Generalizing from oneself to others may be the hallmark of genius or just common sense.
Krueger & Zeiger (1993, p. 670)
Social projection is a losing strategy.
Yamagishi (2012, p. 80)
A large portion of Joachim’s Œuvre deals with social perception. “Who am I?” and “Who are you?” are the questions underlying the process of trying to understand ourselves and others. Social perception concerns important questions from mundane interpersonal situations (e.g., who will pick up the kids from school; Krueger, 2019) to intergroup settings in which social perception is the cause of life or death (e.g., when the outgroup is depicted as “human animals”).
When people know nothing about each other but their group membership, they infer each other’s characteristics from the groups’ stereotypes (Krueger & Rothbart, 1988; Tajfel, 1969). With categorization being at the heart of social perception, how can one not wonder how we perceive the categories and their elements. Joachim and I approached this question from different theoretical perspectives on projection when we first met at a DGPs-Symposium on this topic in Nürnberg 2006. To be clear, neither of us used the term projection in a Freudian or Rorschachian sense (Figure 1). Projection simply refers to perceiving an object as more or less similar to the perceiver. We both sought to understand the relationship between projection and ingroup favoritism. Joachim presented joint work with Theresa DiDonato showing that differential projection from the self to ingroups vs outgroups explains ingroup favoritism (DiDonato et al., 2011). Drawing on Mummendey and Wenzel’s (1999) model, the work I presented showed that differential projection (i.e. relative ingroup prototypicality) from ingroups vs outgroups to a superordinate category predicts ingroup favoritism (Ullrich, 2009).
Figure 1
The author sees himself in this inkblot. What do you see?
Figure credit: Hermann Rorschach (born 1884 in Zurich, deceased 1922 in Herisau), Public domain, via Wikimedia Commons (https://upload.wikimedia.org/wikipedia/commons/8/8b/Inkblot_2.tif).
Despite superficial similarities, the explanations diverge in key points. Joachim assumed that (most) people have a positive self-image and project more strongly to ingroups than to outgroups. For example, to answer the question who is more likable, Rhode Islanders or Massachusettsians, Joachim may be justified in starting from the assumption that he is highly creative – a self-defining attribute – project this positive attribute to his ingroup and conclude that most Rhode Islanders are creative like him, whereas Massachusettsians… not so many creative minds amongst them. Overall, Rhode Islanders are then evaluated more positively than Massachusettsians.
In contrast, Mummendey and Wenzel’s model would suggest two different steps. First, Joachim, faced with the task of evaluating different groups, would turn (Turner et al., 1987) to the superordinate category which includes them both (New England) and compare them on the dimensions defining their higher-level identity. Second, Joachim would construe the prototype of the superordinate category based on typical ingroup (rather than outgroup) attributes. Thus, smallness, for instance, may end up being the dimension on which Joachim compares Rhode Island with Massachusetts, again concluding that his ingroup is more positive than the outgroup.
Projection, in fact, explains everything
Ingroup favoritism is but one explanandum. Accuracy of group judgments is another major theme in Joachim’s work related to projection (see also Jussim & Honeycutt, 2024, this collection). Following Hoch (1987) and Dawes (1989), Joachim questioned the label “false consensus” mainstream social psychology put on the fact that people estimate group consensus to be higher for traits they have or opinions they espouse themselves (Ross et al., 1977). Joachim’s skepticism yielded two insights.
The first insight is that differential projection can be a coherent pattern of induction. Imagine you are to estimate the number of people out of a group of ten who know the Anatolian mystic Hoca Camide (Krueger, 2025). The eleven possible hypotheses are equally likely a priori (Figure 2). Assuming one positive observation from this population (i.e., someone who knows Hoca), the hypothesis most likely to be true following Bayesian calculus is that all members of this group know Hoca. If you are a member of this group, you are justified in believing that everyone in your group knows Hoca if you do. Compared with your prior belief in this hypothesis, you are now twice as certain that everyone in the group knows Hoca. In contrast, if you are not a member of this group, you cannot treat yourself as a sample of n = 1 and you are back at the point where every hypothesis seems equally likely. Thus, differential projection is a coherent induction strategy: Assume the ingroup, but not the outgroup, to be like you.
Figure 2
What a difference a sample of one makes.
The second insight is that a coherent rule for induction does not automatically lead to accurate judgments about groups. As noted by Campbell (1967), it is rather strange that social psychologists have tended to assume all stereotypes to be false. At least some group differences exist and stereotypes sometimes reflect this. For example, Campbell’s work with anthropologist Robert LeVine revealed that the self-image of several East African groups was aligned with the stereotype neighboring groups held of them (e.g., Kamba as prone to witchcraft, Ganda as proud). Similarly, Joachim asked students from Brown University and the Università di Padova to estimate the percentage of Americans and Italians who have a certain trait (Krueger, 1996). Figure 3 shows that the profiles of American and Italian raters were fairly similar. For example, both groups agreed in their perceptions of Americans as more ambitious and of Italians as more artistic.
Figure 3
Mean trait attributions by Americans and Italians (data from Krueger, 1996).
