Women's preferences for men's masculinized faces and voices were assessed after women (n ... more Women's preferences for men's masculinized faces and voices were assessed after women (n = 331) were primed with images of male-on-male aggression, male-on-female aggression, pathogens, and neutral scenes. Male-on-male aggression and pathogen primes were associated with increased preference for masculine traits, but the same effect emerged in the neutral condition. We show the increased preference for masculine traits was due to repeated exposure to these traits, not the priming images themselves. Images of male-on-female aggression were an exception; these elicited feelings of disgust and anger appeared to disrupt the preference for masculinized traits. The results suggest women process men's facial and vocal traits as signals of aggressive potential and lose any preference for these traits with cues indicating men might direct this aggression toward them.
The field of evolutionary psychology is growing in prominence and influence despite the reluctanc... more The field of evolutionary psychology is growing in prominence and influence despite the reluctance of many social scientists to apply evolutionary principles to understanding human behavior (Segerstrale, 2000). Included among the phenomena that are now studied from this perspective are developmental activities and processes, and with this, the emergence of the subfield of evolutionary-developmental psychology (Bjorklund, 1997; Bjorklund & Pellegrini, 2002; Freedman, 1974; Geary & Bjorklund, 2000). One focus of theory and research in this subfield is on the relation between children's evolved cognitive and motivational biases and the demands of academic learning (Geary, 1995, 2001, 2002a; Rozin, 1976). In this chapter, I present an overview of a framework I am developing to understand the relation between evolved abilities and the non evolved academic competencies that are built through instructional practices. The former are called biologically primary abilities, and the latter, biologically secondary abilities. In the first section, I present a taxonomy of primary cognitive domains (see also Geary, 2005; Geary & Huffman, 2002), and in the second, I discuss some of the ways in which these evolved cognitive and associated motivational and developmental systems may be related to academic learning and the construction of secondary abilities.
Groups of first-grade (mean age ¼ 82 months), third-grade (mean age ¼ 107 months), and fifth-grad... more Groups of first-grade (mean age ¼ 82 months), third-grade (mean age ¼ 107 months), and fifth-grade (mean age ¼ 131 months) children with a learning disability in mathematics (MD, n ¼ 58) and their normally achieving peers (n ¼ 91) were administered tasks that assessed their knowledge of counting principles, working memory, and the strategies used to solve simple (4 + 3) and complex (16 + 8) addition problems. In all grades, the children with MD showed a working memory deficit, and in first grade, the children with MD used less sophisticated strategies and committed more errors while solving simple and complex addition problems. The group differences in strategy usage and accuracy were related, in part, to the group difference in working memory and to group and individual differences in counting knowledge. Across grade-level and group, the switch from simple to complex addition problems resulted in a shift in the mix of problem-solving strategies. Individual differences in the strategy mix and in the strategy shift were related, in part, to individual differences in working memory capacity and counting knowledge.
The purpose of this study was to investigate the effects of 1st-grade number knowledge tutoring w... more The purpose of this study was to investigate the effects of 1st-grade number knowledge tutoring with contrasting forms of practice. Tutoring occurred 3 times per week for 16 weeks. In each 30min session, the major emphasis (25 min) was number knowledge; the other 5 min provided practice in 1 of 2 forms. Nonspeeded practice reinforced relations and principles addressed in number knowledge tutoring. Speeded practice promoted quick responding and use of efficient
First-to fifth-grade mathematics and word reading achievement were assessed for children with mat... more First-to fifth-grade mathematics and word reading achievement were assessed for children with mathematical learning disability (MLD, n ϭ 16), persistent low achievement (LA, n ϭ 29), and typical achievement (n ϭ 132). Intelligence, working memory, processing speed, and in-class attention were assessed in 2 or more grades, and mathematical cognition was assessed with experimental tasks in all grades. The MLD group was characterized by low school-entry mathematics achievement and poor word reading skills. The former was mediated by poor fluency in processing or accessing quantities associated with small sets of objects and corresponding Arabic numerals, whereas the latter was mediated by slow automatized naming of letters and numbers. Both the MLD and LA groups showed slow across-grade growth in mathematics achievement. Group differences in growth were mediated by deficits or delays in fluency of number processing, the ability to retrieve basic facts from long-term memory and to decompose numbers to aid in problem solving, and by the central executive component of working memory and in-class attention.
