xavier roberts-gaal

Abstract and results summary

🚨 New preprint 🚨

Across 3 experiments (n = 3,285), we found that interacting with sycophantic (or overly agreeable) AI chatbots entrenched attitudes and led to inflated self-perceptions.

Yet, people preferred sycophantic chatbots and viewed them as unbiased!

osf.io/preprints/ps...

Thread 🧵

i LOVED getting over it! will check out :)

When You Fall on Your Face, a Philosophical Designer Succeeds

My friends @foddy.net and @gcuzzillo.bsky.social's game @babystepsgame.bsky.social came out today and it looks amazing. @foddy.net is an artist and philosopher in the truest sense of the words, who just happens to be using video games as his medium at the moment: www.nytimes.com/2025/09/23/a...

love this really elegant paper spearheaded by Linas!

one of the clearest instances of resource-rational social cognition i've seen

worth a read!

Transmission networks of long-term and short-term knowledge in a foraging society Abstract. Cultural transmission across generations is key to cumulative cultural evolution. While several mechanisms—such as vertical, horizontal, and obli

💙New paper!💙

How is knowledge transmitted across generations in a foraging society?

With @danielredhead.bsky.social
we found: In BaYaka foragers, long-term skills pass in smaller, sparser networks, while short-term food info circulates broadly & reciprocally

academic.oup.com/pnasnexus/ar...

out now in Open Mind: "People Evaluate Agents Based on the Algorithms That Drive Their Behavior"

by Bigelow & me

Paper: direct.mit.edu/opmi/article...

OSF: osf.io/yzbrq/?view_...

Pseudo Effects: How Method Biases Can Produce Spurious Findings About Close Relationships - Samantha Joel, John K. Sakaluk, James J. Kim, Devinder Khera, Helena Yuchen Qin, Sarah C. E. Stanton, 2025 Research on interpersonal relationships frequently relies on accurate self-reporting across various relationship facets (e.g., conflict, trust, appreciation). Y...

In a new paper, my colleagues and I set out to demonstrate how method biases can create spurious findings in relationship science, by using a seemingly meaningless scale (e.g., "My relationship has very good Saturn") to predict relationship outcomes. journals.sagepub.com/doi/10.1177/...

good timing!

Also check out this paper by Jonathan de Quidt, Johannes Haushofer, and Christopher Roth deriving bounds for demand effects in the dictator game (here, we directly replicate their "weak" demand cue in a different sample) www.aeaweb.org/articles?id=...

yes, thanks for your interest! the preprint is here: osf.io/preprints/ps...

(i never know whether the algorithm penalizes threads with a link in the first post)

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haha, well, at least 4% of people say shape-shifting lizards control the govt.

Also, some great work by Seetahul and Greitemeyer suggests that participants are more likely to react when they think studies will counteract their interests (journals.sagepub.com/doi/full/10....)

One thing we can't rule out: a mixture of demand compliance AND reactance in the same person (i.e., feeling pulled in both directions). But I'm not sure what kind of experiment could test this easily. A straightforward within-subjects design could be subject to concerns of "meta demand."

We also don't see a very sharp difference in the standard deviations in both demand conditions (which we'd expect if we have reacters and compliers). Distributions look pretty similar.

Good point! We address this in study 3 (p. 27), where we fit a mixture model testing for latent classes of compliers and reacters. No latent class exhibited significant evidence of a shift from zero, either in the compliance or reactance direction. The subsample which trended closest was <5% of Ps

No Evidence of Experimenter Demand Effects in Three Online Psychology Experiments: https://osf.io/g6xhf

Thrilled to work with Lucas Woodley, @rcalcott.bsky.social, & @fierycushman.bsky.social on this project! (Also, glad that many of our causal estimates seem to be unbiased by demand.) Lots more in the paper if you’re interested: osf.io/g6xhf_v1

meme about demand effects. Darth Maul from Star Wars: The Phantom Menace is igniting his lightsaber in the Naboo palace. The top panel shows Maul igniting the first beam of his lightsaber, with the phrase (from a reviewer, in Comic Sans) "I'm worried these results may be due to demand." The bottom panel shows Maul igniting the second beam of his lightsaber (in dramatic fashion), with the text in large bold font "DEMAND EFFECTS DO NOT EXIST." (Note that we only claim demand effects in online experiments using standard paradigms are weak and/or elusive, and therefore unlikely to bias results. It is a meme :))

In short: do you need to worry about experimenter demand ruining *your* online study? Based on our evidence, probably not.

