Cognitive styles have been regarded as a crucial factor that affects the effectiveness of web-based learning (WBL). Previous research indicated that educational settings that match with students' cognitive styles can enhance students' learning performance, which is, however, linked to their emotion. Various physiological signals can be applied to measure emotion but the pulse is perhaps the most effective indicator. Thus, we conduct an exploratory research, which looks for a link between emotion and the matching/mismatching instructional approach with the condition of cognitive styles through a continuous pulse rate monitoring. The matching/mismatching instructional approach was delivered via a WBL system, which includes an index version and map version. The pulses of individual learners are collected by using a non-intrusive sensor. Our results indicate that the matching condition enables learners to feel more positive emotions than the mismatching condition, and is also linked to better learning performance.