An evolutionary analysis of the dynamics of one-on-one and coalitional male-male competition prov... more An evolutionary analysis of the dynamics of one-on-one and coalitional male-male competition provides a theoretical frame for conceptualizing the evolved functions and proximate developmental forms of the social behavior of boys, and for appreciating why the behavior of boys differs from that of girls. We propose the accompanying selection pressures favored the evolution of motivational and behavioral dispositions in boys and men that facilitate the development and maintenance of large, competitive coalitions and result in the formation of within-coalition dominance hierarchies. Empirical research on boysÕ social development is reviewed using this frame and implications for interpreting boysÕ social behavior are explored.
The purpose of this study was to examine the interplay between basic numerical cognition and doma... more The purpose of this study was to examine the interplay between basic numerical cognition and domain-general abilities (such as working memory) in explaining school mathematics learning. First graders (n=280; 5.77 years) were assessed on 2 types of basic numerical cognition, 8 domain-general abilities, procedural calculations (PCs), and word problems (WPs) in fall and then reassessed on PCs and WPs in spring. Development was indexed via latent change scores, and the interplay between numerical and domain-general abilities was analyzed via multiple regression. Results suggest that the development of different types of formal school mathematics depends on different constellations of numerical versus general cognitive abilities. When controlling for 8 domain-general abilities, both aspects of basic numerical cognition were uniquely predictive of PC and WP development. Yet, for PC development, the additional amount of variance explained by the set of domain-general abilities was not significant, and only counting span was uniquely predictive. By contrast, for WP development, the set of domain-general abilities did provide additional explanatory value, accounting for about the same amount of variance as the basic numerical cognition variables.
Children with a mathematical learning disability (MLD, n = 19) and low achieving (LA, n = 43) chi... more Children with a mathematical learning disability (MLD, n = 19) and low achieving (LA, n = 43) children were identified using mathematics achievement scores below the 11th percentile and between the 11th and 25th percentiles, respectively. A control group of typically achieving (TA, n = 50) children was also identified. Number line and speed of processing tasks were administered in 1st and 2nd grade and a working memory battery in 1st grade. In both grades, the MLD children were less accurate in their number line placements and more reliant on a natural number-magnitude representational system to make these placements than were TA children. The TA children were more reliant on the school-taught linear system in both grades. The performance of the LA children was similar to that of the MLD children in first grade and to the TA children in second. The central executive component of working memory contributed to across-grade improvements in number line performance and to group differences in this performance. Several large-scale population-based, prospective studies and a number of smaller-scale studies have consistently found that between 5% and 10% of children and adolescents will experience a substantive learning deficit-not attributable to low cognitive ability-in at least one area of mathematics before graduating from high school (
In this volume, Ellis et al. have compiled a massive compendium of citations for reported sex dif... more In this volume, Ellis et al. have compiled a massive compendium of citations for reported sex differences. References cited are located on a compact disc that accompanies the book. Ellis et al. placed few constraints on the research they report, including human and nonhuman animal studies, as well as all age groups. Approximately 18,000 studies are cited, some of which report more than one sex difference, for a total of about 30,000 citations. These are condensed into 1,920 tables, organized with the intent of updating as new studies are published. Tables are divided into rows by the direction of the sex difference, or no significant difference, and into columns by age: ''infant'' (in humans,\1 year), ''toddler'' (in humans, 1-2 years), ''early childhood'' (in humans, 3-5 years), ''childhood'' (in humans, 6-12 years), ''adolescent'' (in humans, 13-18 years), and ''adult'' (in humans, 19 years or older). Citations are categorized within cells according to seven world regions (Africa, Asia, Europe, Latin America, Middle East, North America, and Oceania). Nonhuman species, which comprise 10% of the citations, are listed by species and approximate age in human years. Before each table is a brief introduction to the variables addressed in it. The book is organized into 13 chapters. Chapter 1, ''Basic Biological Factors,'' includes sex ratios at birth, weight, and sizes and functioning of various anatomical and physiological organs. Chapter 2, ''The Brain and Biochemistry,'' summarizes findings on neurological functioning, neuroanatomy, neurochemistry, hormones, neurotransmitter receptors, and so forth. Chapter 3, ''Health and Illness Factors,'' includes overall health and illness as determined by use of health care services
We contrasted the long-term mate preferences, reported developmental experiences, life history tr... more We contrasted the long-term mate preferences, reported developmental experiences, life history traits, and current personal traits of low-income women who reproduced with a single man (n = 222), two or more men (n = 145), or had not yet reproduced (n = 106). The mate preferences of the three groups were more similar than different, suggesting that group differences in reproductive strategy may be more strongly related to developmental experiences and current circumstances than to explicit preferences for one type of reproductive partner or another. Path analytic models revealed that the only direct predictor of number of reproductive mates was age of first reproduction, which in turn was predicted by level of education and age of first sexual intercourse. Age of first intercourse, in turn, was predicted by time spent with father. The pattern suggests paternal investment influences timing of adolescent sexual activity, and timing of this activity can set in motion a long-term reproductive trajectory.
