One of the great things of Rachel Laudan's Cuisine and Empire (the New York Review of Book has a very good synopsis/review) is that she offers hypothesis on the history of food that can be tested. Most writers look at cuisines as black boxes, almost magical entities that come and go without underlying logic. Laudan positions them on a continuum of a few dietary philosophies. Why eat what or not? what makes health? what makes good food? There are local influences at work of course but much she explains by what degree competing philosophies left their mark. Two of my favourite episodes from the book are those in which Laudan describes how the various culinary philosophies (Confucian-Taoist in China, Buddhist in India, Islamic coming in from the Middle East, with earlier sacrificial systems remaining present at the background) met and mingled on the Asian continent. Would it be possible to look at major Asian cuisines as they are today (Chinese, Vietnamese, Thai, Korean, Japanese, Indian) and compare and cluster them for their similarity? And would that confirm the clusters of shared influence Laudan's theory predict? If have not a clue.
The above graph takes as input four Chinese and four Indian cookbooks and compares each of them with all others. The result is a cluster of Indian cookbooks matched with each other (to the right, high similarity), four Chinese cookbooks clustered in the middle and the Chinese/Indian books have least similarity. Having established that cookbooks of the same type of cuisines will be more like each other than others (read: having established that comparing foodpairs is perhaps a way to compare cuisines), we have turned them into one big file representing a cuisine. There are six cuisines present here, derived from 24 cookbooks.
These 'cuisine' files were all compared with each other and this resulted in the following:
The horizontal line gives similarity (a 27% similarity between Vietnamese and Chinese food pairs) and the horizontal lines gives the total number of unique foodpairs present (7005 for Vietnamese/Japanese). All cuisines compare least with Indian cooking and that is how theory would predict it (India undergoing most influence from the Middle East) and Chinese and Vietnamese are most alike as I would have predicted it, without any theory to back that up. All the others are roughly equal.
It remains a big question if cookbooks can stand for anything but clumsy representations of the real thing for English-speaking markets. But what are you to do.