There was a -40% price crash of Bitcoin about 3 months before the last halving, so that would correspond to roughly this May:

http://bitcoincharts.com/charts/bitstampUSD#rg1460zczsg2012-04-23zeg2013-01-22ztgSzm1g10zm2g25zv
https://en.bitcoin.it/wiki/Controlled_supply#Projected_Bitcoins_Short_Term

Also the price rise in 2013 followed not only the halving but also the first ASIC miners:

http://bitcoin.stackexchange.com/questions/40944/when-did-the-asic-mining-era-begin

So another possible theory is the ASIC miners had such lower costs, that more and more Bitcoin was being held and not sold to pay expenses. And thus leading to the 2013 bubbles.

Whereas, the opposite economics this halving, in that more miners will have their costs increase unless the price doubles, thus more Bitcoin proportionally being dumped on the market until those marginal miners exit and go mine an altcoin.