A taxonomy of mental time travel and counterfactual thought: Insights from cognitive development

The recursive grammar of mental time travel

One apparent feature of mental time travel is the ability to recursively embed temporal perspectives across different times: humans can remember how we anticipated the future and anticipate how we will remember the past. This recursive structure of mental time travel might be formalized in terms of a 'grammar' that is reflective of but more general than linguistic notions of absolute and relative tense. Here, I provide a foundation for this grammatical framework, emphasizing a bounded (rather than unbounded) recursive function that supports mental time travel to a limited temporal depth and to actual and possible scenarios. Anticipated counterfactual thinking, for instance, entails three levels of mental time travel to a possible scenario ('in the future, I will reflect on how my past self could have taken a different future action') and is centrally implicated in complex human decision-making. This perspective calls for further research into the mechanisms, ontogeny, functions and phylogeny of recursive mental time travel, and revives the question of links with other recursive forms of thinking such as theory of mind. This article is part of the theme issue 'Elements of episodic memory: lessons from 40 years of research'.

An investigation of the effect of logical structures on Chinese preschool children's counterfactual reasoning development

Counterfactual reasoning helps people to learn from the past to prepare for the future. In contrast to English with counterfactual markers that directly signal counterfactual reasoning, Mandarin Chinese indicates counterfactual reasoning by counterfactuality enhancers, which enhance rather than directly signal entry into the counterfactual realm. There are more counterfactuality enhancers in subtractive than additive counterfactual premises. Hence, Chinese-speaking children might more readily interpret subtractive than additive counterfactual premises, leading to better performance on subtractive than additive counterfactual reasoning tasks. This difference between logical structures might be larger in Chinese than English, as English has counterfactual markers, which enable direct inference of counterfactuality regardless of logical structures. Consistent with these propositions, in two experiments, the present study found that Chinese preschool children's accuracy was significantly higher for subtractive than additive counterfactual reasoning. Also, the difference between logical structures was much larger compared to a previous study in UK children using a similar counterfactual reasoning task. Hence, the use of counterfactuality enhancers in Chinese might shape a developmental difference between subtractive and additive counterfactual reasoning. Parents and teachers may attend to this developmental pattern when scaffolding children's counterfactual reasoning growth.

Children cooperate more with in-group members than with out-group members in an iterated face-to-face Prisoner's Dilemma Game

Adults are more likely to cooperate with in-group members than with out-group members in the context of social dilemmas, situations in which self-interest is in conflict with collective interest. This bias has the potential to profoundly shape human cooperation, and therefore it is important to understand when it emerges in development. Here we asked whether 6- to 9-year-old children (N = 146) preferentially cooperate with in-group members in the context of a well-studied social dilemma, the iterated Prisoner's Dilemma Game. We assigned children to minimal groups and paired them with unfamiliar same-age and same-gender peers. Consistent with our predictions, children were more likely to cooperate with in-group members than with out-group members in this minimal group context. This finding adds to the current literature on group bias in children's prosocial behavior by showing that it affects decision making in a context that calls on strategic cooperation. In addition, our analyses revealed an effect of gender, with girls more likely to cooperate than boys regardless of the group membership of their partner. Exploring this gender effect further, we found an interaction between gender and age across condition, with older girls showing less sensitivity to the group membership of their partner than younger girls and with older boys showing more sensitivity to the group membership of the partner than younger boys. Our findings suggest that risky cooperation in the face of social dilemmas is shaped by group bias during childhood, highlighting the potentially deeply rooted ties between cooperation and parochialism in humans.

