5 Infants and the Social World

Children develop in a rich, social world filled with many people, including their parents, siblings, other family members, and other caregivers. The relationships children form with these individuals are essential for their healthy development and proper functioning later in life. In learning how to navigate through these relationships, children must first develop an understanding of others, the foundations of which are established in infancy.

Researchers studying infants’ social understanding are interested in the internal and external factors that contribute to its development. They investigate the neural and cognitive processes that allow children to perceive and attend to social stimuli, make inferences about others’ mental states, and explain and predict others’ behaviours. They also explore the environmental and social factors that influence these processes, such as the types of social stimuli infants encounter and the quality of their attachments to those around them.

In reviewing this line of research, this chapter will cover various topics: the development of infants’ social cognition, their perception of others, their social learning, their conceptual understanding of human behaviour, and the formation of their early relationships. In order to encapsulate the scope of this field, this chapter will draw from foundational and recent literature, compare and contrast various theoretical accounts, and provide real-life applications about infants’ social-cognitive development.

5.1 Development of Social Cognition

One of the distinctive qualities of our species is our sociality, demonstrated in the ways we associate and cooperate with each other. While we may take these behaviours for granted, researchers believe that they have been essential for our survival. How does the human individual develop these social skills? How does our capacity for socialization compare to that of other animals? And what are the cognitive processes that underlie its development?

5.1.1 Social Cognition

Social cognition refers to an organism’s knowledge about its conspecifics- the members of its own species. It can be characterized by the recognition of conspecific individuals and the understanding of conspecific relationships (Seyfarth & Cheney, 2016). For humans, our capability for social cognition is demonstrated in many of our daily activities: caring for family, supporting friends, learning from our teachers, and working within the rules of society.

To successfully navigate through these relationships, we rely on our social-cognitive skills: perceiving and interpreting social behaviour, attributing mental and emotional states to other people, and communicating with them. These social-cognitive skills are thought to have evolved as an adaptation to the pressures of our social environment. For many years, the working hypothesis (i.e., the social intelligence hypothesis) has been that natural selection favours those who are able to effectively cooperate and compete with others, recognize and monitor their relationships, and accurately predict the behaviours of those around them (Seyfarth & Cheney, 2016). Since humans may benefit from knowing and understanding other people, the selective pressures the environment imposes may have played a role in how we have evolved to have social cognition.

However, social cognition may not be an adaptation exclusive to our species. Other animal behaviours like wolves hunting in packs and fish swimming in schools require a level of social cooperation that could be argued to have the same underlying social-cognitive mechanisms as human social behaviour. Because the distinction between our social behaviour and that of other species is unclear, the question of what makes humans socially unique continues to be an ongoing philosophical discussion. To think about this question, evolutionary and developmental psychologists study human infant development and non-human primate behaviour to examine how our social cognition develops at two levels: 1) ontogenetically, or within the human individual, and 2) phylogenetically, across our evolutionary history.

5.1.2 Human and Non-Human Primate Social Cognition

Human Infants

In humans, our social cognition is demonstrated through our skills in processing and monitoring relationships between individuals, making inferences about others’ mental and emotional states, and communicating with language. These abilities are considered higher-order social-cognitive processes and can be easily studied in adults. What developmentalists are interested in are the precursors of these processes- behavioural responses expressing social understanding that can be measured in nonverbal infants.

One of the earliest developing precursors that researchers investigate is the infant’s ability to follow another’s gaze. Gaze-following occurs when an individual perceives another’s gaze and subsequently notices the object or event that the other person is attending to. A person’s gaze typically indicates their attention and the ability to follow their gaze can be adaptive. For ancestral humans in the wild, gaze-following may have been important for foraging or detecting predators. Individuals with this ability benefitted by learning from discoveries made by others, thereby having a selective advantage over non-gaze-followers. New-born infants demonstrate rudimentary forms of gaze-following and, between 6 and 18 months of age, are able to track others’ gaze in response to eye movements alone (Zuberbuhler, 2008).

It is argued that infant behaviours like gaze-following provide the foundation for higher-order social-cognitive processes as they establish joint attention between two individuals (Baron-Cohen, 1995; Gopnik et al., 1994). During an episode of joint attention, the infant and the adult engage with the physical world together, while simultaneously being aware of this shared attention. This enables the infant to come to understand the adult’s knowledge states (Moll & Tomasello, 2010). Upon the proper development of gaze-following, infants are able to engage in joint attention by the end of their first year, marking a developmental milestone in their social competence.

Non-Human Primates

In studying the phylogeny of our social cognition, researchers conduct cross-species comparisons. By observing the behaviour of non-human primates, with whom we share much of our genetic material, we can make inferences about the evolutionary history of our own social cognition.

Similar to humans, primates and many other animals are capable of gaze-following. Studies show that 13-month-old chimpanzees are able to follow another’s gaze at an object. Even monkeys like marmosets and macaques also exhibit gaze-following that becomes more sophisticated as they mature. For these species, gaze typically signals the possession of food. In order to avoid competition, chimpanzees may follow another’s gaze to avoid food that they are looking at (Zuberbuhler, 2008). Tomasello et al. (1998) showed that chimpanzees and various species of monkeys could follow a conspecific’s gaze when that individual was induced to look at food being displayed. Therefore, by following a conspecific’s gaze, chimpanzees seem to be able to discriminate what others can and cannot see.

Do Chimpanzees Have a Theory of Mind?

