Attributing false beliefs about non-obvious properties at 18 months

Reports that infants in the second year of life can attribute false beliefs to others have all used a search paradigm in which an agent with a false belief about an object’s location searches for the object. The present research asked whether 18-month-olds would still demonstrate false-belief understanding when tested with a novel non-search paradigm. An experimenter shook an object, demonstrating that it rattled, and then asked an agent, “Can you do it?” In response to this prompt, the agent selected one of two test objects. Infants realized that the agent could be led through inference (Experiment 1) or memory (Experiment 2) to hold a false belief about which of the two test objects rattled. These results suggest that 18-month-olds can attribute false beliefs about non-obvious properties to others, and can do so in a non-search paradigm. These and additional results (Experiment 3) help address several alternative interpretations of false-belief findings with infants.     

Can an agent's false belief be corrected by an appropriate communication? Psychological reasoning in 18-month-old infants

Do 18-month-olds understand that an agent's false belief can be corrected by an appropriate, though not an inappropriate, communication? In Experiment 1, infants watched a series of events involving two agents, a ball, and two containers: a box and a cup. To start, agent1 played with the ball and then hid it in the box, while agent2 looked on. Next, in agent1's absence, agent2 moved the ball from the box to the cup. When agent1 returned, agent2 told her "The ball is in the cup!" (informative-intervention condition) or "I like the cup!" (uninformative-intervention condition). During test, agent1 reached for either the box (box event) or the cup (cup event). In the informative-intervention condition, infants who saw the box event looked reliably longer than those who saw the cup event; in the uninformative-intervention condition, the reverse pattern was found. These results suggest that infants expected agent1's false belief about the ball's location to be corrected when she was told "The ball is in the cup!", but not "I like the cup!". In Experiment 2, agent2 simply pointed to the ball's new location, and infants again expected agent1's false belief to be corrected. These and control results provide additional evidence that infants in the second year of life can attribute false beliefs to agents. In addition, the results suggest that by 18 months of age infants expect agents' false beliefs to be corrected by relevant communications involving words or gestures.     

Do 18-month-olds really attribute mental states to others? A critical test

In the research reported here, we investigated whether 18-month-olds would use their own past experience of visual access to attribute perception and consequent beliefs to other people. Infants in this study wore either opaque blindfolds (opaque condition) or trick blindfolds that looked opaque but were actually transparent (trick condition). Then both groups of infants observed an actor wearing one of the same blindfolds that they themselves had experienced, while a puppet removed an object from its location. Anticipatory eye movements revealed that infants who had experienced opaque blindfolds expected the actor to behave in accordance with a false belief about the object's location, but that infants who had experienced trick blindfolds did not exhibit that expectation. Our results suggest that 18-month-olds used self-experience with the blindfolds to assess the actor's visual access and to update her belief state accordingly. These data constitute compelling evidence that 18-month-olds infer perceptual access and appreciate its causal role in altering the epistemic states of other people.     

婴儿是否拥有错误信念理解能力?

最近10多年,越来越多的婴儿错误信念理解研究不断拓展自发反应任务的范围,发现婴儿的任务表现具有一定的灵活性。对此,有研究者坚持丰富解释,认为婴儿能理解他人的错误信念;也有研究者坚持贫瘠解释,认为婴儿只是借助行为规则等通过任务;近来还有研究者在新的概念框架下做出一种折衷的解释。最终解决婴儿是否拥有错误信念理解能力这个问题,需要研究者们提出一个判定个体拥有错误信念理解能力的明确标准。     

Are Infants’ Theory-of-Mind Abilities Well Integrated? Implicit Understanding of Intentions,Desires, and Beliefs

The development of theory of mind (ToM) in infancy has been mainly documented through studies conducted on a single age group with a single task. Very few studies have examined ToM abilities other than false belief, and very few studies have used a within-subjects design. During 2 testing sessions, infants aged 14 and 18 months old were administered ToM tasks based on the violation-of-expectation paradigm which measured intention, true belief, desire, and false-belief understanding. Infants’ looking times at the congruent and incongruent test trials of each task were compared, and results revealed that both groups of infants looked significantly longer at the incongruent trial on the intention and true-belief tasks. In contrast, only 18-month-olds looked significantly longer at the incongruent trial of the desire task and neither age group looked significantly longer at the incongruent trial on the false-belief task. Additionally, intertask comparisons revealed only a significant relation between performance on the false-belief and intention task. These findings suggest that implicit intention and true-belief understanding emerge earlier than desire and false-belief understanding and that ToM constructs do not appear to be integrated, as is the case for explicit ToM.     

