I was surprised to read that a person whose brain injury knocked the ability to have emotions was left unable to decide anything. I wrote my dissertation on decision theory and while working on it, I wondered if there could be a time or place or situation where I could not make a decision. I thought I could always decide to follow the dictates of a tossed coin or choose the option the cost the least or had the shortest name or something. Sure, I knew I might later find some other choice might have been better but I am very used to that.
It seems that the person with the brain injury could research and note and weigh choices but could not care enough to make a selection. I've carried a crude picture that some people are rational and careful thinkers while others are emotional types with a sudden hankering for chocolate or a movie or a trip. I guess we all have the ability to want, desire, pursue if we have fully working brains. Who would have thought that emotions, the very essence of not being rational, would be necessary for a decision? Who would have thought that not just those driven by whim but all of us need our emotions to function, even intellectual function?
I guess a good example of the idea and some research that emotions are needed for decision-making is "Descartes' Error" by the neuroscientist Antonio Damasio.