The degree to which chimpanzees’ ability extends to making inferences about what their conspecifics know or believe, like it does for humans, remains an open issue. For humans, our ability to make inferences about others’ behaviours is based on our representations of their intentions, desires, knowledge, and beliefs. This representation of others’ mental states is commonly referred to as theory of mind- a term coined by primatologists Premack and Woodruff (1978). In their seminal paper, they asked whether chimpanzees have the same capabilities to infer the mental states of others.

Evidence for non-human primates’ understanding of conspecifics’ mental states can be observed in competitive situations. Naturalistic observations have recorded that various species of monkeys and apes are able to follow a conspecific’s gaze just to deceive them, seemingly recognizing what they do not know (Whiten & Byrne, 1988). In an experimental study on these behaviours, Hare et al., (2001) found that subordinate chimpanzees were more likely to go for food items that a dominant chimpanzee could not see. In more complex tasks in which the experimenter manipulated the dominant chimpanzees’ knowledge of the food item, they discovered that the subordinates took into account what the dominant chimpanzees had seen earlier and adjusted their behaviour based on the knowledge of their competitor (Hare et al., 2001). This understanding of knowledge states during competitive tasks has led researchers to propose that chimpanzees evolved to have social cognition to deal with an environment in which manipulating and deceiving others were more important than cooperating (i.e., Machiavellian Intelligence Hypothesis) (MacLean, 2016).

While this may be evidence that chimpanzees are able to attribute intentions and knowledge states to conspecifics, the differences between humans and non-human primates arise in more complex tests of social cognition, in which they appear to perform poorly compared to human infants (Seyfarth & Cheney, 2016). These tests have demonstrated that chimpanzees lack the capacity to understand that others may hold beliefs about the world that are mistaken or different from one’s own (Call & Tomasello, 2008). In humans, this ability to understand others’ false beliefs is a hallmark for theory-of-mind acquisition and develops between 3 and 5 years of age. This distinction has led researchers to conclude that chimpanzees may understand others based on a perception-goal psychology, rather than a belief-desire psychology as in humans (Call & Tomasello, 2008). In other words, chimpanzees may have a theory of mind for attributing intentions and goals to conspecifics, but not one for attributing false beliefs as humans do.

5.1.3 Distinctiveness of Human Social Cognition

According to some researchers, our capacity for social cognition is species-specific and emerges early in ontogeny to specifically allow for the participation and exchange of knowledge within cultural groups (Herrmann et al., 2007). Proponents of this “cultural intelligence hypothesis” acknowledge that the development of children’s basic skills for non-verbal communication and joint attention within the first year of life provides the foundation for their cultural learning (MacLean, 2016). The development of their theory of mind over the preschool years then further enables them to share cultural information and reason about the goals, intentions, and beliefs of individuals and their broader cultural groups. Although it was once believed that the understanding of others as intentional agents was exclusive to humans only, evidence of other primates’ abilities for perspective-taking suggests we may be more similar than we previously thought. However, researchers argue that a remaining difference between human and nonhuman primate cognition may be that, unlike apes, humans are tailored for more cooperative and prosocial behaviour, rather than using their social cognition for Machiavellian purposes (Moll & Tomasello, 2007). Thus, it may be that the evolution of our social cognition has diverged from that of other primates due to our propensity for cooperating within cultural groups.

Section Summary

• Social cognition is an organism’s capacity for recognizing and understanding conspecific individuals and conspecific relationships
• The precursors of human social cognition include gaze-following, joint attention, and an awareness of others as intentional agents
• While chimpanzees may be able to attribute intention and knowledge states to conspecifics, false-belief understanding is believed to be exclusive to humans
• Human social cognition may have evolved for use in prosocial and cooperative acts

5.2 Social Perception

From the moment they first open their eyes, infants begin to scan the environment around them. It is one of the few ways that they have active control over what they observe and learn from their surroundings. However, in a world filled with so many things, how do infants distinguish people from other objects? What do they perceive in other people? And how do their early experiences influence their perceptual development?

5.2.1 Perceiving Conspecifics

In order to observe and learn from the people around them, infants are born equipped with perceptual abilities that allow them to receive social information. As mentioned in Chapter 4, humans are predisposed to attend to animate objects over inanimate ones. Tremoulet and Feldman (2000) postulated that objects are perceived as animate when their motions defy the laws of physics and instead appear to move in goal-directed ways- characteristic of all biological motion. Using point-light displays, 2-day-old infants are shown to distinguish biological motion from random motion point-lights (Simion et al., 2008). Moreover, they can distinguish upright walkers from non-upright walkers, indicating their sensitivity to biological motion of humans in particular (Bertenthal et al., 1984; Fox & McDaniel, 1982). In the human brain, detecting animate agents appears to be associated with the extrastriate body area located in the occipital cortex, which has been found to be sensitive to the perception of human bodies, body parts, and biological motion, compared to other objects in the world (Saxe & Kanwisher, 2003).

Face Perception

Along with the human body, faces are among the most prominent and most preferred stimuli of infants’ visual environments. This is evident even in newborns who look longer and orient more towards images of faces than non-face patterns (Johnson et al., 1991). After exposure to their mother over the first few days of life, newborns come to quickly recognize and prefer her face, looking longer at hers than faces of others (Bushnell, Sai, & Mullin, 2011). While infant preference for faces is early emerging, it also develops over time. At one month of age, infants are shown to focus generally on the outer contour of the face and head, where there is relatively high contrast with the background. By 2 months of age, they start to fixate on the more internal features of the face, like the eyes and mouth (Maurer & Salapatek, 1976).

