What are these people doing, and what does it have to do with Dutch footwear? And how does the guy in the center get in or out of his cubicle?

These people, from a Bell Labs ad in the August 1959 issue of Radio Electronics, are helping The Phone Company rate the effects of various kinds of noise and interference. The ad notes that noise is a major distraction to modern living, and “an enemy of the Bell System.” They did all they could to fight it, and that’s what these people were doing.

The gentleman in the center would play a tape with common phrases, such as “the native Hollander wears wooden shoes.” In carefully controlled tests, he would then introduce noise to the line, as well as playing background noise through a loudspeaker. These volunteers would then rate the quality of the call.

As to the last question, how the guy in the center got in and out, I’m not sure, because the ad doesn’t say. I assume it involved crawling underneath, because none of the cubicles appears to have a door. Interestingly, the office cubicle didn’t hit the market until 1967, so this was another case where Bell Labs was ahead of the times.