Judgment and Decision Making, Vol. 17, No. 1, January 2022, pp. 449–486 Both better and worse than others depending on diﬃculty: Replication and extensions of Kruger’s (1999) above and below average eﬀects Max Korbmacher∗ Ching (Isabelle) Kwan† Gilad Feldman‡ Abstract Above-and-below-average eﬀects are well-known phenomena that arise when com- paring oneself to others. Kruger (1999) found that people rate themselves as above average for easy abilities and below average for diﬃcult abilities. We conducted a suc- cessful pre-registered replication of Kruger’s (1999) Study 1, the ﬁrst demonstration of the core phenomenon (N = 756, US MTurk workers). Extending the replication to also include a between-subject design, we added two conditions manipulating easy and dif- ﬁcult interpretations of the original ability domains, and with an additional dependent variable measuring perceived diﬃculty. We observed an above-average-eﬀect in the easy extension and below-average-eﬀect in the diﬃcult extension, compared to the neu- tral replication condition. Both extension conditions were perceived as less ambiguous than the original neutral condition. Overall, we conclude strong empirical support for Kruger’s above-and-below-average eﬀects, with boundary conditions laid out in the extensions expanding both generalizability and robustness of the phenomenon. Keywords: above-average eﬀect, below-average eﬀect, bias, anchoring, egocentrism ∗Co-ﬁrst-author. Department of Health and Functioning, Western Norway University of Applied Sciences, Bergen, Norway, https://orcid.org/0000-0002-8113-2560. †Co-ﬁrst-author. Department of Psychology, University of Hong Kong, Hong Kong SAR. ‡Corresponding author. Department of Psychology, University of Hong Kong, Hong Kong SAR. https:// orcid.org/0000-0003-2812-6599. Email: gfeldman@hku.hk. We would like to thank Leo Chan for reviewing the materials during an early project stage and Raj Aiyer, Hirotaka Imada, Matan Mazor, Nicole Russel, Burak Tunca, and Meng-Yun Wang for reviewing the manuscript prior to submission. Their work led to many helpful comments, which improved the project output substantially. We would also like to thank Prasad Chandrashekar for his help with mixed modelling. All materials, data, and code are available in the OSF supplement at https://osf.io/7yfkc/. Copyright: © 2022. The authors license this article under the terms of the Creative Commons Attribution 3.0 License. 449 Judgment and Decision Making, Vol. 17, No. 1, January 2022 Above and below average 1 Introduction 1.1 Background The above-average eﬀect refers to the tendency to perceive oneself as better than the average person across diﬀerent aspects. Kruger (1999) was the ﬁrst to present instances of the opposite – a below-average eﬀect – the tendency to view oneself as worse than the average person, and he proposed that this opposing eﬀect depends on the diﬃculty of the ability domain. The above-average eﬀect was observed when self-perceived skills in an ability domain were high, whereas the below-average eﬀect occurred when self-perceived skills were low. Hence, Kruger identiﬁed the two eﬀects’ underlying mechanism to be the egocentric nature of comparative ability judgments and suggested an anchoring-and- adjustment account. Individuals anchor onto their own skills and then adjust away from their own anchor when judging the skill of others. Therefore, when considering easy activities, people perceive their ability/skill as high and display the above-average eﬀect, thus failing to account for the “true” distribution curve of such abilities/skills which includes others who are also highly skilled. When activities are diﬃcult and hence absolute domain ability is generally low, a below-average eﬀect results from the failure to consider that others are also not highly skilled. This result was ﬁrst operationalized in Study 1 in Kruger (1999) using a questionnaire in which participants ﬁrst compared themselves with their peers on four relatively easy and four relatively diﬃcult ability domains (or activities). Participants then answered a series of questions concerning: 1) estimates of their own and classmates’ absolute abilities (termed “comparative ability”); 2) desirability; 3) ambiguity of each ability; and 4) past experience of each ability. A strong negative correlation between domain diﬃculty and participants’ comparative ability judgments supported both above and below-average eﬀects (Kruger, 1999). The study demonstrated correlational evidence for the egocentric nature of compar- ative ability judgments, in the form of a strong positive correlation between participants’ ratings of their own and their comparative abilities. For all ability domains, participant judg- ments of their own absolute abilities better predicted their comparative ability judgments than did participants’ judgments of their peers’ skills. Additional experimental studies (2 and 3 in Kruger, 1999) used a situation in which participants received either a very easy or a diﬃcult test, leading to similar results as in Study 1. The anchoring-and-adjustment account was deemed consistent with the fact