The screen era reduced design to a single sense. Visual hierarchy, color theory, typography, layout — the entire discipline of UX operates within a rectangle of light. Sensory design is the expansion back to the full human sensorium.
Jinsop Lee's TED talk on five-sense design rated everyday experiences across all five senses and found that the highest-rated experiences (riding a motorcycle, eating a meal, making love) engaged multiple senses simultaneously. The lowest-rated experiences (using a computer, sitting in traffic) engaged one or two. The correlation between multi-sensory engagement and perceived quality of experience was striking.
In product design, sensory design manifests as deliberate attention to sound (the click of a button, the tone of a notification), touch (surface texture, weight, temperature), and even smell (the leather of a new bag, the wood of a freshly opened box). Bang & Olufsen's aluminum remotes are sensory design — the weight, the thermal conductivity, the mechanical precision of each button. They could make a lighter, cheaper remote. The sensory experience is the product.
The well-being connection is physiological. Multi-sensory engagement activates parasympathetic responses — the body's rest-and-digest mode. A warm ceramic mug in your hands, the sound of water being poured, the smell of coffee — this is a designed sensory sequence that produces calm. Compare: scrolling a feed. One sense, sympathetic activation, cortisol. The sensory design argument is not aesthetic preference — it's nervous system regulation.
For makers in the post-functional era, sensory design is the frontier. When your product can't compete on features (because features are commodified), it competes on how it makes the body feel. And the body feels with all five senses, not just one.