Infants' performance in spontaneous-response false belief tasks: A review and meta-analysis

"Don't stop believing" - Decoding belief dynamics in the brain: An ALE meta-analysis of neural correlates in belief formation and updating

Understanding how individuals form and update their beliefs is a fundamental question in cognitive and social psychology. Belief formation (BF) refers to the initial development of an individual's belief, while belief updating (BU) pertains to the revision of existing beliefs in response to contradictory evidence. Although these two processes are often interwoven, they might operate through different neural mechanisms. This meta-analysis aims to synthesize the existing functional magnetic resonance imaging (fMRI) literature on BF and BU, with a particular focus on how BF is investigated. Approaches based on Theory of Mind paradigms, such as False Belief tasks, are often opposed to other approaches, emphasizing the role of individual or situational factors in belief formation. Notably, we propose that this differentiation might reflect the engagement of social and non-social dynamics within belief formation. Activation likelihood estimation (ALE) analysis revealed shared involvement of the Precuneus (PCu) in both BF and BU, while BF specifically engaged the bilateral activation of the Temporo-Parietal Junctions (TPJ). Additionally, social and non-social BF exhibited distinct neural correlates: social BF was associated with activity in the right TPJ, whereas non-social BF relied on the left dorsolateral prefrontal cortex (DLPFC). These findings support the hypothesis that BF and BU operate via partially dissociable neural networks and highlights the role of TPJ and PCu as essential hubs to build-up neural templates and enabling shifts in viewpoint necessary to adapt beliefs.

How young children use manifest emotions and dominance cues to understand social rules: a registered report

Given the complexity of human social life, it is astonishing to observe how quickly children adapt to their social environment. To be accepted by the other members, it is crucial to understand and follow the rules and norms shared by the group. How and from whom do young children learn these social rules? In the experiments, based on the crucial role of affective social learning and dominance hierarchies in simple rule understanding, we showed 15-to-23-month-olds and 3-to-5-year-old children videos where the agents' body size and affective cues were manipulated. In the dominant rule-maker condition, when a smaller protagonist puts an object in one location, a bigger agent reacts with a positive reaction; on the contrary, when the smaller protagonist puts an object in another location, the bigger agent displays a negative reaction. In the subordinate rule-maker condition, the roles are shifted but the agents differ. Toddlers expect the protagonist to follow the rules (based on anticipatory looks), independent of the dominant status of the rule-making agent. Three-to-five-year-old pre-schoolers overall perform at the chance level but expect the protagonist to disobey a rule in the first trial, and obey the rule in the second trial if the rule-maker is dominant.

Altercentric Memory Error at 9 Months But Correct Object Memory by 18 Months Revealed in Infants' Pupil

It was recently proposed that infants have a memory bias for events witnessed together with others. This may allow infants to prioritize relevant information and to predict others' actions, despite limited processing capacities. However, when events occur in the absence of others, for example, an object changes location, this would create altercentric memory errors where infants misremember the object's location where others last saw it. Pupillometry presents a powerful tool to examine the temporal dynamics of such memory biases as they unfold. Here, we showed infants aged 9 (N = 97) and 18 months (N = 79) videos of an agent watching an object move to one of two hiding locations. The object then moved from location A to B, which the agent either missed (leading to her false belief) or witnessed (true belief). The object subsequently reappeared either at its actual or, surprisingly, its initial location. As predicted by the altercentric theory, 9-month-old infants expected the object where the agent falsely believed it to be and not where it really was, as indicated in their pupil dilation. In contrast, 18-month-old infants seemed to remember the object's actual location. Infants' memory errors did not predict correct action anticipation when the agent reached into one of the locations to retrieve the object. This indicates that infants show altercentric memory errors at a young age, which vanish in the second year of life. We suggest that this bias helps young infants to learn from others, but recedes as they become more capable of acting on the world themselves.

The development of children's and adults' use of kinematic cues for visual anticipation and verbal prediction of action

Expectations about how others' actions unfold in the future are crucial for our everyday social interactions. The current study examined the development of the use of kinematic cues for action anticipation and prediction in 3-year-olds, 4-year-olds, 10-year-olds, and adults in two experiments. Participants observed a hand repeatedly reaching for either a close or far object. The motor kinematics of the hand varied depending on whether the hand reached for the close or far object. We assessed whether participants would use kinematic cues to visually anticipate (Experiment 1; N=98) and verbally predict (Experiment 2; N=80) which object the hand was going to grasp. We found that only adults, but not 3- to 10-year-olds, based their visual anticipations on kinematic cues (Experiment 1). This speaks against claims that action anticipations are based on simulating others' motor processes and instead provides evidence that anticipations are based on perceptual mechanisms. Interestingly, 10-year-olds used kinematic cues to correctly verbally predict the target object, and 4-year-olds learned to do so over the trials (Experiment 2). Thus, kinematic cues are used earlier in life for explicit action predictions than for visual action anticipations. This adds to a recent debate on whether or not an implicit understanding of others' actions precedes their ability to verbally reason about the same actions.