If group differences exist, lack of projection to the outgroup improves accuracy, but accuracy may still be low in an absolute sense. Alas, I might estimate 5 outgroup members to have heard of Hoca Camide and miss the target by 5.
With arbitrary groups (i.e., randomly assigned group members), the typical pattern of differential projection produces differential accuracy (DiDonato et al., 2011). In general, the effect of projection depends on the prototypicality of the judge for the groups to which she projects. Even with large mean differences of 1 standard deviation, the distributions of two groups will overlap (Figure 4). Therefore, in a low-warmth-high-competence group, there will be people who are high on warmth and low on competence. For these people, projection makes for inaccurate perceptions of the ingroup and accurate perceptions of the high-warmth-low-competence outgroup (cf. Koch et al., 2024).
Figure 4
This is not the Monte Verità.
Are two examples sufficient to claim that projection probably explains everything? Here’s another one. Self-enhancement is the tendency to view oneself as better than others (see also Liang et al., 2024, in this collection). According to Joachim’s Inductive Reasoning Model, self-enhancement is equal to self-positivity × (1 – projection_to_ingroup). That’s right, the more people project, the less they can claim they are better than others. It may offer them consolation that by projecting more strongly to the ingroup, they are also making their ingroup look better than outgroups. But that’s only if they stick to the low default value for projection to outgroups.
Thus, projection can turn a society of self-enhancing and ingroup-favoring people into a hippie festival where we love ourselves, but not more than others. It would also challenge Heck et al.’s (2024, this collection) robust finding that those who are less socially intelligent than others claim to be more socially intelligent than others. What is more, in this utopia, there are no social dilemmas. Because maximal projection eliminates unilateral outcomes (i.e. the grey boxes in Figure 5), people merely have to recognize the higher value of mutual cooperation compared with mutual defection (Krueger et al., 2012). Fiedler (2024, this collection) calls this mechanism “Thurstonian sampling”, probably because Lewis Thurstone was such a clever guy.
Figure 5
The Projecting Prisoner’s Non-Dilemma.
In case you are still not convinced that projection probably explains everything, please have a look at Table 1 for further explananda.
Table 1
Selected Explananda of Projection.
| EXPLANANDUM | SOURCE | ROLE OF PROJECTION |
|---|---|---|
| Ingroup Favoritism | Krueger et al. (2024) | Differential projection makes ingroups look more positive than outgroups for people with positive self-images |
| Differential Accuracy | Krueger et al. (2024) | Differential projection makes (prototypical) group members perceive their ingroup more accurately than outgroups |
| Self-Enhancement | Krueger et al. (2024) | Projection reduces self-enhancement |
| Cooperation | Krueger et al. (2012) | Projection induces cooperation by focusing attention on mutual outcomes in a social dilemma |
| Voting | Acevedo & Krueger (2004) | Like projection induces cooperation in general, the voter’s illusion increases turnout |
| Overvolunteering | Krueger et al. (2016) | Projection introduces inefficiencies into a Volunteer’s Dilemma |
| Diachronic Self-Perception | Ullrich et al. (2025) | Differential projection predicts subjective growth |
The teaches of Joachim
A look into Joachim’s CV will reveal that I have only presented a small sample of his voluminous work on projection, which in turn is only one of the topics on his agenda, e.g. we didn’t talk about his debunking of the Dunning-Kruger-Effect (Krueger & Mueller, 2002), his work on null hypothesis significance testing (Krueger, 2001; Krueger & Heck, 2017, 2018, 2019), or his being involved in explosive work on the self-esteem myth (Baumeister et al., 2005).
There must be a recipe for being so productive. The Inductive Reasoning Model gives some clues about the ingredients. Despite some limitations (e.g., Johnson, 2024; Ullrich & Sebben, 2024), within-subject correlations provide a simple and intuitive metric for representing a host of social perception phenomena. The links between these phenomena are not always obvious, but expressing them as within-subject correlations or derivatives thereof, with the self as the common root, allowed Joachim to build an integrative model that makes precise predictions.
Thinking systematically certainly helps, but it would not succeed without creativity in designing simple experiments (Figure 6). A compelling example is the “last-minute intrigue” paradigm, in which prisoner’s dilemma players are offered the opportunity to switch their decisions. Joachim considered nine different hypotheses the classic prisoner’s dilemma cannot discriminate; results from the last-minute-intrigue variant uniquely supported the projection hypothesis (Krueger et al., 2012). Finally, Joachim does not neglect reading what others have written. Innumerable book reviews for the American Journal of Psychology (in which he would observe what authors complain about and then see if they commit the same fallacy) prove this point, as does the fact that he often pits his hypotheses not only against some null hypothesis, but enters them into competition with what other theories would predict.
Figure 6
Joachim as a Confederate (Krüger & Möller, 1982).
The life of many a scholar is filled with years of non-academic work and leisure. Galton travelled, went fishing and hunting for years. Heider installed burglar alarms for a living. Krueger has the habit of renting cars for extended tours through Europe, occupying his mind with such seemingly trivial things as the design of hotel room showers (Krueger, 2011). So let me add a deep, childlike curiosity to the recipe, the will to make sense of details others fail to notice. And of course, a “Westphälischer Dickschädel” (westphalian thick scull; anonymous attendee of the Festschrift), letting him pursue his own ideas and persist.
