Sensory Differentiation Stack
Make similar products distinguishable through multiple sensory cues
- Difficulty
- Advanced
- Time to result
- ~months to results
- Steps
- 5
- Confidence
- 94%
The Sensory Differentiation Stack starts with an observed identification problem, then layers several independent cues into the product and package. Sisterwould's founders learned that shampoo and conditioner could appear, smell, and feel too similar for blind and visually impaired users. They worked with Vision Australia and community members, differentiated the formulations by texture, added Universal Braille, and created simple tactile symbols: horizontal lines for shampoo and dots for conditioner. The mechanism is redundancy. If a customer cannot use fine print or does not read Braille, another cue can still identify the product. The method also requires full-system prototyping because tactile moulding can weaken packaging and textured ingredients must remain compatible with product performance.
Origin
Extracted from The Foundr Podcast
Core principles
- 01Design with underserved users rather than guessing for them
- 02Use redundant cues so one sense is not the only path to identification
- 03Make accessibility part of the product rather than an add-on
- 04Test packaging and formulation together because each constrains the other
How to run it
- 1
Observe the use failure
Identify the exact context in which customers confuse products. Focus on what they currently do to compensate, such as placing bottles on different sides or adding tape and rubber bands.
Pro tip Study the product in its real environment, not only on a retail shelf.
Watch out Do not assume a standard printed label solves an accessibility problem.
- 2
Research with affected users
Speak directly with the underserved community and relevant organisations. Use their feedback to test whether the proposed cue is genuinely usable.
Pro tip Partner with a trusted community organisation when you lack direct access or expertise.
Watch out Do not treat one accessibility feature as universally sufficient.
- 3
Map distinct sensory cues
List the available cues across packaging and formulation, including texture, tactile marks, colour, and scent. Choose cues that remain distinguishable in the intended setting.
Pro tip Prefer simple contrasts that can be learned quickly.
Watch out Avoid cues that disappear once the product is dispensed.
- 4
Layer established and custom signals
Use recognised conventions such as Braille, then add an alternative when the convention does not serve everyone. Sisterwould paired Braille with lines and dots.
Pro tip Use redundant signals so customers have more than one route to identification.
Watch out Custom symbols need to be intuitive and consistently applied.
- 5
Prototype the whole system
Test the formulation, mould, bottle strength, and tactile detail together. Iterate until the accessible features survive manufacturing without compromising the product.
Pro tip Request samples before committing to the minimum order quantity.
Watch out A mould that carries more detail may weaken the package.
In the wild
After learning that some blind and visually impaired users relied on bottle position, tape, or rubber bands, the founders designed multiple identification cues. The shampoo included a different texture, the packaging carried Universal Braille, and the bottle sides used horizontal lines for shampoo and dots for conditioner.
→ Customers gained several ways to tell the two products apart without relying only on printed labels.
Early bottle samples could not reliably hold both Braille and tactile imprinting. Some bottles collapsed when squeezed, so the founders changed suppliers and repeated moulding and injection work rather than accepting an unusable package.
→ The accessibility concept remained intact while the physical package was redesigned for practical use.
Common mistakes
Assuming one cue serves everyone
The founders initially felt Braille alone was insufficient after learning that only a minority of the relevant population could read it, so they added simpler tactile symbols.
Ordering before sampling
Complex moulds and packages can fail in unexpected ways. The founders recommend obtaining and checking samples before a large order.
Separating packaging from formulation
The method depends on both tactile packaging and distinguishable product texture, so testing only one layer leaves identification gaps.
Is it for you?
Best for
It is best for physical products used in low-visibility settings or by customers with visual impairments.
Not ideal for
It is not ideal for teams unwilling to fund user research, prototyping, and packaging iteration.
From the transcript
“kids and adults use tape and rubber band to differentiate shampoo from conditioner in the shower”
“we created our own tactile imprinting system which consisted of horizontal lines for shampoo and dots for conditioner”
“the innovation of the product really stems down to color scent and texture”
From the episode
525: They Made $25,000 in Two Weeks Launching Their Haircare Brand