Cited by 3Artificial Intelligence in GamesDigital Games and MediaEvolutionary Algorithms and Applications

Generating Game Levels by Defining Player Experiences

Open access
Fernandes, Pedro M., Lopes, Manuel, Prada, Rui·2024·Proceedings of the AAAI Conference on Artificial Intelligence and Interactive Digital Entertainment

Abstract

This paper proposes a novel pipeline for generating game levels that elicit predefined emotional experiences from players. Our approach uses evolutionary algorithms alongside data-driven persona agents, predictive emotional models, a PCG parametric level generator, and a newly defined language for the clear and computable definition of player emotional experiences: ExpREx (Experience Regular Expressions). Using these components, we evolve game levels to match the player experience goals specified using the ExpREx language, aiming to create levels that evoke specific emotional experiences for different subsets of players. The efficacy of our method was validated through a user study involving 101 participants, whose continuous annotations of emotional experience were collected and analyzed to assess the congruence between the actual emotional responses elicited and those targeted by our pipeline. We found that 93.73% of the ExpREx goals targeted were also reported by the user study subjects.

AI snapshot

Written from the paper’s full text.

TL;DR

The paper presents ExpREx, a regular-expression-like language for specifying player emotional experiences, and a pipeline that combines persona agents, emotion prediction, parametric level generation, and evolutionary search to create levels matching those specifications. A user study with 101 participants found that 93.73% of targeted ExpREx goals were also reported by players, though the authors frame this as an initial proof-of-concept validation.

Key findings

  • In the validation study, 284 of 303 possible ExpREx expression matches were achieved, corresponding to 93.73% accuracy across 101 participants and 3 targeted expressions per player.
  • The predictive emotion models reached 72.8% accuracy for Pleasure and 73.1% for Arousal, based on leave-one-out classification of 1-second slices.
  • The evolutionary level generator used a population of 100 maps, retained the top 20% as parents, ran for 30 generations, and applied a 10% mutation probability per parameter.
  • ExpREx encodes each second as a word containing room/location and Arousal/Pleasure change markers, enabling temporal and spatial emotional patterns to be matched computationally.

Methods

  • The test bed was a 2D action-adventure game inspired by classic top-down games; 91 participants, primarily first-year Psychology students, played three hand-designed levels while their actions were recorded, then continuously annotated Pleasure or Arousal after gameplay.
  • Persona agents were built by clustering play-traces using Levenshtein distance and evolving parametric agents to mimic each cluster; emotion prediction used random forests trained on gameplay data to predict Pleasure and Arousal changes.
  • Levels were evolved with a parametric PCG genome controlling canvas size, path length, rotation and room frequency, corridor and room dimensions, and enemy/coin/health counts; fitness summed matches between five persona agents’ predicted emotional trajectories and the ExpREx expressions.

Limitations

  • The authors state the user study is only an initial validation and call for further testing across more levels and different games; they also note the pipeline is not yet robustly evaluated beyond proof of concept.
  • The authors state that reliance on ExpREx may limit interpretability and flexibility, may not capture all emotional states, and could benefit from adaptive, context-aware elements and additional experience metrics such as perceived difficulty.
  • The authors note that only behavioral play personas were considered, not experience personas, and raise ethical concerns about emotional manipulation, consent, and privacy; evident from the text, the emotion models’ roughly 73% accuracy and the sample of mostly Psychology students may constrain how broadly the 93.73% result generalizes.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1609/aiide.v20i1.31878

Cites

23 of 23 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 9 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    In the user study, 284 of the possible 303 expressions were successfully matched, an accuracy of 93.73%.

    “In this user study, we were able to successfully match 284 of the possible 303 expressions, which represents an accuracy of 93.73%.”
    Quote in the paperSubstantial claim
  • Findingown data

    The predictive model for the Pleasure emotional dimension achieved 72.8% accuracy.

