Fundamental News Question on Terrorism

I heard on the financial news this morning that the GBP price dropped versus the dollar in the aftermath of the Belgium terror attack. The fear being that this might be a further reason why England would bow out of the EU. I did see that the price did drop and the trend thus far today seems to be leveling out, at least for now.

I can see that yes, England is part of the EU, and the England has been talking about pulling out of the EU for a while, so I can see that there might be some connection between terrorism events in the EU and the price of the GBP. That seems like a simultaneously simple and complex deduction to make.

Did something similar happen when the attacks in Paris occurred? What about price movement when the Paris terror suspect was captured in Belgium just about a week ago? How much effect does terrorism and fear have on market analysis? How can I tell when it would be appropriate to strongly weigh an event as having the potential for moving a price?

It is sad but these terror events are having less effects on markets then they did a few years ago. If a terror act is blamed for the sudden drop in price of stocks, currencies or commodities, the pattern has been they will recover to pre terror levels soon after the news coverage moves on to something else