A Comparison of Visual Familiarization and Object‐Examining Measures of Categorization in 9‐Month‐Old Infants

Abstract

Three studies were conducted to determine whether differential patterns of categorization observed in studies using visual familiarization and object‐examining measures hold up as procedural confounds are eliminated. In Experiment 1, we attempted as direct a comparison as possible between visual and object‐examining measures of categorization. Consistent with previous reports, 9‐month‐old infants distinguished a basic‐level contrast (dog–horse) in the visual task, but not in the examining task. Experiment 2 was designed to reduce levels of nonexploratory activity in an examining task; 9‐month‐olds again failed to distinguish categories of dogs and horses. In Experiment 3, we adopted a paired‐comparison test format in the object‐examining task. Infants did display a novel category preference under paired testing conditions. The results suggest that the different patterns of categorization often seen in looking and touching tasks are a reflection, not of different categorization processes, but of the differential sensitivity of the tasks.

Hold your horses: How exposure to different items influences infant categorization

“…The results of this experiment extend previous findings that have shown infants respond to more exclusive categories when items are presented in pairs than when those same items are presented one at a time (Oakes & Ribar, 2005;Reznick & Kagan, 1983;Younger & Furrer, 2003). Importantly, we observed a robust effect of familiarization with pairs of different items in this experiment in which all infants received the same number of different items during familiarization (six), the same number of familiarization trials (12), the same number of items presented on each trial (two), and the same amount of exposure to each item.…”

“…During the 30-s trial, infants were allowed to manipulate the items any way that they wanted. If an item was dropped on the floor, the experimenter or the parent picked it up and placed it back on the table without adjusting the trial duration (Mandler & McDonough, 1998;Oakes et al, 1991;Ribar et al, 2004;Younger & Fearing, 1998;Younger & Furrer, 2003). At the end of each trial, the experimenter removed the two items and placed them out of sight, and only then initiated the next trial.…”

“…Similarly, Reznick and Kagan (1983) found that 14-month-old infants familiarized with pairs of different airplanes, women, cars, or dogs in a visual familiarization task were more likely to dishabituate to an out-of-category stimulus than were infants familiarized with pairs of identical pictures. Finally, Younger and Furrer (2003) showed that presenting novel items from the familiar category and a contrasting category sideby-side during test enhanced 9-month-old infants' recognition of the exclusive categories horses or dogs in an object-examining task.…”

“…Obviously infants must compare items both when they are presented one-at-a-time and when they are presented in pairs. Despite the fact that some studies have shown infants attend to categorical distinctions only when items are presented in pairs (Oakes & Ribar, 2005;Reznick & Kagan, 1983;Younger & Furrer, 2003), many studies have shown that infants categorize stimuli presented one at a time (e.g., Mandler & McDonough, 1998;Mareschal et al, 2003;Oakes & Ribar, 2005). In these studies, infants must have compared items presented on different trials or else they would not have detected the similarities or differences among them.…”

“…We conducted four experiments examining 10-month-old infants' attention to the distinction between dog and horse in an object-examining task (Oakes, Madole, & Cohen, 1991). Results reported by Younger and Furrer (2003) suggest that attention to this exclusive categorical distinction in this task at this age is relatively fragile-infants attended to this distinction only if items were in pairs during test. We extended this work by assessing how presenting items in pairs -as compared to one-at-a-time -during familiarization trials influences infants' attention to this distinction.…”