Selection for tonic immobility duration does not affect the response to novelty in quail

Genetic selection on a single fear test, the tonic immobility test, seems to result in selection on fearfulness, i.e. the propensity to exhibit fear responses, whatever the fear tests used. However, the conception of fear as a single variable has been challenged by the recognition that fear is multidimensional. This study was designed to test whether genetic selection on a classic index of fear in birds, tonic immobility duration, is accompanied by changes in the response to a single dimension of fear - novelty. Two lines of quail divergently selected for long (LTI) or short (STI) duration of tonic immobility were exposed to a novel object in their home cage. Quail of both lines showed typical fear reactions in response to novelty but there was no difference between lines. We conclude that genetic selection for tonic immobility duration does not affect all dimensions of fear, notably not novelty. Further studies are needed to investigate the dimensions of fear on which the two lines of quail could have been selected. (C) 2007 Elsevier B.V. All rights reserved.