Nothing Personal: What Psychologists Get Wrong about Identity

Which kind of sameness? Disambiguating two senses of identity with a novel linguistic task

When people report that a person's identity has changed, what do they mean by this? Recent research has often assumed that participants are indicating a change in numerical, rather than qualitative, identity. Investigations into this matter have been hampered by the fact that English has no clear way to demarcate one type of identity from the other. To resolve this matter, we develop and test a novel task in Lithuanian, which has lexical markers for numerical and qualitative identity. We apply this task to intuitions about changes in moral capacities, which has previously shown to lead to high ratings in identity change. We discover that, when people say that a morally altered person is dramatically different, they mean the person is qualitatively transformed, but numerically intact. We conclude that this methodology is a valuable tool not only for illuminating the specific phenomenon of the moral self, but for general use in studying folk ascriptions of identity persistence.

Do Obligations Follow the Mind or Body?

Do you persist as the same person over time because you keep the same mind or because you keep the same body? Philosophers have long investigated this question of personal identity with thought experiments. Cognitive scientists have joined this tradition by assessing lay intuitions about those cases. Much of this work has focused on judgments of identity continuity. But identity also has practical significance: obligations are tagged to one's identity over time. Understanding how someone persists as the same person over time could provide insight into how and why moral and legal obligations persist. In this paper, we investigate judgments of obligations in hypothetical cases where a person's mind and body diverge (e.g., brain transplant cases). We find a striking pattern of results: In assigning obligations in these identity test cases, people are divided among three groups: "body-followers," "mind-followers," and "splitters"-people who say that the obligation is split between the mind and the body. Across studies, responses are predicted by a variety of factors, including mind/body dualism, essentialism, education, and professional training. When we give this task to professional lawyers, accountants, and bankers, we find they are more inclined to rely on bodily continuity in tracking obligations. These findings reveal not only the heterogeneity of intuitions about identity but how these intuitions relate to the legal standing of an individual's obligations.

Not the same same: Distinguishing between similarity and identity in judgments of change

What makes someone the same person over time? There are (at least) two ways of understanding this question: A person can be the same in the sense of being very similar to how they used to be (similarity), or they can be the same in the sense of being the same individual (numerical identity). In recent years, several papers have claimed to explore the commonsense notion of numerical identity. However, we suggest here that these researchers have instead been studying similarity. We develop a novel method that uses simple intuitions about objects to illustrate these two notions of "same person", and then asks which concept applies to instances of personal change. Across 4 studies (N = 2446), we find that these previously documented intuitions are best understood as reflecting judgments about similarity, not identity (Experiments 1 and 2). We then use this method to explore the situations in which participants do perceive a change in numerical identity. We find that when a person's entire brain (Experiments 3 and 4) or soul (Experiment 4) has been replaced with that of another person, the majority of participants judge that numerical identity has changed. However, we also note that a substantial minority of participants denied that identity had changed, opening new questions about the role of the body in intuitive judgments of personal identity.

The Aesthetic Self. The Importance of Aesthetic Taste in Music and Art for Our Perceived Identity

To what extent do aesthetic taste and our interest in the arts constitute who we are? In this paper, we present a series of empirical findings that suggest an Aesthetic Self Effect supporting the claim that our aesthetic engagements are a central component of our identity. Counterfactual changes in aesthetic preferences, for example, moving from liking classical music to liking pop, are perceived as altering us as a person. The Aesthetic Self Effect is as strong as the impact of moral changes, such as altering political partisanship or religious orientation, and significantly stronger than for other categories of taste, such as food preferences (Study 1). Using a multidimensional scaling technique to map perceived aesthetic similarities among musical genres, we determined that aesthetic distances between genres correlate highly with the perceived difference in identity (Study 2). Further studies generalize the Aesthetic Self Effect beyond the musical domain: general changes in visual art preferences, for example from more traditional to abstract art, also elicited a strong Self Effect (Study 3). Exploring the breadth of this effect we also found an Anaesthetic Self Effect. That is, hypothetical changes from aesthetic indifference to caring about music, art, or beauty are judged to have a significant impact on identity. This effect on identity is stronger for aesthetic fields compared to leisure activities, such as hiking or playing video games (Study 4). Across our studies, the Anaesthetic Self Effect turns out to be stronger than the Aesthetic Self Effect. Taken together, we found evidence for a link between aesthetics and identity: we are aesthetic selves. When our tastes in music and the arts or our aesthetic interests change we take these to be transformative changes.