Continuity in false belief understanding from 33 to 52 months of age

Conceptual continuity in children's false belief understanding from toddlerhood to childhood was investigated in a longitudinal study of 75 children. Performance in a low-demands false belief task at 33 months of age was significantly correlated with performance in a content false belief task at 52 months independent of language ability and executive function. In contrast, there was no correlation with performance in a location false belief task, which differed from the "Sally-Anne" format of the low-demands task and was high in executive demands. These findings support the view that explicit false belief understanding may be continuous from toddlerhood to childhood and that developmental change may be characterized in terms of enrichment and increasing stability of core conceptual understanding rather than in terms of fundamental change.

Active inference goes to school: the importance of active learning in the age of large language models

Human learning essentially involves embodied interactions with the material world. But our worlds now include increasing numbers of powerful and (apparently) disembodied generative artificial intelligence (AI). In what follows we ask how best to understand these new (somewhat 'alien', because of their disembodied nature) resources and how to incorporate them in our educational practices. We focus on methodologies that encourage exploration and embodied interactions with 'prepared' material environments, such as the carefully organized settings of Montessori education. Using the active inference framework, we approach our questions by thinking about human learning as epistemic foraging and prediction error minimization. We end by arguing that generative AI should figure naturally as new elements in prepared learning environments by facilitating sequences of precise prediction error enabling trajectories of self-correction. In these ways, we anticipate new synergies between (apparently) disembodied and (essentially) embodied forms of intelligence. This article is part of the theme issue 'Minds in movement: embodied cognition in the age of artificial intelligence'.

Verbal Perceptual Prompts Facilitate Children's Sensitivity to False Beliefs

False belief understanding is always regarded as a milestone of Theory of Mind (ToM), which is an important aspect of social intelligence. Recently, some researchers have suggested the existence of two ToM systems in individuals: one that explicitly guides false belief understanding and another that implicitly directs sensitivity to false beliefs. However, studies on sensitivity to false beliefs have encountered challenges with replicability, and the factors influencing the manifestation of sensitivity to false beliefs remain to be explored. Based on the anticipatory looking task, we investigated whether verbal perceptual prompts could improve children's performance of sensitivity to false beliefs. Fifty-eight children aged 5 to 6 were randomly assigned tasks with or without verbal perceptual prompts, involving verbal descriptions and explanations of the protagonist's perceptual state. The findings showed that verbal perceptual prompts could slightly reduce children's propensity to look at the actual location of the object in false belief situations and increase the likelihood of exhibiting accurate anticipatory looking patterns across false belief and true belief situations. The results suggest that children's sensitivity to false beliefs may be situation-dependent, yet further investigation is needed to determine which situational factors can most effectively trigger robust sensitivity to false beliefs in children. The results enlighten educational practice, indicating that introducing cues in social environments that convey insights into others' mental states, akin to the use of learning scaffolding, is advantageous for the development of children's social cognitive abilities.

Reading minds or reading scripts? De-intellectualising theory of mind

Understanding the origins of human social cognition is a central challenge in contemporary science. In recent decades, the idea of a 'Theory of Mind' (ToM) has emerged as the most popular way of explaining unique features of human social cognition. This default view has been progressively undermined by research on 'implicit' ToM, which suggests that relevant precursor abilities may already be present in preverbal human infants and great apes. However, this area of research suffers from conceptual difficulties and empirical limitations, including explanatory circularity, over-intellectualisation, and inconsistent empirical replication. Our article breaks new ground by adapting 'script theory' for application to both linguistic and non-linguistic agents. It thereby provides a new theoretical framework able to resolve the aforementioned issues, generate novel predictions, and provide a plausible account of how individuals make sense of the behaviour of others. Script theory is based on the premise that pre-verbal infants and great apes are capable of basic forms of agency-detection and non-mentalistic goal understanding, allowing individuals to form event-schemata that are then used to make sense of the behaviour of others. We show how script theory circumvents fundamental problems created by ToM-based frameworks, explains patterns of inconsistent replication, and offers important novel predictions regarding how humans and other animals understand and predict the behaviour of others.

