When studying an empirical object or a class of them, you have to decide whether the dimension of time has any significance for your study. In other words, you have to select either one of two possible views on your object of study:
When analyzing development the methods become slightly different depending on, whether you are studying one object which develops with time, or a class of cases where the later ones differ from the earlier ones.
Which kind of information you will want to search in the defined class of objects or cases, depends on the purpose of your study. In the diachronic study of products, their manufacture or employment, there are three different typical targets which lead to distinct styles of research. They are:
Below are given examples of the above mentioned three paradigms: the descriptive, explanatory, and normative approaches.
It goes without saying that in the study of any class of objects or cases, it is essential first to demarcate this class (the population of study), and also the time span from which the objects are taken. Otherwise, your study will probably grow into unexpected directions.
The methods for collecting the material for analysis are discussed on other www-pages. When studying development you will, of course, need material from different points in time during the defined period. Sometimes you will be able to record the data yourself, either by studying existing objects or doing observations from their design, manufacture, or use, etc. If, instead, the period to be studied is distant, you will need to use methods of study of literature.
Descriptive study registers changes in the objects of study and attempts to find and clarify regularities in the visible development.
As a goal of research project, description may seem a modest one, but it can involve quite enough work especially if the changes are complicated and if they have not been studied earlier (that is, when the study is exploratory).
Individual development. Temporal view of an industrial product often includes its entire life cycle from raw materials to the market, as well as its use, wearing down, reparation, discarding and recycling. For long-lived products like buildings it may be interesting to record their modifications, which is often done simply by including a series of pictures like the ones on the right (from Larsson 1973), complete with written explanations of the stages of the process. Today you also have the possibility of elucidating the evolution with spectacular computer or video graphics.
People related to products, like artists, production people and their clients, often interest researchers. Long-time temporal development of people means that they mature and change with time, and for describing it you can consider using the methods of Case Study, Hermeneutic or Phenomenological analysis.
Development of a class. In a long-time perspective, interesting structures of development for a given type of product can be, for example:
If the same development seems to occur several times or in various places, you have reason to call it a dynamic invariance, that is, a general structure or perhaps even a "law" of development.
Once the structure of development is found, it can be represented by selecting or inventing a suitable modelling language. The development of a class of objects can be presented with a series of exemplars, as a quantitative time series of measurements or another arithmetic model, or with various other descriptive models. It is usual to combine different types of presentation, too. Note also the methods under the title Explaining a Development.
Descriptive histories of products study the evolution of a certain type of product. For example, in books called "History of Architecture" you will find descriptions of famous buildings, grouped on the basis of geographical areas, stylistic periods, etc. Descriptions of development often mention mostly factors intrinsic to the community of artists, their families and customers. If reasons for the factual development are not sought from the surrounding society, the descriptive history remains superficial and its findings have seldom much value either theoretically or practically. This type of history can often be found as text in coffee-table books where the main purpose is to publish photos of products.
The pattern of exemplars and followers is often used to describe a development that depends mainly on separate human inventions. Important new inventions occur mostly at long intervals, and whenever made, the novelty will often soon be applied by other makers of the same type of products and it will thus initiate a "school" of followers. This pattern of development provides then a convenient model for later researchers for arranging their material. The method has been very popular in art history, and it is well suited for the study of technological progress, too.
The Exemplar-and-Followers model can be depicted like in the diagram on the right, where red dots mark successful products which have served as exemplars to other more conventional products (the black dots). Blue dots denote extremist products which fail to get understanding and approval.
For the dimension X in the diagram you can take any characteristic of the objects or cases that you think best exposes the development. If you are studying cars, it could be 'speed' or 'fuel economy'; if you study paintings, it could be 'rhythm' or 'religious content' etc.
When studying a very long development, such as the history of paintings, it is possible that the decisive characteristic in each historical revolution is a different one. A logical research approach would then be to make a separate study for each of the successive schools of paradigm, marked as green rectangles in the lower diagram. If you positively want to study the whole process, you could consider dividing your study into distinct chapters.
How to point out the products which have factually served as exemplars? Per definition, the exemplars used for presenting a development should be those products that either were often imitated in later works by other artists, or which were in their time regarded as exemplary, according to contemporary documents. The main thing is that in the selection you should be objective, i.e. not use your own viewpoint but instead that of the period that you are studying.
To be sure, in art history there have been enough examples of selecting whichever material the writer personally thinks meritorious or interesting. Such a research can be useful, too, if you remember that essentially it is not descriptive but normative, the methods of which are explained later on.
Once you have selected the exemplars, you have another decision to make: should you include in the study beside the exemplars also the conventional products (black dots in the diagram above), and if so, how extensively and meticulously it should be done. One alternative is the tradition of art history: to regard only the "great" works and present these as chronological sequences of art in various geographical areas. In any case, it is normal to disregard the exceptional cases (blue in the diagram). Available solutions to this problem are discussed on the page Demarcating the Study.
