I'm a trader by profession (although not a day trader) and making emotional decisions is about the worst thing you can do. The only worse thing is NOT making a call because you happen to be excited.

It's a learned behaviour, but a trader needs to be able to abstract away from the trade. You almost need to pretend that somebody else is doing the trade and you're just watching. I think any trader who stays in the job learns this skill eventually. The first time I traded a few million dollars of risk, I was down to few last red cells in my adrenaline stream. If I kept going that way, I'd be either an unemployed or an alcoholic (or most likely both). Instead I learned not to take it too personally. Now a large trade barely increases my pulse.

I don't think a device can replace this behaviour. In a fast market my heart may be way up due to working on several things at once and trying to keep up with the information. I still need to make trades, I just need to stay rational. A glorified heart rate monitor won't help with this.

The article quotes an intern working on their MBA. $4-6k during an MBA internship is not uncommon and is probably on the lower side. Most investment banks pay MBA interns the same base as first year associates. I don't have up to date figures, but last I heard it worked out to around $8k/mo.