Empirical challenges from the comparative and developmental literature to the Shared Intentionality Theory - a review of alternative data on recursive mind reading, prosociality, imitation and cumulative culture

Humans have an irresistible inclination to coordinate actions with others, leading to species-unique forms of cooperation. According to the highly influential Shared Intentionality Theory (SITh), human cooperation is made possible by shared intentionality (SI), typically defined as a suite of socio-cognitive and motivational traits for sharing psychological states with others, thereby enabling individuals to engage in joint action in the mutually aware pursuit of shared goals. SITh theorises that SI evolved as late as 400,000 years ago, when our ancestors (in particular, Homo heidelbergensis) turned to a kind of food procurement that obligatorily required joint coordinated action. SI is, thus, hypothesized to be absent in other extant species, including our closest genetic relatives, the nonhuman great apes ("apes"). According to SITh, ape psychology is exclusively driven by individualistic motivations, as opposed to human psychology which is uniquely driven by altruistic motivations. The evolutionary scenario proposed by SITh builds on a series of findings from socio-cognitive research with apes and human children, and on the assumption that abilities expressed early in human development are human universals, unlikely to have been shaped by socio-cultural influences. Drawing on the primatological and developmental literature, we provide a systematic - albeit selective - review of SITh-inconsistent findings concerning psychological and behavioural traits theorised to be constitutive of SI. The findings we review pertain to all three thematic clusters typically addressed in SITh: (i) recursive mind reading; (ii) prosociality; (iii) imitation and cumulative culture. We conclude that such alternative data undermine two core SITh claims: the late evolutionary emergence of SI and the radical divide between ape and human psychology. We also discuss several conceptual and methodological limitations that currently hamper reliable comparative research on SI, in particular those engendered by Western-centric biases in the social sciences, where an overreliance on Western samples has promoted the formulation of Western-centric conceptualisations, operationalisations and methodologies.

Differences in self-other control as cognitive mechanism to characterize theory of mind reasoning in autistic and non-autistic adults

In cognitive science, altered Theory of Mind is a central pillar of etiological models of autism. Yet, recent evidence, showing comparable Theory of Mind abilities in autistic and non-autistic people, draws a more complex picture and renders previous descriptions of Theory of Mind abilities in autism and their role in autistic symptomatology insufficient. Here, we addressed self-other control as a potential candidate cognitive mechanism to explain subtle Theory of Mind reasoning differences between autistic and non-autistic adults. We investigated flexible shifting between another's and one's own congruent or incongruent points of view, an ability that is important for reciprocal social interaction. Measuring response accuracy and reaction time in a multiple-trial unexpected location false belief task, we found evidence for altered self-other control in Theory of Mind reasoning in autistic adults, with a relative difficulty in flexibly considering the other's perspective and less interference of the other's incongruent viewpoint when their own perspective is considered. Our results add to previous findings that social cognitive differences are there but subtle and constitute one step further in characterizing Theory of Mind reasoning in autism and explaining communication and interaction difficulties with non-autistic people in everyday life.

How robust are egocentric and altercentric interference effects in social cognition? a test with explicit and implicit versions of a continuous false belief task

It has been long assumed that meta-representational theory of mind (ToM) -our ability to ascribe mental states to ourselves and other people- emerges around age four as indicated in performance on explicit verbal false belief tasks. In contrast, newer studies assessing false belief understanding with implicit, non-verbal measures suggest that some form of ToM may be present even in infancy. But these studies now face replication issues, and it remains unclear whether they can provide robust evidence for implicit ToM. One line of research on implicit ToM, however, may remain promising: Studies that tap so-called altercentric biases. Such biases occur when agents in their judgments about the world are influenced (perform slower, more error-prone) in light of another agent's deviating perspective even if that perspective is completely irrelevant to the task; they thus can be seen as indicators of spontaneous and implicit ToM. Altercentric biases are the mirror images of egocentric biases (agents are influenced by their own perspective when evaluating another agent's deviating perspective). In three studies with adults, we aimed to tap both egocentric and altercentric interference effects within the same task format. We used the so-called Sandbox task, a false belief task with continuous locations. In Study 1, we tested an online adaptation of the Sandbox task, which we also used to explore potential cross-cultural differences in these biases. Studies 2 and 3 combined the Sandbox task with mouse-tracking measures. These studies revealed neither egocentric nor altercentric biases. These null results are discussed with regard to the question whether absence of evidence here may present evidence of absence of such spontaneous perspective-taking biases or merely false negatives.

