Matthew I. Billet
matthewibillet.bsky.social
Matthew I. Billet
@matthewibillet.bsky.social
Culture | Religion | Environmental Decision Making

Postdoc UC Irvine | PhD S/P Psychology University of British Columbia
Reposted by Matthew I. Billet
Revision posted! An evolutionary model of identity signaling with nested/overlapping/intersectional identities, complex multidimensional signaling capabilities, and a primer on ancient Mesopotamia. What more could you ask for?
osf.io/preprints/so...
New preprint w/ Nathan Gabriel & @avbell.bsky.social: The Evolution of Identity Signals for Coordination in Diverse Societies

The model tackles multiple nested/overlapping identities and complex signaling structure. Recovers lots of old results and adds several new ones osf.io/preprints/so...
October 27, 2025 at 8:09 PM
New pre-print analyzing 25,000 Christian sermon transcripts across the USA. Churches account for most systematic variance in sermon content, geographic region accounts for none. We identify niches in sermon content that may guide religious competition in USA.

osf.io/preprints/ps...
OSF
osf.io
October 22, 2025 at 7:43 PM
Interested in the psychology of people's spiritual connections with nature, and how it shapes well-being and sustainable behavior?

Check out my open-access Current Directions article with Adam Baimel (@abaimel.bsky.social), Mark Schaller, and Ara Norenzayan: journals.sagepub.com/doi/full/10....
Ecospirituality - Matthew I. Billet, Adam Baimel, Mark Schaller, Ara Norenzayan, 2025
Many people in many cultures have a spiritual connection with nature. Research is beginning to reveal the implications of this “ecospiritual” orientation for tw...
journals.sagepub.com
September 2, 2025 at 8:02 PM
Reposted by Matthew I. Billet
Below is my new post about our Three Stages of Religious Decline paper (www.nature.com/articles/s41...).

We argue that a similar process of decline affects countries on every populated continent, including countries in which Christianity, Islam, Buddhism or Hinduism is the largest religion.

A🧵
How religion declines around the world
A country’s religious affiliation tends to decline in three transitional stages that unfold across generations, a new paper using Center data proposes.
www.pewresearch.org
September 2, 2025 at 5:16 PM
An incredible resource on Social Psychology today spanning 50 beefy chapters written by some of the greatest scholars today. The best part is, the new Handbook of Social Psychology is completely free and available online to download. Here's the link.

openpublishing.princeton.edu/projects/the...
The Handbook of Social Psychology (6th Edition) in PDF | The Handbook of Social Psychology | Open Publishing
<b>You can download individual chapters and/or the complete book in PDF below.</b><br><br> <i>The Handbook</i> is designed to be read online as a continuous-scroll e-book. PDFs may contain inelegant p...
openpublishing.princeton.edu
May 20, 2025 at 5:29 PM
Reposted by Matthew I. Billet
April 8, 2025 at 2:27 PM
Reposted by Matthew I. Billet
Fully-funded PhD position on the cultural evolution of environmental management!

Link evolution, ecology and behavioral science in the ACE Lab timwaring.info Details: forms.gle/gZWK9BpwYfoG...
@culturalevolsoc.bsky.social @alexmesoudi.com @hyperadapthyrax.bsky.social @michael.muthukrishna.com
ACE Lab: Applied Cultural Evolution Laboratory
culture, evolution, cooperation, and sustainability
timwaring.info
March 10, 2025 at 1:01 PM
Reposted by Matthew I. Billet
After a long wait, the working paper for the Many-Economists Project: The Sources of Researcher Variation in Economics. We had 146 teams perform the same research three times, each time with less freedom. What source of freedom leads to different choices and results? papers.ssrn.com/sol3/papers....
The Sources of Researcher Variation in Economics
We use a rigorous three-stage many-analysts design to assess how different researcher decisions—specifically data cleaning, research design, and the interpretat
papers.ssrn.com
February 25, 2025 at 7:17 PM
Reposted by Matthew I. Billet
How can we sustain both our planet and ourselves? Drawing on a new review of research by @matthewibillet.bsky.social, @abaimel.bsky.social, and colleagues - as well as faith and climate scientist leaders like @katharinehayhoe.com, my article for @psychologytoday.com explores what we can do.
The New Science of Ecospirituality
How can we sustain both our planet and ourselves? The new science of ecospirituality has some ideas and some suggestions to try.
www.psychologytoday.com
February 24, 2025 at 3:55 PM
Reposted by Matthew I. Billet
Where do moralizing religions come from? Useless cognitive by-products?Cultural group selection for complex societies?

