Rob Giampietro is a principal at Giampietro+Smith, a design firm based in New York City. Rob is also an adjunct faculty member at Parsons School of Design and RISD, and a contributor to Design Observer and Dot Dot Dot. Rob blogs at Lined & Unlined.

From the MS Encarta entry on the image:
Despite his mother’s beckoning, an infant hesitates to cross the “visual cliff” — an apparently steep drop that is actually covered by transparent glass. Psychologists in the 1960s found that most infants 6 to 14 months of age were reluctant to crawl over the cliff, suggesting they had the ability to perceive depth.

From Rob:
I guess the idea that interests me would be that even babies in the earliest stages of cognition have certain expectations about the physical properties of the world, and violating those expectations leaves them a bit dumbfounded, confused, trying to make sense of why the violation occurred. I also think the description of the experiments themselves, the ball rolling through the wall, the idea of crawling into thin air on the visual cliff - they're really visually evocative.

For more, check out this entry at Lined & Unlined.