Theory of mind tested by implicit false belief: a simple and full-fledged mental state attribution

About 40 years have passed since 'theory of mind (ToM)' research started. The false-belief test is used as a litmus test for ToM ability. The implicit false-belief test has renewed views of ToM in several disciplines, including psychology, psychiatry, and neuroscience. Many important questions have been considered via the paradigm of implicit false belief. We recently addressed the phylogenetic and physiological aspects of ToM using a version of this paradigm combined with the chemogenetic technique on Old World monkeys. We sought to create animal models for autism that exhibit behavioral phenotypes similar to human symptoms. The simultaneous manipulation of neural circuits and assessments of changes in phenotypes can help identify the causal neural substrate of ToM.

Seeing the World From Others' Perspective: 14-Month-Olds Show Altercentric Modulation Effects by Others' Beliefs

Humans have a propensity to readily adopt others' perspective, which often influences their behavior even when it seemingly should not. This altercentric influence has been widely studied in adults, yet we lack an understanding of its ontogenetic origins. The current studies investigated whether 14-month-olds' search in a box for potential objects is modulated by another person's belief about the box's content. We varied the person's potential belief such that in her presence/absence an object was removed, added, or exchanged for another, leading to her true/false belief about the object's presence (Experiment 1, n = 96); or transformed into another object, leading to her true/false belief about the object's identity (i.e., the objects represented under a specific aspect, Experiment 2, n = 32). Infants searched longer if the other person believed that an object remained in the box, showing an altercentric influence early in development. These results suggest that infants spontaneously represent others' beliefs involving multiple objects and raise the possibility that infants can appreciate that others encode the world under a unique aspect.

Evidence for goal- and mixed evidence for false belief-based action prediction in two- to four-year-old children: A large-scale longitudinal anticipatory looking replication study

Unsuccessful replication attempts of paradigms assessing children's implicit tracking of false beliefs have instigated the debate on whether or not children have an implicit understanding of false beliefs before the age of four. A novel multi-trial anticipatory looking false belief paradigm yielded evidence of implicit false belief reasoning in three- to four-year-old children using a combined score of two false belief conditions (Grosse Wiesmann, C., Friederici, A. D., Singer, T., & Steinbeis, N. [2017]. Developmental Science, 20(5), e12445). The present study is a large-scale replication attempt of this paradigm. The task was administered three times to the same sample of N = 185 children at two, three, and four years of age. Using the original stimuli, we did not replicate the original finding of above-chance belief-congruent looking in a combined score of two false belief conditions in either of the three age groups. Interestingly, the overall pattern of results was comparable to the original study. Post-hoc analyses revealed, however, that children performed above chance in one false belief condition (FB1) and below chance in the other false belief condition (FB2), thus yielding mixed evidence of children's false belief-based action predictions. Similar to the original study, participants' performance did not change with age and was not related to children's general language skills. This study demonstrates the importance of large-scaled replications and adds to the growing number of research questioning the validity and reliability of anticipatory looking false belief paradigms as a robust measure of children's implicit tracking of beliefs. This article is protected by copyright. All rights reserved.

The Neurological Asymmetry of Self-Face Recognition

While the desire to uncover the neural correlates of consciousness has taken numerous directions, self-face recognition has been a constant in attempts to isolate aspects of self-awareness. The neuroimaging revolution of the 1990s brought about systematic attempts to isolate the underlying neural basis of self-face recognition. These studies, including some of the first fMRI (functional magnetic resonance imaging) examinations, revealed a right-hemisphere bias for self-face recognition in a diverse set of regions including the insula, the dorsal frontal lobe, the temporal parietal junction, and the medial temporal cortex. In this systematic review, we provide confirmation of these data (which are correlational) which were provided by TMS (transcranial magnetic stimulation) and patients in which direct inhibition or ablation of right-hemisphere regions leads to a disruption or absence of self-face recognition. These data are consistent with a number of theories including a right-hemisphere dominance for self-awareness and/or a right-hemisphere specialization for identifying significant social relationships, including to oneself.

