated future guilt have already proven to be effective, anticipated future shame has not been explored yet. In the present research, we test a modified planned behavior model in which anticipated guilt and shame feelings are differentially effective in promoting people's intention to act in a more conservational manner depending on how individualistic their cultural background is. To my knowledge, such a differential hypothesis has not yet been tested. Methods: Using four cross-sectional surveys of 801 university students from four different cultures (high vs. low on individualism, and English vs. Spanish-speaking), we expected anticipated guilt feelings to be relevant as an additional determinant of intention in cultures high on individualism, whereas anticipated shame was expected to be crucial in cultures low on individualism. Findings: Our differential hypothesis was tested and falsified by means of structural equation analyses. Surprisingly, anticipated shame had virtually the same effect as anticipated guilt across all four cultures. Including either anticipated guilt or shame universally increased the explanatory power of people's intention to act conservationally.