that cognitive load increased bias during comparative ability judgments. We conducted a close replication and extensions of Kruger (1999) with two main goals; 1) test the robustness of above- and below-average eﬀects, and 2) examine extensions to test whether ambiguities regarding domain diﬃculty may moderate this eﬀect. Two between-subject conditions were added to the original design to test whether an easier or more diﬃcult version of Kruger’s original ability domains would moderate the eﬀects. Furthermore, we added an additional dependent variable to assess the phenomenon using 450 Judgment and Decision Making, Vol. 17, No. 1, January 2022 Above and below average ratings of perceived domain diﬃculty more directly. We begin by introducing the literature on above-and-below-average eﬀects and the choice of target article for replication, then provide information on the original ﬁndings, and outline our added extensions. 1.2 Above-and-below-average eﬀects In the 1980s, researchers began to assess subjects’ self-evaluations in relationship to their peers with the results showing over-estimations of own chances for positive outcomes compared to the average population (e.g., Weinstein, 1980, 1983). Focusing on comparisons with others, the phenomenon became later known as above or better-than-average eﬀect (Kruger, 1999). Research picked up quickly on the above-average eﬀect, testing boundary conditions such as culture (Heine & Lehman, 1997) or self-appraisal (Wilson & Ross, 2001). Kruger (1999) was the ﬁrst to add that there is not only an above- but also below-average eﬀect. 1.2.1 Underlying mechanisms Throughout the last decades, a range of diﬀerent underlying mechanisms was proposed to explain the above-average eﬀect (less research focused on the below-average eﬀect), such as informational diﬀerences (i.e., knowing more about oneself than others), focalism (i.e., focussing on oneself during comparative judgments), naïve realism, and egocentrism (Brown, 2012). The ﬁnal mechanism was also used in the chosen study for replication (Kruger, 1999); when people assess how they compare with their peers, they may focus egocentrically on their own skills and insuﬃciently account for the skills of the comparison group. However, Kruger (1999) reported not only an above-average eﬀect, but also a below-average eﬀect, both explained by egocentrism. 1.2.2 Theoretical grounding Originally, the above-average eﬀect has been described as motivated by self-enhancement needs (i.e., to induce positive aﬀect towards oneself) or a byproduct of motivated reasoning (Alicke, 1985; Brown, 1986; Kunda, 1990; Taylor & Brown, 1988). Self-enhancement enables the maintenance of a global self-concept allowing for both positive attributes un- der personal control and negative attributes resulting from factors beyond personal control (Alicke, 1985).1 Self-veriﬁcation can be used as another explanation for the above-average eﬀect (Zell et al., 2020). Expanding on self-enhancement, the self-veriﬁcation theory de- scribes that both self-enhancement and exposure to information which creates and strength- ens a biased view of oneself can lead to phenomena such as the above-and-below-average 1See Ziano et al. (2021) for a recent successful direct replication of Alicke (1985), showing that people rate more desirable traits to be more descriptive of themselves than of others, and extending that the eﬀect was stronger for more controllable traits. This study was diﬀerent from the current work as it focused on traits whereas the focus here is on skills. 451 Judgment and Decision Making, Vol. 17, No. 1, January 2022 Above and below average eﬀects (Zell et al., 2020). In that sense, higher self-esteem has been linked with stronger above-average eﬀects (e.g., Bosson et al., 2000; Chung et al., 2016). Support for the mo- tivational perspective and the ubiquity of the above-average eﬀect was provided by those objectively being below-average in certain characteristics displaying the above-average ef- fect (e.g., Sedikides et al., 2014). For instance, prisoners comparing themselves with non-prisoners on pro-social characteristics rated themselves as above-average in most char- acteristics (Sedikides et al., 2014). Another explanation can be found in social comparisons during which people evaluate their social position compared to relevant peers – with the tendency of positioning oneself as higher-standing (Gerber et al., 2018). An example of both eﬀects applying during social comparisons is when Democrats and Republicans compare their own warmth and competency with the average person of their in- and out- group (Eriksson & Funcke, 2013). In-group comparisons lead to below-average ratings for warmth among Democrats and above-average eﬀects among Republicans, which reversed for outgroup comparisons (Eriksson & Funcke, 2013). Above-and-below-average eﬀects have also been found to vary across ages, with egocentrism accounting for age diﬀerences (Zell & Alicke, 2011). Young, middle-aged, and older adults displayed an above-average eﬀect for most ability and trait dimensions, whereas a below-average eﬀect was observed for older adults with clear deﬁciencies (Zell & Alicke, 2011). 