Kindergarten to 3 rd grade mathematics achievement scores from a prospective study of mathematica... more Kindergarten to 3 rd grade mathematics achievement scores from a prospective study of mathematical development were subjected to latent growth trajectory analyses (n = 306). The four corresponding classes included children with mathematical learning disability (MLD, 6% of sample), and low (LA, 50%), typically (TA, 39%) and high (HA, 5%) achieving children. The groups were administered a battery of intelligence (IQ), working memory, and mathematical-cognition measures in 1 st grade. The children with MLD had general deficits in working memory and IQ, and potentially more specific deficits on measures of number sense. The LA children did not have working memory or IQ deficits, but showed moderate deficits on these number sense measures and for addition fact retrieval. The distinguishing features of the HA children were a strong visuospatial working memory, a strong number sense, and frequent use of memory-based processes to solve addition problems. Implications for the early identification of children at risk for poor mathematics achievement are discussed. About 7% of children and adolescents will experience a substantive learning deficit in at least one area of mathematics (MLD) before graduating from high school (Barbaresi, Katusic,
Children's gains in problem-solving skills during the elementary school years are characteriz... more Children's gains in problem-solving skills during the elementary school years are characterized by shifts in the mix of problem-solving approaches, with inefficient procedural strategies being gradually replaced with direct retrieval of domain-relevant facts. We used a well-established procedure for strategy assessment during arithmetic problem solving to investigate the neural basis of this critical transition. We indexed behavioral strategy use by focusing on the retrieval frequency and examined changes in brain activity and connectivity associated with retrieval fluency during arithmetic problem solving in second- and third-grade (7- to 9-year-old) children. Children with higher retrieval fluency showed elevated signal in the right hippocampus, parahippocampal gyrus (PHG), lingual gyrus (LG), fusiform gyrus (FG), left ventrolateral PFC (VLPFC), bilateral dorsolateral PFC (DLPFC), and posterior angular gyrus. Critically, these effects were not confounded by individual differen...
This commentary focuses on one of the many issues raised in Geary's target article: the impor... more This commentary focuses on one of the many issues raised in Geary's target article: the importance of gender differences in spatial ability to gender differences in mathematics. I argue that the evidence for the central role of spatial ability in mathematical ability, or in gender differences in it, is tenuous at best.
Using strict and lenient mathematics achievement cutoff scores to define a learning disability, r... more Using strict and lenient mathematics achievement cutoff scores to define a learning disability, respective groups of children who are math disabled (MLD, n 5 15) and low achieving (LA, n 5 44) were identified. These groups and a group of typically achieving (TA, n 5 46) children were administered a battery of mathematical cognition, working memory, and speed of processing measures (M 5 6 years). The children with MLD showed deficits across all math cognition tasks, many of which were partially or fully mediated by working memory or speed of processing. Compared with the TA group, the LA children were less fluent in processing numerical information and knew fewer addition facts. Implications for defining MLD and identifying underlying cognitive deficits are discussed.