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     

Six-and-a-half-month-old children positively attribute goals to human action and to humanoid-robot motion

Recent infant studies indicate that goal attribution (understanding of goal-directed action) is present very early in infancy. We examined whether 6.5-month-olds attribute goals to agents and whether infants change the interpretation of goal-directed action according to the kind of agent. We conducted three experiments using the visual habituation paradigm. In Experiment 1, we investigated whether 6.5-month-olds attribute goals to human action. In Experiment 2, we investigated whether 6.5-month-olds attribute goals to humanoid-robot motion. In Experiment 3, we tested whether infants attribute goals to a moving box. The agent used in Experiment 3 had no human-like appearance. The results of the three experiments show that infants positively attribute goals to both human action (Experiment 1) and humanoid motion (Experiment 2) but not to a moving box (Experiment 3). These results suggest that 6.5-month-olds tend to interpret certain actions in terms of goals, their reasoning about these actions is based on a sophisticated teleological representation, and that human-like appearance of agents may influence this teleological reasoning in early infancy.     

Belief-based action prediction in preverbal infants

Successful mindreading entails both the ability to think about what others know or believe, and to use this knowledge to generate predictions about how mental states will influence behavior. While previous studies have demonstrated that young infants are sensitive to others’ mental states, there continues to be much debate concerning how to characterize early theory of mind abilities. In the current study, we asked whether 6-month-old infants appreciate the causal role that beliefs play in action. Specifically, we tested whether infants generate action predictions that are appropriate given an agent’s current belief. We exploited a novel, neural indication of action prediction: motor cortex activation as measured by sensorimotor alpha suppression, to ask whether infants would generate differential predictions depending on an agent’s belief. After first verifying our paradigm and measure with a group of adult participants, we found that when an agent had a false belief that a ball was in the box, motor activity indicated that infants predicted she would reach for the box, but when the agent had a false belief that a ball was not in the box, infants did not predict that she would act. In both cases, infants based their predictions on what the agent, rather than the infant, believed to be the case, suggesting that by 6 months of age, infants can exploit their sensitivity to other minds for action prediction.     

Eighteen-month-old infants show false belief understanding in an active helping paradigm

Recently, several studies have claimed that soon after their first birthday infants understand others’ false beliefs. However, some have questioned these findings based on criticisms of the looking-time paradigms used. Here we report a new paradigm to test false belief understanding in infants using a more active behavioral response: helping. Specifically, the task was for infants to help an adult achieve his goal - but to determine that goal infants had to take into account what the adult believed (i.e., whether or not he falsely believed there was a toy inside a box). Results showed that by 18 months of age infants successfully took into account the adult’s belief in the process of attempting to determine his goal. Results for 16-month-olds were in the same direction but less clear. These results represent by far the youngest age of false belief understanding in a task with an active behavioral measure.     

Encoding of others’ beliefs without overt instruction

Under what conditions do people automatically encode and track the mental states of others? A recent investigation showed that when subjects are instructed to track the location of an object but are not instructed to track a belief about that location in a non-verbal false-belief task, they respond more slowly to questions about an agent’s belief, suggesting that belief information was not encoded or tracked automatically [Apperly, I. A., Riggs, K. J., Simpson, A., Samson, D., & Chiavarino, C. (2006). Is belief reasoning automatic? Psychological Science, 17, 841-844]. In the current experiments, we show that if belief probes occur closer in time to the events that signal the content of the agent’s false belief, responses to those probes are faster than responses to probes about reality, and as fast as responses to probes about belief when instructed to track them, suggesting (i) beliefs may get encoded automatically in response to certain cues and (ii) that belief information rapidly decays unless it is maintained via ‘top-down’ instructions.     

