The terms
ability, cognitive ability, achievement, aptitude, aptitude-achievement are
tossed around in contemporary psychological and educational assessment circles,
often without a clear understanding of the similarities and differences between
and among the terms. For example, what
does an “aptitude-achievement” discrepancy, in the context of contemporary
models of SLD identification (see Flanagan & Fiorrello, 2010), mean? Where are the aptitudes in the CHC model? It is argued here that it is critical
that intelligence assessment professionals and researchers begin to use agreed upon terms to
avoid confusion and to enhance collaboration and to facilitate research
synthesis. In this spirit, the figure below illustrates the conceptual distinction between abilities, cognitive abilities,
achievement abilities and aptitudes.
These conceptual distinctions are drawn primarily from Carroll (1993)and the work of Snow and colleagues (Corono et al., 2001). [Click on image to enlarge]
As reflected
in the figure, all constructs in the CHC model are abilities. As per Carroll (1991), “as used to describe an attribute of individuals, ability refers to the possible variations over
individuals in the liminal levels of task difficulty (or in derived
measurements based on such luminal levels) at which, on any given occasion in
which all conditions appear favorable, individuals perform successfully on a
defined class of tasks” (p. 8, italics in original).[1] In more simple language,“every ability is
defined in terms of some kind of performance, or potential for performance (p.
4).” The overarching domain of abilities
includes cognitive and achievement abilities as well as aptitudes (see figure). Cognitive
abilities are abilities on tasks “in
which correct or appropriate processing of mental information is critical to
successful performance” (p. 10; italics in original). The key component to the operational
definition of cognitive abilities is the processing
of mental information (Carroll, 1993).
Achievement abilities “refers to the degree of
learning in some procedure intended to produce learning, such as an informal or
informal course of instruction, or a period of self study of a topic, or
practice of a skill” (p. 17). As reflected
in the above figure, the CHC domains of Grw and Gq are consistent with this definition
and Carroll’s indication that these abilities are typically measured with
achievement tests. Most assessment
professionals use the terms cognitive and achievement abilities in accordance
with these definitions. However, the
term aptitude is often misunderstood.
Carroll
(1993) uses a narrow definition of aptitude—“to
refer to a cognitive ability that is possibly predictive of certain kinds of future learning success” (p. 16;
emphasis added). The functional emphasis
on prediction is the key to this narrow definition of aptitude and is so
indicated by the two horizontal arrows in the figure. These arrows, which connect the shaded CHC
narrow abilities that are combined to predict an achievement ability outcome
domain, are the definition of aptitude used in this paper.
This definition of aptitude is much narrower
than the broader notion of aptitude as reflected in the work of Richard
Snow. Snow’s notion of aptitude
includes both cognitive and non-cognitive (conative) characteristics of
individuals (Corno et al., 2002; Snow et al., 1996). This broader definition of aptitude focuses
on human aptitudes which represent “the characteristics of human beings that
make for success or failure in life's important pursuits. Individual
differences in aptitudes are displayed every time performance in challenging
activities is assessed” (Corno et al., 2002, p. xxiii). Contrary to many
current assumptions, aptitude is not the same as ability. According to Corno et al. (2002), ability is the power to carry out
some type of specific task and comes in many forms—reading comprehension,
mathematical reasoning, spatial ability, perceptual speed, domain-specific
knowledge (e.g., humanities), physical coordination, etc. This is consistent with Carroll’s definition
of ability. According to Snow and
colleagues, aptitude is more aligned with the concepts of readiness,
suitability, susceptibility, and proneness, all which suggest a “predisposition
to respond in a way that fits, or does not fit, a particular situation or class
of situations. The common thread is potentiality—a latent quality that enables
the development or production, given specified conditions, of some more
advanced performance” (Corno et al., 2002, p. 3; see Scheffler, 1985). This broader definition includes non-cognitive
characteristics such achievement motivation, freedom from anxiety,
self-concept, control of impulses, and other (see Beyond IQ project).
As reflected in the model in the above figure, cognitive
and achievement abilities differ primarily in the degree of emphasis on degree
of mental information processing (cognitive) and the degree which the ability
is an outcome acquired more from informal and formal instruction (achievement). Here, aptitude
is defined as the combination, amalgam or complex of specific cognitive
abilities that when combined best predict a specific achievement domain. Cognitive abilities are always cognitive
abilities. Some cognitive abilities
contribute to academic or scholastic
aptitudes, which are pragmatic functional measurement entities—not trait-like
cognitive abilities. Different academic
or scholastic aptitudes, depending on the achievement domain of interest,
likely share certain common cognitive abilities (domain-general) and also
include cognitive abilities specific to certain achievement domains
(domain-specific). A simple and useful
distinction is that cognitive abilities and achievements are more like unique
abilities in a table of human cognitive elements while different aptitudes
represent combinations of different cognitive elements to serve a pragmatic
predictive function. For the quantoid
readers, the distinction between factor-analysis based latent traits (cognitive
abilities) and multiple regression based functional predictors of achievement
outcomes (cognitive aptitude) may help clarify the sometimes murky discussion
of cognitive and achievement abilities and aptitudes.
[1] As
noted by Carroll (1993), luminal refers to specifying threshold values used “in order to take advantage o the fact that
the most accurate measurements are obtained at those levels” (p. 8).
