Optimistic update bias holds firm: three tests of robustness following Shah et al

“This has been demonstrated in a series of experimental studies (Garrett & Sharot, 2017; Sharot, Guitart-Masip, Korn, Chowdhury, & Dolan, 2012; Sharot, Kanai, et al., 2012; Sharot, Korn, & Dolan, 2011; Sharot, Riccardi, Raio, & Phelps, 2007).”

“…self-reported anxiety significantly explained the variance in information integration parameters for bad news, B (F(1,22) 10.52, p 0.004, p 2 0.32, bi 0.05; Table 4), an effect that remained significant if estimation errors are also controlled for (F(1,21) 9.79, p 0.005; Garrett and Sharot, 2017).”

“There have few psychology studies on optimism bias in humans (West, 2008; Sharot, 2011; Moutsiana et al., 2013; Garrett and Sharot, 2017).”

“In addition to the magnitude, the direction of expectation violation may influence cognitive responses; for instance, in optimism biases, with stronger immunization tendencies for unpleasant compared to pleasant expectation violations (Sharot et al., 2011; Garrett and Sharot, 2017).”

“The way we modelled the effect of cue-independent expectations, as shaping the prior distribution that was informed by the cue, was inspired by work on cognitive expectations where optimism bias modulates participants’ ability to learn from the information they are given (Garrett & Sharot, 2017).”

“Believing that one is attractive and intelligent (Eil and Rao, 2011; Korn et al., 2012) or that one’s future will be bright (Sharot et al., 2011) has a positive subjective value, which is why people tend to be motivated to maintain such beliefs (Sharot and Garrett, 2016).”

“Specifically, a repeated measures ANOVA on the percentage of accept decisions with option (best, intermediate, worst) and environment (rich, poor) as repeated factors revealed a main effect of environment (Experiment 1: F(1, 39)= 15.”

“This also excluded the possibility that the results presented below were a statistical artifact resulting from skewed base rates at the individual level (Garrett & Sharot, 2017).”

“This result has translational potential, and should motivate con fi rmation of these effects in human studies.”

“When exposed to positive events, healthy individuals typically make the previous negative events irrelevant (Garrett and Sharot, 2017; Sharot, 2011).”

“In addition, the valence of expectations and disconfirming events plays a role as individuals tend to change their expectations more after better-than-expected events rather than worse-than-expected events (Garrett & Sharot, 2017; Sharot et al., 2011).”

“This task has been used numerous times in the literature (Chowdhury et al., 2014; Garrett et al., 2018; Garrett et al., 2014; Garrett and Sharot, 2016; Garrett and Sharot, 2014; Kappes et al., 2018; Korn et al., 2014; Kuzmanovic et al., 2016; Kuzmanovic et al., 2014; Ma et al., 2016; Moutsiana et al., 2015; Moutsiana…”

“Studies show that people discount bad news (Sharot, 2011), update beliefs in a more Bayesian way after receiving good news than bad news (Garrett and Sharot, 2017), weight more positive information on themselves relative to others (e.”

“71,84,87 The Belief Updating tasks 43,101 also distinguishes social versus non-social related beliefs, yet the included study 43 did not analyze this dimension of data.”

“(f) Human participants nonetheless show an optimistic bias in updating for both positive and negative life events using these same base rates (Garrett and Sharot, 2017).”

“Similarly, people integrate different sources of information according to their credibility for good news in a Bayes optimal manner, while they systematically deviate from Bayes optimal choice for bad news [156, 157].”

“…controlled for differences in estimation errors for good versus bad news in each condition to ensure that differences in learning for good versus bad news do not reflect differences in the initial estimates (i.e., prior beliefs) between conditions or mean estimation errors (Garrett & Sharot, 2017).”

“…is optimism bias, where individuals tend to revise their beliefs to a greater degree when receiving good news (e.g. initially overestimating an event perceived as bad) than when receiving bad news (e.g. initially overestimating an event perceived as good; Garrett and Sharot 2017; Ma et al.”

“…it results from neglecting the base rates of the events (Shah, Harris, Bird, Catmur, & Hahn, 2016), others have provided evidence that biased updating is robust and that the raised concerns are not supported by additional data (Garrett & Sharot, 2014, 2017; Kuzmanovic, Jefferson, & Vogeley, 2016).”

“…presented with disconfirming evidence (Sutton and Barto, 2018), humans update their expectations more in response to positive than negative feedback, consistent with a normative positivity/optimism bias (Sharot et al., 2011; Garrett and Sharot, 2017; Lefebvre et al., 2017; Marks and Baines, 2017).”

“…tasks, belief updating paradigms and prey selection, information integration shows a positive bias (Eil & Rao, 2011; Garrett & Daw, 2019; Garrett & Sharot, 2014, 2017; Garrett et al., 2014; Garrett, González-Garzón, Foulkes, Levita, & Sharot, 2018; Korn, Prehn, Park, Walter & Heekeren,…”

“Thereby, they seem to complement biased updating with signed prediction errors (Garrett and Sharot, 2017; Kuzmanovic et al., 2018), where people preferentially update their beliefs in response to outcomes that are better than expected, resulting in optimism for signed value.”

“For example, Garrett and Sharot (2017) and Sunstein et al.”

“According to the model, a destabilization of expectation is probably triggered by the offset of interventions, which may provide a pleasant violation of expectation [52].”

