People have explored the contrast of wildness versus tameness throughout recorded history. Human selection included tameness, but domestication is not achieved without a suitable evolutionary response. Human selection included tameness, but without a suitable evolutionary response then domestication was not achieved. The tameness theorem was conjectured by Marden. Throughout the stories, Sam criticizes their predictability and tameness. These arise even when tameness is the only trait under selective pressure. The show judges evaluate pet hamsters on their tameness and health. The next step was "to locate individual genes that influence tameness and aggression". The Mauritius blue pigeon was easy to catch due to island tameness. Similar results for tameness and fear have been found for mink and Japanese quail. At times the extent of the animals' tameness surprised even the researchers. This often resulted in flightlessness, or unusual levels of tameness. These genes are thought to affect tameness and emotional processing ability. Unfortunately, this tameness is dangerous to the well-being of the species. Research has found that tameness brings associated physical changes, including coat colouring and patterning.