Working Memory in ATC Selection: What It Tests and How to Improve It

Working memory is one of the core cognitive abilities assessed in ATC selection — both in the NATS aptitude battery and the Eurocontrol FEAST test. This guide explains what working memory is, why it matters for air traffic controllers, and how to genuinely improve your performance before your assessment.

What Is Working Memory?

Working memory is the cognitive system that temporarily holds and manipulates information while you are using it. It is distinct from long-term memory (stored knowledge) and from short-term memory (passive retention).

In practice, working memory is what lets you:

When psychologists talk about working memory capacity, they typically mean how much information a person can actively hold and use simultaneously — their "mental workspace."

Why Working Memory Is Critical for ATC

Air traffic control is one of the most working memory-intensive professions in existence. A controller at a busy sector might simultaneously:

Research on ATC performance consistently identifies working memory capacity as one of the strongest predictors of training success. Controllers who can hold more information active simultaneously make fewer errors and handle higher traffic loads.

The Digit Span Test

The most common working memory assessment in ATC selection is the digit span test. In this test:

1. A sequence of digits is presented one at a time on screen

2. After the last digit, you must recall them in order (forward span) or in reverse order (backward span)

3. The sequence length increases when you answer correctly and decreases when you answer incorrectly

4. Your "span" — the longest sequence you can reliably recall — is recorded

A forward span of 7 is average for adults. A backward span of 5 is typical. ATC candidates with spans of 8–9 forward and 6–7 backward have a meaningful advantage in training.

How to Genuinely Improve

Working memory can be trained, though the evidence suggests that practice effects are task-specific. The most effective strategies:

**Chunking** — Instead of remembering 7 individual digits (8, 3, 1, 7, 4, 2, 9), group them into meaningful units (83, 17, 429). This reduces the number of items in working memory from 7 to 3. Experienced controllers do this automatically with callsigns and squawk codes.

**Subvocal rehearsal** — Silently repeating the sequence in your head as digits are presented activates the phonological loop and maintains the information in working memory. This is effective, though it becomes harder as sequences get longer.

**Visualisation** — For some people, mentally "placing" digits in physical locations (a mental map) provides a second encoding channel alongside verbal rehearsal.

**Regular targeted practice** — Working memory training shows the most transfer when it is consistently practised in the specific format you will be tested on. Daily short sessions (10–15 minutes) over several weeks are more effective than occasional long sessions.

Backward Recall

Backward digit span is harder and more demanding because it requires not just retention but active manipulation — you must reverse the sequence in your head while holding it. This is closer to the real cognitive demands of ATC, where you often need to rearrange or transform information rather than simply replay it.

To practise backward recall, say the sequence forward first to fix it in memory, then systematically recite it from the end. With practice, this transformation becomes faster and less effortful.

The Broader Picture

Working memory practice is valuable, but it is one part of a broader ATC cognitive profile. Spatial reasoning, divided attention, and situational judgement all contribute independently to selection outcomes. The candidates who perform best in ATC selection are those who practise systematically across all assessed areas rather than focusing intensively on any single one.