The origins of belief representation: Monkeys fail to automatically represent others’ beliefs

Young infants’ successful performance on false belief tasks has led several researchers to argue that there may be a core knowledge system for representing the beliefs of other agents, emerging early in human development and constraining automatic belief processing into adulthood. One way to investigate this purported core belief representation system is to examine whether non-human primates share such a system. Although non-human primates have historically performed poorly on false belief tasks that require executive function capacities, little work has explored how primates perform on more automatic measures of belief processing. To get at this issue, we modified Kovács et al. (2010)’s test of automatic belief representation to examine whether one non-human primate species—the rhesus macaque (Macaca mulatta)—is automatically influenced by another agent’s beliefs when tracking an object’s location. Monkeys saw an event in which a human agent watched an apple move back and forth between two boxes and an outcome in which one box was revealed to be empty. By occluding segments of the apple’s movement from either the monkey or the agent, we manipulated both the monkeys’ belief (true or false) and agent’s belief (true or false) about the final location of the apple. We found that monkeys looked longer at events that violated their own beliefs than at events that were consistent with their beliefs. In contrast to human infants, however, monkeys’ expectations were not influenced by another agent’s beliefs, suggesting that belief representation may be an aspect of core knowledge unique to humans.     

False-belief understanding i 2.5-year-olds: evidence for violation-of-expectation change-of-location and unexpected-contents tasks

Until recently, it was generally assumed that the ability to attribute false beliefs did not emerge until about 4 years of age. However, recent reports using spontaneous- as opposed to elicited-response tasks have suggested that this ability may be present much earlier. To date, researchers have employed two kinds of spontaneous-response false-belief tasks: violation-of-expectation tasks have been used with infants in the second year of life, and anticipatory-looking tasks have been used with toddlers in the third year of life. In the present research, 2.5-year-old toddlers were tested in violation-of-expectation tasks involving a change-of-location situation (Experiment 1) and an unexpected-contents situation (Experiment 2). Results were positive in both situations, providing the first demonstrations of false-belief understanding in toddlers using violation-of-expectation tasks and, as such, pointing to a consistent and continuous picture of early false-belief understanding.     

Fourteen‐month‐old infants track the language comprehension of communicative partners

Infants employ sophisticated mechanisms to acquire their first language, including some that rely on taking the perspective of adults as speakers or listeners. When do infants first show awareness of what other people understand? We tested 14‐month‐old infants in two experiments measuring event‐related potentials. In Experiment 1, we established that infants produce the N400 effect, a brain signature of semantic violations, in a live object naming paradigm in the presence of an adult observer. In Experiment 2, we induced false beliefs about the labeled objects in the adult observer to test whether infants keep track of the other person's comprehension. The results revealed that infants reacted to the semantic incongruity heard by the other as if they encountered it themselves: they exhibited an N400‐like response, even though labels were congruous from their perspective. This finding demonstrates that infants track the linguistic understanding of social partners. A video abstract of this article can be viewed at https://youtu.be/pQUv8yFhnbk .     

When representations conflict with reality: the preschooler's problem with false beliefs and "false" photographs

It has been argued that young preschoolers cannot correctly attribute a false belief to a deceived actor (Wimmer & Perner, 1983). Some researchers claim that the problem lies in the child's inadequate epistemology (Chandler & Boyes, 1982; Wellman, 1988); as such, it is specific to the child's theory of mind and no such problem should appear in reasoning about nonmental representations. This prediction is tested below in the "false photograph" task: here an actor takes a photograph of an object in location X; the object is then moved to location Y. Preschool subjects are asked: "In the picture, where is the object?" Results indicate that photographs are no easier to reason about than are beliefs. Manipulations to boost performance on the photograph task proved ineffective. Further, an explanation of the failure as a processing limitation having nothing to do with the representational nature of beliefs or photographs was ruled out. It is argued that young children's failure on the false belief task is not due to an inadequate epistemology (though they may have one) and is symptomatic of a larger problem with representations.     

Infant's Inductive Generalization of Bodily,Motion, and Sensory Properties to Animals and People

It has been proposed that infants can form global categories such as animate and inanimate objects (Mandler, 2004). The inductive generalization paradigm was used to examine inferences made by infants about the bodily, motion, and sensory capabilities of people and animals. In Experiment 1, 14-month-old infants generalized bodily and sensory properties from dogs to cats and vice-versa. In Experiment 2, 16- and 20-month-olds generalized motion and sensory properties modeled with a person more often to mammals than to vehicles. Findings from Experiment 3 indicated that motion properties are generalized broadly to people and mammals but that by 20 months of age, infants may be beginning to attribute sensory properties preferentially to people more than to animals.     

