- Abstract The dependence on ν of the period doubling scaling indices for unimodal maps with a critical point of the form| x| ν is numerically investigated. A new symbolic dynamics based computation technique working in configuration space is introduced. The existence of an upper bound for δ (ν→∞) is numerically verified. An accurate estimate of 29.8 is given for this limit. Moreover, the global functional form of δ (ν) is shown to have an interesting symmetry.