    “For the Pleasure dimension, we were able to achieve an accuracy of 72.8%.”
    Quote in the paperSubstantial claim
  • Findingown data

    In the user study, 93.73% of the ExpREx goals that the pipeline targeted were also reported by participants.

    “We found that 93.73% of the ExpREx goals targeted were also reported by the user study subjects.”
    • Also stated in: § 1 Introduction · plain
      “The generated level matched the desired emotional experience on 93.73% of the tested ExpREx expressions.”
    Quote in the paperSubstantial claim
  • Findingown data

    The predictive model for the Arousal emotional dimension achieved 73.1% accuracy.

    “For the Arousal dimension, we were able to obtain a slightly better 73.1% of accuracy.”
    Quote in the paperSubstantial claim
  • Study design and conductown data

    The authors conducted a user study with 101 participants as an initial validation of the approach.

    “To validate the effectiveness of our approach, we conducted a user study involving 101 participants.”
    • Also stated in: § 8 Conclusion · plain
      “An initial validation of the approach was conducted through an empirical study involving 101 participants.”
    Quote in the paperSubstantial claim
  • May combine two claims. 11
  • Classified as probably not a substantial claim. 19
  • May combine two claims.

    Findingown data

    The evolved levels differ in topology and in the density and placement of in-game objects and enemies.

    “These levels differ not only on topology but also on the density and location of the different in game objects and enemies.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingreasoning

    The levels generated with unique ExpREx expressions per persona do not guide players along as strict a path as the levels in Fig. 6, allowing greater behavioral choice and different experiences for each persona.

    “These generated levels no longer guide the players to follow such a strict path as the levels found in Fig. 6, allowing for a higher degree of behavioural choice and thus allowing each play persona to have a different experience while playing the level.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    Three different levels were evolved to match sets of ExpREx expressions for five different personas.

    “We begin this section by showcasing three different levels that were evolved to match sets of ExpREx expressions for five different personas.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingreasoning

    The levels evolved to elicit the same ExpREx patterns across different personas guide players to take similar paths, despite allowing some choice.

    “It is not surprising then that these levels, although allowing for some degree of choice, guide the players to take similar paths.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    Participants were randomly allocated to annotate one of the two emotional dimensions.

    “Each participant was randomly assigned one of the dimensions to annotate and provided with a clear explanation of the assigned dimension.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Interpretationreasoning

    Dividing a generated map into locations gave a per-second location at a coarser granularity than in-game coordinates, which the authors considered more meaningful for the emotional experiences they aimed to encode.

    “Having this division, we now had a general location for each second of the game which was of a much lower granularity than the in game coordinates and thus more meaningful for the experiences we wished to encode.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Interpretationreasoning

    Levels with higher fitness scores are more likely to survive and propagate in the evolutionary process, resulting in game environments that are emotionally engaging for a diverse range of players and scenarios.

    “Levels achieving higher fitness scores are more likely to survive and propagate through the evolutionary process, leading to game environments that are emotionally engaging for a diverse range of players and scenarios.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Study design and conductown data

    Model accuracy was computed as the average classification accuracy of 1-second slices using leave-one-out, with each player's slices classified by a model trained on all other players.

    “The accuracy was based on the correct classification of 1 second slices using the “leave one out” method, where we measured the average classification accuracy of the slices from one of the players with a model trained with the data from all the other players.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Interpretationnone given

    The ExpREx language is a novel contribution that uses regular expressions to define and analyze emotional experiences in a clear and computable way.

    “The ExpREx language is a novel contribution that leverages regular expressions to define and analyze emotional experiences in a clear and computable manner.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Interpretationnone given

    The genome parameters directly affect the structure and complexity of the generated game maps.

    “The genome for the evolutionary algorithm in our level generation process consists of several parameters which directly influence the structure and complexity of the generated game maps.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Interpretationreasoning

    ExpREx can convert an emotional experience into a string that carries temporal, spatial, and emotional information.

