Using the law to set an interface-option limit is a cross-paradigm error

What it is

Using Sternberg memory scanning to prescribe a maximum number of interface options is a cross-paradigm error. The original task is a membership judgment over items held in short-term memory. Interface options involve visual search, label comprehension, probability, hierarchy, pointing, and learning—different task structures.

Why it happens

Treating “set size” in one experiment as “option count” in another hides the processes that determine actual cost. An interface may be searched quickly through salient features or slowly through unclear labels; frequency and skill further change choice. A slope or fixed limit cannot transfer without evidence that the processes are equivalent.

Studying it

Study interface option count directly by varying item count, grouping, ordering, labels, frequency, and search access in the target interface. Decompose finding, understanding, choosing, and pointing. If memory scanning is a theoretical comparison, state which processes match and which do not, and supply external-validity evidence.

Where it stops holding

Cross-paradigm analogies can inspire hypotheses because both concern limited processing, but analogy is not evidence. An interface that genuinely asks a user to retain a small set then make a probe judgment may partially resemble the paradigm; its presentation and goal still require measurement.

Applying it

• Do not apply memory-scan milliseconds or a fixed item limit to menus and toolbars; measure complete real tasks.
• Diagnose whether delay comes from finding, understanding, choosing, or reaching, then revise architecture, wording, choice structure, or layout accordingly.
• In review material, state whether the experimental paradigm actually matches the interface task instead of letting a familiar law replace user testing.

Related

• Same group: B1.06.1 Judging membership in a memory set takes longer linearly as the set grows · B1.06.2 Scanning is exhaustive rather than self-terminating · B1.06.3 The finding concerns memory judgment, not visual search · B1.06.4 Reaction time rises by tens of milliseconds per remembered item · B1.06.5 Similar slopes for yes and no responses indicate exhaustive scanning · B1.06.6 The result concerns small short-term sets, not long-term retrieval
• Nearby: B1.04 Hick-Hyman law · B1.07 Power law of practice
• Search terms: paradigm transfer · memory scanning · interface evaluation