The exemplars (and perhaps a few followers) are normally presented as pictures with comments. However, it is often difficult to present any lengthy series of development coherently as comments only, and for such extensive explanations it can be better to use the styles of presentation that are discussed later on under the titles Other Descriptive Models of Development and Explaining a Development.
A typical example of describing historical development of design by presenting exemplars can be seen in Raymond Loewy's book Industrial Design. The author illustrates the development by presenting a long series of his projects and gives the reasons for their gradual evolution. On page 74 is found an often cited illustration, "Evolution Chart of Design", part of which is seen on the right. (See the complete series.) Loewy gives no explanation or general "law" of this evolution.
In descriptive study of products these usually are examined holistically as individual objects where all their attributes are simultaneously observed. Nevertheless, it is also possible to study the progress of just a few attributes of the objects; however in such a case it is common that the researcher "operationalizes" these attributes into measurable variables. A time series is a line of variable values collected under a period of time, usually at even intervals.
The curve is the most usual presentation for time series.
Time is normally presented on the horizontal x-axis. Several variables or
series of data can be fitted into the same diagram if necessary. This is
sensible especially when their connections are being investigated or shall
be emphasized. When presenting two different time series with different
scales in one figure, you may place one scale next to the left margin of
the figure and the other scale next to the right.
Both the measured and the predicted values can be shown in the same curve if necessary, see figures below.
If the range of the variable is very
small, it can be emphasized by shortening the y-scale, i.e. by cutting off
the part containing no values, usually from the bottom of the scale.
The figure on the right has exactly the same contents as the one on the left, but the variation has been made more visible by cutting off the scale from the bottom. - If, on the contrary, the variable varies on a very large scale, the scale of the y axe can be made logarithmic.
All time series are inherently discontinuous, i.e., they obtain only one discrete value for every period. This is why the presentation chosen for a time series is often a "staircase" curve, which is in principle the same as a histogram where the columns are drawn next to each other. See figure on the left.
If we take a closer look at the variation of the time series, it often reveals components, all of which have their specific regularities which can be analysed. The most usual of these components are:
A trend is a linear direction of
development over a period of time. If you have presented the original
time series as a curve, you can simply add an approximate line
describing the trend. An example is seen below, where the trend is
shown in red colour.
A more refined and exact method for the above task is the regression analysis. Once you have found the optimally fitting equation for the trend, it is usually also presented graphically, possibly together with the original values of the time series.
A periodic variation is a cyclical variation
recurring in a similar form all over again. The period of variation is often a
natural time unit, like a year or a day.
For example, the energy consumption of a building varies simultaneously on three frequencies: on yearly, weekly and daily rhythms. These are calculated, one at a time, by the following method which is basically the same in all the three cases:
When periodic variation has been found, it is presented either graphically as a curve of one period's length, or numerically as an index. This index is usually made to average the figure of 100 (or 1.00), and its periodic values are obtained when the periodic (e.g. monthly) averages are divided by the common average of the whole data
Conjuncture variation occurs repeatedly in the same way as
a periodic variation, but its length and form vary.
To reveal the conjuncture variation, the trend and the periodic variations of the data have to be found first. After this, the trend and the periodic variations are eliminated from the data. This is done for example by dividing all the original values by the index of periodic variation, and by the formula of the trend as found by the regression analysis method.
After these operations, the data only include (in addition to random variation) the conjuncture variation. The conjuncture variation is presented either graphically as a curve, or numerically as a conjuncture index in the same way as the above mentioned periodic variation index.
Random variation is usually
eliminated by means of the flexible average method. E.g. in data
containing monthly values, it is done by substituting for each monthly
value the mean of that month and both the neighbouring months.
The average of five or seven months can also be used, although the disadvantage of this is that it may obscure even the variation that would interest the researcher.
Random variation is not necessarily a disturbance which has to be eliminated. If there is a lot of it, the researcher could try to contemplate the reasons for this variation: is it caused by an important or interesting factor which should be included in the hypothesis of the research project?
All the above mentioned analyses of time series are normally performed with a computer. Nevertheless it remains the researcher's task first to decide which type of time-bound variation - trend, periodic or conjuncture variation - shall be examined, and after this decision the computer will find out if such a variation exists in the data or not.
Any development can be described by making a written essay about it, but today's public would not like to read lengthy treatises without pictures. Indeed, many aspects of development can be clarified with suitable illustrations or diagrams made with one or another of the various modelling languages enumerated elsewhere.
Style and stylistic period have been cardinal theoretical structures when describing the development of arts. Similar structures can be used as backbones in the study of other products, too. It often turns out that for each generation of people the designers or artesans have created a different style. Each generation seems to have its own preferences for the appearance of a product, and also the practical requirements get changed.