Gaze Perception

By the time infants are 4 months of age, when they are looking at the face, they will primarily fixate on the eyes. As mentioned in the previous section, the ability to follow another’s gaze may have a selective advantage as it allow us to pay attention to what others deem important in the environment. For many animals, detecting head direction may be sufficient enough to work out what others are looking at. However, for species who have adapted to live on the ground, gaze shifts not requiring a head turn motion may have been more advantageous in detecting stimuli across the horizontal plane (Doherty, 2009). This may have been the case for humans who move their eyes without turning their heads more than any other primates (Kobayashi & Kohshima, 2001). Although this makes it hard to determine what humans are looking at by head direction, it is balanced by the unique feature of the human eyes: its visible white sclera. Humans are the only primate species that have a white sclera, suggesting that it might be a specific adaptation. A visible sclera may have made it easier for other humans to detect our gaze direction. In conjunction, humans may have adapted to pay attention to the eyes, such that clear signalling evolved alongside the improved ability for gaze detection (Doherty, 2009).

5.2.2 Influences of Social Experiences on Perception

CONSPEC/CONLEARN

In the human brain, face perception is associated with the fusiform face area, located in the inferior temporal cortex. This particular brain region is responsive when viewing faces compared to scrambled faces and objects (Kanwisher, McDermott, & Chunn, 1997). The discovery of this specialized brain region, along with the extrastriate body area, suggests that our perception of conspecifics may be domain-specific and innate. These findings are consistent with theories proposing that humans have an innate ability for conspecific recognition. Proponents of this nativist theory hypothesize that we are born with a specialized visual system called CONSPEC. This visual system is based on a coarse template of the human face and body and orients our attention towards conspecific stimuli. This innate mechanism is then responsible for ensuring that a second system, the CONLEARN, receives ample stimuli during the first few months of life. The CONLEARN then allows us to learn more of the subtle cues about the people around us (Morton & Johnson, 1991).

Perceptual Narrowing

This concept of the CONLEARN system is consistent with the observed phenomena of perceptual narrowing. As covered in the previous chapters, infants’ perceptions of stimuli are shaped by their experiences, narrowing their perception to only familiar sounds and objects as well as other people. At 6 months of age, infants are equally as good at discriminating between monkey faces and human ones. However, at around 9 months, they demonstrate greater difficulty. This suggests that they have become better at perceiving dimensions that matter for discriminating human faces but become worse at perceiving dimensions that are not prominent in their environment, such as monkey faces (Pascalis, de Haan, & Nelson, 2002). In social experiences, this perceptual narrowing can be observed in the phenomenon of the other-race effect, in which children have more difficulty distinguishing between faces of different races than their own. Compared to new-borns who have no preferences, 3-month old infants prefer looking at own-race faces over other-race faces, and by 9 months, have more difficulty discriminating faces not of their own race (Kelly et al., 2007). These effects are not driven by the infant’s own race per se, but rather are a result of the features of the individuals in their immediate environment. This emphasizes the role the environment plays in children’s perception of other people.

Section Summary

• Infants are predisposed to detect and attend to conspecific stimuli: human biological motion, bodies, faces, and eye gazes
• Specialized brain regions for detecting bodies and faces suggests the existence of innate perceptual systems orienting our attention towards other people
• Infants’ perception of others is shaped by their immediate environment, specializing to make finer distinctions in the social stimuli they experience

5.3 Social Learning

Once infants can detect biological motion, they will recognize that animate objects move in peculiar but specific ways, as if they have goals behind their every move. As infants learn about their social environment, how do they come to interpret others’ actions as intentional? When does this ability to recognize others as intentional agents develop? And what cognitive mechanisms underlie this social learning?

5.3.1 Infant Social Learning

Learning Theories

In the early days of psychology, theorists placed a large emphasis on environmental factors to explain all human behaviour. Radical behaviourists, like John B. Watson and B.F. Skinner, proposed that the child’s social environment solely determines their learning development through processes of conditioning. They argued that all human behaviours are merely responses to the environment and that we learn these behaviours based on past experiences. This can be applied to the context of child-rearing, in which certain behaviours can be reinforced through reward or eliminated through punishment. Although external factors may have an influence on child development, modern psychology has leaned away from such radical ideas. For instance, Albert Bandura proposes, in his concept of reciprocal determinism, that child-environment influences operate in both directions. While he also considered the child’s social environment, he also posits that internal, cognitive processes play a role in their development as well. In his social learning theory, Bandura proposes that children’s learning processes are based on acts of observation and imitation. This observational learning depends on cognitive processes like attending to others’ behaviours, encoding what is observed, storing it in memory, and retrieving it to reproduce the behaviour.

Indeed, children’s observation of others’ behaviours proves to be an important source of their learning. Parents may become well aware of how much children learn through simple observation when they find their toddlers attempting to reproduce their actions. This ability to copy others’ actions, either through mimicry, emulation, or imitation, appears to be present early in life, and is argued to have important consequences for higher-order social cognition.

