Which characteristic of Natto: appearance, odor, or taste most affects preference for Natto

In this experiment, we defined each subject’s changes in brain hemodynamics as (+) or (？) corresponding to an increase or a decrease in total hemoglobin concentration after stimuli compared to that before stimuli. As a result, there was no relation between preference for Natto and change in brain hemodynamics by the stimuli of “looking at” or “smelling”, while there was a significant relationship between preference and stimulus of “ingestion”; (+) : (？)？=？21:15 in the subjects of the “favorite” group and (+):(？)？=？30:7 in the subjects of the “non-favorite” group (P？=？0.034).This result indicated that characteristic “taste” of Natto most affects preference for Natto.