R^2 for Generalized Mixed Models

Note for myself. Check this:

Nakagawa, S. & Schielzeth, H., 2013, A general and simple method for obtaining R2 from generalized linear mixed-effects models.  Methods in Ecology and Evolution, 4: 2, pp 133–142, DOI: 10.1111/j.2041-210x.2012.00261.x

EDIT 20131027:

R implementation is available: http://jslefche.wordpress.com/2013/03/13/r2-for-linear-mixed-effects-models/ 

Also MuMIn package contains implementation (http://cran.r-project.org/web/packages/MuMIn/index.html)

Facial expressions of (some) emotions are inborn?

Couple of staring points for reading (beyond Paul Ekman’s publications):

  • Peleg et al, 2006, Hereditary family signature of facial expression. PNAS, 103: 43. DOI: 10.1073/pnas.0607551103 
  • Matsumoto &  Willingham, 2009, Spontaneous facial expressions of emotion of congenitally and noncongenitally blind individuals. Journal of Personality and Social Psychology, 96: 1. DOIi: 10.1037/a0014037



Models for Story Consistency and Interestingness in Single-Player RPGs

Petri Lankoski

Published in Academic MindTrek 2013

(c) Petri Lankoski 2013. This is the author’s version of the work. It is posted here for your own personal use. Not for redistribution. The definitive version was published in Academic MindTrek 2013. http://dx.doi.org/ [LINK TO BE ADDED]


What are the elements that aect story interestingness or consistency in single-player videogames? The question is approached by comparing player evaluations (N=206) of 11 videogames against a set of features derived by formal (qualitative) analysis. Ordinal regression was used to analyze the collected data. The study posits that dialogue system, romance, moral choice, appearance customization, and support for dierent play styles relate to story evaluation. Females tend to judge game stories more favorably and those with doctoral degree less favorably than players with other education.

Categories and Subject Descriptors K.8.4 [Personal Computing]: General|Games

General Terms: Experimentation

Keywords: ordinal regression, games, storytelling, story consistency, story interestingness

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My MindTrek2013 presentation on game story

My MindTrek 2013 presentation: http://www.slideshare.net/slideshow/embed_code/26820610

The presentation relates to my paper

Model–data comparison

I wrote some code to check my ordinal / clmm models against the data (and to learn to use ggplo2).

The function pred() is from clmm tutorial to calculate predictions based on the model. The function plot.probabilities3() is for plotting prediction and distribution form the data.

Update: changed extreme subject visualization.  Area seemed not appropriate when average player is not always inside the area.

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CFP: Game Research Methods


During the last few years, several textbooks for game students have become available. While these cover many areas well, the objective of this book is to provide a collection of research methods for undergraduate and graduate level students. The aim of the book is to provide a comprehensive overview of that ways games and phenomena surrounding them can be researched. The book is planned to consist of several individual chapters which are organized into sections showing three main approaches for game research:

  • studying games as artifacts
  • studying playing and gaming as activities
  • studying players and gamers

Each section is planned to include chapters that focus on basic research methods as well as methods for on design-oriented research.

Examples of topic for the sections include (but are not limited to):

  • methods for formal gameplay analysis
  • visual analysis of games
  • video analysis of gaming
  • methods of interviewing gamers
  • using statistical analysis
  • experimental or critical game design research
  • action research through game design
  • close readings of games
  • data mining of gameplay statistics
  • participatory observations of games

As a textbook, the chapters are intended to provide rationales for using methods, descriptions of best practices, as well as critically discussing the pros and cons of the method in focus.

1000-1500 word (+ references) abstract giving clear outline of chapter as well as the short author bio. Email your submission to petri.lankoski@sh.se as a plain text (no attachments).

Deadline for the abstract submission: October 20, 2013.

Petri Lankoski & Staffan Björk

Used game sales

A study suggest that preventing used game sales would cut game companies profits unless the game prices are lowered: “We find that this policy would reduce the average profits per game by 10% if publishers do not adjust their prices. However, if they adjust prices optimally, it would increase the average profits per game by 19%”They base the claim on data from Japan.

Ishira and Ching also notes that “We also find evidence that consumers are forward-looking, suggesting that the future resale opportunity could increase consumers’ willingness-to-pay for new copies.”1

With a quick look at the report, the assumptions seems to well formulated (I did not went through the report in detail; it has 63 pages and plenty of math, so detailed reading would take some time).


  1. Ishihara & Ching, 2012, Dynamic Demand for New and Used Durable Goods without Physical Depreciation: The Case of Japanese Video Games, Rotman School of Management Working Paper No. 2189871, http://ssrn.com/abstract=2189871 (full report available on the page).

Measuring character identification and attitude towards a wheelchair

A note for myself.

An article about how wheelchair is considered as an extension of ones body:

  title={A Functionally Relevant Tool for the Body following Spinal Cord Injury},
  author={Pazzaglia, Mariella and Galli, Giulia and Scivoletto, Giorgio and Molinari, Marco},
  journal={PloS one},
  publisher={Public Library of Science},

An article about measuring character identification:
  title={Identification with characters and narrative persuasion through fictional feature films},
  author={Igartua, Juan-Jos{\'e}},