“When the base rates of life events are not normally distributed (i.e. skewed towards low percentages), participants may be likely to update their beliefs more for bad news compared with good news for positive life events; and vice versa for negative life events (Garrett & Sharot, 2017).”

“Moreover, the tendency to update information asymmetrically (Garrett & Sharot, 2017) and belief that others younger than the self are at greatest may further exacerbate this.”

“Thus, previous studies found a so-called optimism bias through asymmetric coping depending on the valence of the expectation violation: individuals showed stronger accommodation after better-than-expected events than after worsethan-expected events (Chowdhury et al., 2014; Garrett and Sharot, 2017; Lefebvre et al., 20…”

“But optimism does not always lead to accurate predictions: People tend to update their beliefs to a greater extent after receiving positive information compared with receiving negative information, which is often referred to as optimism bias (Garrett & Sharot, 2017; Sharot et al., 2011).”

“When confronted with potential risks for their personal future, people usually prefer to integrate desirable information over undesirable information into their beliefs (Kube & Rozenkrantz, 2021; Sharot & Garrett, 2016).”

“…it concerns feedbacks from others about one ’ s own personal characteristics (M ¨ obius et al., 2022) or the likelihood of personally experiencing particular life events (Garrett and Sharot, 2017; Kuzmanovic et al., 2015; Marks and Baines, 2017; Moutsiana et al., 2015; Sharot et al., 2011; 2012).”

“information about adverse life events, participants updated their beliefs more in 70 response to desirable information (better than expected) than to undesirable 71 information (worse than expected) [17-19] (but also see [20, 21]).”

“This relatively nascent research area has focused mostly on how people use novel information to update beliefs about their personal future (Garrett & Sharot, 2017; Moutsiana et al., 2013; Sharot et al., 2011).”

“Humans have been described as being overly optimistic about their future and, when informed about risks, selectively updating beliefs more in response to new positive information (Garrett & Sharot, 2017; Kuzmanovic et al., 2015; Sharot et al., 2011, 2012).”

“…using the theoretical framework of the ViolEx model (Panitz et al., 2021): the offset of the preexposure threat represents a pleasant surprise (Garrett & Sharot, 2017), which weakens the validity of the previously established internal negative expectation and increases sensitivity to the new…”

“Previous research indicates that individuals accommodate more strongly after receiving unexpected positive feedback and assimilate or immunize more strongly after receiving unexpected negative feedback (e.g., Garrett & Sharot, 2017; Kube & Glom-biewski, 2021; Lefebvre et al., 2017).”

“For negative events, beliefs are updated more in response to learning the likelihood of the negative event is lower than expected (Garrett & Sharot, 2017; Kappes et al., 2018; Kuzmanovic et al., 2018, 2016, 2015; Kuzmanovic & Rigoux, 2017; Oganian et al., 2019; Sharot et al., 2011).”

“We argue that under normal, non-adverse contexts, belief updating should also be optimistically biased for positive life events, as shown by previous research ( Marks and Baines, 2017 ; Garrett and Sharot, 2017 ).”

“…many people display optimism and confirmation biases: they tend to take pleasant experience into account, while dismissing unpleasant experience more easily, and preferentially attend to information which confirms their prior beliefs (Garrett et al., 2017; Klayman, 1995; Sharot et al., 2011).”

“Although clinicians may be providing accurate information, optimistic outlooks may create barriers to patients’ comprehension of the information (Garrett & Sharot, 2017).”

“This asymmetry correlates with negative emotional processing involving the amygdala and the dorsolateral prefrontal cortex [7].”

“A common finding in this area of research is that decision makers underestimate the likelihood of negative events even if they are presented with realistic information about the actual risks they face (e.g., Garrett & Sharot, 2017; Sharot et al., 2011).”

“This includes changing the response scale and skewing event probabilities (see Supplementary Figure 1), thus introducing confounds that are well known (Garrett and Sharot, 2017; Sharot & Garrett, 2021), not least to the authors themselves who were previously criticised for generating spurious results in this way.”

“…reinforcement-learning tasks, belief updating paradigms and prey selection, information integration shows a positive bias (Eil & Rao, 2011; Garrett & Sharot, 2014, 2017; Garrett, González-Garzón, Foulkes, Levita & Sharot, 2018; Garrett et al., 2014; Korn, Prehn, Park, Walter, & Heekeren,…”

“It has also been shown that a person’s beliefs are more likely to be changed when he or she has received good news as opposed to bad news (Garrett & Sharot, 2017), suggesting that both immediate and future behavior are more likely to be changed through an emphasis on optimism.”

“Additionally, Garrett and Sharot argue that people asymmetrically incorporate positive information more than negative information into their belief system [140].”

“Considering an individual ’ s news use can be understood on a continuum (De Bruin et al., 2021; Garrett and Sharot, 2017), this study attends to the notion of selective engagement .”

“Future studies may be able to better test the hypotheses by either conducting the news task using positive events (Garrett & Sharot, 2017; Schönfelder et al., 2017) while keeping the scale (SOM) unchanged or by using scale that measures state pessimism while keeping the news task the same, thereby…”

“…first estimate participants gave, but rather are related to differences in the subsequent learning process, we controlled for the difference in estimation errors in line with the methodological recommendations on measuring biases in learning (Garrett & Sharot, 2014, 2017; Sharot & Garret, 2022).”