    “By sequencing these words, we are able to transform an emotional experience into a string which contains temporal, spacial and emotional information.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Interpretationreasoning

    ExpREx can describe complex sequences of gameplay experiences by using regular-expression constructs such as quantifiers, character classes, and logical operators.

    “By utilizing regex constructs like quantifiers, character classes, and logical operators, ExpREx can effectively describe complex sequences of gameplay experiences.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Interpretationreasoning

    ExpREx enables precise encoding of complex emotional trajectories over time and space in game levels, making it a robust tool for experience-driven game design.

    “This language allows for the precise encoding of complex emotional trajectories over time and space within game levels, providing a robust tool for experience-driven game design.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Premisecitation

    PAD represents emotion using three continuous axes: Pleasure, Arousal, and Dominance.

    “The PAD model describes emotions along three continuous dimensions: Pleasure (P), Arousal (A), and Dominance (D).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Russell and Mehrabian 1977 source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Core Affect maps basic emotions to points on two axes: pleasure-displeasure and activation-deactivation.

    “The Core Affect model, on the other hand, represents basic emotional states as points in a two-dimensional space defined by the dimensions of pleasure-displeasure and activation-deactivation.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Russell 2003 source
  • May combine two claims.

    Interpretationown data

    Overall, the methodology provides a structured approach to experience-driven game design, enabling the creation of game levels tailored to evoke specific emotional experiences in players.

    “Overall, the methodology outlined in this paper provides a structured approach to experience-driven game design, enabling the creation of game levels that are tailored to evoke specific emotional experiences in players.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The known accuracy of the emotional predictive models (approximately 73%) is a sufficient benchmark for judging the 93.73% match rate as promising.
  • Classified as probably not a substantial claim.

    Interpretationreasoning

    When an emotional experience is represented as a string, regular expressions can be used to encode intended emotional journeys during gameplay.

    “Once this information is in string format, we can then leverage the flexibility and precision of regular expressions to encode desired emotional journeys during gameplay.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Premisenone given

    Pleasure and Arousal are present in both the PAD and Core Affect models and can jointly represent many basic emotional states.

    “These dimensions are present in both the PAD model and the core affect model, being able to jointly represent a plethora of basic emotional states.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    Emotional annotations were collected continuously after gameplay using a method similar to prior work by Lopes et al. (2017) and Fernandes et al. (2023a).

    “The annotation method was conducted post-gameplay and was continuous, akin to the method described in Lopes et al. (2017) and Fernandes et al. (2023a).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Lopes et al. (2017) source
    • cites Fernandes et al. (2023a)

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    PAD offers a broad framework that captures complex human emotions with just three values, which the authors argue makes it well suited for predicting player experience in games.

    “This model provides a comprehensive framework for capturing the complexity of human emotions using only three dimensional values, making it highly suitable for predicting player experiences in games.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Russell and Mehrabian 1977 source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    Using ExpREx to define and predict emotional trajectories introduces limitations in the interpretability and flexibility of those definitions.

    “The dependence on the ExpREx language to define and predict emotional trajectories introduces limitations related to the interpretability and flexibility of these definitions.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The persona agents used in this paper were created using the pipeline described by Fernandes et al. (2023b).

    “The persona agents used for this paper were created using this pipeline, of which a brief description can be found in Sec.4.1.”
    • Also stated in: § 4.1 The Persona Agent Pipeline · plain
      “The persona agents used for this paper followed the same principles and algorithms as the ones described in the work of Fernandes et al. (2023b)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Fernandes et al. (2023b)

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    ExpREx may not cover all emotional states that occur during gameplay, especially those that do not fit predefined categories.

    “While ExpREx provides a computable and structured way to encode emotional responses, it might not encompass all possible emotional states that arise during gameplay, particularly those that do not fit neatly into predefined categories.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Core Affect concerns the basic structure of emotional experience, which is later interpreted into more complex states.

