Information Processing Chain
The brain processes sensory information in a chain of stages. Wickens & Hollands (Engineering Psychology and Human Performance, 3rd ed., 2000) describe the model most cited in aviation, adopted by ICAO Doc 9683 §3 among others.
The stages
- Sensory input — vision, hearing, vestibular (see [[aufbau-des-auges]], [[hoeren]], [[vestibulaeres-system]]).
- Sensory memory (ultra-short term) — visual trace ~0.5 s (iconic), auditory trace ~2–4 s (echoic). Contents fade if not attended.
- Attention / perception — selection of relevant stimuli. Here awareness of "what do I see?" arises.
- Short-term / working memory — see detail below.
- Long-term memory — procedures, emergency checklists, experience. Available through practice and routine.
- Decision / plan — based on perception + memory + goals.
- Execution / motor — control input, radio call.
- Feedback — result re-enters via senses → loop.
Short-term memory — capacity and duration
Research has refined the figures over the years. Both pairs are relevant for the PPL exam:
| Source | Capacity | Duration |
|---|---|---|
| Miller (1956) The Magical Number Seven, Plus or Minus Two | 7 ± 2 items (chunks) | ~15–30 s without rehearsal |
| Cowan (2001) The magical number 4 — modern replication | 4–5 items (true chunks without rehearsal) | ~10–20 s |
| EASA / PPL exam materials (standard assumption) | 5 ± 2 items | 10–20 s |
In the cockpit context: radio clearances, frequencies, altitudes are held briefly in short-term memory. Long ATC clearances ("cleared via H4, then direct ABC, climb FL85, squawk 1234") can exceed this capacity — hence writing down and read-back are essential.
Bottlenecks and consequences
Sensory limits. What isn't in the visible area (e.g. behind the cockpit pillar) cannot be processed — hence the active scan pattern [[visuelles-scannen]].
Attentional breadth. Humans cannot execute two cognitively demanding tasks in parallel ("attentional bottleneck"). Control precision drops while speaking — see [[aufmerksamkeit-workload-situational-awareness]].
Working-memory overflow. Long ATC clearances exceed 5–7 elements → error-prone. Solution: write down, read-back, standard phraseology.
Tunnel thinking under stress. High arousal narrows perceivable information; peripheral cues (fuel quantity, altitude) escape.
Practical implications
- Chunking (CTR → radio clearance → setup → briefing) reduces working-memory load.
- Mnemonics (e.g. "GUMPF" for final check) replace lists with one memorised word.
- Checklists offload information into the software (S in SHELL).
- Read-back secures working memory through immediate sensory feedback.