TIME TO THINK?
The question in a larger context: Brain=behavior?
"The Brain - is wider than the Sky -
For - put them side by side -
The one the other will contain
With ease - and You - beside-"
Emily Dickinson, 1830-1886
Among the most significant intellectual developments of the twentieth century is the increasing recognition that all aspects of human behavior and experience are actually functions of a material structure, the nervous system. Such an idea seems to have been on the mind of the nineteenth century poet, Emily Dickinson
, when she wrote that the brain can contain the sky "With ease - and You -beside". Still, as we move into the twenty-first century, the notion that "brain=behavior, there isn't anything else
" is far from generally accepted, to say nothing of being fully appreciated in terms of its implications. In part, this is because of the continuing appeal of earlier ways of thinking about behavior and human experience. But, in addition, the brain=behavior idea seems odd or extreme to many because the kinds of observations it reflects and summarizes are not widely known. As a contribution to general discussion of the "brain=behavior" notion, we provide here (as elsewhere on Serendip
) an opportunity to share the experience of one kind of observation which underlies the "brain=behavior" idea. We invite and encourage you also to make use of the exhibit in further inquiries of your own, and would be delighted to hear about your thoughts and experiences, which can be posted in our Brain and Behavior Forum Area
, or sent by Serendip
And in a historical/cultural context
In the later part of the nineteenth century
, both anatomical and physiological observations had developed to the point where many aspects of behavior were comfortably attributed to the nervous system, but "thinking" continued to be considered by many as something different, something non-material, "mental", or "spiritual". In this context, the finding that thinking "takes time" had a significant impact, suggesting that thinking, like other aspects of behavior/human experience, actually had a material basis, and hence might too be equated with nervous system processing.
The Dutch physiologist, Franciscus Cornelis Donders, was the first person to conceive of a way to measure "thinking time", and did so in studies performed in the middle part of the 1860's. The continuation of these studies became a central part of the program of the German physiologist, Wilhelm Wundt, whose laboratory in Leipzig was a major breeding ground of the new discipline of "physiological psychology". James McKeen Cattell, an American who trained in Leipzig, and who himself published papers using the new technique of "psychometry" (Mind, Volume 11, 1886, pp 220-242), wrote of it "It should also be noticed that psychometrical experiment has brought, perhaps, the strongest testimony we have to the complete
parallelism of physical and mental phenomena; there is scarcely any doubt but [p. 46] that our determinations measure at once the rate of change
in the brain and of change in consciousness" (Mind, Volume 13, 1888, pp 37-51).
And in practice
To show that thinking takes time, Donders (and others, to the present day) first measured the time taken for a simple action in response to a sensory input signal. This time includes the time for the input signal to be transduced into neural activity, the time for neural signals to move from the sensory structure to the muscles involved in action, and the time for muscle contractions. With this baseline "reaction time" measured, one then needs to measure the time taken for a task that involves more "thinking". Ideally, one uses input signals and actions that are the same as in the first task, to be sure that the transduction and muscle contraction times are the same in both cases. If, as observed, the times taken for the task involving more "thinking" are longer than for the simple reaction task, the difference between them can be taken as a measure of "thinking" time.
Because the times involved are quite short (fractions of a second in general), Donders had to develop new technology to make the observations in which he was interested, and technological developments have played a significant role in the continuing development of reaction time research. The process continues. Prior to the advent of high speed computers and the internet, such research required special equipment and associated technical expertise. Today, however, you can do such research yourself on Serendip.
Clicking on "Making Observations" below will take you to a page where you can use Serendip to measure simple reaction times, as well as reaction times in a number of increasingly complex "thinking" tasks. You can use this page to make measurements on your self. You can also use it to conduct studies of your own to see how times vary with any of a number of characteristics such as time of day, subject age, subject sex, and so forth (a Literature Review on Reaction Time by Robert J. Kosinski of Clemson University is available on line). If you do, we'd like to hear about your studies. Clicking on other links below will take you to additional information about reaction time research, the history of thinking about brain and mind, and related materials.
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Saturday, 01-Jul-2006 22:59:19 EDT