# **CATegories** Materials, data, and analysis for a study on the development of category-based word knowledge/ expertise in word meanings. [authors removed for peer review] (Stage 2 registered report under review). Becoming word meaning experts: Infants’ processing of familiar words in the context of typical and atypical exemplars. In-principle acceptance of Stage 1 RR at *Child Development*. Preprint: [redacted for peer review]. ## **Abstract** How do infants become word meaning experts? This registered report investigated the structure of infants’ early lexical representations by manipulating the typicality of exemplars from familiar animal categories. 14- to 18-month-old infants (N=84; 51 female; M=15.7 months; race/ethnicity: 64% White, 8% Asian, 2% Hispanic, 1% Black, 23% multiple categories) were tested on their ability to recognize typical and atypical category exemplars after hearing familiar basic-level category labels. Infants robustly recognized both typical (d=0.79, 95% CI [0.54, 1.03]) and atypical (d=0.73, 95% CI [0.48, 0.97]) exemplars, with no significant difference between typicality conditions (d=0.13, 95% CI [-0.08, 0.35]). These results support a broad-to-narrow account of infants’ early word meanings. Implications for the role of experience in the development of lexical knowledge are discussed. ## **Stage 1 Registration** https://osf.io/rqbtn ## **Components** ### **Experiment0_lookit_pilot** Design info, stimuli, data, and analysis from an initial study piloting testing word recognition for typical and atypical category items using the Lookit platform (https://lookit.mit.edu/) * **data_analysis**: Data and analysis scripts for the pilot experiment * **pilot_experiment**: Lookit json code used to run the pilot experiment * **stimuli**: Audio and image stimuli from the pilot experiment * **trial_orders**: Trial orders/ counterbalancing conditions used in the pilot experiment. ### **Experiment1_registered_report** Design info, stimuli, analysis plan, data, and analysis scripts for a registered report testing word recognition for typical and atypical category exemplars * **pilot**: Folder containing data, analysis scripts, power simulations, stimuli, and trial orders for the pilot experiment. This folder focuses on elements of the pilot study that are reported in the Registered Report, e.g., power analyses that use the pilot data (as compared to **Experiment0_lookit_pilot**, which contains more comprehensive information focused on the pilot experiment) * **registered_report**: Folder containing data, analysis scripts, and materials from the experiment in the Registered Report. - **analysis**: Main analysis scripts (see README for details: https://osf.io/8e5kp) - **data**: All data files needed to reproduce confirmatory and exploratory analyses (see README for details: https://osf.io/q8ucb) - **stimuli**: The images and audio stimuli - **trial_orders**: The trial orders for the 8 counterbalancing conditions * **stage_1_manuscript**: PDF files of the final Stage 1 Registered Report