The haptic budget should follow event importance

What it is

Haptics are a finite budget to be allocated by event importance. Treat the number of vibrations available per unit time as a fixed resource, spend it first on the highest-consequence events, and consider lower-priority uses only with what remains. This runs opposite to adding a vibration whenever a use case appears.

Why it happens

The budget exists because habituation and interruption cost both rise with volume. Every vibration consumes attention and accelerates habituation, so adding cues for low-frequency events erodes high-frequency ones on two fronts. Allocating by importance concentrates a scarce resource where consequences are heaviest, keeping those events discriminable and un-habituated. Allocation also includes choosing not to spend: some events do not need haptics at all and can appear quietly on screen, freeing budget for others.

Studying it

Use total volume and distribution as the independent variable: fix weekly vibration volume and compare concentrating it on a few critical events against spreading it across many, measuring critical-event identification, response time, and overall disable rate. Variables include the event list, consequence levels, and what users may disable. Include disable rate, since abandoning the channel is overload's end state.

Where it stops holding

Budget figures depend on context: a high-frequency interaction app such as keyboard feedback sustains far more total haptics than a low-frequency utility. When consequences vary sharply, naive per-event allocation clearly fails and weighted allocation is required. If users can customize haptics, the budget becomes a joint outcome, and the design still owes a default allocation that does not overload.

Applying it

• List every event that might use haptics, marking consequence level and whether a substitute channel exists.
• Set a per-interval vibration cap, allocate by consequence, and route unallocated events to other channels.
• Review the allocation periodically, reclaiming quota from low-value events for new critical ones.
• Verification: track critical-event identification and overall haptic disable rate over time; rising disable with falling critical identification means the allocation needs rework.

Related

• Within the group: D3.08.1 Frequent haptic cues make users less sensitive to them · D3.08.2 After overload, users turn off all haptics
• Adjacent: D2.10.1 Simultaneous alarms need arbitrated ordering, not overlapping playback · D4.08.2 In low-load settings, redundancy has limited marginal value and may overload
• Search terms: haptic budget · event priority · resource allocation