We culturally-evolved plains apes often have problems dealing with scalar predicates, flipping direction even when negation isn't involved. Here's the UK "terror threat level" scale:
On Friday, the British government raised the level from "substantial" to "severe". Several news outlets described this as "the fourth highest" level — thus Laura Smith-Spark, Andrew Carey and Greg Botelhom, "UK raises terror threat level, citing risks out of Syria, Iraq", CNN 8/30/2014:
The UK government raised its terror threat level Friday from "substantial" to "severe," the fourth highest of five levels, in response to events in Iraq and Syria, where ISIS militants have seized a large swath of territory.