Bernanke is talking about the deflationary period that started with the Great Depression in 1929. He does describe a "potential deflationary bias" of the gold

Bernanke is talking about the deflationary period that started with the Great Depression in 1929. He does describe a "potential deflationary bias" of the gold standard during the interwar period (which was different from the gold standard that existed before 1914) that arose as a result of the sterilisation policies that some countries adopted: > In theory, under the "rules of the game", central banks of countries experiencing gold inflows were supposed to assist the price-spice flow mechanism by expanding domestic money supplies and inflating, while deficit countries were supposed to reduce money supply and deflate. In practice, [...] no sanction prevented surplus countries from sterilizing gold inflows and accumulating reserves. In other words, under the gold standard, surplus countries were expected to experience inflation, while deficit countries were supposed to experience deflation. Some surplus countries (e.g. France) conducted policies that prevented this mechanism from taking place by not letting the money supply grow with gold inflows. It was these policies, not the gold standard itself, what created a deflationary bias.