Specifying links between infants' theory of mind, associative learning, and selective trust

The psychological mechanisms underlying infants' selective social learning are currently a subject of controversy. The main goal of the present study was to contribute data to this debate by investigating whether domain-specific or domain-general abilities guide infants' selectivity. Eighteen-month-olds observed a reliable and an unreliable speaker, and then completed a forced-choice word learning paradigm, two theory of mind tasks, and an associative learning task. Results revealed that infants showed sensitivity to the verbal competence of the speaker. Additionally, infants with superior knowledge inference abilities were less likely to learn from the unreliable speaker. No link was observed between selective social learning and associative learning skills. These results replicate and extend previous findings demonstrating that socio-cognitive abilities are linked to infants' selective social learning.

Implicit Theory of Mind under realistic social circumstances measured with mobile eye-tracking

Recently, there has been a debate whether implicit Theory of Mind can be reliably measured using anticipatory looking tasks. Previous anticipatory looking paradigms used video stimuli to measure implicit Theory of Mind; however, numerous replications of these paradigms were unsuccessful. This lack of replications may be due to video stimuli not being sufficiently engaging. As Theory of Mind is an inherently social phenomenon, robust evidence might only be observed in a real social situation. Therefore, the current preregistered study aimed to test anticipatory looking with real-life social stimuli. A mobile eye-tracker was used to measure gaze patterns indicative of Theory of Mind while participants observed a real-life interaction of an experimenter and a confederate. The realistic scenario did not provide clear evidence for implicit Theory of Mind. Furthermore, anticipatory looking behavior did not reliably occur during familiarization trials, in line with previous research. However, looking patterns were slightly more in line with belief tracking than in some more controlled studies using video stimuli. In general, implicit Theory of Mind was not reliably reflected in anticipatory looking patterns even if they were measured in realistic social situations. This questions the suitability of anticipatory looking measures for implicit Theory of Mind.

Naïve Theories of Biology, Physics, and Psychology in Children with ASD

Theory of mind is defined as the understanding that mental states predict and explain people's behaviors. It develops around the age of 4 but seems to remain deficient in people with ASD, whereas other forms of naïve understanding remain intact. This study compares children with ASD to neurotypical children on tasks measuring naïve psychology, physics, and biology (biological parts). Results suggest that children with ASD only underperform on an implicit false belief task. Performances in naïve biology and physics were equivalent across the two groups and uncorrelated to performance on the false belief task. This confirms that naïve physics and biological reasoning are intact in children with ASD but that tracking false beliefs is challenging for this population.

Infants' performance in the indirect false belief tasks: A second-person interpretation

Research in the last 15 years has challenged the idea that false belief attribution develops at 4 years of age. Studies with indirect false belief tasks contend to provide evidence of false belief attribution in the second year of life. We review the literature on indirect false belief tasks carried out in infants using looking and active helping paradigms. Although the results are heterogeneous and not conclusive, such tasks appear to capture a real effect. However, it is misleading to call them “false belief” tasks, as it is possible to pass them without making any false belief attribution. Infants need to keep track of the object's and agent's positions, trajectories, and focus of attention, given an intentional understanding of the agent, to pass these new tasks. We, therefore, argue that the evidence can be better explained in terms of second‐person attributions, which are transparent, extensional, nonpropositional, reciprocally contingent, and implicit. Second‐person attributions can also account for primates' mentalizing abilities, as revealed by similar indirect tasks.

This article is categorized under:

Cognitive Biology > Cognitive Development

Philosophy > Foundations of Cognitive Science

Cognitive Biology > Evolutionary Roots of Cognition

Testing the stability of theory of mind: A longitudinal approach

An explicit understanding of false belief develops around the age of four years. However, tasks based on spontaneous responses have revealed an implicit understanding of belief and other theory of mind constructs in infants in their second year of life. The few longitudinal studies that have examined conceptual continuity of theory of mind from infancy to early childhood have reported mixed findings. Here we report two longitudinal experiments to investigate the developmental relation between implicit and explicit theory of mind. No link was observed in the first experiment between false belief and intention understanding measured at 14 and 18 months with the violation of expectation paradigm and tasks measuring explicit and implicit false belief at four or five years of age. In the second experiment, infants aged 18 months were tested with a battery of tasks that measured knowledge inference and false belief. They were then tested with the theory of mind scale at five years of age. The parents completed the Children's Social Understanding Scale (CSUS) and the Social Communication Questionnaire (SCQ). As in the first experiment, there were no associations between early and later forms of theory of mind. We suggest that these findings do not support the view that there is conceptual continuity in theory of mind development.