Young children experience both regret and relief in a gain-or-loss context

Recent research has provided compelling evidence that children experience the negative counterfactual emotion of regret, by manipulating the presence of a counterfactual action that would have led to participants receiving a better outcome. However, it remains unclear if children similarly experience regret's positive counterpart, relief. The current study examined children's negative and positive counterfactual emotions in a novel gain-or-loss context. Four- to 9-year-old children (N = 136) were presented with two opaque boxes concealing information that would lead to a gain or loss of stickers, respectively. Half of the children chose between two keys that matched each box, whereas the other half were compelled to select one box because only one of the two keys matched. After seeing inside the alternative, non-chosen box, children were significantly more likely to report a change in emotion when they could have opened that box than when they could not have. The effects were similar for children who lost stickers and won stickers, and neither effect varied with age. These findings suggest that children may become capable of experiencing regret and relief around the same time, although their expression of these counterfactual emotions may vary with actual and counterfactual gains and losses.

Why imagining what could have happened matters for children's social cognition

Counterfactual thinking is a relatively late emerging ability in childhood with key implications for emerging social cognition and behavior.

Counterfactual choices and moral judgments in children

When making moral judgments of past actions, adults often think counterfactually about what could have been done differently. Considerable evidence suggests that counterfactual thinking emerges around age 6, but it remains unknown how this development influences children's moral judgments. Across two studies, Australian children aged 4-9 (N = 236, 142 Females) were told stories about two characters who had a choice that led to a good or bad outcome, and two characters who had no choice over a good or bad outcome. Results showed that 4- and 5-year-olds' moral judgments were influenced only by the actual outcome. From age 6, children's moral judgments were also influenced by the counterfactual choices that had been available to the characters.

A plausible role of imagination in pretend play, counterfactual reasoning, and executive functions

A notable observation is the similarities in the cognitive processes of pretend play (PP) and counterfactual reasoning (CFR) as both involve thinking about alternatives to reality. It is argued by Weisberg and Gopnik (Cogn. Sci., 37, 2013, 1368) that alternative thinking in PP and CFR is underpinned by an imaginary representational capacity but few studies have empirically investigated this link. We use a variable latent modelling approach to test a hypothetical model of the structural relationship of PP and CFR predicting that if PP and CFR are cognitively similar; they should have similar patterns of associations with Executive Functions (EFs). Data were collected on PP, CFR, EFs and Language from 189 children (M = 4.8 years, males = 101, females = 88). Confirmatory factor analyses showed that measures of PP and CFR loaded onto single latent constructs and were significantly correlated (r = .51, p = .001) with each other. Hierarchical multiple regression analyses revealed that EF accounted for unique significant variance in both PP (β = 21) and CFR (β = 22). The results of the structural equation modelling revealed that the data were a good fit for the hypothetical model. We discuss the plausible role of a general underlying imaginative representational capacity to explain similarities in the cognitive mechanisms of different states of alternative thinking like PP and CFR.

Thinking about possibilities: mechanisms, ontogeny, functions and phylogeny

Humans possess the remarkable capacity to imagine possible worlds and to demarcate possibilities and impossibilities in reasoning. We can think about what might happen in the future and consider what the present would look like had the past turned out differently. We reason about cause and effect, weigh up alternative courses of action and regret our mistakes. In this theme issue, leading experts from across the life sciences provide ground-breaking insights into the proximate questions of how thinking about possibilities works and develops, and the ultimate questions of its adaptive functions and evolutionary history. Together, the contributions delineate neurophysiological, cognitive and social mechanisms involved in mentally simulating possible states of reality; and point to conceptual changes in the understanding of singular and multiple possibilities during human development. The contributions also demonstrate how thinking about possibilities can augment learning, decision-making and judgement, and highlight aspects of the capacity that appear to be shared with non-human animals and aspects that may be uniquely human. Throughout the issue, it becomes clear that many developmental milestones achieved during childhood, and many of the most significant evolutionary and cultural triumphs of the human species, can only be understood with reference to increasingly complex reasoning about possibilities. This article is part of the theme issue 'Thinking about possibilities: mechanisms, ontogeny, functions and phylogeny'.

