PS-REP-152 · r1 REPRESENTATION OBSERVED ENGAGED

CONTEXT ACROSS SURFACES

The judgement needs three surfaces, and nothing carries between them except memory.

01 DEFINITION

Condition in which the information required for one decision is distributed across separate display surfaces, so the operator rebuilds context from memory each time the eye crosses between them.

02 CONDITIONS

UNCERTAINTY UNRECORDED What was held in mind on the previous surface is not written anywhere on the next one.

TIME PRESSURE SHORT The crossing happens inside the window, not before it.

ERROR ASYMMETRY SYMMETRIC Losing context in either direction costs about the same, so neither surface can be made primary by default.

OPERATOR STATE CONCURRENT The eye crosses while other work is already running, and the crossing is not the task.

03 WHERE IT APPEARS

MARITIMEA judgement made by ear has to survive being redrawn as a trace on glass.

ENERGYA slow drift is plotted at a scale on which slow drift looks flat.

AVIATIONThe instrument is exact, and what it is exact about is not what is being asked.

RAILPosition is drawn precisely while the margin around it is not drawn at all.

04 WHAT AEON WORKED THROUGH HERE

This surfaced from watching where attention actually went between surfaces, rather than from where each surface assumed it went. The assumption failed in both directions — some surfaces held state no one was reading, others lost state someone was partway through. The work was on what one surface owes another when neither can know it has the reader.

What stays unresolved is what one surface owes the one beside it — whether the crossing is removed altogether or simply made cheaper.

05 LINKED TERMS

PS-DET-016 ATTENTION NARROWING PS-MOD-075 NESTED MODE DEPTH PS-LOD-103 INTERRUPTION RECOVERY COST PS-REP-157 STANDING FIGURE COST PS-INP-158 POINTER CONTINUITY LOSS PS-COO-171 ROLE-SPLIT SURFACE PS-REP-179 WHOLE AND INSTANCE PS-REP-201 ALIGNED INTO AGREEMENT