The collection of articles in this special issue and related studies over the past decade provide... more The collection of articles in this special issue and related studies over the past decade provides a fine example of the substantial progress that has been made in our understanding and remediation of mathematical learning disabilities and difficulties since 1993 (Geary, 1993). The originally proposed procedural and retrieval deficits have been supported and a number sense deficit has been identified. There is evidence for visuospatial contributions to some aspects of mathematical learning, but identification of a core visuospatial deficit underlying some forms of mathematics learning disabilities and difficulties has been elusive. The contributions of working memory to the development and expression of these deficits is more nuanced than I originally proposed as are the brain systems supporting mathematical learning. Although much has been learned about children's difficulties in learning mathematics, but there is just as much and likely more than remains to be discovered. Cirino and Berch asked me to reflect on the articles in this special issue with respect to my 1993 review of what was then known about mathematical learning disabilities (MLD; Geary, 1993). At the time of my 1993 review, there were less than a score of cognitively-motivated studies of MLD and LA (low achievement), a somewhat richer literature in neuropsychology, and only a few behavioral genetic analyses of individual differences in mathematics achievement. The revolution in brain imaging technology was just underway and thus there were few such studies on mathematical processing and even fewer randomized control studies of cognitively-motivated interventions for MLD. In fact, there was no agreed upon criterion for diagnosing MLD. Substantial progress has been made in all of these areas, and the set of articles in this issue provides a fine illustration of how far our understanding of MLD and mathematical difficulties associated with LA has come since 1993. I reflect on some of these gains following the organization of the 1993 review; specifically, cognitive, neuropsychological, and genetic components of MLD. Unless otherwise noted, hereafter MLD refers to both MLD and LA children, as these groups were conflated in much of the earlier research. COGNITIVE COMPONENT With the early cognitively-motivated studies, the methods and theories used in the study of typical development were adopted to better understand the achievement deficits of children
Groups of first-grade (mean age=82 months), third-grade (mean age=107 months), and fifth-grade (m... more Groups of first-grade (mean age=82 months), third-grade (mean age=107 months), and fifth-grade (mean age=131 months) children with a learning disability in mathematics (MD, n=58) and their normally achieving peers (n=91) were administered tasks that assessed their knowledge of counting principles, working memory, and the strategies used to solve simple (4 + 3) and complex (16 + 8) addition problems. In all grades, the children with MD showed a working memory deficit, and in first grade, the children with MD used less sophisticated strategies and committed more errors while solving simple and complex addition problems. The group differences in strategy usage and accuracy were related, in part, to the group difference in working memory and to group and individual differences in counting knowledge. Across grade-level and group, the switch from simple to complex addition problems resulted in a shift in the mix of problem-solving strategies. Individual differences in the strategy mix and...
First- to fifth-grade mathematics and word reading achievement were assessed for children with ma... more First- to fifth-grade mathematics and word reading achievement were assessed for children with mathematical learning disability (MLD, n = 16), persistent low achievement (LA, n = 29), and typical achievement (n = 132). Intelligence, working memory, processing speed, and in-class attention were assessed in 2 or more grades, and mathematical cognition was assessed with experimental tasks in all grades. The MLD group was characterized by low school-entry mathematics achievement and poor word reading skills. The former was mediated by poor fluency in processing or accessing quantities associated with small sets of objects and corresponding Arabic numerals, whereas the latter was mediated by slow automatized naming of letters and numbers. Both the MLD and LA groups showed slow across-grade growth in mathematics achievement. Group differences in growth were mediated by deficits or delays in fluency of number processing, the ability to retrieve basic facts from long-term memory and to deco...
Kindergarten to 3 rd grade mathematics achievement scores from a prospective study of mathematica... more Kindergarten to 3 rd grade mathematics achievement scores from a prospective study of mathematical development were subjected to latent growth trajectory analyses (n = 306). The four corresponding classes included children with mathematical learning disability (MLD, 6% of sample), and low (LA, 50%), typically (TA, 39%) and high (HA, 5%) achieving children. The groups were administered a battery of intelligence (IQ), working memory, and mathematical-cognition measures in 1 st grade. The children with MLD had general deficits in working memory and IQ, and potentially more specific deficits on measures of number sense. The LA children did not have working memory or IQ deficits, but showed moderate deficits on these number sense measures and for addition fact retrieval. The distinguishing features of the HA children were a strong visuospatial working memory, a strong number sense, and frequent use of memory-based processes to solve addition problems. Implications for the early identification of children at risk for poor mathematics achievement are discussed. About 7% of children and adolescents will experience a substantive learning deficit in at least one area of mathematics (MLD) before graduating from high school (Barbaresi, Katusic,
Women's preferences for men's masculinized faces and voices were assessed after women (n ... more Women's preferences for men's masculinized faces and voices were assessed after women (n = 331) were primed with images of male-on-male aggression, male-on-female aggression, pathogens, and neutral scenes. Male-on-male aggression and pathogen primes were associated with increased preference for masculine traits, but the same effect emerged in the neutral condition. We show the increased preference for masculine traits was due to repeated exposure to these traits, not the priming images themselves. Images of male-on-female aggression were an exception; these elicited feelings of disgust and anger appeared to disrupt the preference for masculinized traits. The results suggest women process men's facial and vocal traits as signals of aggressive potential and lose any preference for these traits with cues indicating men might direct this aggression toward them.