1.2.3 Follow-up research Due to the large number of citations of Kruger’s (1999) ﬁndings, it is diﬃcult to generalize the publication’s impact. However, focusing on follow-up research on the above and below-average eﬀects’, more recent studies provided information about the eﬀects’ wide applicability and boundary conditions, with a large body of work supporting the original ﬁndings (e.g., Aucote & Gold, 2005; Burson et al., 2006; Johansson & Allwood, 2007; Sweeny & Shepperd, 2007). For example, building on the original ﬁndings, Giladi and Klar (2002) demonstrated that individual items within a positive group tend to be rated as above- average and individual items within a negative group tend to be rated as below-average. These eﬀects can be reversed depending on the timing of the denotation of the target item, which aﬀects the direction and size of the comparative biases (Windschitl et al., 2008b). Much subsequent research also continued to explore underlying mechanisms, such as motivations and debiasing factors inﬂuencing egocentrically biased comparative judgments. Epley and Caruso (2004) discussed how unconscious, automatic features of human judgment result in egocentric judgments that appear objective to the judges themselves. Windschitl et al.’s (2008a) experiments attempting to debias over-optimism for easy tasks and under- optimism for hard tasks through feedback was only successful under restrictive conditions. Yet, their results support the pervasiveness of egocentric biases as participants failed to generalize non-egocentric tendencies to new contexts. 452 Judgment and Decision Making, Vol. 17, No. 1, January 2022 Above and below average 1.3 Choice of study for replication Kruger’s (1999) work made an important contribution to the ﬁeld by introducing the below- average eﬀect and conditions in which occurs, which adds to the understanding of a highly prevalent eﬀect with importance to daily reasoning. A recent meta-analysis of better-than- average-eﬀect studies found the eﬀect to be robust across studies, yet, with the eﬀect being smaller for abilities compared to personality traits (Zell et al., 2020). Problematically, deﬁnitions and measurement of skill are incongruent which leads to biased assessment and operationalizations diﬀer strongly between studies testing above-and-below average- eﬀects, generally (Zell et al., 2020), and in speciﬁc contexts such as drivers’ overconﬁdence in their driving skills (Sundström, 2008). Hence, despite the proliﬁc literature that followed, the above-average eﬀect’s robustness has been repeatedly called into question (Sundström, 2008; Zell et al., 2020). However, some studies failed to conceptually replicate mechanisms and boundary con- ditions originally reported by Kruger, such as the relationship of estimates about others in relationship to estimates about oneself. For example, Moore and Kim (2003) found mixed evidence for the relationship between comparative ability and the evaluations of others’ ability. This was also shown in a practical context by Walsh and Ayton (2009). After presenting an imaginary scenario in which a doctor provides information about a serious diagnosis applying to the participant and how that aﬀects others’, own happiness estimates by participants were indeed inﬂuenced by information about others’ happiness. We chose Kruger’s (1999) study for replication based on the following factors: impact, open questions about boundary conditions of the above and below-average eﬀects, and absence of direct replications. To the best of our knowledge, no direct replications of Kruger (1999) have been publshed. Yet, the article has had a signiﬁcant impact on several scientiﬁc and practical ﬁelds, including management (Bazerman & Moore, 2012), economy (DellaVigna, 2009; Koellinger et al., 2007), medicine (Stewart et al., 2013), education, or the workplace in general (Dunning et al., 2004). At the time of writing (May 2021), there were 1178 Google Scholar citations of the article and many important follow-up theoretical and empirical articles (Chambers & Windschitl, 2004; Moore, 2007; Moore & Cain, 2007; Moore & Small, 2007; Whillans et al., 2020; Windschitl et al., 2008b). We chose Study 1, as it was the ﬁrst demonstration of the core phenomenon. We aimed to revisit this classic phenomenon in a well-powered preregistered close replication (e.g., Brandt et al., 2014). 1.4 Original hypotheses in target article In the original study, participants compared themselves to their peers on eight ability domains of varying diﬃculty. Kruger proposed that (Horig1:) compared to judgments of their peers’ abilities, people’s judgments of their own abilities account for more variance in their comparative ability judgments. 453 Judgment and Decision Making, Vol. 17, No. 1, January 2022 Above and below average Past research on reasons for people’s tendency to focus on their own ability when comparing themselves to others oﬀers insight on why comparative ability judgments are egocentric in nature. One’s own skills are more likely to be assessed ﬁrst when comparing