UNDER INVESTIGATION // 02

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COGSCI 2027 · MANUSCRIPT IN PREPARATION

Choice Complexity and Decision-Making in Chess

What makes a decision hard when several options are all annoyingly reasonable?

We study whether decision difficulty can be understood not only from the position itself, but from the structure of the available choice set. Using engine-evaluated candidate moves, we build computational measures of choice complexity and relate them to how long people deliberate and the quality of the decision they eventually make.

A hand hovering over a chessboard beside a clock
Several plausible moves // one increasingly irritated decision-maker.

because “there are too many annoyingly reasonable moves here” is not yet a scientific metric

research brief // 02

At a Glance

Question
How does the structure of a choice set relate to decision time and decision quality?
Setting
Expert chess decisions with engine-evaluated candidate moves.
Representation
Choice distributions derived from the relative viability of available alternatives.
Core measure
Entropy-inspired measures of how concentrated or dispersed the choice landscape is.
Outcomes
Decision time · move quality · within-player variation
My role
Choice-complexity formulation · large-scale engine analysis · evaluation pipeline · statistical analysis
Status
Manuscript in preparation for CogSci 2027

the model

The Core Idea

Difficulty can live in the structure of the choice set.

A position with one clearly dominant move presents a very different decision environment from one where several alternatives remain similarly viable.

We represent this difference using entropy-inspired measures over engine-evaluated candidate moves. A concentrated distribution corresponds to a choice set dominated by one alternative; a more dispersed distribution reflects several competitive options.

Entropy is not intended as a direct measure of subjective difficulty. It gives us a computational description of the decision environment that exists before the human choice is made.

01

Low choice complexity

one option dominates

Move A
Move B
Move C
Move D
concentrated distribution · lower entropy
02

High choice complexity

several plausible alternatives

Move A
Move B
Move C
Move D
dispersed distribution · higher entropy
Illustrative distributions for intuition — not study data.

the central claim

Difficulty is not only a property of the person. It can also be a property of the choice set.

from alternatives to outcomes

How We Measure Choice Complexity

We begin with the alternatives available in a position and progressively turn them into a representation of the decision environment.

  1. 01

    Candidate moves

    Evaluate available alternatives

    Use engine analysis to evaluate the viable alternatives available in a position.

  2. 02

    Choice distribution

    Represent relative viability

    Transform those candidate evaluations into a relative distribution over alternatives.

  3. 03

    Complexity

    Describe the choice landscape

    Compute entropy-inspired measures describing whether the choice set is concentrated or dispersed.

  4. 04

    Human decision

    Connect structure to behavior

    Relate those measures to decision time and the quality of the eventual move.

engine candidates → choice distribution → entropy → decision time + quality

contribution ledger

What I Built

01

Choice-complexity formulation

Designed computational representations of the choice set using engine-evaluated candidate alternatives.

02

Engine-analysis pipeline

Built large-scale analysis workflows for extracting candidate evaluations and decision-context features from chess positions.

03

Decision linkage

Connected choice-set measures to human deliberation time and eventual move quality.

04

Analysis framework

Developed the statistical workflow used to compare alternative definitions of complexity and examine within-player variation.

the interaction question

Why This Is an HCI Question

Interactive systems often infer that a person is struggling from what happens after a choice: longer response time, lower confidence, more errors, or poorer outcomes.

But difficulty can also come from the structure of the options the system presents.

This project asks whether we can describe that decision environment computationally and use it to better interpret human deliberation. Chess is useful here because the available alternatives can be evaluated at scale while the human decision itself remains observable.

The broader question extends beyond chess: how should systems represent choice complexity when trying to understand, support, or adapt to human decision-making?

public takeaway

What We’re Learning

A single difficulty score does not fully describe the decision environment.

Positions with one dominant option and positions with several competitive options can look very different from the perspective of a human decision-maker, even when a conventional engine summary makes them appear similarly difficult.

Our ongoing analyses examine whether measures of broader choice structure help explain variation in deliberation time and decision quality beyond simpler descriptions of the position.

Detailed model comparisons, effect sizes, and final statistical results are staying with the manuscript while the analysis is being finalized.

entropy made it onto the website. the coefficients did not.

methods

Methods

large-scale engine analysis · MultiPV candidate evaluation · choice-set modeling · entropy-based complexity · decision-time analysis · move-quality analysis · within-player comparison · statistical modeling

current status

Manuscript in preparation for CogSci 2027.

The current version focuses on formalizing choice complexity, comparing alternative representations of the choice landscape, and relating those measures to human deliberation and decision quality.

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