In this study, 40 Japanese, 44 German and 39 Mexican women were presented with 18 everyday odorants. They were asked to rate them for intensity on a six-point scale from not detectable to very strong, for pleasantness on an 11-point scale from -5, to neutral at 0, to +5, and for familiarity on a six-point scale from completely unknown to extremely familiar. Consistent positive correlations were found between paired rating scores for the three measures, and although they were not particularly strong (r(s) range, 0.19-0.60), for most odorants all three correlations were significant. Similar results were obtained whether the data were analyzed on an individual or a national basis. Most notable were the consistent positive correlations between perceived intensity and ratings of familiarity and hedonic strength. It is suggested that the perceived intensity of the odorants depended not only on stimulus concentration but probably also on experience-dependent factors.

We sought evidence for postnatal resource limitation among littermates of the domestic rabbit Oryctolagus cuniculus, and asked whether deaths of indi~vidual pups benefit survivors by increasing their share of milk. Milk ingestion, growth and mortality of 10 chinchilla‐breed captive litters were recorded between birth and age 21 d. That milk limits growth and survival was indicated by larger litters showing lower weight gain and higher mortality, and by a significant positive correlation between milk ingested by individual pups and weight increase. Within litters, pups with higher birth weights grew faster, and weight hierarchies became increasingly stable over the 3 weeks, suggesting that advantages accrued during gestation were progressively consolidated during lactation. After individual pups died, the total daily milk weight obtained by the litter was generally unaffected but per capita milk consumption and growth of surviving pups increased, and increases in per capita consumption were greater in smaller litters. The most successful competitors for milk apparently benefit from the deaths of their littermates by obtaining an increased share of an undiminished daily food supply. This relationship has not previously been demonstrated in any vertebrate.