Can someone point me to any recent studies that have followed up very old AT&T work on training people to hear differences? I vaguely remember an old AT&T or Bell Labs study showing that people who could not identify a low frequency tone mixed in with noise were able to reliable identify the sound after it had been shown to them in non-blind conditions first? Also I wonder if audio engineers have databases that allow meta-studies of their work? I'm thinking that in this age of big data that the potential for discovering subtle but persistent effects is there. I'm minded of this when looking at the new biology studies of genes and intelligence. Many small scale studies could not find effects that were significant but when combined with other studies people have managed to publish studies (usually with enormous sample sizes on the order 500k or 1M participants) showing clear links between certain genes and a) educational attainment and b) IQ in serious bio journals. I remember once looking at a large cable test that seemed to show negative results but when I looked through the data it was clear that a subset of listeners could -- at statistically significant levels -- tell which cable was which. There was no followup nor paper on this and the people doing the test didn't respond to queries from me. But I haven't seen many studies that are large enough and recombinable enough to allow one to use the most sophisticated stats to ferret out subset effects. I am not an audio engineer though I work with large scale statistical data. So I'd appreciate it if an expert could give me some references. Thanks.