Measuring Behavior 96: Looking Back...

Berry Spruijt, Rudolf Magnus Institute, Utrecht University, Utrecht, The Netherlands

Sequential organization of behavior
Over the past decades we have observed an accelerating development of scientific tools for measuring biological responses. The study of behavior under variable circumstances is special in that it requires a very flexible and non-invasive approach. Technology first appeared at the level of data acquisition. Behaviors were no longer handwritten but registered with a computer keyboard. This was at first an extension of the human "subjective observation" ability. This ability to estimate what is essential in behavior remains indispensable for defining new parameters and guiding new developments in behavioral measurements. Next, novel analysis methods yield new parameters which may so far have escaped our intuitive understanding of behavior. The sequential organization of behavior, which can be expressed in rigidity or plasticity, is not always noticed by our eyes. Nice examples of this phenomenon were given by Dr. M.S. Magnusson (Reykjavik) in his talk on pattern detection and by Dr. M.R. Kruk (Leiden) in his thought-provoking closing lecture.

Implicit or explicit intentions
What we measure is no longer solely determined by what we can measure, but rather by what we want to measure. For instance, behavioral physiologists and neuro-ethologists want to apply their knowledge of the underlying neural substrate on the output of the brain, i.e., behavior. Their goal is not so much an understanding of the biological function of the behavior itself, but they use behavior as an indicator, e.g., of the efficacy of a drug. However, we must always be aware of the danger of incorporating the assumed intentions of a particular behavior in the definitions of the ethogram and now - even more dangerous - in the algorithms of computer programs automatically recording behavioral patterns. Behaviors such as 'approach' and 'avoidance' implicitly presume an intention of the animal, in contrast to spatial displacements and directions measured by an automated system. Assumed intentions of behavior implied in their definition become explicit for the designer of automatic behavior recognition software, but may remain hidden for the user of such a program! Whether that is acceptable, depends on the arguments one may have to presume an intention. This potential danger in the automation of behavioral observations was recognized at the workshop, but it should receive more attention.

Technological advances
At the workshop, several exciting methodological and technical innovations were presented. To mention just a few:

Implications of automation which deserve special attention
The validity of parameters measured by automatic systems depends on the scientific and experimental context of the parameters, and this context must be delineated clearly. The bottleneck is not so much anymore what you would like to measure, but rather what would you like to know? There is a danger that we completely rely on computer algorithms and forget what is actually measured. Since different researchers will rarely want to measure the same behaviors in exactly the same way, a solution is to have trainable' systems which can be adapted to special research questions without losing the advantage of objectivity. In fact one would like to be able to tell the program which behaviors have to be recognized in a particular context. The Eureka project in which the Rudolf Magnus Institute, Noldus Information Technology and several European drug companies work together, is aimed at developing such a system. It is evident that new research tools can only be developed in close collaboration between behavioral and technical disciplines. The more sophisticated tools for measuring behavior are desired, the more discussion on the input and output of such tools is required. And we should not hesitate to borrow ideas from other research areas. Measuring Behavior '96 was intended to provide a forum for a cross-fertilization between different research fields and the stimulation of new forms of collaboration. I have the impression that this goal was accomplished. The workshop organizers hope that this stimulating meeting was the first of a series of regular events!
This article is based on the closing remarks presented at Measuring Behavior '96, International Workshop on Methods and Techniques in Behavioral Research, 16-18 October 1996, Utrecht, The Netherlands