Our Psych Review paper argues: neither. Let’s rethink their cognitive & evolutionary origins🧵
w/ @manvir.bsky.social @nbaumard @jbaptistandre.bsky.social

doi.org/10.1037/rev0...
February 11, 2025 at 6:20 PM
Reposted by Matthew I. Billet
Does poverty lead to risk taking or risk avoidance? Turns out, to both. Our new paper (with D. Nettle & W. Frankenhuis) in @royalsocietypublishing.org explains why, and conducts preregistered tests of our ‘desperation threshold’ model.

royalsocietypublishing.org/doi/10.1098/...

A 🧵
February 7, 2025 at 2:12 PM
Reposted by Matthew I. Billet
Critical comms about climate change is increasingly happening on social media. But it is challenging to study climate comms on popular social media platforms, so researchers often rely on survey research. How much do survey responses tell us how things will play out on social media? Thread 🧵
February 6, 2025 at 3:05 PM
Does anyone have recommendations for more recent textbooks on environmental psych / conservation psych? I love this one by Gardner and Stern, but it's quite outdated now. #APA34 #environmentalpsych #conservationpsych #sustainability
January 30, 2025 at 2:03 AM
Check out our new article on ecospirituality!
Takeaways: Ecospirituality is associated with environmental concern and well-being, and changes in ecospirituality are associated with changes in these variables too! (plus a large pre-registered outdoor experiment that kinda failed!)
January 28, 2025 at 9:25 PM
Super interesting - another great article from Gordon Hodson
Since 2004, different forms of prejudicial attitudes have become increasingly inter-correlated with one another and increasingly linked to conservatism. journals.sagepub.com/doi/full/10....
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journals.sagepub.com
January 27, 2025 at 6:04 AM
Very interesting results in this new meta-analysis of why people turn to conspiratorial thinking. Conspiratorial thinking is a response to external threats, not really a trait of specific kinds of people. I want to know... 1/2
🚨Our meta-analysis of the motives associated with conspiracy beliefs has been accepted at Psychological Bulletin!🚨“Reasons to believe: A systematic review and meta-analytic synthesis of the motives associated with conspiracy beliefs” osf.io/preprints/ps... 🧵👇 1/16
December 17, 2024 at 4:38 PM
New open access article assessing the common ground between liberals and conservatives on why nature is worth preserving. Turns out they share a lot in common!

I did this work with Adam Baimel (@abaimel.bsky.social ), Taciano Milfont, and Ara Norenzayan. 1/n

journals.sagepub.com/doi/10.1177/...
December 12, 2024 at 5:44 PM
Reposted by Matthew I. Billet
{ggeffects} version 2.0.0 is out now! Read more about this #rstats package at strengejacke.github.io/ggeffects

What does {ggeffects} do? The 📦 helps you to understand (complex) models and results by calculating and plotting *estimated marginal means* or more generally, *adjusted predictions*. 🧵
Create Tidy Data Frames of Marginal Effects for ggplot from Model Outputs
Compute marginal effects and adjusted predictions from statistical models and returns the result as tidy data frames. These data frames are ready to use with the ggplot2-package. Effects and predictio...
strengejacke.github.io
November 29, 2024 at 10:45 AM