Child in the Preoperational Stage

A study was carried out by two third year psychology students to investigate Piaget’s stage theory. A 4 years old female child was tested in task of comprehension of more and less, followed standard and modified versions of conservation and class inclusion tasks. Results indicated that child exhibited difficulties in both modified conservation and class inclusion tasks despite the removal of some confounds in standard tasks. This infers that children of pre-operational stage do lack the ability to conserve and categorize objects, as predicted by Piaget.

Further research need to address children’s numerical abilities, as well as attending to perceptive seductions. This research needs to compare children who are able and unable to attend to number logics, as well as modifying the class inclusion task so that perceptive seduction cannot take place.

Child in the preoperational stageMany researchers have been interested in various confounds which are present in Jean Piaget’s stage theories. His studies have postulated that children in the pre-operational stage lack the ability to perform conservation and class inclusion tasks (White, Hayes, Livsey, 2005).

The methodologies of the study however, have been criticized by many researchers. Flaws and alternatives found in the standard Piagetian tasks include conversational confusions, perceptual seduction, and linguistic misunderstandings (Light, 1986, Siegel, 1978, 2003, Meadows, 1988). These issues have been addressed with modifications to the standard tasks. Majority of the research have found modified tasks to be better predictors of child’s abilities in conservation and class inclusion tasks. (Light, 1986, Siegel, 1978, 2003, Meadows, 1988).

According to Piaget’s stage theory, children in the pre-operational stage are non-conservers (White et al, 2005).

Their tendency of centration causes them to focus on only one aspect of the problem at a time (White et al, 2005). This implies that they are unable to comprehend that quantitative properties of certain objects remain unchanged despite changes in its appearance (White et al, 2005). For example, pre-operational children typically judge water of the same volume to be more, after the transformation in standard liquid conservation tasks (Siegal, 2003). A problem in this procedure however, lies within the confusion caused by children’s conversational experience (Siegal, 2003). This theory proposes that rather than actually responding to the logic behind the transformations of the liquid, children misinterprets the repetition of the same question as a cue to switch their answer in order to please the adult experimenter (Siegel, 2003).

To address conversational confusion, liquid conservation tasks had been modified by the means of incidental transformation (Light, 1986). The intention of this modification is to contextualize the intentions of adults in repeating the same question. Light (1986) administered the standard Piagetian conservation procedure up to the point when both beakers of the same size and volume. However, during the transformation, the experimenter “incidentally” noticed that one of the beakers was chipped, and found a taller and thinner beaker as the replacement container for the original content. The result found that only 5 percent of children correctly responded to the conservation task in the standard condition, while 70 percent correctly responded to the incidental condition (Light, 1986).

An alternative to Piaget’s theory of conservation is that non-conservers may actually be perceptually seduced (Siegel, 2003). This theory postulates that children pay more attention to the post-transformation state and disregards the pre-transformation state(Siegel, 2003). They fail the question about conservation because all of their attention are diverted into the new state and they perceive it as different from the old state (Siegel, 2003). Research had shown that children who do not witness the process of transformation are much more likely to conserve than children who sees the transformation taking place (Siegel, 2003).

Another difficulty that Piaget found in pre-operational children is their ability to attend to class inclusion tasks (Siegel, 2003). In a study, pre-operational children were presented with a set of 6 cars and 4 trucks. When asked the question “are there more trucks or vehicles”, children will typically answer cars (White et al, 2005). Explanation for this result as proposed by Piaget is that children are unable to conceptualize cars as a more inclusive category of the hierarchy (White et al, 2005).

Limitations however, were found in this theory in terms of children’s linguistic misunderstandings. A study by Sigel (1978) compared the performance of 4 year old children who were asked whether they would like to eat candy with those asked if there were more candy in the array. Results found that significantly more children passed the eat-candy task (50%) as opposed to 26% in the more-candy task. This implicates that pre-operational children performs better on tasks of class inclusion when linguistic cues were made salient with age-appropriate cues as opposed using comprehension of relational terminology such as “more” and “less” (Sigel, 1978).

A modified class inclusion task was designed in the current experiment to address the linguistic issues associated with child’s performance. Previous studies have found that children experience confusion when similar words are used in each level of the hierarchy (e.g. black cows, cows) (White et al, 2003). They are however, more familiar with the relationships where each member makes up part of a whole (White et al, 2003). Hence, when children were taught, or are familiar with the superordinate class such as “family”, they are more likely to have certainty about its relation with the subordinates (e.g. three baby horses, two parent horses) (Meadows, 1998).

The present study is aimed to investigate whether children in their pre-operational stage experience difficulties in conservation and class-inclusion tasks as predicted by Piaget. From the research examined, it was anticipated that the child’s performance on modified tasks will be better than the standard tasks. It was hypothesized that the child will perform poorly in standard conservation and class inclusion tasks. It was also hypothesized that the child’s performance in the standard tasks were influenced by factors other than those intended in the standard Piagetian procedure.

MethodParticipantThe subject is a four year and old female who is living at home with both of her parents in Petersham. She currently attends the local pre-school. The test was conducted inside the child’s house with two experimenters. One of the experimenter, who is her aunty, was responsible for interviewing the child, while the other transcribes the events.

MaterialsFor comprehension of more or less, a total of 11 blocks were used. 5 blue and 5 yellow blocks were used in the standard number conservation task. 2 bottles of the same size and a thinner and taller bottle were used in the standard liquid conservation task. A picture with 4 black horses and 2 white horses was used in the standard class inclusion task.

In the modified liquid conservation task, 2 toy horses were used as characters for picnic. 2 bottles of the same size, with one missing the label was used in the pre-transformation stage. A taller, thinner bottle was used in the post-transformation stage.

