KNOWLEDGE IN CHILDREN'S ADDITION
4.2 The Staircase versus the Overlapping Waves
knowledge without understanding.
This particular sequence ofconcepts before procedures is not a universal mathematical sequence.
Historically, in the development of mathematics, procedures often come before concepts. An example of this is calculus. Rittle-Johnson and Siegler (1998) assert that procedures come first in the domains ofcounting and fraction multiplication (although, as noted, the domain ofcounting is still open to debate) while concepts may come first in single digit addition, fraction addition and proportional reasoning and the order of acquisition in the domain of multi-digit addition and subtraction appears to be variable. All that can be generally concluded is that there appears to be a relation between procedural and conceptual knowledge and perhaps an order of acquisition.
Since two ofthe possible relations (the possibility that the two may develop concurrently and the possibility that they develop iteratively) have not been explored, the exact nature of "the relationship is still not well understood. It could also be argued that procedures without the associated concepts is knowledge without understanding.
relatively small period. While traditional stage theories have depicted change as being abrupt, the various microgenetic studies have suggested that it is more gradual (Siegler, 1995).
4.2.1 The One-to-One Correspondence Experiment
Siegler's (1995) conclusions dispute Piaget's (1952) depiction of the development of number concept through three stages. For Piaget (1952) level one children's perceptions govern their evaluation of quantity, while at the second level the perceptions compete with conservation and at the third level the ability to conserve frees children from their perceptual limitations. Siegler's (1995) results indicate that individual children and the group as a whole are best described as using a variety of reasons for their quantity evaluations throughout the Piagetian sequence, both before and after the level three type reasoning has been discovered. Siegler (1995) claims that Piaget and his colleagues over simplified the developmental sequence and did so because of the limitations of the traditional experimental methods. Siegler (1995) states:
The monolithic character ofthese depictions seems unlikely to have sprung from any deep conviction that all children progress through the same path of change.
Instead, it seems attributable to traditional methods not yielding sufficiently rich data to differentiate among individual children's change patterns, and to investigations therefore having little to say about the variability of the change process (p.233).
4.2.2 Variability
For many years Piaget's theory offered a paradigm for the study of cognitive development. The cognitive variability, that Siegler (1994) claims is a important aspect ofcognitive functioning, was previously regarded as measurement error, something to be eliminated or classified asdecalage.
It is precisely this variability that has now become crucial, in a Gestalt-like switch that, according to Kuhn (1970 as cited in Grannott, 1998), often characterises a change in the dominant paradigm.
This variability, according to Siegler (1996), is a vital part of understanding and explaining cognitive development. Siegler (1995) claims that the children who learned best on the number conservation task described above, continued to display cognitive variability within and between trials. Also, Siegler (1995) found that learning appears to be enhanced by having children explain the reasoning ofothers. Thus, on a practical level, we may be able to improve children's learning by encouraging them to explain the reasoning of others.
Variability is a characteristic of human action and has been described by a number of different researchers. Harry CoIlins (1992), for example, illustrates the importance of the role that variability plays in human behaviour in his critique of artificial intelligence. While it is not necessary to detail Collin's entire critique, it is worth noting that variability in behaviour is one aspect that separates humans from machines. Ittakes a great deal of training for a sports player, for example, to deliver a consistent stroke. One only needs to think ofthe amount oftime that golf players spend practising their shots. Beginners will tend to vary from stroke to stroke, while experts are able to deliver relatively consistent shots. Computers, on the other hand, are able to execute a procedure in exactly the same way over and over again. This topic is discussed by learning theorists such as Skinner, where it serves as the source ofa variety ofoperants. The point is that variability is an integral aspect of human behaviour.
For Siegler (1994) cognitive variability has several aspects: it occurs between children ofdifferent ages; between different children of the same age; within the same child when presented with similar problems; within the same child when presented with the same problem on more than one
occasion (and this can not necessarily be explained by learning since the more advanced strategy is often used first); and within the same child on the same problem. Indeed, a new generation of research has documented the extent of this variability across many different domains. Siegler (1994) proposes that variability contributes directly to cognitive development and cites varied evidence to support this.
He points out that variability in simple addition is especially pronounced on the trial immediately before the discovery of a new strategy and on the trial when this new strategy is first attempted (Siegler, 1994; Siegler& Jenkins, 1989). (The latter point should be obvious since the use of a new strategy must increase the variability.) Thus, there is a proximal relationship between variability and strategy discovery. Also, children who display greater variability tend to be better learners (Siegler 1994; 1995). Furthermore, Siegler (1994) believes that many modern researchers in the area of cognitive development have found it necessary to incorporate some degree of cognitive variability into their models. Moreover, Siegler argues that if variability is related to learning, then thinking would be most variable during the period in our development when learning is more important than performance (Siegler, 1994); Apparently this is the case during infancy and childhood.
Perhaps then, according to Siegler (1994), this is why infants and children up to the age of seven have more synaptic connections than older children and adults. It is conceivable that this abundance of neural pathways is the source of this observed variability. Greenough, Black and Wallace (1987) describe a Darwinian process of selection where the connections are gradually pruned. Moreover, this mechanism is involved in both the processes oflearning and development, suggesting that these two processes are more closely related than previously thought.
The notion ofcognitive vari.lbility appears to be a major difference between the Piagetian tradition and Siegler's theory. The difference may have much to do with the fact that Piaget adopted a macro-perspective by focussing on variation in cognition across childhood, while Siegler has adopted a micro-perspective by concentrating on the variation within the stages described by Piaget.
4.2.3 Learning and Development
Siegler and Piaget differ in terms of how they view the processes of development and learning.
Piaget frequently made the distinction between learning and development, regarding the two as fundamentally different processes. For Piaget, development involves the active construction of knowledge while learning referred to the passive formation of associations (as cited in Siegler, 2000). Siegler recognises the difference between these two processes, however, the distinction, according to him, has become increasingly blurred. Development, according to Siegler (2000, p.32), refers to change that is universal, species specific, occurs over a longer period and in response to a "broader variety ofexperiences", while learning appears to be the opposite. The rise ofPiaget's theory saw the decline oflearning as an area of research. Siegler (2000) believes that his theory is one ofthe few modern theories that have addressed the issue oflearning directly. He argues that the two processes share the same underlying psychological and physiological processes. Siegler (2000) cites the research produced by Greenough etal. (1987) that suggests that both learning and development involve an initial increase in the number of synaptic connections and a later pruning in support of his argument.