Publication Date


Advisor(s) - Committee Chair

Dr. Kelly Madole (Director), Dr. J. Farley Norman, Dr. Carrie Pritchard

Degree Program

Department of Psychology

Degree Type

Master of Experimental Psychology


Young children’s attention to a variety of object features has been studied. However, very few studies have examined young children’s understanding of object weight. In order to investigate developmental changes in perception and categorization of weight, three tasks were given to 59 18-month-old to 3-year-old children. Three age groups (20; 27 and 34 months old) were analyzed for the final results. The first two tasks used a familiarization and novelty preference paradigm in which attention was assessed by measuring each child’s looking time.

The first task’s goal was to evaluate young children’s ability to discriminate objects on the basis of weight. Children were familiarized with an object of one weight and then tested with an identical looking object that had a novel weight. Half of the subjects were familiarized to a heavy weight and half to a light weight object. Results showed a decrease in looking time over the familiarization trials (p = .0001) and an increase in attention to the novel weight (p = .0001). Thus, all children in the first task were able to discriminate object weight. Additional analyses for the first task assessed physical discrimination of object weight by examining the amount of arm movement each child exhibited within 250 milliseconds after taking an object. A significant difference in arm movement was found between the last familiarization and novel weight trials of the heavy (p = .0097) and light (p = .0001) conditions.

The second task’s goal was to evaluate children’s ability to attend to object weight when appearance varies. Children were familiarized to four objects that had the same weight but differed in appearance. Half of the subjects were familiarized to heavy objects and half to light objects. After familiarization, the children were tested with one object that had the same weight but a different appearance and another object that had the same appearance but a different weight. Results revealed that the children’s looking time decreased over the familiarization trials (p = .0001). Analyses of test trials revealed that only the two older age groups had significant novelty preference scores for both the new weight and new appearance trials.

The third task used a balance scale to measure understanding of weight by observing a child’s ability to pick a heavy object to make a balance scale tip. Children were given a light and heavy object with the same appearance and asked to choose which one would tip the balance scale. Results showed that only 34 month olds had significantly more correct trials (p < 0.05). In conclusion, the study’s results indicated that all young children are capable of discriminating object weight when familiarized to one object but that only the two older age groups were significantly capable of doing this when familiarized to more than one object. Results also indicated that only 34 month olds were capable of using weight differences in a more functional way, namely to tip a balance scale.


Cognition and Perception | Developmental Psychology | Psychology