Mimicry, Emulation, and Imitation

Mimicry is defined as learning about another person’s actions without understanding the objects involved or the end state of that action (Tomasello et al., 1993). To demonstrate this in children, Bjorklund and Blasi (2012) give the example of a 2-year-old child stepping on a scale, looking up at the numbers of the scale, and then stepping off, just like how their father did, despite not understanding what the purpose of the scale is and what the numbers mean. As such, mimicry is considered to be a matching behaviour that does not require explicit awareness. On the other hand, acts of emulation and imitation are considered to be more cognitively sophisticated processes. Recall from Chapter 4 that emulation occurs when the observer attempts to attain the same end goal as someone interacting with an object but does not reproduce the same actions. In contrast, imitation occurs when the observer recognizes the end state and reproduces the specific actions that were used to bring about that state (Tomasello, 1990). Children are able to emulate and imitate others early in their development.

By around 6 months, infant imitation becomes more robust, allowing them to not only imitate facial gestures, but also novel actions performed on objects. Even after a delay of 24 hours, infants as young as 6 to 9 months were able to imitate novel actions they witnessed (Barr, Dowden, & Hayne, 1996). By 14 months, infants were able to imitate actions a full week after first seeing them (Meltzoff, 1988). Furthermore, towards the end of the first year, infants are able to analyze the intention behind a person’s behaviour.

In one study looking at infants’ intentional understanding, Gergely and colleagues (2002) had 14-month-olds watch as an actor turned on lights by pressing a button with their head. In one condition, the actor had their hands free, and in another condition, had their hands wrapped in a blanket and so were not available to turn on the lights. They found that infants who observed the hands-free trials tended to imitate the actor’s behaviour by turning the lights on with their heads in the same way. However, the infants who observed the hands-occupied trials tended towards emulation, using their hands to turn on the light instead of their heads. This hands-occupied condition demonstrated that infants were able to focus on the end state (i.e., turning on the light), not the means (i.e., using your head), when there was a reason why the actor did not use their hands. In contrast, when there was no such reason for them to use their heads as in the hands-free condition, infants reproduced the actor’s exact behaviour, demonstrating their focus on the actor’s actions as well as their intentions. Researchers argue that demonstrations of imitation such as this requires the individual to take the perspective of their social partner, understand their goals, and reproduce the same action to reach that goal (Bjorklund & Blasi, 2012).

5.3.2 Understanding Intentions and Actions

An essential component of the human experience is the perception that our social world is filled with intentional agents. Intentions are mental states like “wanting” or “desiring” that lead agents to set goals and complete actions (Call & Tomasello, 1998). Researchers generally agree that infants are able to understand others as intentional agents well before their first birthday. This ability to understand intentions plays a foundational role in broader developmental processes as it is believed to be a precursor to more complex mental processes like theory of mind, moral reasoning, and cultural learning (Woodward et al., 2009). However, our comprehension of others’ intentions seems both mundane and mysterious as people’s actions are concrete, but the intentions behind them are abstract.

In isolating infants’ analysis of others’ actions, researchers often use visual habituation paradigms which rely on infants’ looking responses. When shown a particular event repeatedly, infants are observed to attend to it less and less, demonstrating a habituation response. Once they have habituated, infants exhibit increased attention to events that differ from the habituation event. Thus, the infants’ pattern of regaining visual attention may indicate the structure of their representations of events. Researchers can then use this paradigm to determine whether infants have a novelty response to changes in others’ intentional action.

Using a visual habituation task, Woodward (1998) showed that 5-month-old infants have some understanding of goal-directed behaviour, being able to distinguish between a person’s goals and their actions. In their study, infants are habituated to an actor reaching for one of two objects. Thereafter, the location of the objects are switched and the infants are presented either two conditions: the new-goal trial, in which the actor reaches to the same location for a new object, thus performing the same action but with new goals; or the new-side trial, in which the actor reaches to the other location to grasp the same object, thus moving in a different way, but still acting on the same goal. Researchers found that by 5 months, infants looked longer at the new-goal trials, suggesting that they could distinguish between the two trials. Further, it suggested that infants may have attributed goal-directed action to the actor, expecting them to keep reaching for their original target, even once that target had been moved.

In order to explain how infants may be representing the intentions behind these actions, some theories have been put forth. Nativist accounts propose that there are innate mechanisms through which infants can attribute intentional mental states to interpret actions (Leslie, 1994; Meltzoff, 2002). As such, infants’ ability to interpret goal-directed actions may not be a precursor to a later-emerging theory of mind, but rather already represents their genuine mentalistic understanding of actions. On the other hand, some researchers argue that infants possess a naïve theory about the most efficient means to achieve an end goal (i.e., rational action) in order to interpret and predict others’ goal-directed actions (Gergely & Csibra, 2003). Using a habituation task, Gergely et al. (1995) observed that 12-month-old infants were able to understand that intentional agents act in rational ways. This principle of rational action then guides the development and refinement of their representational systems of human behaviour.

Statistical Learning

Along with conditioning, habituation, and observational learning, children may also come to understand the relation between agents and the objects they manipulate by keeping track of the statistical regularities of human behaviour. This “statistical learning” occurs when infants are presented with strings of various stimuli: linguistic units, words, tones, and objects (Saffran, Johnson, Aslin, & Newport, 1999; Kirkham, Slemmer, & Johnson, 2002). It may also be applied to how infants learn about human behaviour, such as how adults generally interact with objects in the world. Infants as young as 6 months are shown to be aware of typical agent-object interactions (Hunnius & Bekkering, 2010). For instance, when observing someone raise a cup or telephone, infants can anticipate its trajectory and look to the correct area on the person’s face (e.g., mouth, ear). As such, they are able to pay attention to agent actions and agent-object relations and develop knowledge and expectations based on the frequency of occurrences (Ruffman, 2014). Eventually, they become able to attach epistemic mental states to these actions, such as the person’s intentions with those objects.

