1980: Jean Piaget dies

On 16 September 1980, Jean Piaget died in Geneva, Switzerland, aged 84. The Swiss biologist-turned-psychologist had spent a lifetime studying how children think, producing a body of work that would quietly reshape not only education and developmental psychology but also the emerging field of artificial intelligence.

Piaget proposed that children actively construct their understanding of the world through successive stages: the sensorimotor stage of infancy, the preoperational stage of early childhood, the concrete operational stage, and finally the formal operational stage of abstract reasoning. Knowledge, he insisted, is not poured into a passive mind but built through exploration, assimilation and accommodation—processes he meticulously documented by observing his own children and countless others.

These ideas crossed into computing through Piaget’s collaboration with Seymour Papert. In the 1960s Papert, who had worked with Piaget in Geneva, joined Marvin Minsky at the MIT Artificial Intelligence Laboratory. There he developed the Logo programming language and the philosophy of constructionism: the belief that people (and potentially machines) learn best by building things and reflecting on the process. Logo turtles and children’s computational-thinking exercises became living laboratories for Piagetian principles applied to silicon.

The thread continues today. Curriculum learning in machine learning—training neural networks on simpler examples before harder ones—echoes Piaget’s staged progression. Developmental robotics explicitly seeks to endow robots with infant-like learning trajectories. Cognitive architectures and educational AI tutors still draw on constructivist foundations. Even large language models, which refine their internal representations through successive layers of abstraction, invite comparison with the journey from concrete operations to formal thought.

Piaget never wrote a line of code, yet his insistence that intelligence is constructed, not merely programmed, remains one of the deepest intellectual currents feeding contemporary AI. On the anniversary of his death we remember how a careful observer of children’s sandcastles helped shape the way we build thinking machines.