In the small number of children that Dr Parker and his colleagues have been able to look at, this trend was apparent which suggests that, sometimes at least, the defect is inherited.
Among the apparent victims of this trend are holders of the Charles Schwab Bank Visa, which not long ago charged no annual fee and paid holders a flat 2% cash back on purchases.
In each case the trend has already been apparent for a generation or more (the Japanese steel industry, for instance, cut its workforce by close to half in the 1980s).