Cognitive Ergonomics
The design of tools and workflows to fit human cognitive capacities — reducing load, supporting recall and preserving orientation in complex tasks.
Overview
Human cognitive capacity is limited and unevenly distributed across task types. Good tool design works with those limits rather than against them.
Cognitive ergonomics concerns the fit between task design, information architecture, tool behaviour, and human cognitive capacity. Unlike physical ergonomics — which addresses load on muscles and joints — cognitive ergonomics addresses load on attention, working memory, and decision-making. The central finding is that much of what passes for intrinsic task complexity is actually unnecessary load generated by poor design: friction that could be eliminated, context that could be surfaced, decisions that could be deferred until they matter.
John Sweller's Cognitive Load Theory (1988) remains the most influential framework. Sweller distinguishes three types of load: intrinsic (inherent to the material — a difficult problem is difficult), extraneous (arising from poor design — unnecessary steps, irrelevant information, confusing layouts), and germane (load that builds schemas and supports long-term competence). The design implication is stark: eliminate extraneous load completely; manage intrinsic load through chunking and progressive disclosure; create conditions for germane load when learning is the goal. Much knowledge work is dominated by extraneous load that well-designed tools could remove.
George Miller's 1956 paper established that working memory holds roughly seven items (±2) at a time — a limit that shapes everything from interface design to task sequencing. Donald Norman's The Design of Everyday Things (1988) operationalised these limits into design principles: affordances that make correct action obvious, feedback that confirms action was registered, constraints that prevent error, and conceptual models that allow users to predict what a system will do. Daniel Kahneman's dual-process framework — System 1 (fast, automatic, heuristic) and System 2 (slow, deliberate, effortful) — explains why well-designed tools reduce cognitive cost: they support System 2 reasoning with System 1-compatible affordances rather than demanding deliberate attention for routine operations.
Christopher Wickens' Multiple Resource Theory adds a further dimension: attention is not a single pool but a set of resources (visual, auditory, spatial, verbal, manual) that can be selectively taxed. Tasks competing for the same resource interfere; tasks using different resources do not. This informs the design of multi-modal interfaces and the allocation of information across visual and verbal channels.
Key Texts
Foundational works in this research tradition.
Intrinsic, extraneous, and germane cognitive load. The design principle: eliminate extraneous load; manage intrinsic load through structure; create conditions for germane load when learning matters. The most influential framework in instructional design and tool ergonomics.
Working memory capacity limits: conscious attention holds roughly seven chunks at a time. The foundational paper establishing that cognitive capacity is limited and that chunking — organising information into meaningful units — is the primary way to extend effective capacity.
Affordances, feedback, constraints, mappings, and mental models in everyday design. The canonical HCI text: good design makes correct action obvious and incorrect action difficult, without requiring users to consult documentation or remember conventions.
System 1 (fast, automatic, heuristic) and System 2 (slow, deliberate, effortful) processing. The dual-process framework and its implications for decision support: tools should offload routine processing to automatic responses, preserving deliberate attention for genuinely complex decisions.
Attention is not a single pool but a set of separable resources (visual, auditory, spatial, verbal). Tasks competing for the same resource interfere; tasks using different resources can be performed simultaneously. Shapes multi-modal interface design and information allocation across channels.
Related Research
Connected areas of inquiry.