The same phenomenon or action may evoke different imaginations across the minds of people. For instance, locking the door could be construed either as putting the key into the lock or as securing the house. According to the construal level theory, the former (latter) is more likely to happen among people with a low (high) level of construal, who have an intrinsic inclination to focus on peripheral details (central features) of the phenomena or action. Given that object's peripheral details are more concrete and less abstract than its central features, people with a low (high) level of construal have better developed concrete-mindset (abstract-mindset). Previous research has been consistently assuming that people with a low (high) level of construal are better at cognitively processing the concrete (abstract) phenomenon or action. However, this assumption has not yet been empirically tested with EEG methodology. In this paper, we test this assumption through within-subject experimental design (n = 44) conducting EEG methodology. Results of the P-300 component of the event-related brain potential, which is an indicator of mental workload, demonstrated that people with a low (high) level of construal experienced a greater mental workload when they were processing abstract (concrete) phenomena.