Research

I study how children build the meanings of their first words; and how the field's measures, samples, and procedures shape what we think we know about that process. My work uses meta-analysis, cross-linguistic data, and behavioral experiments to ask which findings about early word learning generalize, and which don't.

Research Interests

  • Early word learning and the shape bias
  • Cross-linguistic and cross-cultural variation in word extension
  • Measurement quality, heterogeneity, and what findings actually generalize
  • Meta-analysis and open science practices in developmental psychology

PhD Projects

1. Meta-analysis of the shape bias as a word-learning strategy

The shape bias is one of the most studied tendencies in early word learning, with creative experiments giving us insights and a window into how children build the concepts behind words. But the literature has been hard to consolidate; and therefore hard to build on; because studies use such heterogeneous procedures, stimuli, and measures.

In this project, we use meta-analysis to synthesize the existing evidence and identify covariates that explain the variation across studies. The goal is to better adjudicate between competing theoretical accounts of a phenomenon; the shape bias; that's often treated as a foundational learning bias for vocabulary development.

Published as: Abdelrahim, S., & Frank, M. C. (2026). Examining the robustness and generalizability of the shape bias: a meta-analysis. Journal of Child Language, 1–18. https://doi.org/10.1017/S0305000926100749

An earlier version appeared as: Abdelrahim, S. O, & Frank, M. C. (2024). Proceedings of the Annual Meeting of the Cognitive Science Society, 46. Read here

2. Do early lexical statistics explain cross-cultural differences in word extension?

US English-speaking children show a stronger word-extension shape bias than children learning some East Asian languages. Why? One hypothesis is that the early vocabularies themselves differ; that the statistics of nouns young children hear and learn vary across languages in ways that shape generalization; and, more broadly, that the structure of the input language plays a role in shaping early conceptual organization. Across 16 languages, we ask whether such variation actually exists, and how much of the cross-cultural pattern it could plausibly explain.

See: Abdelrahim, S. O, & Frank, M. C. (2024). Limited cross-linguistic variation in the lexical statistics of nouns in early vocabulary (BUCLD49 2024, Boston, USA)

See: Lexical Statistics in Early Noun Vocabularies: A Cross-Linguistic and Rater-Origin Perspective. Samah Abdelrahim, Jongmin Jung, Claire Lee, Eon-Suk Ko, Michael Frank (BUCLD50 2025, Boston, USA)

3. Measurement of the shape bias: age, stimuli, and procedure variation

Different studies of the shape bias use different children, different objects, and different tasks. We ask how much of the apparent inconsistency in the literature is explained by these procedural choices. Study in progress.

See: Investigating heterogeneity in shape bias: a study on procedural, stimuli, and age-related variations. Samah Abdelrahim, Sadio Abdi, Meesha Ryan, Michael Frank (The 15th Annual BCCCD Conference, January 9-11 2025 - BCCCD25) (YouTube video here)

4. What exactly is a complex object? And what does complexity even mean? Implications for early word learning

A new line of work asking what "complexity" actually means for an object; and what that has to do with how children learn its name. More soon!

5. Does the shape bias require vision or language or both?

Most of what we know about the shape bias comes from studies with sighted children who encounter objects visually, what about blind children?

What about large language models (LLMs), vision-language models (VLMs) and convolutional neural networks (CNNs)? More soon!

Papers & Conference Talks

Journal articles

In preparation

  • Shape is a good cue, not a common one: lexical statistics of early nouns in English and Korean. Abdelrahim, Jung, Ko, &Frank. (in prep)
  • Word extension tasks as a measurement of the shape bias. Abdelrahim et al. (in prep)

Conference and Journal articles

  • Abdelrahim, S., & Frank, M. (2026). Examining the Robustness and Generalizability of the Shape Bias: A Meta-Analysis. Journal of Child Language 1–18, https://doi.org/10.1017/S0305000926100749
  • Abdelrahim, S., Jung, J., Lee, C., Ko, E.-S., & Frank, M. C. (2025). Lexical statistics in early noun vocabularies: a cross-linguistic and rater-origin perspective. BUCLD50 2025, Boston, USA.
  • Abdelrahim, S., Abdi, S., Ryan, M., & Frank, M. C. (2025). Investigating heterogeneity in shape bias: a study on procedural, stimuli, and age-related variations. The 15th Annual BCCCD Conference (BCCCD25), January 9–11, Budapest, Hungary.
  • Abdelrahim, S. O, & Frank, M. C. (2024). Limited cross-linguistic variation in the lexical statistics of nouns in early vocabulary. BUCLD 2024, Boston, USA.
  • Abdelrahim, S. O, & Frank, M. C. (2024). Examining the robustness and generalizability of the shape bias: a meta-analysis. Proceedings of the Annual Meeting of the Cognitive Science Society, 46. Sydney, Australia. Read here
  • Bisbee, N., Tang, J. E., Yu, S. J., Lyu, Z. X., Abdelrahim, S., & Gordon, P. (July 7–10, 2022). Relations between exact number and exact equality: developmental and cross-cultural perspectives. [Conference Poster]. International Congress on Infant Studies (ICIS) 2022 XXIII Biennial Congress, Ottawa, Canada.
  • Tang-Lonardo, J., Bisbee, N., Jain, M., Kirby, E., Kim, S. B., Abdelrahim, S., Gerami, S., Sezcon-Cepeda, D., Coffel, M., & Gordon, P. (May 26–29, 2022). The neural mechanisms of parallel individuation and numerical approximation. [Conference Poster]. Association for Psychological Science (APS) 2022 Annual Convention, Chicago, IL, USA.
  • Tang, J. E., Bisbee, N., Jain, M., Kirby, E., Kim, S. B., Gerami, S., Sezcon-Cepeda, D., Gilchrist, K., Abdelrahim, S., Coffel, M., & Gordon, P. (July 27–30, 2022). The neurobehavioral basis of parallel individuation and numerical approximation. [Conference Poster]. Cognitive Science Society 2022, 44th Annual Conference, Toronto, Canada.