New research shows that infants as young as five months can tell the difference between helpful and harmful behaviors. The study, published in Social neuroscience, used brainwave monitoring to observe how babies’ brains respond to prosocial (helpful) and antisocial (harmful) actions. This research provides new insights into the early development of social cognition and moral evaluation in infants.
The motivation for this study stems from a long-standing curiosity in the scientific community about the roots of moral behavior and cognition. Previous research has shown that from an early age, infants pay more attention to certain social cues, such as attractive faces and emotional expressions. Additionally, studies have indicated that infants can distinguish between positive and negative behaviors toward others.
However, the neural basis of these early moral evaluations in infants has remained largely unexplored. Researchers sought to fill this gap by studying how the infant brain processes and responds to prosocial and antisocial actions.
“Understanding the roots and early development of moral cognition is a hot and highly debated topic within developmental cognitive neuroscience over the past 20 years,” said study author Elena Nava, associate professor at the University of Milan-Bicocca. and member of the Bicocca Child & Baby Lab.
“Indeed, understanding whether human beings are prone to moral thought provides a window into how we become moral animals, if we ever become one, and into the experiences that promote prosocial or antisocial behavior.”
“In particular, in this study we were interested in the neural correlates of early moral cognition, because evidence for neurophysiological underpinnings is sorely lacking in infants on this specific topic. There are several reasons why studying the neural correlates of moral cognition (and all cognition in general!) is important: first, it can add content to the idea that babies are endowed with sense primitive of morality. Second, it suggests that babies already have brain circuits to encode complex cognitive information.
To conduct this study, researchers recruited 24 healthy, full-term infants aged five to six months. These infants were selected from a larger group, with others excluded due to factors such as agitation or problems with brain wave data. The study consisted of two phases: a familiarization phase and a test phase.
During the familiarization phase, infants watched short videos showing puppets engaging in helpful (prosocial) or distracting (antisocial) actions. The test phase consisted of showing the infants still images from these videos, simulating the course of actions. During both phases, the infants’ brain waves were monitored using an electroencephalography (EEG) headset, providing data on their neural responses to the stimuli.
During the familiarization phase, there was no significant difference in the amount of time infants watched prosocial or antisocial videos, indicating equal initial interest in both types of actions. However, data on brain activity paints a more complex picture. Researchers have focused on specific patterns of brain activity known as event-related potentials (ERPs), which are brain responses to specific sensory, cognitive, or motor events. They found that infants’ brains responded differently to prosocial and antisocial scenes in several ways.
One important finding was related to a brain response called the N290, which showed greater amplitude, or a stronger brain response, to prosocial scenes, such as a puppet helping another puppet. This suggests that infants may inherently find purposeful actions more engaging or meaningful. Another brain response, called Nc, was greater in amplitude for antisocial actions, such as one puppet getting in the way of another. This could mean that negative actions attract more attention in infants, possibly due to their more exciting or uncomfortable nature. Additionally, a late brain response called LPP was greater in response to prosocial scenes, indicating deeper processing of these positive social interactions.
“Babies begin very early in life to develop a sense of morality, which helps them distinguish between those who behave ‘good’ and those who behave ‘bad’. Although it is difficult to determine whether this discrimination also corresponds to a moral judgment, our data reveal that by 5 months of age, the baby’s brain is able to detect and discriminate actions that qualify individuals as act morally or immorally,” Nava told PsyPost.
The study also explored the relationship between infants’ temperament and their brain responses. Intriguingly, higher scores on “intensive control” – a trait linked to self-regulation – were associated with increased neural bias toward antisocial interactions. This finding suggests that temperament may play a role in how infants handle social interactions.
However, when it came to the manual choice task, where infants were given a choice between a prosocial and antisocial puppet, no significant preferences were found. This lack of preference contrasts with some previous studies and raises questions about the consistency of infants’ behavioral responses to moral scenarios.
“We were disappointed by the mismatch between the behavior and the neural data,” Nava said. “We expected that infants would also prefer the prosocial individual over the antisocial individual, as assessed using manual choice, and that this would correlate with the neural findings. However, this was not the case, as we found no differences between prosocial and antisocial individuals (behaviorally).
While the study highlights the early development of moral cognition in infants, it is not without limitations. A major challenge in studies involving infants is the high rate of data exclusion due to factors such as movement or agitation. This was also the case in this study, where a significant number of infants initially tested had to be excluded. Additionally, the limited number of trials each infant could participate in before losing attention could have affected the depth of the results. Future research could benefit from shorter, more engaging stimuli that could hold infants’ attention longer, allowing for more comprehensive data collection.
“There are so many questions that still need conclusive answers,” Nava said. “For me, two questions/interests deserve to be studied: first, the role of individual differences in promoting moral cognition; Second, more longitudinal studies investigating whether early sensitivity to moral cognition predicts higher moral behavior later in childhood.
The study, “Neural Signatures of Prosocial and Antisocial Interactions in Young Infants,” was authored by Victoria Licht, Margaret Addabbo, Elena Nava and Chiara Turati.
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