5.3.3 Selective Social Learning

While infants may seem highly impressionable, they do not pay attention to everybody’s actions, but are found to be selective in who they learn from. For instance, infants prefer to learn from adults who use pedagogical cues – signals that indicate the adults’ intentions to teach the child (Csibra & Gyorgy, 2009). These are behaviours like engaging a child in joint attention (e.g., through gaze or pointing), infant-directed speech, or demonstrating actions in slow, rhythmic movements like “motionese”. These cues make it easier for children to pick out the important pieces of information that adults want them to attend to. If individuals fail to use these cues, infants are less likely to treat them as agents worthy of their attention or to learn from them (Csibra & Gyorgy, 2009). Moreover, infants also exhibit preferences for particular individuals and objects based on the individuals’ characteristics. For instance, 10 to 12-month-old infants are shown to prefer toys and food that are selected by individuals who share their native language (Kinzler, Dupoux, & Spelke, 2009; Shutts et al., 2009). While infants may be dependent on others for information, these findings demonstrate that through their selectivity in learning, children also play an active role in their conceptual development.

Section Summary

• Infants may learn about human behaviour through various processes: conditioning, habituation, observational learning or statistical learning
• By the end of their first year, infants are able to imitate others’ actions, demonstrating their understanding of others as intentional agents
• Infants play an active role in their conceptual development through selective social learning

5.4 Early Theory of Mind

The abilities to follow gaze, engage in joint attention, comprehend animacy, and recognize others as intentional agents are believed to set the foundation for children’s theory of mind. However, how these representations form in childhood is still not fully understood. What are the underlying cognitive and neural mechanisms of theory of mind? How is theory-of-mind ability measured? And are there any indications these abilities appear earlier on in development?

5.4.1 Understanding Others

Theory of Mind

By the time children enter first grade, they have learnt a lot about other people: how they behave, how they feel, and how they think. This ability to make inferences about others’ mental states was first investigated by Jean Piaget who claimed that children are not able to take on others’ perspectives until 7 years of age. These conclusions were based on his classic mountains study, in which children under age 7 failed to appreciate another person’s viewpoint; when asked what the other person sees on their side of a model mountain range, children instead described what they saw on their own side of the same model. He therefore concluded that prior to age 7, children’s reasoning is inherently egocentric, limiting their understanding of the world to their own perspectives. However, Piaget’s work has been criticized by other researchers for underestimating children’s abilities. In investigating his claims further, Wimmer and Perner (1983) tested children’s perspective-taking with a novel measure of their false-belief attribution. In contrast to Piaget’s findings, they found that children actually develop this ability earlier on- between the ages of 3 and 5 years old.

Along with words like mentalizing, mind-reading, and cognitive empathy, this ability to take on others’ perspectives falls under the umbrella term of theory of mind– the conceptual framework we use to make inferences and reason about others’ mental states, such as their desires, intentions, and beliefs. Considered to be the most sophisticated form of higher-order social cognition, theory of mind is what we use to predict and explain human behaviour, allowing us to successfully navigate through the social world. Since Premack and Woodruff (1978) coined the term, research on theory of mind has flourished, with researchers innovating ways to measure it, observing its typical and atypical development, and uncovering its underlying cognitive and neural mechanisms.

To measure this ability differently from Piaget, Wimmer and Perner (1983) developed the false-belief task. This task presents the child with a series of animated pictures, describing a narrative in which one character leaves an object in a box, but upon leaving, another character takes the object out of the box and transfers it to a different location without the other’s knowledge. To assess their theory of mind, children are instructed to make an explicit judgment about the first character’s belief- where the first character will look for the object when he/she comes back for it. When asked this question, children who pass the false-belief task will respond by indicating that the character will look for the object in the location they last left it in- a demonstration of their capability for theory-of-mind reasoning. However, 3-year-olds incorrectly respond by saying that the character will look for the object in its new location, despite the fact that they never saw the item get moved. This inability to understand another’s false beliefs persists over preschool years. Only upon reaching age 5, children become able to understand that others may hold beliefs distinct from their own, exhibiting a change in their conceptual understanding that people’s beliefs are based on their own idiosyncratic experiences. This developmental pattern has been observed consistently and universally, establishing the false belief task as a robust measure of theory of mind and marking the emergence of false-belief understanding as a major developmental milestone in children’s social competence (Wellman, Cross, & Watson, 2001).

Theory-theory vs. Simulation Theory

Since our representations of others’ mental states are amongst the most abstract concepts we have, it makes it difficult to understand how theory-of-mind reasoning develops in childhood. In attempting to explain the origins of our theory of mind, researchers have put forth a couple competing theories.Theory-theory vs. Simulation Theory

One account, termed “theory-theory”, proposes that children’s conceptualizations of others are formed through experimenting and testing their hypotheses about how humans behave. Based on this idea, theory of mind may be akin to actual scientific theories that undergo revision as new information about the world is discovered (Gopnik & Wellman, 1992, 1994). It is through their social experiences that children’s theories of human behaviour are gradually informed. As they grow and explore more of the world, they may encounter confirmatory evidence that reinforces their held theories as well as disconfirmatory evidence that would prompt changes in their theories. In turn, their representations of others’ minds are continuously updated, becoming more complex as they mature and encounter new evidence about the mental states of others. Although theory-theory can explain much of our social experiences, research has yet to explain when these theories start to form in childhood and why false-belief understanding emerges only at the end of children’s preschool years.

