Apple has become a regular at Stanford University's VR lab

Founding director Jeremy Bailenson told The Wall Street Journal that Apple's recent visits were the first since the lab was founded in 2003. Bailenson was on hand at the 2016 CIO Network conference.

"Apple hasn't come to my lab in 13 years, except they've come three times in the last three months," he said. "They come and they don't say a word, but there's a data point for you."

The Apple reps were put through immersive VR experiences, Bailenson said, mentioning a project that aims to teach empathy through forced perspective virtual reality interventions. For example, a male subject entering the VR world might be given a female persona and exposed to prejudice.

Another of Bailenson's projects teaches sustainable behaviors like reducing paper use and saving hot water. Stanford's team is not only pushing the boundaries of current VR hardware and software, but is investigating how best to leverage such technology in new and meaningful ways.

As for Apple, the company is widely rumored to be working on its own consumer VR solution to rival hardware from the likes of Facebook's Oculus. The VR space is heating up with Oculus Rift and HTC Vive set to ship this year, to be followed by Sony's PlayStation VR and Microsoft's Hololens projects.

Apple's plans for VR are largely unknown, but the company has filed numerous patent covering virtual displays, augmented reality, computer vision and other related technologies. Hard evidence of AR/VR systems development came last year when Apple purchased German AR firm Metaio, real-time motion capture specialists Faceshift and computer vision startup Perceptio.

More recently, Apple hired Doug Bowman, a top researcher in the VR field, and is said to have "hundreds" of employees working on secret virtual and augmented reality projects.