Stability and robustness of idiosyncratic choice bias

Lior Lebovich, Lea Kaplan, David Hansel, Yonatan Loewenstein
Communications Psychology. 2025-05-17; 3(1):
DOI: 10.1038/s44271-025-00263-0

1. Commun Psychol. 2025 May 17;3(1):79. doi: 10.1038/s44271-025-00263-0.

Stability and robustness of idiosyncratic choice bias.

Lebovich L(1)(2)(3), Kaplan L(4), Hansel D(5), Loewenstein Y(4)(6).

Author information:
(1)The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of
Jerusalem, Jerusalem, Israel. .
(2)Department of Collective Behavior, Max Planck Institute of Animal Behavior,
Konstanz, Germany. .
(3)Centre for the Advanced Study of Collective Behaviour, University of
Konstanz, Universitätsstraße 10, 78464, Konstanz, Germany.
.
(4)The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of
Jerusalem, Jerusalem, Israel.
(5)Cerebral Dynamics, Plasticity and Learning Laboratory, CNRS, 45 Rue des
Saints Pères, 75270, Paris, France.
(6)The Alexander Silberman Institute of Life Sciences, Dept. of Cognitive and
Brain Sciences and The Federmann Center for the Study of Rationality, The Hebrew
University of Jerusalem, Jerusalem, Israel.

A well-known observation in repeated-choice experiments is that a tendency to
prefer one response over the others emerges if the feedback consistently favors
that response. Choice bias, a tendency to prefer one response over the others,
however, is not restricted to biased-feedback settings and is also observed when
the feedback is unbiased. In fact, participant-specific choice bias, known as
idiosyncratic choice bias (ICB), is common even in symmetrical experimental
settings in which feedback is completely absent. Here we ask whether
feedback-induced bias and ICB share a common mechanism. Specifically, we ask
whether ICBs reflect idiosyncrasies in choice-feedback associations prior to the
measurement of the ICB. To address this question, we compared the long-term
dynamics of ICBs with feedback-induced biases in two longitudinal experiments
involving 319 participants. We show that while feedback effectively induced
choice preferences, its effect was transient and diminished within several
weeks. By contrast, we show that ICBs remained stable for at least 22 months.
These results indicate that different mechanisms underlie the idiosyncratic and
feedback-induced biases.