Human–Instrument Interaction & Musical Agency
This research direction studies the interaction between human motor behavior and instrument geometry. Kaduk approaches the instrument as an extension of the human motor system rather than a neutral mechanism. The samples below highlight points where empirical observation forced fundamental changes in interface design assumptions.
Jankó Keyboard × Clinical Hand Imaging
A historical Jankó keyboard (Francke pianino), on long-term loan from the Geelvinck Museum, was studied for years at Kaduk as a comparative and daily-play interface to understand how alternative keyboard geometries redistribute load in damaged hands. In collaboration with hand surgeon C.A.J. Holtzer, extensive MRI imaging at Beatrixziekenhuis was used to correlate internal hand damage with specific movement patterns enforced by conventional grand piano keyboards. The research showed which movements can be bypassed using alternative geometries—and where new wrist-related problems emerge—making it impossible to treat keyboard geometry as neutral. From this point on, internal interface geometry, proportioning, and mechanical configuration became explicit health-critical design variables rather than historical givens.
Performer control depends on whether an instrument satisfies the nervous system’s implicit expectations at micro-timescales: tiny deviations in response feel immediately “off,” even when they are hard to isolate consciously. Kaduk treated this as a psychophysics problem (JND): what changes in haptic response and transient behavior are detectable, learnable, and musically usable in context. Using high-resolution sensing, we replayed identical keystrokes through different interpretation models—one “average-velocity” model typical of digital pianos, and one ballistic model consistent with real piano mechanics—and obtained vastly different musical outcomes from the same physical input. This forced a non-negotiable conclusion: to remain part of the piano family (easy to begin, hard to master), the instrument must be acceleration/ballistics-meaningful, not velocity-smoothed.
