if one calculates the age curves separately for major
and minor works within careers, the resulting functions are basically
identical. Both follow the same second-order polynomial
(as seen in Equation 1), with roughly equal parameters. Second,
if the overall age trend is removed from the within-career tabulations
of both quantity and quality, minor and major contributions
still fluctuate together. Those periods in a creator’s life that
see the most masterpieces also witness the greatest number of
easily forgotten productions, on the average. Another way of
saying the same thing is to note that the “quality ratio,” or the
proportion of major products to total output per age unit, tends
to fluctuate randomly over the course of any career. The quality
ratio neither increases nor decreases with age nor does it assume
some curvilinear form. These outcomes are valid for both artistic
(e.g., Simonton, 1977a) and scientific (e.g., Simonton,
1985b) modes of creative contribution (see also Alpaugh, Renner,&
Birren, 1976, p. 28). What these two results signify is
that if we select the contribution rather than the age period as
the unit of analysis, then age becomes irrelevant to determining
the success of a particular contribution. For instance, the number
of citations received by a single scientific article is not contingent
upon the age of the researcher (Oromaner, 1977).
The longitudinal linkage between quantity and quality can
be subsumed under the more general “constant-probability-ofsuccess
model” of creative output (Simonton, 1977a, 1984b,
1985b, 1988b, chap. 4). According to this hypothesis, creativity
is a probabilistic consequence of productivity, a relationship
that holds both within and across careers. Within single careers,
the count of major works per age period will be a positive function
of total works generated each period, yielding a quality ratio
that exhibits no systematic developmental trends. And
across careers, those individual creators who are the most productive
will also tend, on the average, to be the most creative:
Individual variation in quantity is positively associated with
variation in quality. There is abundant evidence for the application
of the constant-probability-of-success model to cross-sectional
contrasts in quantity and quality of output (Richard A.
Davis, 1987; Simonton, 1984b, chap. 6; 1985b, 1988b, chap.
4). In the sciences, for example, the reputation of a nineteenthcentury
scientist in the twentieth century, as judged by entries
in standard reference works, is positively correlated with the
total number of publications that can be claimed (Dennis,
1954a; Simonton, 1981 a; see also Dennis, 1954c). Similarly, the
number of citations a scientist receives, which is a key indicator
of achievement, is a positive function of total publications
(Crandall, 1978; Richard A. Davis, 1987; Myers, 1970; Rushton,
1984), and total productivity even correlates positively
with the citations earned by a scientist’s three best publications
(J. R. Cole & S. Cole, 1973, chap. 4). [...]
The constant-probability-of-success model has an important
implication for helping us understand the relation between total
lifetime output and the location of the peak age for creative
achievement within a single career (Simonton, 1987a, 1988b,
chap. 4). Because total lifetime output is positively related to
total creative contributions and hence to ultimate eminence,
and given that a creator’s most distinguished work will appear
in those career periods when productivity is highest, the peak
age for creative impact should not vary as a function of either
the success of the particular contribution or the final fame of
the creator. Considerable empirical evidence indeed demonstrates
the stability of the career peak (Simonton, 1987a). In the
sciences, for instance, the correlation between the eminence of
psychologists and the age at which they contribute their most
influential work is almost exactly zero (Zusne, 1976; see also
Lehman, 1966b; of. Homer et al., 1986). And in the arts, such
as literary and musical creativity, the age at which a masterpiece
is generated is largely independent of the magnitude of the
achievement (Simonton, 1975a, 1977a, 1977c). Thus, even
though an impressive lifetime output of works, and subsequent
distinction, is tied to precocity, longevity, and production rate,
the expected age optimum for quantity and quality of contribution
is dependent solely on the particular form of creative expression
(also see Raskin, 1936).
(part 2)