IntroductionPrevious studies have reported the slowing of reaction times to attentionally demanding tasks due to a reduction in cognitive resource as a result of chronic high‐altitude exposure. However, it is still largely unknown whether this reaction slowness can be attributed to the attentional allocation change and/or response patterns.MethodsTo clarify this issue, this study investigated attention‐related (N2pc and N2 cc) and response‐related (MP and RAP) event‐related potentials (ERPs) to identify the performance of a visual search task by individuals who had lived in high‐altitude areas for three years compared with those living at sea level.ResultsThis study showed that the reaction times in response to a visual search task were significantly longer in the high‐altitude subjects than in the sea level subjects. Corresponding to this behavioral observation, we found a significantly lower N2pc amplitude and a larger N2 cc amplitude in the high‐altitude subjects, suggesting a reduction in spatial attention allocation to the target (N2pc) in these subjects, indicating they need to work harder to preclude cross‐talk between response selection and attention direction (N2 cc). Moreover, we also discovered higher MP amplitudes and longer RAP latencies in the high‐altitude subjects, which further indicated that these subjects were slower and required greater cortical activation while preparing and executing correctly selected responses (MP and RAP).ConclusionNevertheless, this study collectively provided new insights into the attention reaction slowness from high‐altitude exposure.