It's also a leap to say the world would be a better place. One person's version of rationality can be quite different to another's. Imagine of someone feels that the only rational thing for them to do is to do something "normally rational" people would find irrational- like kill your neighbour's dog because it's bark is keeping you up at night, but social pressures, anxiety and fear actually keep them in check from the perspective of the whole population.
Are psychopaths not a good indicator of what might happen if your self limiting emotions/thoughts were turned off?
Well, rationality doesn't exist in a vacuum. Those societal pressures are taken into account in a rational choice.
> Are psychopaths not a good indicator of what might happen if your self limiting emotions/thoughts were turned off?
Possibly? If your goal is the ultimate advancement of the self, then sociopathic tendencies might yield the best results. We've evolved to have strong emotions regarding our offspring and those of our tribe, because that's proven a beneficial strategy for the species, but that is, in some respect, to the detriment of the individual. Most of us are fine with this decision, because of our feelings regarding our and our future offspring, but if you have no care for family, friends or the species as a whole, then gaming the system for your own advancement is probably the rational choice.
There are interesting implications to your sentence though. The blogger explained the loss of (generally perceived as) negative emotions, but what if they were not put in a situation to notice, or were unable to because of the condition itself, a loss in what we generally perceive as positive emotions, such as empathy and sympathy? This of course assumes that there was some emotional state change, and it wasn't a placebo effect.
Psychopaths aren't simply a normal person with some morals turned off. They exhibit a number of other differences, including some that you might consider closer to 'brain damage' than 'rational', like an insensitivity to losses or punishment which makes them show worse performance on the Iowa Gambling Task.
I'm not sure it is that much of a leap. That's not to say that a person will be rational by suppressing those emotions, but as long as the emotions are suppressed, but not the information about any situations that led to those emotions, the person may be able to more objectively assess a situation.
That is, there are assumptions involved, but I think a case could be made that emotions are a way to bypass rational thought when it's less efficient, useful (too slow for the situation) or lack of information (or lack of our own capability) causes us to fall into local maxima thinking (e.g. love, distrust of the different, etc).
If tDCS helps test this in some manner, that would also be good. We of course need a lot more information on what tDCS actually does first though. It's entirely possible that the described effects are not what is happening at all, just what it feels like. Measuring the state of the mind is weird.
