Mice were given control drinking water or drinking water containing 0.01% (w/v) scallop-derived plasmalogen or drinking water containing 0.01% (w/v) chicken-derived plasmalogen for 6 weeks. After the treatment period, cognitive function was assessed using behavioral tests of short-term and long-term memory. The results showed that both the scallop-derived and chicken-derived plasmalogen groups exhibited statistically significant improvements in short-term memory. In contrast, for long-term memory, a significant improvement compared with the control group was observed only in the scallop-derived plasmalogen group (p < 0.05).