Patterns within a family need a structural relation

What it is

Patterns in one family should share a structural rule. A common base rhythm can mark the category while pulse count or interval marks the subcategory. Structure lets users derive meanings from the rule instead of memorizing each pattern; without it, the table collapses into a list of arbitrary conventions.

Why it happens

Rules shift the memory burden from "remember every entry" to "remember one rule plus exceptions." Once a user grasps that more pulses mean a higher level, they can infer the meaning of patterns they have not seen or have forgotten, which directly relieves both the limited discriminable set and the learning cost. Structure also helps at the perceptual level: a shared base rhythm gives members family resemblance while the varied dimension remains salient. With arbitrary variation, members may happen to sit close together perceptually and become easier to confuse.

Studying it

Compare structured and arbitrary layouts on learning and inference: give the same pattern count, one set following a stated rule and one randomly assigned, and measure learning speed, final accuracy, and accuracy at inferring unseen patterns. Variables include the rule dimension (count, interval, duration), family size, and how much documentation is provided. Include inference accuracy, since it shows whether the structure was actually acquired.

Where it stops holding

Structure must be perceptible. If the rule relies on very fine timing differences, users cannot separate members and a self-consistent structure still fails. With very small families of two or three, arbitrary assignment costs little and structure returns little. If the rule runs against users' existing intuitions, learning can cost more than no structure at all.

Applying it

• Fix one statable rule per haptic family and document it in a reference users can consult.
• Restrict variation to one or two dimensions so member differences remain noticeable.
• Keep the rule consistent across products so family meaning does not drift.
• Verification: teach users the rule, then present an unused member and measure inference accuracy; near-chance inference means the structure was not acquired or was drowned by fine differences.

Related

• Within the group: D3.03.1 Discriminable haptic patterns are far fewer than sounds · D3.03.2 Pattern-to-meaning mappings must be learned
• Adjacent: D2.01.2 Alert-tone families need a discriminable structural relation · D2.13.4 A brand's sound family needs a legible internal consistency
• Search terms: haptic grammar · family structure · pattern design