That's good news for the field! As we argue, demand effects appear, at least in their simplest form, to be more phantom than menace (7/8)

Then we measured participants' dictator game behavior, moral vignette judgments, and change in ingroup attitudes after an intervention (we used an inert subliminal priming intervention for measurement purposes).

Control and demand conditions were statistically indistinguishable! (6/8)

To answer this, we used obvious ("We hypothesize...") and subtle demand manipulations ("These images are designed to make you feel more warmth toward the average [conservative/liberal]")

In each case we verified participants correctly understood study hypotheses. (5/8)

...and demand effects are most often observed with small student samples or very heavy-handed cues ("You will help us if you...")

But modern psychology experiments use experienced online samples and standardized paradigms. Is demand a realistic concern in this setting? (4/8)

Some background: meta-analysis (@nicholascoles.bsky.social, Morgan Wyatt, & Michael C. Frank) and prior large-scale studies using economic games (@jondequidt.bsky.social, @johanneshaushofer.com, & Christopher Roth) find small though inconsistent demand effects... (3/8)

In three preregistered studies (N=2,254), we revealed the study’s hypothesis. Participants’ beliefs changed but their behavior didn’t.

In other words, in a dictator game, a moral vignette, and an attitudes intervention, we created experimenter demand but it had no effect! (2/8)

Summary of design and results from our three studies. (A: Design) Each study used a similar experimental design, measuring both positive and negative demand in an online experiment, with three commonly-used task types (dictator game, vignette, intervention). Our experiments had ns ≈ 250 per cell. (B: Results) Observed demand effects were statistically indistinguishable from zero. The plot shows means and 95% confidence intervals for standardized mean differences derived from frequentist analyses of each experiment and an inverse variance-weighted fixed-effect estimator pooling all experiments (solid bars). Prior measurements of experimenter demand from a previous dictator game experiment (de Quidt et al., 2018; standardized mean difference from regression coefficient) and a meta-analysis primarily including small-sample, in-person studies (Coles et al., 2025; Hedge’s g statistic) are also shown for comparison (striped bars). The main text includes Bayesian analyses that quantify our uncertainty.

We often hear from reviewers: "what about demand effects?" So we developed a method to eliminate them. Something weird happened during testing: We couldn’t detect demand effects in the first place! (1/8)

Mark Chen | Department of Psychology

My website is official 🙌 Excited to share that I am interested in reviewing applications for Harvard’s Clinical Science PhD program this fall as I look for the first student to join my lab! I appreciate it if you can share with your network :)
psychology.fas.harvard.edu/people/mark-...

🔥Exciting news in experimental philosophy🔥
Very happy to announce that there will be soon a new journal named “Experimental Philosophy”.
It will be open access, free of charge for authors and follow all Open Science principles.

Editors and Editorial Board below.

More information coming soon...

grateful for the chance to collaborate with the inimitable arthur le pargneux and @fierycushman.bsky.social

check out our preprint: osf.io/preprints/ps...

our findings are consistent with recent work in contractualist moral cognition by @sydneylevine.bsky.social @jbaptistandre.bsky.social @jaredlcm.bsky.social and others

moral judgments often track what we believe negotiating agents would agree to!

by contrast, in a donation context where bargaining does not apply, moral intuitions completely reverse!

people instead think it's most fair to redistribute money to the party who can earn less on their own -- or to split the money equally

people say how money should be split between two parties who differ only in what they can earn on their own

when the parties are negotiating, people think it's most fair for the party with a better outside option to take a larger share as a function of their bargaining power

should we treat people equally? give more to the needy? sometimes, people think it's fair for those who start out already advantaged to get more -- think bonuses, salary negotiations, and so on

in two experiments, we show how the logic of bargaining can govern these moral intuitions!

figure 2 from our preprint, reporting the results from two experiments we measure moral judgments about dividing money between two parties and manipulate the degree of asymmetry in the outside options each party has we find that moral judgments track predictions from rational bargaining models like the nash bargaining solution and the kalai-smorodinsky solution in a negotiation context by contrast, in a donation context, moral intuitions completely reverse, instead tracking redistributive and egalitarian principles preprint link: https://osf.io/preprints/psyarxiv/3uqks_v1

the functional form of moral judgment is (sometimes) the nash bargaining solution

new preprint👇