| Course | PS 101 Psychology |
|---|---|
| Unit | Unit 6 |
| Paper type | Development or personality paper |
| Length | About 980 words, 6 pages |
| Format | APA 7 student paper |
| School | Herzing University |
| Program | BS in Psychology |
| Updated | October 2026 |
Free sample paper for PS 101 Unit 6
Two Glasses of Juice and a Theory Under Test: What Piaget Predicts About Conservation in a Composite Five-Year-Old and Seven-Year-Old, and Where the Prediction Missed
Student Name
Psychology, Herzing University
PS 101: Psychology
Instructor Name
February 18, 2026
Two Glasses of Juice and a Theory Under Test: What Piaget Predicts About Conservation in a Composite Five-Year-Old and Seven-Year-Old, and Where the Prediction Missed
The Choice and the Theory
This paper takes the development option and commits to one theory, Piaget's account of how children's thinking changes in stages, and to one prediction within it, conservation. Piaget (1952) studied how children come to grasp that an amount is unchanged when only its shape or arrangement is altered. In his best-known task a child agrees that two identical glasses hold the same amount of liquid; then the liquid from one is poured into a taller, thinner glass, and the child is asked whether the two amounts are still the same.
Piaget held that children between about two and seven, whom he placed in the preoperational stage, usually answer that the tall glass has more. He explained this by centration, focusing on one dimension such as height while ignoring width, and by a lack of reversibility, the understanding that the pouring could be undone. Children in the concrete operational stage, roughly seven to eleven, usually answer that the amounts are the same and can say why. Piaget also noted that children do not master every kind of conservation at once; liquid and number tend to come before weight and volume, an unevenness he called horizontal decalage.
The Theory as a Testable Prediction
Stated as a test, the theory predicts the following. A typical five-year-old will say the taller glass has more and will justify the answer by height. A typical seven-year-old will say the amounts are equal and will give a reason based on reversibility or on height and width compensating for each other. The same seven-year-old may still fail a conservation task involving weight. And the younger child's error should be fairly stable, because it reflects the structure of preoperational thought rather than a misunderstanding of the question.
The Case
This case was assembled for the paper as a composite, drawing on the kind of informal demonstration students in this course are encouraged to observe; it describes no real family. Two siblings, a five-year-old and a seven-year-old, sat at a kitchen table with an adult who poured equal amounts of juice into two identical short glasses. Both children agreed the amounts were the same. The adult poured one glass into a tall, narrow glass and asked each child, separately, whether the two now had the same amount or whether one had more.
The five-year-old pointed to the tall glass and said it had more because "it goes up higher." The seven-year-old said they were the same, and when asked how she knew, said, "You just poured it. You could pour it back." A few minutes later the adult rolled one of two equal balls of clay into a long sausage and asked whether they weighed the same. The seven-year-old hesitated and said the sausage was heavier because it was longer.
In a second round, the adult asked the five-year-old the question only once, after the pouring, rather than before and after. This time the child said, "It's the same juice," and then, asked again, changed the answer to the tall glass.
Point-by-Point Comparison
| Prediction | What the case showed | Verdict |
|---|---|---|
| The five-year-old judges by height | Chose the tall glass, citing height | Predicted well |
| The seven-year-old conserves liquid with a reversibility reason | Said same; "you could pour it back" | Predicted well |
| The seven-year-old may still fail weight | Said the clay sausage was heavier | Predicted well |
| The younger child's error is stable | Answer changed with how the question was asked | Not predicted |
Where the Theory Could Not Account for the Case
The miss matters. Piaget's account treats the five-year-old's error as a feature of how preoperational children think. But the child's answer shifted when the question was asked differently, which suggests that part of the error came from how the child understood the adult's questions. McGarrigle and Donaldson (1974) tested this idea with number conservation. When an adult deliberately rearranged a row of counters and asked again, many young children said the number had changed; when a toy bear, the naughty teddy, appeared to mess up the row by accident, far more children said the number was the same. A child asked the same question twice by an adult may reasonably assume the adult expects a different answer.
Gelman (1969) showed something related from another direction: five-year-olds who were trained to attend to the relevant features of the materials learned to conserve, which suggests the ability is closer to the surface at that age than a strict stage account implies.
What a Single Case Can and Cannot Do
A single case is weak evidence for a theory and somewhat stronger evidence against a specific prediction. Three confirmed predictions in one family say little, because Piaget's account was built on observations of many children and has been confirmed in broad terms many times. One failed prediction is more informative, because the theory said the younger child's error should be stable and it was not. Even so, the failure could have other explanations: the child may have been tired, may have wanted to please the adult, or may simply have been guessing. A composite case also carries the writer's expectations, since the details were chosen to illustrate the task. What the case can do honestly is show a reader what each prediction looks like in practice and point to the research, such as the naughty teddy studies, that tested the weak spot properly with many children and controlled conditions.