The moral self and moral duties

Recent research has begun treating the perennial philosophical question, “what makes a person the same over time?” as an empirical question. A long tradition in philosophy holds that psychological continuity and connectedness of memories are at the heart of personal identity. More recent experimental work, however, has suggested that persistence of moral character, more than memories, is perceived as essential for personal identity. While there is a growing body of evidence supporting these findings, a recent critique suggests that this research program conflates personal identity with mere similarity. To address this criticism, we explore how loss of someone’s morality or memories influences perceptions of identity change and perceptions of moral duties toward the target of the change. We present participants with a classic “body switch” thought experiment and after assessing perceptions of identity persistence, we present a moral dilemma, asking participants to imagine that one of the patients must die (Study 1) or be left alone in a care home for the rest of their life (Study 2). Our results highlight the importance of the continuity of moral character, suggesting that lay intuitions are tracking (something like) personal identity, not just mere similarity.

Putting your money where your self is: Connecting dimensions of closeness and theories of personal identity

Studying personal identity, the continuity and sameness of persons across lifetimes, is notoriously difficult and competing conceptualizations exist within philosophy and psychology. Personal reidentification, linking persons between points in time is a fundamental step in allocating merit and blame and assigning rights and privileges. Based on Nozick's (1981) closest continuer theory we develop a theoretical framework that explicitly invites a meaningful empirical approach and offers a constructive, integrative solution to current disputes about appropriate experiments. Following Nozick, reidentification involves judging continuers on a metric of continuity and choosing the continuer with the highest acceptable value on this metric. We explore both the metric and its implications for personal identity. Since James (1890), academic theories have variously attributed personal identity to the continuity of memories, psychology, bodies, social networks, and possessions. In our experiments, we measure how participants (N = 1, 525) weighted the relative contributions of these five dimensions in hypothetical fission accidents, in which a person was split into two continuers. Participants allocated compensation money (Study 1) or adjudicated inheritance claims (Study 2) and reidentified the original person. Most decided based on the continuity of memory, personality, and psychology, with some consideration given to the body and social relations. Importantly, many participants identified the original with both continuers simultaneously, violating the transitivity of identity relations. We discuss the findings and their relevance for philosophy and psychology and place our approach within the current theoretical and empirical landscape.

Are future selves treated like others? Comparing determinants and levels of intrapersonal and interpersonal allocations

People often make tradeoffs between current and future benefits. Some research frameworks suggest that people treat the future self as if it were another person, subordinating future needs to current ones just as they might subordinate others' needs to their own. Although people make similar choices for future selves and others in some contexts, it remains unclear whether these behaviors are governed by the same decision policies. So, we identify and compare the unique influence of four relevant factors (need, deservingness, liking, and similarity) on monetary decisions in both the interpersonal and intrapersonal domains. Do people treat the future self and others similarly? Yes and no. Yes, because the influence of these factors on allocations is similar for both types of targets. No, because monetary allocations to the future self are consistently higher than allocations to others. Although the future self is treated like others in some ways, important differences remain that are not fully captured by this analogy.

Addiction, Identity, Morality

Background: Recent literature on addiction and judgments about the characteristics of agents has focused on the implications of adopting a “brain disease” versus “moral weakness” model of addiction. Typically, such judgments have to do with what capacities an agent has (e.g., the ability to abstain from substance use). Much less work, however, has been conducted on the relationship between addiction and judgments about an agent’s identity, including whether or to what extent an individual is seen as the same person after becoming addicted. Methods: We conducted a series of vignette-based experiments (total N = 3,620) to assess lay attitudes concerning addiction and identity persistence, systematically manipulating key characteristics of agents and their drug of addiction. Conclusions: In Study 1, we found that U.S. participants judged an agent who became addicted to drugs as being closer to “a completely different person” than “completely the same person” as the agent who existed prior to the addiction. In Studies 2–6, we investigated the intuitive basis for this result, finding that lay judgments of altered identity as a consequence of drug use and addiction are driven primarily by perceived negative changes in the moral character of drug users, who are seen as having deviated from their good true selves.

Identity Over Time: Perceived Similarity Between Selves Predicts Well-Being 10 Years Later

When individuals feel similar to their future self, they are more likely to delay present gratification and make plans for the long run. But do these feelings of similarity actually correspond with heightened well-being for the future self? Theoretically, making patient decisions in the present could lead to a future self who is better off and thus more satisfied. Alternatively, perceived overlap with the future self could cause people to continually deny themselves pleasures in the present, diminishing satisfaction over time. To adjudicate between these possibilities, we use a 10-year longitudinal data set ( N = 4,963) to estimate how thoughts about one’s future self in an initial survey predict life satisfaction 10 years later. Controlling for initial life satisfaction, greater perceived similarity to the future self is linearly associated with greater life satisfaction 10 years after the original prediction, a finding that is robust to a number of alternative analyses.