"Currently pursuing a BS, MS or PhD in computer science or a related technical field." is verbatim from the intern job listing (http://www.google.com/support/jobs/bin/answer.py?answer=1262...), and I suppose it is there because the target audience for Google Engineering internships is students who are aiming to work some place like Google Engineering after graduating - not exactly the same category as "technically qualified students". So if you'd consider working at some place Google Engineering post graduation, then you should definitely apply.
For the record, I would consider economics to be a related technical field
(cf. John von Neumann, cf. "Evolution of Cooperative Problem-Solving in an Artificial Economy" - http://www.whatisthought.com/hayek32000.pdf)...
The clearest description of what CS researchers talk about when they talk about "intelligence" (see http://www.vetta.org/definitions-of-intelligence/) is probably a production function from economics.
For the record, I would consider economics to be a related technical field (cf. John von Neumann, cf. "Evolution of Cooperative Problem-Solving in an Artificial Economy" - http://www.whatisthought.com/hayek32000.pdf)...