The development of a word-learning strategy

Two studies investigated young infants' use of the word-learning principle Mutual Exclusivity. In Experiment 1, a linear relationship between age and performance was discovered. Seventeen-month-old infants successfully used Mutual Exclusivity to map novel labels to novel objects in a preferential looking paradigm. That is, when presented a familiar and a novel object (e.g. car and phototube) and asked to "look at the dax", 17-month-olds increased looking to the novel object (i.e. phototube) above baseline preference. On these trials, 16-month-olds were at chance. And, 14-month-olds systematically increased looking to the familiar object (i.e. car) in response to hearing the novel label "dax". Experiment 2 established that this increase in looking to the car was due solely to hearing the novel label "dax". Several possible interpretations of the surprising form of failure at 14 months are discussed.     

Do infants bind mental states to agents?

Recent findings suggest that infants understand others’ preferential choice and can use the perspectives and beliefs of others to interpret their actions. The standard interpretation in the field is that infants understand preferential choice as a dispositional state of the agent. It is possible, however, that these social situations trigger the acquisition of more general, not person-specific knowledge. In a looking-time study we showed an Agent A demonstrating a choice, that only could have been interpreted as preferential based on the perspective (and thus the belief) of the agent, not the observer. Then we introduced a new agent (Agent B), who chose consistently or inconsistently with Agent A; also varying whether Agent B was an adult or a child. Results show that infants expected Agent B (both the adult and the child) to choose as Agent A, but only in the condition where according to Agent A’s knowledge two objects were present in familiarization(confirming previous evidence on the importance of contrastive choice). We interpret these results in the following way: (1) infants do not encode the perspectives of other agents as person-specific sources of knowledge and (2) they learn about the object, rather than the agent’s disposition towards that object. We propose that early theory of mind processes lack the binding of belief content to the belief holder. However, such limitation may in fact serve an important function, allowing infants to acquire information through the perspectives of others in the form of universal access to general information.     

Children's beliefs about instances of mechanical and electrical causation

Two main questions were asked regarding young children's beliefs about causal mediation: What sorts of beliefs about causal mediation are reflected by children's incomplete explanations of causal situations? In particular, do children hold a false belief in action at a distance or do they realize that something must mediate between cause and effect? When presented with a non-visible connection between cause and effect (Experiment I), the children's incomplete (Piagetion Stage 1) explanations either reflected the correct expectation of a mediating connection or else merely reflected identification of the causal agent and no concern one way or another with the issue of causal mediation. This was also the case when the mediating connection was visible and present at the outset (Experiment II). In neither experiment (both of which involved mechanical causation) was there evidence of a false belief in action at a distance. A third experiment involved instances of electrical causation in order to maximize the chances of tapping a false belief. The rationale was that, in their everyday lives, although children do have first-hand experience with the mediating connection in instances of mechanical causation, they do not have such experience with instances of electrical causation. The results from the third experiment were analogous to the results in the other two. It was concluded that, with respect to instances of physical causality, young children do not hold a false belief (in action at a distance) that is later relinquished. Rather, their concerns are, at first, restricted to identifying the causal agent and do not include any beliefs, true or false, about the issue of causal mediation. When they eventually do deal with the question of causal mediation, children hold approximately correct beliefs. In terms of school situations, these findings suggest a shift from providing the child with disconfirming data that will aid him in relinquishing his false beliefs to providing him, instead, with additional data that will supplement his existing, approximately correct beliefs.     

False-belief understanding in 2.5-year-olds: evidence from two novel verbal spontaneous-response tasks

Recent research indicates that toddlers and infants succeed at various non-verbal spontaneous-response false-belief tasks; here we asked whether toddlers would also succeed at verbal spontaneous-response false-belief tasks that imposed significant linguistic demands. We tested 2.5-year-olds using two novel tasks: a preferential-looking task in which children listened to a false-belief story while looking at a picture book (with matching and non-matching pictures), and a violation-of-expectation task in which children watched an adult 'Subject' answer (correctly or incorrectly) a standard false-belief question. Positive results were obtained with both tasks, despite their linguistic demands. These results (1) support the distinction between spontaneous- and elicited-response tasks by showing that toddlers succeed at verbal false-belief tasks that do not require them to answer direct questions about agents' false beliefs, (2) reinforce claims of robust continuity in early false-belief understanding as assessed by spontaneous-response tasks, and (3) provide researchers with new experimental tasks for exploring early false-belief understanding in neurotypical and autistic populations.