Submentalizing Cannot Explain Belief-Based Action Anticipation in Apes

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.

Evolutionary foundations of knowledge and belief attribution in nonhuman primates

Recent findings from anticipatory-looking false-belief tests have shown that nonhuman great apes and macaques anticipate that an agent will go to the location where the agent falsely believed an object to be. Phillips et al.'s claim that nonhuman primates attribute knowledge but not belief should thus be reconsidered. We propose that both knowledge and belief attributions are evolutionary old.

Dogs follow human misleading suggestions more often when the informant has a false belief

We investigated whether dogs (Canis familiaris) distinguish between human true (TB) and false beliefs (FB). In three experiments with a pre-registered change of location task, dogs (n = 260) could retrieve food from one of two opaque buckets after witnessing a misleading suggestion by a human informant (the 'communicator') who held either a TB or a FB about the location of food. Dogs in both the TB and FB group witnessed the initial hiding of food, its subsequent displacement by a second experimenter, and finally, the misleading suggestion to the empty bucket by the communicator. On average, dogs chose the suggested container significantly more often in the FB group than in the TB group and hence were sensitive to the experimental manipulation. Terriers were the only group of breeds that behaved like human infants and apes tested in previous studies with a similar paradigm, by following the communicator's suggestion more often in the TB than in the FB group. We discuss the results in terms of processing of goals and beliefs. Overall, we provide evidence that pet dogs distinguish between TB and FB scenarios, suggesting that the mechanisms underlying sensitivity to others' beliefs have not evolved uniquely in the primate lineage.

Knowledge before Belief

Research on the capacity to understand others' minds has tended to focus on representations of beliefs, which are widely taken to be among the most central and basic theory of mind representations. Representations of knowledge, by contrast, have received comparatively little attention and have often been understood as depending on prior representations of belief. After all, how could one represent someone as knowing something if one doesn't even represent them as believing it? Drawing on a wide range of methods across cognitive science, we ask whether belief or knowledge is the more basic kind of representation. The evidence indicates that non-human primates attribute knowledge but not belief, that knowledge representations arise earlier in human development than belief representations, that the capacity to represent knowledge may remain intact in patient populations even when belief representation is disrupted, that knowledge (but not belief) attributions are likely automatic, and that explicit knowledge attributions are made more quickly than equivalent belief attributions. Critically, the theory of mind representations uncovered by these various methods exhibit a set of signature features clearly indicative of knowledge: they are not modality-specific, they are factive, they are not just true belief, and they allow for representations of egocentric ignorance. We argue that these signature features elucidate the primary function of knowledge representation: facilitating learning from others about the external world. This suggests a new way of understanding theory of mind-one that is focused on understanding others' minds in relation to the actual world, rather than independent from it.

On the domain specificity of the mechanisms underpinning spontaneous anticipatory looks in false-belief tasks

Many studies proposed that infants' and adults' looking behavior suggest a spontaneous and implicit ability to reason about others' beliefs. It has been argued, however, that these successes are false positives due to domain-general processes, such as retroactive interference. In this study, we investigated the domain specificity of mechanisms underpinning participants' looking behavior by manipulating the dynamic cues in the event stimuli. Infants aged 15 and 20 months and adults saw animation events in which either a self-moving triangle, or a hand holding an identical inert triangle, chased an animated disk. Most 20-month-olds and adults showed belief congruent anticipatory looks in the agent-triangle condition, whereas they showed no bias in the inert triangle control condition. These results are not consistent with submentalizing accounts based on domain-general low-level processes and provide further support for domain-specific explanations positing an early-emerging mentalistic reasoning.

Great apes use self-experience to anticipate an agent's action in a false-belief test

Human social life depends on theory of mind, the ability to attribute mental states to oneself and others. A signature of theory of mind, false belief understanding, requires representing others' views of the world, even when they conflict with one's own. After decades of research, it remains controversial whether any nonhuman species possess a theory of mind. One challenge to positive evidence of animal theory of mind, the behavior-rule account, holds that animals solve such tasks by responding to others' behavioral cues rather than their mental states. We distinguish these hypotheses by implementing a version of the "goggles" test, which asks whether, in the absence of any additional behavioral cues, animals can use their own self-experience of a novel barrier being translucent or opaque to determine whether another agent can see through the same barrier. We incorporated this paradigm into an established anticipatory-looking false-belief test for great apes. In a between-subjects design, apes experienced a novel barrier as either translucent or opaque, although both looked identical from afar. While being eye tracked, all apes then watched a video in which an actor saw an object hidden under 1 of 2 identical boxes. The actor then scuttled behind the novel barrier, at which point the object was relocated and then removed. Only apes who experienced the barrier as opaque visually anticipated that the actor would mistakenly search for the object in its previous location. Great apes, therefore, appeared to attribute differential visual access based specifically on their own past perceptual experience to anticipate an agent's actions in a false-belief test.

Infants attribute false beliefs to a toy crane

The mentalistic view of early theory of mind posits that infants possess a robust and sophisticated understanding of false belief that is masked by the demands of traditional explicit tasks. Much of the evidence supporting this mentalistic view comes from infants' looking time at events that violate their expectations about the beliefs of a human agent. We conducted a replication of the violation-of-expectation procedure, except that the human agent was replaced by an inanimate agent. Infants watched a toy crane repeatedly move toward a box containing an object. In the absence of the crane, the object changed location. When the crane returned, 16-month-old infants looked longer when it turned toward the object's new location, consistent with the attribution of a false belief to the crane. These results suggest that infants spontaneously attribute false beliefs to inanimate agents. A video abstract of this article can be viewed at https://youtu.be/qqEPPhd9FDo.