The phases in the development of a design style are conventionally defined with an analogy to the life of a living organism (i.e. with a model of analogy):
In relation to the stylistic period, individual artists are often described either as avant-garde, i.e. the original creators of novelties; or followers who adapt and refine the ideas created by the avant-garde.
Styles are not born from empty space, nor do they disappear into nothingness. Like works of art, they can be arranged in chains. Below is an example from Jencks (1973, part of the diagram on p. 28), which shows some relations between architectural styles, and how a few notable architects can be placed in the framework of styles.
Typical of descriptive diachronic diagrams is that there is no attempt to relate the development to any other phenomenon in society. The only factor outside the pertinent field of art (in this example, architecture) is time. Nothing prevents, however, including in the textual part of the treatise explanations that refer to the community outside, which approach of research is the main topic in the following section.
Often a mere description of the changes in the object of study does not suffice, and the researcher is asked to uncover also the reasons and/or effects of the changes. The reasons can be taken either from the past (causal explanation), from the concurrent context, or alternatively from the future (i.e. from the intentions of people).
For example, in the book Electrical appliances Penny Sparke explained the evolution of household electrical appliances on the basis of changes in home life conventions and in the industry, see diagram on the right.
In a historical study of a given type of product these are viewed as illustrative cases only, while the principal object of study is the activity of design and production as a social, economic and ecological process. Explaining factors are, for example, changes in society demographics, in industry or in economic conditions, inventions, education, political changes, wars, and the acquisition or loss of colonies. When the creators of products are studied, they are viewed as members of society: "The designer is seen as a part of the surrounding society, and his work and values are examined in connection with social, cultural and economic conditions... We have to understand how and why design has evolved and whose interests it supports" (Wiberg, 1992).
Historians started to explain events with the help of social development first in 18 century, see the page Early Explanatory Models of Development. Today, the factors used for explaining the development of products include typically changes in the conditions and organizations of manufacture, inventions, political decisions, international treaties, social reforms, changes in education and in the attitudes of customers. Stabilizing factors, which nevertheless can vary from country to country, are climate, the availability of raw materials and other natural resources, transportation system, and local preferences of people.
For example, Sparke (1986) explained the development of furniture between 1860 and 1985 with the help of following factors:
Another example of explaining the development of products is Ulla-Kirsti Junttila's (1986) study of lighting fixtures and other street installations. Junttila describes historical sequences of products like the one above, and moreover she explains the reasons of this evolution. They are:
A model for methodology for the explaining-type history of products can be found in a parallel development in the study of art, often called "sociology of art".
Theory of design as explanation. Most design projects take as a starting point the goals of design, primarily those requirements that the finished product should fulfil. These may involve, for example, the usability , beauty , meaning , ecology and economy of the product. As a consequence, the historical evolution of a type of product can often be explained with changes that have happened in the goals of design during the same period.
It is often difficult to study the historical goals of design, because of the scarcity of documents where the goals are explained. Instead, there is sometimes another source which specifies at least the commonly employed goals: the theory of design that the designers have based their work on. Design theory exists, of course, only for certain types of products. When there is such a theory, its influence persists normally for many years and affects most design projects during that time. This influence often appears as style of design in the finished products.
Any researcher that studies styles of such products for which there is design theory, should consider including its influence in the model of development. If the study concerns just a short time span and a small geographical area, the influence of design theory will perhaps be quite constant and thus of little interest. The case is different in studies with a prolonged time span where the design theories sometimes have undergone veritable revolutions of paradigm which normally generate distinct reverberations in the designs produced after the upheaval.
We can take as an example the history of European architectural styles which is well documented. Since antiquity there have been several drastic changes of styles that have been unquestionably caused by changes in the goals of building. These changes are also explicitly recorded in historical treatises of architectural theory. They are presented in the table on the right.
|Dominant goal in
the design theory
|Beauty||Doric, Ionian and
|Religious salvation||The Gothic style|
|Individualism.||l'Art Nouveau and
other personal styles
Beside the above mentioned four cardinal reformations there have been also smaller adjustments of architectural style. Usually we distinguish about ten architectural styles in Europe (see Theory of Architecture). Many of the minor changes in style can be attributed to just small shifts in the relative weights of the goals of design. For example, the changeover to Neo-classicism (about 1800) is said to originate from the concurrent rise in the wages of workers, which invited to savings in labour time and therefore to less ornamented architecture. Such relatively small shifts require no change in design theory, and indeed the theory books of architecture had almost unvarying contents from 16th to 19th centuries (all were based on Vitruve and Alberti). These minor changes in design styles have then been explained by researchers in various ways. One explanation for the constant renewal of fashions comes from perception psychology: the inborn human appreciation of novelty, cf. Expectation and Distinction.
You may wish to study a process in the purpose of steering it (or perhaps of steering other similar, subsequent processes). The methods of Normative Study of Development are explained on a separate page.
August 3, 2007.
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Original location: http://www2.uiah.fi/projects/metodi