HAGENDOORN, Ivar. Cognitive dance improvisation: how study of the motor system can inspire dance (and vice versa). LEONARDO, v.36, n.3, p.221–227, 2003.
ABSTRACT: This paper describes several dance improvisation techniques inspired by the study of the motor system. One technique takes experiments on interlimb coordination from the laboratory to the dance studio. Another technique, termed fixed-point technique, makes use of the fact that one can change which part of the body is fixed in space. A third technique is based on the idea that one can maintain the action, as it were, by “reversing the acting limb.” All techniques target a specific capacity of the motor system and as such may inspire new psychophysical experiments. The present approach to generating movements, which merges dance improvisation with insights from cognitive neuroscience and biokinesiology, may also be fruitfully extended to robotics.
- A dance performance can be seen as a journey through the state space of all possible movements. In a choreography the dancer, who acts as a guide to the audience on this journey, has to follow the path set out by a choreographer, who has mapped out an itinerary in advance. In dance improvisation, by contrast, the journey is created on the spot, which is what makes improvisation interesting to both dancer(s) and audience. p.221
- Improvisation introduces an additional problem, as the dancers have to make their decisions on the fly. The moment they have made up their minds, they are confronted by the same problem all over again. Dancers thus face two conflicting challenges. On the one hand they have to structure their movements so as to create an interesting performance, while on the other hand they have to avoid “getting stuck” in the same patterns of movements. p.222
- Habits are unconscious and can therefore get in the way of desired movements. As a matter of brain processing, habits are computationally efficient. An action can unfold without requiring every individual step to be worked out in advance. It is therefore not surprising that, when improvising, dancers also tend unconsciously to repeat certain movements. p.222
- Instead of applying constraints, one can also design rules or techniques for generating a particular type of movement. An improvisation technique should be generic in that it can apply to different body configurations and movements. It should also be specific in that it offers a cognitive shortcut to describing a particular class or subset of (the space of all possible) movements. p.222
- In my own work, I look for sources of movement strategies in the way that movements are processed by the brain. The idea is that, when made explicit, the implicit properties of the motor system can be put under conscious control. And because these properties are hardwired in the brain, they may be easily generalized and extended to other movements or body configurations. For instance, a default property of the motor system can be seen as a specific instance of a range of movements, while a solution to a particular behavioral problem can be generalized to other situations. p.222
- A number of my improvisation techniques relate to the representation of space. The brain does not accommodate a single, uniform representation of space, but a multiplicity of sensory and motor spaces subserving perception and action [10. M.A. Arbib, “Interactions of Multiple Representations of Space in the Brain,” in J. Paillard, ed., Brain and Space (Oxford, U.K.: Oxford Univ. Press, 1991) pp. 379–403] To construct a representation of space, the brain builds on information delivered by the senses. p.222
- In order for one to reach for an object, say, an apple, visual information about its location and information about the position and orientation of the body have to be combined with information about the position of the hand relative to the apple, its estimated size and weight and the use to which it will be put . p.222
- The first thing to observe is that we can fix an intrinsic relationship between two or more parts of the body and maintain that relationship as we move across extrinsic space . For instance, we can stretch an arm and walk around, squat, lie down on the floor, etc., while keeping the arm stretched—that is, while maintaining the intrinsic relationship between arm and chest. p.223
- In motor control experiments, the emphasis is on measuring the interference during the repetitive performance of two trajectories. What is most interesting from the perspective of dance improvisation, however, is switching between two modes: e.g. changing from small clockwise circular movements with the right foot and both hands to a large counterclockwise circle with one arm and small lines with the other hand and foot. p.225
- A motor schema is an abstract representation of a prototypical movement sequence such as a tennis serve or an arabesque. It refers to the pattern or the structure of a movement sequence rather than giving a full description of its dynamics. An arabesque remains an arabesque whether it is performed slowly or quickly, with grace or with vigor. A motor schema can be either simple or complex, which is what makes it such an attractive concept. Schemas are recursive in that they can be decomposed into smaller schemas down to the level of their neural foundation or alternatively embedded in or combined with other schemas to form a new higherorder schema. It follows that new schemas evolve as instances of existing schemas or, in the words of neuroscientist and computer scientist Michael Arbib, “They start as composite, emerge as primitive schemas” [Arbib, 1991]. p.225