A cybernetic movement is one that incorporates a feedback loop between two separate oscillators to improve timekeeping.
The first movement to be called “cybernetic” was the 1969 Longines Ultra-Quartz. It used the interaction between a quartz oscillator and vibration motor in cybernetic fashion. This would be the first quartz watch announced for production. Although also participating in the Beta 21 project, Longines developed the Ultra-Quartz in-house. The company would sell both Ultra-Quartz and “Quartz-Chron” (Beta 21) models in 1970 and 1971.
Bulova was next with a cybernetic hybrid movement, though they did not use the term. The 1971 Accuquartz combined the tuning fork of the Accutron with a quartz crystal. The concept was similar to the Ultra-Quartz, though Bulova was able to use an integrated circuit to reduce power consumption, complexity, and cost. By leveraging components of the Accutron, Bulova was able to sell the Accuquartz far cheaper than competing quartz watches. It was also the first quartz watch available in the United States market, and the first produced there.
The cybernetic concept was not used again until F.P. Journe's “resonance” line in the 2000s. Later dual-balance and double-tourbillon movements have also incorporated the concept in recent years.