<p>According to dual cognition theory, corporate social responsibility (CSR) motive attribution arises from the interaction between explicit and implicit mental processes. However, existing research has largely overlooked implicit attributional processes, which occur unconsciously and cannot be observed using traditional methods. To address this gap, we employ the neuroscientific method of event-related potential (ERP) to observe investors’ brain activity while they assess CSR motives of anonymous firms. Our results reveal an N400-like brainwave associated with cognitive conflict, emerging regardless of whether participants explicitly affirm or deny more altruistic/egoistic motives. This demonstrates that in our experimental context, explicit attributions consistently conflict with implicit ones. Through statistical analysis of N400-like waves, we identify two key investor attribution tendencies: win–win preference and egoistic prejudice. These constitute the connotation of a general implicit attribution for CSR motives: selfishness-first win–win. Furthermore, the N400-like effect helps elucidate the CSR attribution mechanism: the attribution task first activates implicit processes to establish a baseline (selfishness-first win–win), after which explicit processes can adjust to any explicit attribution based on situational information. A significant adjustment means inconsistences or conflicts between explicit and implicit attributions, as evidenced by the N400-like effect when explicit attributions deviate from the implicit baseline. Our findings advance CSR motive attribution research by incorporating dual explicit-implicit cognitive perspectives, offering new neuroscientific insights into this complex psychological process.</p>