As a contrasting perspective, proponents of “simulation theory” claim that children do not need to form theories about others’ mind. Instead, they argue that children already have a working model of the human mind- their own. Based on the assumption that all minds work the same, children may predict how others will act by predicting how they would act in the same situation. In other words, they can reason about others’ minds by projecting their own mental states onto them, much like a simulation (Harris, 1992). This theory rests on children’s capacity for pretense, as by age 2, they can pretend and imagine non-existent objects, and by age 3, are hypothesized to be able to pretend to have mental states they do not hold (e.g., pretending to want a glass of milk even if they are not thirsty) (Harris, 1992). This timeline aligns with the typical emergence of false-belief understanding over preschool years. Further, this theory can explain, for instance, how we can empathize with others by imagining how they must feel. However, one argument against it is that it cannot explain the errors we make in judging human behaviour. Situations in which we wrongly predict how we will behave suggests that we may not be using simulation as it makes us question our own understanding of ourselves (Saxe, 2005). These errors are thus inconsistent with what simulation theory proposes and could be better explained with the idea of conceptual change as hypothesized by theory-theorists.

It is important to note that although these theoretical accounts are presented as contrasting viewpoints, it may be possible that our representations of others develop as a combination of both of these mechanisms. Moreover, there are theories of other mechanisms that could be involved that is beyond the scope of this chapter (for review, see Mahy, Moses, & Pfeifer, 2014).

Biology of Theory of Mind

In examining the biology of theory of mind, researchers use neuroimaging techniques like EEG and fMRI to study the associations between regional developmental changes in the brain and children’s performance in theory-of-mind tasks. Due to the different lines of thinking about theory-of-mind acquisition, research has produced a diverse range of results surrounding its neurobiological basis.

Proponents of the theory-theory approach, for instance, suggest that the right temporo-parietal junction (rTPJ) is involved in theory-of-mind reasoning. In adults, the TPJ is thought to play a role in disengaging from one’s own internal perspective to attend to an external others’ point of view (Corbetta et al., 2008). By disengaging from one’s internal perspectives, it allows the integration of external information into our internal states, prompting changes in our theories. In testing this, Sabbagh et al. (2010) used a load-force adaptation task in which participants had to adapt their lifting behaviour to lift an unexpectedly heavy object. They observed that as children learnt to lift the object more proficiently, the rTPJ is engaged, suggesting its involvement in updating the child’s prior hypotheses about the weight of the object towards more accurate ones about its true weight. Further, they found that children’s performance in the load-force adaption task is related to their performance in a theory-of-mind battery (Sabbagh, 2017). Moreover, children’s superior ability in both tasks were related to their resting EEG alpha activity, indicating a common neural basis for conceptual change. While this evidence provides further support for the theory-theory approach to understanding theory-of-mind development, more research is required on how the rTPJ is activated while engaging in theory-of-mind reasoning in the moment and how its neuromaturation may influence the emergence of false-belief understanding.

Simulation theorists, on the other hand, argue for the involvement of different theory-of-mind brain regions. Simulation theory became popular amongst neuroscientists upon the discovery of the mirror neuron system in macaques. This mirroring system is proposed to be activated when an individual is performing an action, as well as when they are observing someone else perform the same action, suggesting a process of simulation when interpreting human behaviour. In attempting to explain theory of mind, they hypothesize that a similar system to the mirror neuron system in monkeys exists in the human brain. In macaques, this activity is observed in the ventral premotor cortex, whereas in humans, it is thought to involve the right inferior parietal cortex and the inferior frontal gyrus (Rizzolatti et al., 1988; Ramnani & Miall, 2004). Suppression of EEG mu activity over these regions is considered as an index of the mirror neuron system (Fan et al., 2010; Perry, Troje, & Bentin, 2010). Infants as young as 6 months are shown to exhibit this mu suppression during goal-directed action and observation of the same action (Marshall & Meltzoff, 2011). However, some researchers argue that mu activity is an unreliable measure of mirror neuron activity as it can be easily confounded with alpha suppression. Attentional processes has been associated with alpha suppression, suggesting that mu activity may instead be indexing attention as well, rather than actual mirroring processes (Hobson & Bishop, 2016).

5.4.2 Infant Theory of Mind

Do Infants Have a Theory of Mind?

Although the emergence of a representational theory of mind between 3 and 5 years old is observed as a universal phenomenon, some researchers believe that false-belief understanding might present itself earlier on in development, reigniting a debate within the field about when children actually start to attribute mental states to others.

In their seminal study, Onishi and Baillargeon (2005) provide evidence that infants as young as 15 months are able to understand false beliefs. To test this, they used a violation-of-expectation paradigm that assumes infants look longer at unexpected events compared to familiar ones. In their task, 15-month-old infants watched as an actor places an object (e.g., a toy) into one of two boxes; upon placement, the actor watches the object move to the opposite box (i.e., true-belief condition) or the actor is hidden away so that they are unable to see the object move locations (i.e., false-belief condition). Since the actor does not see the object move in the false-belief condition, it would be reasonable to assume that they will look for the object in the last place they left it in. However, in this experiment, the actor unexpectedly reaches for the correct location instead. The researchers found that infants can recognize this violation in expectation and look longer at such a surprising event than they do when she reaches for the object in the original, incorrect location. This suggests that infants expect her to reach for the wrong location, leading the experimenters to conclude that 15-month-old infants might have an implicit understanding of false beliefs (Onishi & Baillargeon, 2005). This finding ultimately began a new line of research looking at infant theory of mind, influencing the development of different paradigms using anticipatory looking (Southgate, Senju, and Csibra, 2007) or active helping (Buttelmann, Carpenter, and Tomasello, 2009).