Counterfactual thinking elicits emotional change in young children

Adults often reason about what might have happened had they chosen an alternative course of action in the past, which can elicit the counterfactual emotion of regret. It is unclear whether young children's emotions are similarly impacted by counterfactual thinking about past possibilities. In this study, 4- to 9-year-old children (N = 160) opened one of two boxes, which concealed small and large prizes, respectively. Some children had the means to open either box, whereas other children only had the means to open one box. After seeing that the prize they did not obtain was larger than the one they did obtain, children were significantly more likely to report a negative change in emotion when the non-obtained prize had been a straightforward counterfactual possibility than when it had not. This shows that even young children experience counterfactual emotions following choices, which may ultimately drive them to make better choices in the future. This article is part of the theme issue 'Thinking about possibilities: mechanisms, ontogeny, functions and phylogeny'.

Anchored in the present: preschoolers more accurately infer their futures when confronted with their pasts

People often speculate about what the future holds. They wonder what will happen tomorrow, and what the world will be like in the distant future. Nonetheless, people's ability to consider future possibilities may be restricted when they consider their own futures. Adults show the 'end of history' illusion, believing they have changed more in the past than they will in the future. Further, preschoolers are even more limited in anticipating future change, as 3-year-olds insist their current desires will persist later in life. These findings suggest a deficit in children's and adults' abilities to simulate alternative possibilities that pertain to themselves. However, we report four experiments (n = 233) suggesting otherwise, at least for children. We find that 3-year-olds accurately infer their futures when prompted to consider their past rather than present preferences. Children also succeed at inferring their past preferences when not shown items they currently prefer. This shows that children can reason about their pasts and futures, though this ability is hindered when they are shown items that anchor them to the present. Our findings suggest that children's difficulties with mental time travel reflect a failure to shift away from the present rather than an inability to simulate alternative possibilities. This article is part of the theme issue 'Thinking about possibilities: mechanisms, ontogeny, functions and phylogeny'.

How do children overcome their pragmatic performance problems in the true belief task? The role of advanced pragmatics and higher-order theory of mind

The true belief (TB) control condition of the classical location-change task asks children to ascribe a veridical belief to an agent to predict her action (analog to the false belief (FB) condition to test Theory of Mind (ToM) abilities). Studies that administered TB tasks to a broad age range of children yielded surprising findings of a U-shaped performance curve in this seemingly trivial task. Children before age four perform competently in the TB condition. Children who begin to solve the FB condition at age four, however, fail the TB condition and only from around age 10, children succeed again. New evidence suggests that the decline in performance around age four reflects pragmatic confusions caused by the triviality of the task rather than real competence deficits in ToM. Based on these results, it can be hypothesized that the recovery of performance at the end of the U-shaped curve reflects underlying developments in children's growing pragmatic awareness. The aim of the current set of studies, therefore, was to test whether the developmental change at the end of the U-shaped performance curve can be explained by changes in children's pragmatic understanding and by more general underlying developmental changes in recursive ToM or recursive thinking in general. Results from Study 1 (N = 81, 6-10 years) suggest that children's recursive ToM, but not their advanced pragmatic understanding or general recursive thinking abilities predict their TB performance. However, this relationship could not be replicated in Study 2 (N = 87, 6-10 years) and Study 3 (N = 64, 6-10 years) in which neither recursive ToM nor advanced pragmatic understanding or recursive thinking explained children's performance in the TB task. The studies therefore remain inconclusive regarding explanations for the end of the U-shaped performance curve. Future research needs to investigate potential pragmatic and general cognitive foundations of this developmental change more thoroughly.

Perceptual Access Reasoning (PAR) in Developing a Representational Theory of Mind