    “This model focuses on the underlying structure of emotional experiences which are then interpreted to form more complex emotional states.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Russell 2003 source
  • Classified as probably not a substantial claim.

    Interpretationown data

    ExpREx expressions can encode expected emotional trajectories concisely in a computable and flexible form.

    “Each of these examples demonstrates how ExpREx can be used to succinctly encode the expected emotional trajectories in a way that is both computable and flexible.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Interpretationreasoning

    The procedural generation method can dynamically create game maps that are varied, interesting, and tailored to enhance player experience through structured yet unpredictable design.

    “This procedural method allows for the dynamic creation of game maps that are not only varied and interesting but also tailored to enhance player experience through structured yet unpredictable level design.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationnone given

    The results are promising but insufficient beyond a proof of concept; robust evaluation requires further user studies in more levels and different games.

    “The results here presented show promise, but they are insufficient beyond a proof of concept and further user studies in several different levels and even several different games are required for a robust evaluation of the pipeline.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The known accuracy of the emotional predictive models (approximately 73%) is a sufficient benchmark for judging the 93.73% match rate as promising.
  • May combine two claims.

    Interpretationreasoning

    Using persona agents, the pipeline can generate play traces and then forecast the expected emotional response for a given level.

    “Using the previously described Persona Agents, we could thus generate traces and then predict the expected emotional response of players given a level.”
    Quote in the paperSubstantial claim
28 of 28
  • The paper relies on this without support.

    Conventional playtesting and feedback from players tend to be subjective and hard to measure.

    “Traditional methods of playtesting and player feedback are often subjective and difficult to quantify.”
  • The paper relies on this without support.

    A key difficulty for automatic level design driven by experience is specifying emotional experiences in a computable and verifiable manner.

    “One of the primary challenges in experience based automatic level design is the clear definition of emotional experiences in a way that is both computable and verifiable.”
  • The paper relies on this without support.

    The chosen 2D action-adventure game was simple but allowed more varied player behavior and experience than the simpler games common in PCG studies, so it was deemed a suitable test bed.

    “This game was selected due to its simplicity, while at the same time enabling a wider range of player behaviors and experiences than the simpler games often used in PCG research.”
  • The paper relies on this without support.

    The known accuracy of the emotional predictive models (approximately 73%) is a sufficient benchmark for judging the 93.73% match rate as promising.

    “This is a promising result for the approach, especially given the known accuracy of both the emotional predictive models to be ≈ 73% (Sec.4.2).”
4 of 4

Cites

Flagged first, then by citations

Research works printed but not linked: 1

  1. [24]24. Yannakakis, G. N.; and Togelius, J. 2018. Artificial Intelli- gence and Games. In Springer.

Cited by

Sorted by citations

Authors
Fernandes, P. M., Lopes, M., & Prada, R.
Affiliations
Instituto de Engenharia de Sistemas e Computadores Investigação e Desenvolvimento (PT)
Venue
Proceedings of the AAAI Conference on Artificial Intelligence and Interactive Digital Entertainment
Published
2024-11-15
Volume
20
Issue
1
Pages
179-188
ISSN
  • 2326-909X (ISSN-L)
  • 2334-0924
OpenAlex
W4404445400
Cited by
3
References
20
Citations by year
2026: 1 · 2025: 2
FWCI
0.87
Type
conference paper
Language
en
Open access
Locations
Proceedings of the AAAI Conference on Artificial Intelligence and Interactive Digital Entertainment (publishedVersion)
Funders
Fundação para a Ciência e a Tecnologia (UIDB/50021/2020)
Topics
  • Physical Sciences › Computer Science › Artificial Intelligence › Artificial Intelligence in Games
  • Social Sciences › Sociology and Political Science › Digital Games and Media
  • Physical Sciences › Computer Science › Artificial Intelligence › Evolutionary Algorithms and Applications
Keywords
game level generation, procedural content generation, emotion induction, evolutionary algorithms, user study

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