Infants' understanding of the causal power of agents and tools

Two distinct neural pathways for mechanical versus digital technology

Technology pervades every aspect of our lives, making it crucial to investigate how the human mind deals with it. Here we examine the cognitive and neural foundations of technological cognition. In the first fMRI experiment, participants viewed videos depicting the use of mechanical tools (e.g., a screwdriver) and digital tools (e.g., a smartphone) compared to simple object movements. Results revealed a key dissociation: mechanical tools extensively activated the dorsal and ventro-dorsal visual streams, which are motor- and action-oriented brain systems. Conversely, digital tools largely engaged the ventral visual stream, associated with conceptual and social cognition. A second behavioral experiment showed a pronounced tendency to anthropomorphize digital tools. A third experiment involving a priming task confirmed that digital tools activate the social brain. The discovery of two different neurocognitive systems for mechanical versus digital technology offers new insights into human-technology interaction and its implications for the evolution of the human mind.

Causal relational problem solving in toddlers

We investigate young children's capacity for "causal relational reasoning": the ability to use relational reasoning to design novel interventions and bring about novel outcomes. In two experiments, we show that 24-30-month-old toddlers and three-year-old preschoolers use relational reasoning in a causal problem-solving task. Even toddlers rapidly inferred relational causal rules and applied this knowledge to solve novel problems--thus demonstrating both surprisingly early competence in relational reasoning and sophisticated causal inference. In both experiments, children observed a handful of trials in which a mechanistically opaque machine made objects larger or smaller. When prompted to solve a new problem, they used the machine to change the relative size of a novel object - even though its appearance and absolute size differed from previous observations, and even though subjects had never seen the machine generate objects of the required size before. This suggests that children quickly inferred abstract causal relations and then generalized these relations to determine which intervention would bring about the novel outcome required to solve the problem. These findings suggest a close link between early relational reasoning and active causal learning and inference.

Abstract thematic roles in infants' representation of social events

Infants' thoughts are classically characterized as iconic, perceptual-like representations.1,2,3 Less clear is whether preverbal infants also possess a propositional language of thought, where mental symbols are combined according to syntactic rules, very much like words in sentences.4,5,6,7,8,9,10,11,12,13,14,15,16,17 Because it is rich, productive, and abstract, a language of thought would provide a key to explaining impressive achievements in early infancy, from logical inference to representation of false beliefs.18,19,20,21,22,23,24,25,26,27,28,29,30,31 A propositional language-including a language of thought5-implies thematic roles that, in a sentence, indicate the relation between noun and verb phrases, defining who acts on whom; i.e., who is the agent and who is the patient.32,33,34,35,36,37,38,39 Agent and patient roles are abstract in that they generally apply to different situations: whether A kicks, helps, or kisses B, A is the agent and B is the patient. Do preverbal infants represent abstract agent and patient roles? We presented 7-month-olds (n = 143) with sequences of scenes where the posture or relative positioning of two individuals indicated that, across different interactions, A acted on B. Results from habituation (experiment 1) and pupillometry paradigms (experiments 2 and 3) demonstrated that infants showed surprise when roles eventually switched (B acted on A). Thus, while encoding social interactions, infants fill in an abstract relational structure that marks the roles of agent and patient and that can be accessed via different event scenes and properties of the event participants (body postures or positioning). This mental process implies a combinatorial capacity that lays the foundations for productivity and compositionality in language and cognition.

Children's representation of coincidence

People relish thinking about coincidences-we puzzle over their meanings and delight in conveying our experiences of them to others. But whereas some research has begun to explore how coincidences are represented by adults, little is known about the early development of these representations. Here we explored factors influencing coincidence representations in both adults and children. Across two experiments, participants read stories describing co-occurring events and then judged whether these constituted coincidences. In Experiment 1 we found that adults' coincidence judgments were highly sensitive to the presence or absence of plausible explanations: as expected, adults were more likely to judge co-occurrences as a coincidence when no explanation was available. Importantly, their coincidence judgments were also modulated by the number of events that co-occurred. Adults tended to reject scenarios involving too many co-occurring events as coincidences regardless of whether an explanation was present, suggesting that observing suspiciously many co-occurrences triggered them to infer their own underlying explanation (and thus blocking the events' interpretation as a coincidence). In Experiment 2 we found that 4- to 10-year-old children also represent coincidences, and identify them via the absence of plausible explanations. Older children, like adults, rejected suspiciously large numbers of co-occurring events as coincidental, whereas younger children did not exhibit this sensitivity. Overall, these results suggest that representation of coincidence is available from early in life, but undergoes developmental change during the early school-age years.

Infants' understanding of the causal power of agents and tools

Tools are objects that are manipulated by agents with the intention to cause an effect in the world. We show that the cognitive capacity to understand tools is present in young infants, even if these tools produce arbitrary, causally opaque effects. In experiments 1-2, we used pupillometry to show that 8-mo-old infants infer an invisible causal contact to account for the-otherwise unexplained-motion of a ball. In experiments 3, we probed 8-mo-old infants' account of a state change event (flickering of a cube) that lies outside of the explanatory power of intuitive physics. Infants repeatedly watched an intentional agent launch a ball behind an occluder. After a short delay, a cube, positioned at the other end of the occluder began flickering. Rare unoccluded events served to probe infants' representation of what happened behind the occluder. Infants exhibited larger pupil dilation, signaling more surprise, when the ball stopped before touching the cube, than when it contacted the cube, suggesting that infants inferred that the cause of the state change was contact between the ball and the cube. This effect was canceled in experiment 4, when an inanimate sphere replaced the intentional agent. Altogether, results suggest that, in the infants' eyes, a ball (an inanimate object) has the power to cause an arbitrary state change, but only if it inherits this power from an intentional agent. Eight-month-olds are thus capable of representing complex event structures, involving an intentional agent causing a change with a tool.