I conclude this Editorial by copying a strategy Joachim used for his Introduction to the Festschrift for Robyn Dawes (Krueger, 2008). I asked attendees of the Festschrift held at Monte Verità to send me two paragraphs, one about the impact Joachim had on them personally, and one about Joachim’s most important intellectual impact. Below I reproduce a few of the paragraphs without attributing them to their author.
Joachim, attendees of the Festschrift, your colleagues and friends on both sides of the Atlantic, we all take our hats off to you!
Anonymous comments on Joachim’s impact and contributions
Intellectual impact
“The importance of theory, theory, theory (Repeat)”
“It’s no easy task to single out just one of JK’s contributions — his intellectual curiosity branches wide, and from this came a manifold nameworthy intellectual contributions to the field. His research on social projection and social dynamics in dyadic games stands out as an apparent landmark. Yet, for me, the most noteworthy contribution is his thinking on uncertainty and risk in the social context, precisely because so few have ventured into it. I only truly grasped how impactful the differentiation of uncertainty and risk is – and that the latter is rarely found in any social interaction while the former inhabits every social interaction one can name – when we co-authored a book chapter on the social uncertainties of Alexei Ivanovich’s tragic life.”
“Joachim Krueger’s work on the false consensus effect offered a more nuanced and constructive understanding of how people perceive social consensus. Challenging the traditional view that the false consensus effect reflects cognitive bias or egocentric distortion, Joachim argued that these perceptions often arise from reasonable inferences based on one’s social environment and limited information. His research emphasized that such judgments can be adaptive and statistically grounded, rather than simply erroneous. By reframing the phenomenon in this way, Joachim advanced a more balanced perspective on human judgment and contributed to a broader reevaluation of how psychological “biases” are interpreted in social cognition.”
Personal impact
“I really admire Joachim’s sharp theoretical thinking, his meticulous approach, and his fearless intellectual independence. These aren’t just impressive qualities—they’re something we can all learn from, whether we’re just starting out or have been around for a while. Joachim’s a true maverick—in the best possible way!”
“JK has been the mentor in my life so far. He has accompanied me through my whole academic journey, shaping so many opportunities on the professional side of things. He challenged me a lot, and backed me up when it was tough. However, I’m most grateful for the personal companionship, not just being the mentor but a close friend. Hoca would probably muse about how it all began with a single email about an idea for expertise levels in decision-making. Now we are here.”
“Many years ago I, I was seeking a seat at a table for a conference dinner when I was fortunate to find one at the table where Mark Alicke seemed engaged in an intense conversation with someone whom I did not know. They invited me to join, and immediately resumed their conversation. From the first minute on, however, they made friendlily sure to include me in it. And so, over the starter and the main course we chatted away about, not precisely in that order and by far not clearly delineated, psychological theories, gyms, academic life, religion, food, families, Europe, and beer. Because of the natural manner in which they had drawn me into their conversation, we never really introduced ourselves. By dessert time we slowly circled back to psychology and to research that each of us had done… which was when it dawned on me that Mark’s friend must be Joachim Krueger. Of course, I shared that insight with my table companions. The announcement that he was Joachim Krueger did not exactly surprise Joachim himself (Strangely enough, he seems to have known that), although it greatly surprised Mark that the two of us had never met before. Needless to say, the conversation became even more vivid after that. Little did I know that this first meeting was absolutely representative of who and how Joachim is. Passionate about psychology, but always also making the time to also celebrate the treasures of culture, enjoy the good things of life, and revel in the company of others. An academic who, no matter how hard he works, never forgets to live. Who is not afraid to choose his own path in life but who generously shares the views that he thus discovers with others. For whom the adagio ‘strangers are friends whom you have not yet have had the chance to meet’ is far more than a cliché… and who keeps a genuine interest in the work and well-being of others, even when, by all reasonable standards, it would be fair to say that his own scientific merit towers high above theirs. To me, Joachim is the living image of the insight that one can be a dedicated academic and still be a Mensch.”
“Joachim took me on as a ‘wildcard’ admit into the PhD program at Brown (n.b., this is an inference I made that was never confirmed). In my first official meeting with Joachim he fist-bumped my puns and chided my statistical copy. Six years later he was chiding my puns and fist-bumping yet another journal acceptance. Joachim’s personal impact on me cannot be overstated, and this is not a false alarm. Under his mentorship I was able to travel to Austria and Germany. To SPP and SPSP. To SJDM and ASA. And to conduct rigorous, curious social science research at Ivies, hospital systems, and the federal government. Today I exclaim new ideas with one finger in the air as he would in his office during our exchanges. I regularly speak up when the food is terrible and the portions are too small. And I always remind my junior colleagues to “keep the faith” when the right answer is elusive. Thank you, Joachim, for your investment in me as a student, a colleague, and a friend.”
Competing Interests
The author has no competing interests to declare.