These studies are hampered by large natural variation from person to person, which makes it hard to align brain scans to reveal key differences in specific structures. (newscientist.com)
One must always keep in mind that the models do not include the possibility of large natural variation. (judithcurry.com)
Little can be determined from these short term records other than that there are large natural variations doe to variability in ocean and atmospheric flows — and thus the energy budget of the planet. (watertechbyrie.com)