Due to its subversion of the literature, these findings have prompted a debate as to how infants can pass the false-belief task when 3-year-old children were shown to consistently fail at it. In order to explain why children cannot succeed on standard false-belief tasks after preschool years, they propose that explicit and verbal responses to the tasks places too much cognitive load on the infants. Prior to age 5, children do not have the executive functioning required to inhibit their own perspectives. Executive function plays a role in theory of mind since in order to understand others, we need to inhibit our own perspectives in order to attend to the perspectives of others. Although these findings may lead to the conclusion that infants have false-belief understanding, some researchers still question these findings, targeting the replicability and generalizability of implicit measures of theory of mind (Sabbagh & Paulus, 2018).

Altercentricism

In a recent paper, Southgate (2019) proposes an alternative hypothesis to this discussion of an infant theory of mind. Contrary to Piaget’s claims that we transition from an egocentric perspective to an allocentric one, she hypothesizes that infants are instead born attuned to others’ perspectives from birth and then develop a sense of self later on. Southgate coins this innate perspective-taking “altercentricism” and it may explain infants’ successful anticipation of others’ behaviours in implicit theory-of-mind tasks. She argues that older children have better self-representation than infants, and that this produces conflicts in their perspective-taking, resulting in 3-year-olds’ difficulties with explicit theory-of-mind tasks. It is not until children develop the proper executive functions at around age 5 that they are able to inhibit their newfound self-perspectives and succeed in these explicit theory-of-mind tasks. In attempting to explain infants’ success in implicit theory-of-mind tasks, Southgate proposes that it may be that infants are already able to represent others’ minds before they even form representations of their own mind.

Section Summary

• Theory of mind is the conceptual framework we use to reason and make inferences about others’ mental states
• False-belief understanding develops over the preschool years, with its emergence at around age 5 marked as one of the most important milestones in children’s social-cognitive development
• Theory-theorists claim that children hold theories about human behaviour that are continuously updated as they gain more experience in the social world
• Simulation theorists claim that children predict human behaviour by projecting their own mental states onto others
• Using implicit theory-of-mind measures, some researchers argue that infants as young as 15 months are able to understand false beliefs

5.5 Early Relationships

Humans are amongst the most altricial species as their offspring require long-term and intensive care from others. These early relationships are argued to be conducive to infants’ proper social and behavioural development, but what exactly are its influences? In contrast, how does social neglect impact children’s development? And what role do families play in the development of children’s social understanding?

5.5.1 Need for Social Connection

Studies on parent-infant attachment emphasize our need to connect to others shortly after birth. For new parents and their new-born infants, the relationship between parent and child will be one of the most important relationships they form in their lifetime. Many early researchers agreed that parents and infants share a special bond, but there was initially some uncertainty over why this bond was formed. Proponents of behaviourism believed that infants form social bonds with their mother simply because they provide sustenance. Infants may link food with their mother through conditioning, with the food as the unconditioned stimulus and the mother as the conditioned stimulus. According to behaviourists, this association between food and mother forms the basis of the parent-infant relationship by motivating infants to seek out their mother for nourishment (Dollard & Miller, 1950).

Psychologist Harry Harlow had a different idea that was influenced by his work with monkeys. He observed that when raised separate from their mothers, infant rhesus monkeys had normal physical development but suffered from emotional and behavioural problems unless given some form of affection. Based on this observation, Harlow developed his infamous experiment on the importance of physical comfort. Harlow separated new-born monkeys from their mothers and raised them in cages with artificial surrogates: a wire tube wrapped in cloth designed to provide comfort (i.e., cloth mother) and another tube left bare, with only the wire exposed (i.e., wire mother). In one condition, infants were fed by experimenters through the cloth mother and he observed that they spent no time with the wire mother. In another condition, the infants were fed through the wire mother. This time, he observed that infant monkeys would only visit the wire mother only when they were hungry but still spent most of their time clinging onto the cloth mother (Harlow, 1958). These observations led to Harlow’s conclusion that infant monkeys preferred, and thus likely needed, the comfort provided by the cloth mother. These findings informed developmental psychologists about the infant’s needs for physical comfort, but the monkeys involved in the experiment nonetheless developed severe emotional and behavioural problems from being separated from their real mothers. While this study may have been influential in establishing that infants need more than their physical needs met to adapt in the world, the experiment was criticized as unethical and cruel.

5.5.2 Parent-Infant Attachment

Attachment Theory

The studies on the effects of social neglect on children and monkeys has since reshaped the way psychologists think about infants’ early relationships. In response to the findings on social neglect in infancy, John Bowlby (1953) proposed in his attachment theory that the way we relate with others is influenced by our very first relationships with our caregivers. Since infants require comfort and a feeling of safety, caregivers who provide these needs establish themselves as a secure base. This provides the infants a sense of security so that they feel comfortable exploring and learning about the world. This secure base also serves as a source of comfort when the infant is threatened or insecure. Deriving such comfort and pleasure from the caregiver, the infant thus forms an attachment to them.

