Brain and Language Lab
Individual and Group Differences
We investigate variability in language and memory: across individuals; within individuals, as a function of fluctuations such as endocrine changes; and between groups, as a function of factors such as sex, handedness, and genotype. In particular, we focus on whether and how language learning and use may be influenced by individual differences in memory abilities, within-subject changes such as of endocrine status, and group differences such as sex, handedness, and genotype.
DOES INDIVIDUAL VARIABILITY IN LEARNING AND MEMORY RELATE TO LANGUAGE ABILITIES?
We examine correlations between learning and memory abilities and language abilities. We focus on investigating the relation between learning abilities in declarative and procedural memory, on the one hand, and lexical and grammatical abilities, on the other. Based on the Declarative/Procedural model of language, we predict correlations between declarative memory and lexical abilities, as well as grammatical abilities in certain circumstances, and between procedural memory and grammatical abilities in other circumstances (Ullman, 2016, 2020). Whether grammar correlates with procedural and/or declarative memory should be a function of multiple factors that modulate declarative and/or procedural memory abilities (Ullman, 2004, 2015, 2016, 2020; Ullman & Pullman, 2015). We also examine correlations between language and working memory abilities. More recent work probes the relation between the learning and memory systems and other domains, in particular reading and math.
We have found (Lum et al., 2012; Conti-Ramsden et al., 2015) that in both typically developing (TD) children and those with developmental language disorder (DLD; previously known as specific language impairment), declarative memory correlates with lexical abilities, supporting the hypothesis that lexical knowledge must be learned at least in part in declarative memory. In contrast, grammar correlates with procedural memory in TD children, but with declarative memory in DLD children, supporting the hypotheses that grammar generally depends on procedural memory, but in DLD declarative memory compensate for grammatical difficulties. Working memory was found to correlate with neither lexical nor grammatical abilities in either TD children or children with DLD.
More recently we examined correlations between language and memory in a meta-analysis of published language/memory correlation studies in both first language in children and second language in adults (Ullman & Hamrick, 2018). This paper combines results from multiple studies involving a total of 665 participants. It ties lexical abilities to only declarative memory (not procedural memory). Grammar, across syntax and morphology, was tied to both systems, but differently in first and second language. Of particular interest, in second language grammar correlated only with learning in declarative memory (not procedural memory) at low levels of second language experience, but only with procedural memory at high levels. The meta-analysis convincingly links lexical memory only to declarative memory, but grammar to both systems, depending on the specific circumstances.
Finally, we have found relations between reading abilities in children on the one hand, and learning abilities in both declarative and procedural memory, on the other. In a longitudinal of 140 children in their first four years of school, we found that declarative learning performance predicted reading ability in first grade, while procedural learning performance predicted reading ability in second grade (Earle et al., 2020). The findings suggest that reading acquisition may depend in part on these two general-purpose learning and memory systems.
Publications:
Morgan-Short, K., Hamrick, P., & Ullman, M. T. (2022). Declarative and Procedural Memory as Predictors of Second Language Development. In S. Li, P. Hiver, M. Papi (Eds.) The Routledge Handbook of Second Language Acquisition and Individual Differences (pp. 67-81). (Supporting Table 1). For link to Supporting Table in Open Science Framework click HERE.
Hamrick, P., Lum, J. A., & Ullman, M. T. (2018). Child first language and adult second language are both tied to general-purpose learning systems. Proceedings of the National Academy of Sciences, 115(7), 1487-1492. (Supporting Information)
EFFECTS OF SEX DIFFERENCES
Evidence from studies of human and non-human animals suggest that females tend to show advantages at declarative memory, as compared to males (Ullman et al., 2008). This sex difference may be at least partly explained by estrogen, which enhances the functionality of declarative memory. The sex difference in declarative memory leads to the following predictions for language (Ullman, 2004; Ullman et al., 2008). Girls and women should tend to show advantages, as compared to boys and men, at lexical abilities, which appear to necessarily depend on declarative memory. Additionally, those functions, such as grammar, that can (at least to some extent) be learned and processed in declarative as well as procedural memory, should depend more on declarative memory in females, relative to males. Moreover, females should be more successful at compensating with declarative memory than males for deficits of grammar and other such functions (Ullman & Pullman, 2015).
Our empirical studies have found evidence for enhanced lexical abilities in girls as compared to boys (Walenski et al., 2008) and enhanced melody recognition in women as compared to men (Miles et al., 2016); greater frequency or imageability effects (which suggest lexical storage) for rule-governed complex forms in girls and women than boys and men, in English and Spanish (Ullman et al., 2002; Prado & Ullman, 2009; Dye et al., 2013); greater over-regularization in girls than boys, apparently due to girls generalizing in associative lexical memory from stored similar forms (e.g., generalizing from flow-flowed to grow-growed (Hartshorne & Ullman, 2006); a greater dependence of rule-governed complex forms on lexical/semantic than grammatical brain processes, as suggested by event-related potentials (Ullman et al., 2002; Steinhauer & Ullman, 2002); retrieval from memory of rule-governed complex forms in elderly women but not men (Ullman et al., 2002; Estabrooke et al., 2002); and compensation for grammatical impairments by lexical/declarative memory in female but not male patients with Parkinson’s disease (Johari, Walenski, et al., 2019; Reifegerste, Estabrooke, et al., 2020). Additionally, evidence suggests that female patients with Parkinson's diseases over-regularize more than male patients, due to the females generalizing in associative memory from stored similar forms (e.g., generalizing from flow-flowed to grow-growed) (Johari et al., 2019).
Publications:
Pliatsikas, C., Veríssimo, J., Babcock, L., Pullman, M. Y., Glei, D. A., Weinstein, M., Goldman, N., & Ullman, M. T. (2019). Working memory in older adults declines with age, but is modulated by sex and education. Quarterly Journal of Experimental Psychology, 72(6), 1308-1327. (Supplemental Material).
Miles, S., Miranda, R. A., & Ullman, M. T. (2016). Sex differences in music: A female advantage at recognizing familiar melodies. Frontiers in Psychology, 7, 278. (Supplemental Data).
EFFECTS OF GENETIC VARIABILITY
Interest in the genetics of language has increased dramatically in recent years. Different alleles (versions) of the same gene often vary in their functionality. This variation can help explain disorders as well as subtle phenotypic differences well within the normal range. One can take advantage of such variation to examine the genetic basis of differences in language and other cognitive functions between individuals or groups. Of particular interest to our group, according to the declarative/procedural model variability in genes that modulate declarative memory and/or procedural memory functionality should analogously modulate language abilities (Ullman, 2016). In particular, genes playing roles in declarative memory may analogously affect both lexical and grammatical abilities, while genes playing roles in procedural memory may affect grammatical abilities. We are currently investigating these predictions, as well as other aspects of the genetics of language and cognition.
Publications:
EFFECTS OF ENDOCRINE CHANGES
How do hormones, and sex hormones in particular, affect language learning and use? How does the variation of sex hormones within and between subjects affect language? Do the natural fluctuations of estrogen, progesterone, and other hormones during the menstrual cycle affect language? Does Hormone Replacement Therapy (HRT) modulate language processing? We are currently investigating these and related questions.