Psychological Review - Harvard Graduate School of Education ...

482 KURT W. FISCHER
conception. Indeed, the term behavior
class might be superior to the term set,
but class is commonly used in psychology
to refer to a type of concept, and set has no
such surplus meaning.
Skills, schemes, and operants. Set and
action are clearly synonyms within the
theory. How do they relate to skills? A
skill is a unit of behavior composed of one
or more sets. The characteristic structure
for each level is a type of skill, varying in
complexity from a single set at Level 1 to a
very large number of sets at the highest
levels. What makes a group of sets into a
skill is the person's control over both each
individual set and the relations between the
sets. For example, an infant who can shake a
rattle in order to listen to it has a skill composed
of two related sets, shaking the rattle
and listening to the noise it makes.
The relation between the concept of skill
in the theory and the concepts of scheme
and operant from Piaget and Skinner may
help to clarify the meaning of skill. Piaget's
general word for cognitive structure is
scheme 1 —a structure for knowing, a procedure
that the child actively applies to
things in order to understand them. In broad
conception, there are many similarities between
scheme and skill, as already indicated
in the discussion of action, but there are also
major differences. One of the most important
differences involves the organismenvironment
problem: Piaget's schemes
allot much less importance to the environment
than the skills of the present theory
do. Schemes are assumed to have a high
degree of generality, encapsulated in
Piaget's concept of the structure d'ensemble
(Piaget, 1957, 1968/1970; Inhelder & Piaget,
1955/1958). This powerful generality of
schemes should produce a high degree of
synchrony in development. Two tasks that
according to Piagetian analysis require the
same scheme should develop at the same
time. Yet rather than synchrony, researchers
typically find unevenness in development
(e.g., Flavell, 1971b; Jamison,
1977; Liben, 1977; Toussaint, 1974).
The number of well documented instances
of unevenness has been increasing
astronomically in recent years; American
psychologists seem to take special delight
in documenting new instances, especially
when the unevenness can be attributed to
environmental causes. Unevenness has
been found so often and synchrony so
seldom that many developmental psychologists
have begun to suggest that unevenness
may well be the rule in development, and
synchrony the exception (e.g., Carey, 1973;
Cole & Bruner, 1971; Feldman & Toulmin,
1975). Unevenness has been demonstrated
repeatedly for every Piagetian period of
development. 2
The concept of skill, in contrast to
Piaget's scheme, requires that unevenness
be pervasive in development, because skills
are defined in terms of the environment as
well as the organism. Changes in the environmental
context of action produce
changes in a skill. In this regard, skills
share important similarities with Skinnerian
operants (Skinner, 1938). The term operant
refers to a behavior that is emitted by an
organism, not elicited by a stimulus. At the
same time, the specific form of the behavior
and the probability that the organism will
emit the behavior are affected by environmental
stimuli. The behavior is therefore
controlled by both the individual organism
and environmental stimuli. Hunt (1969) and
Aebli (1978, Note 2) have pointed out that
most of the behaviors studied by Piaget and
his colleagues are in fact operants.
The phenomena of developmental unevenness
make good sense from a behaviorist
perspective. Behavioral research
has shown repeatedly that task factors have
potent effects on most kinds of behavior in
1 Many of the English translations of Piaget's works
use the word schema instead of scheme to translate
the French scheme. There is a problem with this
usage: In recent years Piaget has differentiated scheme
from schema (Furth, 1969; Piaget & Inhelder, 1966/
1971). Schema refers to an internal image of something,
which is very far from the meaning of scheme.
2 Here are just a few of the relevant references: for
the sensory-motor period, Butterworth, 1976; Jackson,
Campos, & Fischer, 1978; Kopp, O'Connor,
& Finger, 1975; Uzgiris & Hunt, 1975; for the preoperational
period, Gelman, 1978; Goldstein &
Wicklund, 1973; Watson & Fischer, 1980; for the concrete
operational period, Achenbach & Weisz, 1975;
Hooper et al., 1971; Jackson, 1965; Smedslund, 1964;
and for the formal operational period, Martarano,
1977; Neimark, 1975; Piaget, 1972; Wason, 1977.