How/why does foreign investment get scared by the monetary policy? In an interview with Daron Acemoglu, he says "the hot money which was floating through Turkey has stopped after FED's declaration that we are going to give much more attention on monetary policy".
Basically I know some fundamental things like monetary policy interests with the foreign currency but dont get exactly how does it effect directly. Why or how do foreign investments get scared by monetary policy?
Monetary policy affects the value of a country's currency (e.g. interest rate &amp; money supply changes affect the value of cash).
Foreign investment is made by purchasing that country's currency (via currency exchange), then purchasing financial instruments in that country (stocks, exchange traded funds, bonds, etc.)
If a country decides to lower their currency's value over time (to make their goods cheaper to foreigners, for example), then any foreign investment would be exposed to currency devaluation.
A concrete example…

Turkish commodity market, sells 1 ton of cotton for 230 Lira (~$100USD) on January 1, 2015.

US investor exchanges $100USD into 230 Lira, buys 1 ton cotton on 1/1/2015.

Turkey decides to lower currency value by decreasing interest rate, increasing money supply, reduce reserve requirements. Value of Lira drops from 230 Lira for 100 USD to 270 lira for 100 USD.

US investor sells 1 ton cotton a year later for 250 Lira.  Exchanges Lira to USD. Receives $92.60USD.


What would normally be a modest ~9% gain from price appreciation of the cotton from 230 to 250 turns out to be an ~8% loss due to currency devaluation which occurred from monetary policy changes.
If a foreign investor isn't confident that monetary policy will drive up a country's currency value (in which they will be investing), then they should rightly be scared by monetary policy changes a government plans to make.