Alexandre R.J. Francois

This is the last post in the series Brain - Time - Music - Computing . Previous: Time and the Brain The notion of computation was explicitly created for use outside of the flow of MWT. Models of computation provide primitives for describing processes in a purely timeless context (computability), or in an artificial and abstract flow of time marked by computational operations (algorithmic complexity). The resulting abstract manifestation of time in computing is enforced as a strong invariant, universally and implicitly relied upon. This state of affairs has serious implications for the design and use of computing artifacts in MW. Music exists at the confluence of creation, representation and performance, where inherent limitations of time representations in computation become evident. Music systems fall into two broad categories: online or real-time systems, and off-line system. The significance of these categories in the context of interaction is explored in [1]. Henkjan Honing more speci...

This is part 4 of 5 in the series Brain - Time - Music - Computing . Previous: Time and Perception Next: Time in Computation If the flow of MWT is immutable, the human brain hardly perceives it as such. Gooddy, in his book Time and the Nervous System [3], distinguishes between Personal Time (PT) and Government Time (GT). The former marks the flow of time (MWT) as perceived by the individual brain; the latter refers to the passage of time as measured by a collectively recognized reference clock, from the brain’s perspective an external synchronization device to MWT. Alteration in the perception of time, of the flow of one’s PT, occur within the perceiving agent’s mind. Fraisse emphasizes the necessity to separate the perception of duration, which takes place in the psychological present, and the estimation of duration which “takes place when memory is used either to associate a moment in the past with a moment in the present or to link two past event” [2]. Memory frees the mind from the c...

This is part 3 of 5 in the series Brain - Time - Music - Computing . Previous: The Brain in Middle World Next: Time and the Brain Scales of time in MW play a crucial role in the recognition and interpretation of temporal patterns, by the brain, as symbolic relationships such as causality and synchrony. Events that are perceived as shortly following each other in time tend to be interpreted in a causality relationship. Brains learn the range of latencies that may separate an action and the perception of its effect in MW. The quantitative characterization of acceptable latencies is crucial to the understanding of interaction. Human-computer interaction researchers [4][1] categorize acceptable time delays into three orders of magnitude, which coincide with Newell’s cognitive band in his time scale of human actions [5]: the 0.1s (100ms) scale characterizes perceptual processing, perceived instantaneous reaction; the 1s scale characterizes immediate response, continuous flow of thought (cons...

This is part 2 of 5 in the series Brain - Time - Music - Computing . Previous: Middle World Next: Time and Perception Even though perpetual contingency characterizes Middle World , the underlying dynamics are not random. On the contrary, their complexity thinly veils a rich variety of spatio-temporal patterns [4]. The term pattern, here, denotes “a regular and intelligible form or sequence discernible in certain actions or situations; esp. one on which the prediction of successive or future events may be based” (Oxford English Dictionary). Under such conditions, the brain has evolved into a highly effective spatio-temporal pattern detection and prediction system [2]. Moreover, the brain exhibits an “infovorous” behavior [1]: it craves for new experiences. More specifically, studies have linked sensory novelty and surprise to pleasure and reward activity in the brain. This is consistent with the continuous refinement of the prediction system through acquisition of new knowledge. Both the...

This is part 1 of 5 in the series Brain - Time - Music - Computing . Next: The Brain in Middle World Dawkins remarks that brains have evolved to help animals survive within the orders of magnitude of size and speed at which their bodies operate. He calls Middle World (MW) this relatively narrow range of phenomena directly and intuitively accessible to perceptual and cognitive processes [2]. Dawkins invokes the human brain’s evolutionary entanglement with MW to explain humans' difficulty in grasping, and coping with, the physical realities of the universe outside of its familiar confines, from the sub-atomic scales of quantum physics to the universe-size scales of relativity. But the fundamental properties of MW can also help characterize the nature of the tasks at which brains came to excel, in particular the fundamentally dynamic nature of these tasks. Everything in MW is subject to what the human brain perceives and understands as time, “the continuum of experience in which even...

The next 5 posts are excerpts from a chapter, titled "Time and Perception in Music and Computation," which appears in the book New Computational Paradigms for Computer Music , pp.125-146. The Oxford English Dictionary defines music as “the art or science of combining vocal or instrumental sounds to produce beauty of form, harmony, melody, rhythm, expressive content, etc.” Composers and performers of music invent and produce sounds, carefully organized with the intent and purpose to trigger emotional responses from the listeners, usually humans. Creating music therefore involves deep understanding and mastery, whether intuitive of explicit, of the human auditory perceptual and cognitive apparatus. A reflexion on the nature of the phenomena involved points towards the ability of the mind to move in and out of flows of time, real or imaginary, as a defining feature of perceptual and cognitive activities. A comprehensive computational paradigm for computer music must afford the mode...