Augustsson, H., Van de Weerd, H. A., Kruitwagen, C. L. J. J. et al. 2003. Effect of enrichment on variation and results in the light/dark test. Laboratory Animals 37, 328-251.

The aim of this study was to investigate if cage enrichment induces an effect on experimental mean values and on inter-individual variation in the light/dark paradigm using diazepam as the anxiolytic drug. The behaviour of 216 naive adult male mice of two different strains (BALB/c and C57BL/6) was studied. The animals were housed in groups of four in 'non-enriched', 'enriched' (nesting material) or 'super-enriched' (nest-box, nesting material, wooden gnawing stick and PVC tube) cages. .. Mice housed in enriched and super-enriched cages gained more weight than mice in non-enriched cages, although food intake was not affected. Generally, the strain of mouse had the greatest impact on both mean values and variation. .. None of the [statistical] methods showed any significant differences between standard and enriched conditions on variability in any of the parameters measured.