I have no idea about the rest, but I have heard of people getting quite a bad aversion to coriander.One of those cooking channel shows said it was something to do with the chemicals in the spice that is doing it.Maybe they all share similar chemical properties?

When I was in 8th grade science class, the teacher gave each student a small paper strip which we were instructed to taste. Some of the students said the paper tasted bitter, and the rest of the students said it had no taste. The teacher then told us that the paper contained a chemical that only people who had a certain gene could taste. This helped me to understand how different people can have widely different perceptions about how things taste.There may be a chemical that you, through some rare genetic factor, are extraordinarily sensitive to in all of those things you mentioned.

Aniseed, Caraway, Coriander, Cumin and Fennel are all members of two closely related families of plants, Apiaceae and Araliaceae. They all have high concentrations of essential oils, which makes them delightfully useful (for some) in cooking. An analysis of the essential oils in each plant’s fruit (mistakenly referred to as a seed) indicates that there is a considerable overlap in the components, particularly alcohols, hydrocarbons, aldehydes and ketones.Your sense of taste is complex and linked to your perception of smell. My educated guess at your aversion to these first five spices is that for some reason, your senses have picked up on their botanical similarity and the similarity in chemical composition of their essential oils.In addition, your body may have a sound reason for your aversion. We are now only discovering that the body keeps you from ingesting substances that may not actually be good for it, due to differences in genetic makeup between individuals.The remaining three offenders – well that’s where my educated guess doesn’t do so well. Tarragon, Cardamom and Capers are from different plant families. In addition, Tarragon is a leaf, Cardamom is composed of pods and fruits, and Capers are flower buds. However Tarragon and Cardamom have similar essential oil components and concentrations to the first five spices.I am a chemical engineer by training and a cook with a sense of curiosity. Thanks for stimulating my interest in both.

All of these contain a class of chemicals called Terpenes which are responsible for that "aniseedy" sort of taste. These can actually be seen if you take a spirit such as Sambuca (tastes aniseedy, not actually sure what it is brewed from) and add some water, the terpenes come out of solution and make the liquid go cloudy as the terpenes are not reasily soluble in water (the high concentration of alcohol keeps it dissolved usually).

There’s a school of thought amongst food scientists in regards to the phonetics of a substances name and the way the brain interprets flavours in conjunction with that name. Spices are of particular interest as they are often accompanied by foreign sounding names (for English speakers at least). Think of it as a type of subconscious word association that manifests itself in your sense of taste. I myself have an aversion to sausage skins. Although quite tasteless, for me the word sausage has a strong association with alarm clocks, which in turn has an association with fish fingers which I’m not a fan of purely for ethical reasons. I’m not saying this is your issue, but it may be worth some further investigation.