Detecting Degrees of Density in Aggregates:Can we hear a cluster?

Considering a cluster to be a psycho-physiological phenomenon of which the individual constituents are losing perceptibility in favor of its contour, a double experiment was set up to study the aural perception of aggregates with varying degrees of density within a fixed contour. The primary interest was vested in detecting quantity (number of tones), quality (identity of tones), cohesion (gaps in the accumulation) and contour (size of the interval)