In the modified class inclusion task, 2 larger “parent” toy horses and 3 smaller “baby” toy horses were placed next to one another.

ProcedureThe experiment was carried out in the order test of comprehension of more and less; standard number conservation; standard liquid conservation; standard class inclusion; modified liquid conservation; and modified class inclusion.

In the comprehension of more and less task, the experimenter takes out 8 blocks, but separates them so there were 4 each side. There is also another basked with 3 spare blocks in it. The child is then asked to make one pile more than the other, followed by the prompt to make the now larger pile less than the other pile.

In the standard number conservation task, the blue and yellow blocks were placed in 2 lines equidistant of each other. On post-transformation, spaces between the yellow blocks were enlarged by the experimenter. Please refer to the appendix for details on rest of the tasks.

ResultsOutcome of the study shows that the child is able to comprehend when something is more, but was unable transform the pile that had more objects to be less than the smaller pile.

Results have also shown that the child was able to correctly answer the pre-transformation questions of standard number and liquid conservation, as well as modified liquid tasks, but failed in post-transformation and justifications of these tasks.

Finally, the results have shown that the child was unable to correctly answer any of the class inclusion tasks, even after concept of family was eventually introduced to her by the experimenter in the modified class inclusion task. For the full results, please refer to the results summary in Appendix A.


Contrary to the anticipations, the child did not perform better in any of the modified tasks as compared to standard tasks. The results provide support for the hypothesis that child will perform poorly in standard conservation and class inclusion tasks. The child performed consistently poorly across all three standard Piagetian tasks. As a result, the child’s performance in the tests clearly places her in Piaget’s preoperational stage of development. The results are consistent with all critics in the current field, who found children of preoperational stage to perform poorly across standard tasks (Light, 1986, Siegel, 1978, 2003, Meadows, 1988). Hence, the validity of the criticisms relies on the child’s performance on modified tasks. A notable aspect of the results indicates that child’s performance in the standard tasks may be hindered by her ability to correctly comprehend the concept of more and less.

The results did not support the hypothesis that child’s performance in the standard tasks were influenced by factors other than those intended in the standard Piagetian procedure. No support of conversational confusion was found in the present experiment whereby despite the removal of such confounds. The incidental transformation in the modified liquid conservation task did not produce better results compared to the standard tasks. This result did not support Light’s (1986) experiment where children in modified tasks performed significantly better than those doing the standard tasks. The reasons behind this result may be that the child does not have a correct grasp of the concept of more and less. Alternatively, the child, who is in her preoperational stage, may genuinely lack the ability to conserve, as proposed by Piaget (White et al, 2005).

A limitation behind this result may be attributed to the theory that the child may be perceptually seduced (Siegel, 2003). In essence, despite the transformation being “incidental”, the child still witnessed it taking place. Hence, child’s attention was diverted to the post-transformation state of the water “got bigger” in the taller, thinner bottle. Future research may incorporate the “incidental” transformation task that prevents the child from witnessing the process of transformation taking place.

No evidence for linguistic misunderstanding was found in the current experiment. The child performed equally poorly in both standard and modified class inclusion tasks despite the removal of such confound. The result shows that even after introducing the concept of the family to the child with evidence of learning, she was still unable to comprehend that the “family” was a superordinate of class with subordinates of parent and baby horses. This finding does not support Meadow’s (1988) theory in that grasp of the relationship between superordinate and subordinates helps children perform better in class inclusion tasks.

The child’s problem in all class inclusion tasks may be attributed to Piaget’s theory of centration whereby children in the preoperational stage are only able to attend to one aspect of the problem at a time (White et al, 2005). In this case, the child may be centrated on the old concept that there are more baby horses and disregard the new concept that the baby horses were a part of the “family”. Alternatively, the child’s performance may be hindered by their inability to comprehend more and less.

A further limitation of the study was that results of the experiment were strongly hindered by the fact that the child was unable to comprehend when something is less. This confound creates ambiguity to the question whether child in the preoperational stage genuinely lack the ability in conservation and class inclusion tasks, or if the outcomes were attributed to their lack of logics with numbers. Future research could overcome this problem by comparing the results of preoperational children who are able, and unable to correctly attend to the concept of more and less. An alternative way to overcome this problem is to employ age-specific linguistic cues in class inclusion tasks as opposed to using concepts of “more” and “less” (Siegel. 1978).

Overall, the results of the study suggest that children in the preoperational stage do indeed lack the ability to correctly perform conservation and class inclusion tasks despite the removal of some confounds. However, the results were not clear cut to whether they were caused by child’s ability to comprehend to more and less or if they were perceptually seduced. Future research could compare children who are able and unable to attend to number logics, as well as modifying the class inclusion task to remove the confound of perceptive seduction.


Light, P. C.(1986). Context, conservation and conversation. In M. Richards. & P. Light (Eds.) Children of social worlds : Development in a social context. Cambridge, U.K.: Polity Press.

Meadows S (1988) Piaget’s contribution to understanding cognitive development. In K Richardson & S. Sheldon (Eds.) Cognitive Development to Adolescence. Hove: Lawrence Erlbaum.

Siegel, L., McCabe A., Brand J, & Mathews J (1978) Evidence for understanding of class inclusion in preschool children: Linguistic factors and training effects. Child Development, 49, 688-693.

Siegal, M. (2003). Cognitive development. In A. Slater & G. Bremner (Eds.) An introduction to developmental psychology. Malden, MA: Blackwell. Chapter 8White. F, Hayes. B, Livesey. D (2005). Evaluating Piaget’s claims: Preoperational period. Developmental Psychology: From infancy to adulthood .Pearson Prentice Hall. Chapter 5