These early relationships form the individual’s internal working model of attachment, a mental representation of the self, of attachment figures, and of relationships in general. These models are based on the child’s perception of whether the attachment figure provided a secure base for them. Bowlby believed that this internal working model would guide infants’ expectations about relationships throughout their life. Parents who provide a secure base form a positive working model of attachment in the child that when they grow up, they will expect to find secure relationships similar to the ones with their attachment figures.

Attachment Styles

Mary Ainsworth, a colleague of Bowlby, expanded upon his attachment theory. Based on her observations of mother-infant interactions, Ainsworth came up with two factors that she believed provided information on the quality of the infant’s attachment to the caregiver: 1) the degree to which the infant uses the caregiver as a secure base, and 2) how the infant reacts when they are separated or reunited with their caregiver. Considering these factors, Ainsworth developed the Strange Situation task. In this task, infants’ behaviours are observed as they play and experience different scenarios: the mother leaving them alone in the room, the mother leaving them alone with a stranger, and the mother coming back to reunite with them. Ainsworth aimed to examine the infants’ behaviours at all three stages of the Strange Situation task, including their attempts to seek contact with their parents, resistance against the parent when they returned, and interactions with the stranger in the presence and absence of the parent. From her study, Ainsworth discovered four distinct patterns of infant behaviour that provide insight into the quality of the parent-infant attachment: secure, insecure-resistant, insecure-avoidant, and disorganized. These attachments are ultimately influenced by the parents’ behaviours towards the child at home (see Table 1).

Table 1

Influence of Child and Parent Characteristics on Attachment Styles

Individual Differences

Even though humans are biologically predisposed for attachment, there are still individual differences that produce variability in children’s attachment styles. To explain this, scientists point to a few factors: parental sensitivity, cultural variations in parenting, and genetic predispositions.

Parental sensitivity is characterized by the parent’s expression of warmth and their responsiveness to their child’s needs. In order to build a secure attachment with the child, parents must express warmth through positive exchanges with the child like mutual smiling and playing (Bigelow et al., 2010). They must also respond quickly to their child’s needs in a consistent way. Research shows that inconsistent parenting tends to result in insecure-resistant attachment styles in the child, whereas emotionally unavailable parents increase the risk for insecure-avoidant children.

Further differences in attachment styles can be observed when comparing cultural variations in parenting. For instance, in studies done in Japan and Korea, insecurely attached children were classified as only insecure-resistant (Takahashi, 1986; Jin et al., 2012). Children raised in these cultures tended not to exhibit insecure-avoidant attachment styles compared to children in Western cultures. Researchers speculate that this may be due to the child-rearing practices in these cultures that foster parent-infant closeness and physical intimacy (Rothbaum et al., 2000). As such, children there tend to remain close to their parents and experience greater anxiety around strangers.

In terms of genetic influences, researchers have found that allelic variants in the serotonin transporter gene (SLC6A4), which has been associated with vulnerability in the face of adversity, affects children’s behaviour in Strange Situation tasks. Researchers compared the effects of this allelic variant on the behaviours of Ukrainian preschoolers raised in an institution and those raised with their biological families in the Strange Situation task. They observed that children with the variant who were raised in an institution had less attachment security. However, those with the same variant who were raised with their biological families exhibited more attachment security. In contrast, children who had a different genotype that was associated with less reactivity to stress exhibited no adverse attachment behaviours (Bakermans-Kranenburg, Dobrova-Kral, & Ijzendoorn (2012).

These studies further reinforce the idea that both internal and external factors play a role in children’s development and in this case produces the wide variety of attachment styles observed in the population. It also emphasizes that even though there may be biological predispositions towards certain styles, insecure attachments can be mitigated by sensitive parenting and provision of stimulating and loving environments.

5.5.3 Family Influences on Theory of Mind

While children’s understanding of minds is commonly studied in terms of their success in false-belief tasks, it can also be studied in relation to external characteristics like family dynamics and parenting variables.

Generally, the way family members interact with one another has been shown to play an important role in children’s theory-of-mind performance. Dunn et al. (1991) found that the parents’ tendency to talk about feelings and use causal state language positively influences the child’s social-cognitive development. More specifically, parents’ mind-mindedness, that is their propensity to view the child as a mental agent, has been shown to encourage the child’s understanding of others as mental agents (Meins et al., 1998). Recent research also emphasizes the role of parental mental state talk, the tendency to use words that refer to another’s cognition (e.g., believe, think, know), desire (e.g., want, like), and emotions (e.g., happy, upset), in children’s theory-of-mind development (Devine et al., 2019).

Alongside the parents, it is believed that siblings can also influence the child’s social understanding. This may be accomplished through the discussion of internal states, joint play, shared jokes, and reasoning about moral issues (Dunn, 1994). Indeed, preschoolers with older siblings have been shown to outperform those without siblings on theory-of-mind tasks (Lewis et al., 1996). The number of child-aged siblings also predicts false-belief understanding during early childhood (Devine & Hughes, 2016).

These studies emphasize the importance of relationship quality between children and family members in the infant’s social-cognitive development. It also demonstrates that the content of the discourse between infants and their family members influences the child’s theory-of-mind development.

Section Summary

• Infants need comfort and interpersonal connection for proper social and behavioural development
• Infants’ attachment styles are influenced by parent’s behaviours and the infant’s own genetic predispositions
• Infants’ early attachment to others determines their attachment styles in relationships later in life
• Parental social interactions using mind-mindedness and mental state talk is positively correlated with children’s theory-of-mind development