Vicarious representation: A new theory of social cognition

Theory of mind, the attribution of mental states to others is one form of social cognition. The aim of this paper is to highlight the importance of another, much simpler, form of social cognition, which I call vicarious representation. Vicarious representation is the attribution of other-centered properties to objects. This mental capacity is different from, and much simpler than, theory of mind as it does not imply the understanding (or representation) of the mental (or even perceptual) states of another agents. I argue that the most convincing experiments that are supposed to show that non-human primates have theory of mind in fact demonstrate that they are capable of vicarious representation. The same is true for the experiments about the theory of mind of infants under 12 months.

Analogical Comparison Promotes Theory-of-Mind Development

Theory-of-mind (ToM) is an integral part of social cognition, but how it develops remains a critical question. There is evidence that children can gain insight into ToM through experience, including language training and explanatory interactions. But this still leaves open the question of how children gain these insights-what processes drive this learning? We propose that analogical comparison is a key mechanism in the development of ToM. In Experiment 1, children were shown true- and false-belief scenarios and prompted to engage in multiple comparisons (e.g., belief vs. world). In Experiments 2a, 2b, and 3, children saw a series of true- and false-belief events, varying in order and in their alignability. Across these experiments, we found that providing support for comparing true- and false-belief scenarios led to increased performance on false-belief tests. These findings show that analogical comparison can support ToM learning.

Theory of mind development: State of the science and future directions

This chapter offers a brief overview of how research on theory of mind development has developed over the recent years, with a focus on current research and theoretical accounts of theory of mind during the infancy period. The topics covered include the factors contributing to individual differences in theory of mind skills in preschoolers, the current replication crisis in theory of mind in infancy, the stability of theory of mind from infancy to childhood, and recent research suggesting that infants' concept of false belief is, at best, immature (e.g., overattribution to inanimate agents). Future directions in theory of mind research are suggested.

Do Non-Human Primates Really Represent Others' Beliefs?

Over two decades of research have produced compelling evidence that non-human primates understand some psychological states in other individuals but are unable to represent others' beliefs. Recently, three studies employing anticipatory looking (AL) paradigms reported that non-human primates do show hints of implicitly understanding the beliefs of others. However, measures of AL have been increasingly scrutinized in the human literature owing to extensive replication problems. We argue that new reports of belief representation in non-human primates using AL should be interpreted cautiously because of methodological and theoretical challenges paralleling trends in the human literature. We explore how future work can address these challenges, and conclude by identifying new evolutionary questions raised by the prospect that non-human primates implicitly represent others' beliefs without an explicit belief representation system that guides fitness-relevant behavior.

The Lens Shapes the View: on Task Dependency in ToM Research

Purpose of Review

This article provides an overview of current findings on Theory of Mind (ToM) in human children and adults and highlights the relationship between task specifications and their outcome in socio-cognitive research.

Recent Findings

ToM, the capacity to reason about and infer others’ mental states, develops progressively throughout childhood—the exact time course is still a matter of debate. Neuroimaging studies indicate the involvement of a widespread neuronal network during mentalizing, suggesting that ToM is a multifaceted process. Accordingly, the tasks and trainings that currently exist to investigate and enhance ToM are heterogeneous, and the outcomes largely depend on the paradigm that was used.

Summary

We argue for the implementation of multiple-task batteries in the assessment of socio-cognitive abilities. Decisions for a particular paradigm need to be carefully considered and justified. We want to emphasize the importance of targeted research on the relationship between task specifications and outcomes.

Perioperative Sleep Disturbances and Postoperative Delirium in Adult Patients: A Systematic Review and Meta-Analysis of Clinical Trials

Background: The aim of this systematic review and meta-analysis of clinical trials was to investigate the effects of perioperative sleep disturbances on postoperative delirium (POD). Methods: Authors searched for studies (until May 12, 2020) reporting POD in patients with sleep disturbances following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results: We identified 29 relevant trials including 55,907 patients. We divided these trials into three groups according to study design: Seven retrospective observational trials, 12 prospective observational trials, and 10 randomized controlled trials. The results demonstrated that perioperative sleep disturbances were significantly associated with POD occurrence in observational groups [retrospective: OR = 0.56, 95% CI: [0.33, 0.93], I ² = 91%, p for effect = 0.03; prospective: OR = 0.27, 95% CI: [0.20, 0.36], I ² = 25%, p for effect < 0.001], but not in the randomized controlled trial group [OR = 0.58, 95% CI: [0.34, 1.01], I ² = 68%, p for effect = 0.05]. Publication bias was assessed using Egger's test. We used a one-by-one literature exclusion method to address high heterogeneity. Conclusions: Perioperative sleep disturbances were potential risk factors for POD in observational trials, but not in randomized controlled trials.