An important part of children's social and cognitive development is their understanding that people are psychological beings with internal, mental states including desire, intention, perception, and belief. A full understanding of people as psychological beings requires a representational theory of mind (ToM), which is an understanding that mental states can faithfully represent reality, or misrepresent reality. For the last 35 years, researchers have relied on false‐belief tasks as the gold standard to test children's understanding that beliefs can misrepresent reality. In false‐belief tasks, children are asked to reason about the behavior of agents who have false beliefs about situations. Although a large body of evidence indicates that most children pass false‐belief tasks by the end of the preschool years, the evidence we present in this monograph suggests that most children do not understand false beliefs or, surprisingly, even true beliefs until middle childhood. We argue that young children pass false‐belief tasks without understanding false beliefs by using perceptual access reasoning (PAR). With PAR, children understand that seeing leads to knowing in the moment, but not that knowing also arises from thinking or persists as memory and belief after the situation changes. By the same token, PAR leads children to fail true‐belief tasks. PAR theory can account for performance on other traditional tests of representational ToM and related tasks, and can account for the factors that have been found to correlate with or affect both true‐ and false‐belief performance. The theory provides a new laboratory measure which we label the belief understanding scale (BUS). This scale can distinguish between a child who is operating with PAR versus a child who is understanding beliefs. This scale provides a method needed to allow the study of the development of representational ToM.

In this monograph, we report the outcome of the tests that we have conducted of predictions generated by PAR theory. The findings demonstrated signature PAR limitations in reasoning about the mind during the ages when children are hypothesized to be using PAR. In Chapter II, secondary analyses of the published true‐belief literature revealed that children failed several types of true‐belief tasks.

Chapters III through IX describe new empirical data collected across multiple studies between 2003 and 2014 from 580 children aged 4–7 years, as well as from a small sample of 14 adults. Participants were recruited from the Phoenix, Arizona metropolitan area. All participants were native English‐speakers. Children were recruited from university‐sponsored and community preschools and daycare centers, and from hospital maternity wards. Adults were university students who participated to partially fulfill course requirements for research participation. Sociometric data were collected only in Chapter IX, and are fully reported there.

In Chapter III, minor alterations in task procedures produced wide variations in children's performance in 3‐option false‐belief tasks. In Chapter IV, we report findings which show that the developmental lag between children's understanding ignorance and understanding false belief is longer than the lag reported in previous studies. In Chapter V, children did not distinguish between agents who have false beliefs versus agents who have no beliefs. In Chapter VI, findings showed that children found it no easier to reason about true beliefs than to reason about false beliefs. In Chapter VII, when children were asked to justify their correct answers in false‐belief tasks, they did not reference agents’ false beliefs. Similarly, in Chapter VIII, when children were asked to explain agents’ actions in false‐belief tasks, they did not reference agents’ false beliefs. In Chapter IX, children who were identified as using PAR differed from children who understood beliefs along three dimensions—in levels of social development, inhibitory control, and kindergarten adjustment.

Although the findings need replication and additional studies of alternative interpretations, the collection of results reported in this monograph challenges the prevailing view that representational ToM is in place by the end of the preschool years. Furthermore, the pattern of findings is consistent with the proposal that PAR is the developmental precursor of representational ToM. The current findings also raise questions about claims that infants and toddlers demonstrate ToM‐related abilities, and that representational ToM is innate.

Scientific reasoning and counterfactual reasoning in development

In this chapter, we bridge research on scientific and counterfactual reasoning. We review findings that children struggle with many aspects of scientific experimentation in the absence of formal instruction, but show sophistication in the ability to reason about counterfactual possibilities. We connect these two sets of findings by reviewing relevant theories on the relation between causal, scientific, and counterfactual reasoning before describing a growing body of work that indicates that prompting children to consider counterfactual alternatives can scaffold both the scientific inquiry process (hypothesis-testing and evidence evaluation) and science concept learning. This work suggests that counterfactual thought experiments are a promising pedagogical tool. We end by discussing several open questions for future research.

Temporal Junctures in the Mind

Humans can imagine what happened in the past and what will happen in the future, but also what did not happen and what might happen. We reflect on envisioned events from alternative timelines, while knowing that we only ever live on one timeline. Considering alternative timelines rests on representations of temporal junctures, or points in time at which possible versions of reality diverge. These representations become increasingly sophisticated over childhood, first enabling preparation for mutually exclusive future possibilities and later the experience of counterfactual emotions like regret. By contrast, it remains unclear whether non-human animals represent temporal junctures at all. The emergence of these representations may have been a prime mover in human evolution.