Provision of cognitive decline inhibitors and learning ability improvers. A cognitive function decrease inhibitor or learning ability improver comprising as an active ingredient a liver hydrolyzate having a lipid content of less than 2% by mass or a phosphatidylcholine content of less than 1% by mass.認知機能低下抑制剤、学習能力向上剤の提供。 脂質含有量が2質量%未満、又はホスファチジルコリン含有量が1質量%未満の肝臓水解物を有効成分とする認知機能低下抑制剤又は学習能力向上剤。