A Qualified Verdict
Piaget's theory predicted three of the four observations in this case, including the decalage in the older child, which is a strong showing for a theory more than seventy years old. It missed the fourth, and the miss points in the direction later research took: young children's competence is often greater than standard tasks reveal, because the tasks also test their reading of the social situation. A single composite case cannot overturn a theory, and this one does not try to. It shows, on a small scale, why developmental psychologists now treat Piaget's stages as a broad description of how thinking develops rather than as fixed boundaries that a child is entirely inside or outside of.
References
Gelman, R. (1969). Conservation acquisition: A problem of learning to attend to relevant attributes. Journal of Experimental Child Psychology, 7(2), 167-187. https://doi.org/10.1016/0022-0965(69)90041-1
McGarrigle, J., & Donaldson, M. (1974). Conservation accidents. Cognition, 3(4), 341-350. https://doi.org/10.1016/0010-0277(74)90003-1
Piaget, J. (1952). The child's conception of number. Routledge & Kegan Paul.
The Herzing PS 101 Unit 6 instructions
Unit 6 of PS 101 asks students to write about either development or personality, choosing one theory and doing it properly. Expect to present the theory as its author set it out, with attribution, convert it into testable predictions, describe a case in enough detail to check those predictions, compare predictions with the case point by point and give a qualified verdict. Development theories with clear stages often make cleaner tests than personality theories. Concluding that a theory does not fit part of the case is acceptable and often stronger. A composite case is preferred, since using a friend or relative would share personal details without their agreement. The case should be described only as far as the predictions require.
How this PS 101 Unit 6 example is built
Opening with the choice of development and a description of Piaget's conservation task, the sample defines centration, reversibility and decalage. A section restates the theory as four predictions. The composite case follows, describing what each sibling said in two rounds and with clay. A table compares predictions with the case and marks three hits and one miss. A section explains the miss using McGarrigle and Donaldson's naughty teddy study and Gelman's training study. Another discusses what a single case can and cannot show. The close gives a qualified verdict and explains why Piaget's stages are now treated as a broad description rather than fixed boundaries.
Reading the PS 101 Unit 6 rubric
The rubric for the development or personality paper generally rewards an accurately attributed theory, testable predictions, a well-described case, point-by-point comparison and a qualified verdict, plus clear writing. Attribution earns credit when the theory is described in its author's terms rather than in loose summary. Predictions score highest when they could fail. The case criterion rewards enough detail to check predictions, and no more. Comparison is often weighted most heavily, rewarding papers that mark misses as clearly as hits. The verdict earns points when it is qualified by the limits of a single case. Instructors also credit papers that connect a miss to later research, as this shows the student knows where the theory has been tested since.
PS 101 Unit 6 help: mistakes that cost points
These papers lose points when they cover two theories thinly instead of one properly. Another common mistake is describing a theory without turning it into predictions, which leaves nothing to test. Students often choose a case that fits perfectly, which proves little. Some report only the predictions that worked. Others declare a theory wrong on the basis of one case. Using a real friend or family member as the case raises privacy issues. Forgetting that a single case cannot overturn a well-tested theory is a final trap. If you are torn between development and personality, or unsure how to make a theory testable, our writers can help you set up the comparison.
Get a PS 101 Unit 6 example written to your instructions
Pass along the Unit 6 instructions with your PS 101 rubric and the theory your section expects, plus any case the assignment provides. We write a custom example that states the framework in its author's terms, derives predictions before the case, and weighs the misses as carefully as the hits. First custom sample free, returned in 24 to 48 hours.
More PS 101 papers and psychology samples
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- PS 101 Unit 3: Biological basis short paper
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PS 101 Unit 6 questions, answered
Development or personality, which is the safer choice?
Whichever your readings gave you more to work with. Personality frameworks usually offer clearer predictions to test, while developmental accounts give you a sequence and a case that moves through time. Some sections choose for you or supply a case that points one way. Decide before you draft, and say in the opening which you selected, because a paper drifting between the two satisfies neither.
Is it acceptable to conclude the theory does not fit?
It is often the better paper. A framework that fails to predict something in the case gives you a finding, provided you show the prediction, show the detail that contradicted it, and stop short of declaring the theory wrong on one case. Markers read that as engagement with evidence. What costs points is announcing a poor fit without having derived the predictions first.
May I use a friend or relative as the case?
A composite is the cleaner route and most sections accept one. Writing up a friend's upbringing or a relative's temperament puts a real person into a graded document without their agreement, and anything drawn from a counseling record or a school file is theirs rather than yours. Assemble a case from ordinary patterns, mark it as constructed, and keep every detail inside it.
Where can I find a free PS 101 Unit 6 sample paper?
The PS 101 Unit 6 development paper testing Piaget's conservation predictions can be read here from start to finish without charge, with the comparison table and margin notes. Testing another theory? Share the prompt and a matching paper is drafted for you free, typically within 48 hours.
Is it acceptable to conclude the theory does not fit in PS 101 Unit 6?
Yes, for the parts the evidence contradicts. The sample finds Piaget predicted three of four observations and explains the miss with later research rather than discarding the theory.