The field of evolutionary psychology is growing in prominence and influence despite the reluctanc... more The field of evolutionary psychology is growing in prominence and influence despite the reluctance of many social scientists to apply evolutionary principles to understanding human behavior (Segerstrale, 2000). Included among the phenomena that are now studied from this perspective are developmental activities and processes, and with this, the emergence of the subfield of evolutionary-developmental psychology (Bjorklund, 1997; Bjorklund & Pellegrini, 2002; Freedman, 1974; Geary & Bjorklund, 2000). One focus of theory and research in this subfield is on the relation between children's evolved cognitive and motivational biases and the demands of academic learning (Geary, 1995, 2001, 2002a; Rozin, 1976). In this chapter, I present an overview of a framework I am developing to understand the relation between evolved abilities and the non evolved academic competencies that are built through instructional practices. The former are called biologically primary abilities, and the latter, biologically secondary abilities. In the first section, I present a taxonomy of primary cognitive domains (see also Geary, 2005; Geary & Huffman, 2002), and in the second, I discuss some of the ways in which these evolved cognitive and associated motivational and developmental systems may be related to academic learning and the construction of secondary abilities.
Groups of first-grade (mean age ¼ 82 months), third-grade (mean age ¼ 107 months), and fifth-grad... more Groups of first-grade (mean age ¼ 82 months), third-grade (mean age ¼ 107 months), and fifth-grade (mean age ¼ 131 months) children with a learning disability in mathematics (MD, n ¼ 58) and their normally achieving peers (n ¼ 91) were administered tasks that assessed their knowledge of counting principles, working memory, and the strategies used to solve simple (4 + 3) and complex (16 + 8) addition problems. In all grades, the children with MD showed a working memory deficit, and in first grade, the children with MD used less sophisticated strategies and committed more errors while solving simple and complex addition problems. The group differences in strategy usage and accuracy were related, in part, to the group difference in working memory and to group and individual differences in counting knowledge. Across grade-level and group, the switch from simple to complex addition problems resulted in a shift in the mix of problem-solving strategies. Individual differences in the strategy mix and in the strategy shift were related, in part, to individual differences in working memory capacity and counting knowledge.
The purpose of this study was to investigate the effects of 1st-grade number knowledge tutoring w... more The purpose of this study was to investigate the effects of 1st-grade number knowledge tutoring with contrasting forms of practice. Tutoring occurred 3 times per week for 16 weeks. In each 30min session, the major emphasis (25 min) was number knowledge; the other 5 min provided practice in 1 of 2 forms. Nonspeeded practice reinforced relations and principles addressed in number knowledge tutoring. Speeded practice promoted quick responding and use of efficient
First-to fifth-grade mathematics and word reading achievement were assessed for children with mat... more First-to fifth-grade mathematics and word reading achievement were assessed for children with mathematical learning disability (MLD, n ϭ 16), persistent low achievement (LA, n ϭ 29), and typical achievement (n ϭ 132). Intelligence, working memory, processing speed, and in-class attention were assessed in 2 or more grades, and mathematical cognition was assessed with experimental tasks in all grades. The MLD group was characterized by low school-entry mathematics achievement and poor word reading skills. The former was mediated by poor fluency in processing or accessing quantities associated with small sets of objects and corresponding Arabic numerals, whereas the latter was mediated by slow automatized naming of letters and numbers. Both the MLD and LA groups showed slow across-grade growth in mathematics achievement. Group differences in growth were mediated by deficits or delays in fluency of number processing, the ability to retrieve basic facts from long-term memory and to decompose numbers to aid in problem solving, and by the central executive component of working memory and in-class attention.
An evolutionary analysis of the dynamics of one-on-one and coalitional male-male competition prov... more An evolutionary analysis of the dynamics of one-on-one and coalitional male-male competition provides a theoretical frame for conceptualizing the evolved functions and proximate developmental forms of the social behavior of boys, and for appreciating why the behavior of boys differs from that of girls. We propose the accompanying selection pressures favored the evolution of motivational and behavioral dispositions in boys and men that facilitate the development and maintenance of large, competitive coalitions and result in the formation of within-coalition dominance hierarchies. Empirical research on boysÕ social development is reviewed using this frame and implications for interpreting boysÕ social behavior are explored.
The purpose of this study was to examine the interplay between basic numerical cognition and doma... more The purpose of this study was to examine the interplay between basic numerical cognition and domain-general abilities (such as working memory) in explaining school mathematics learning. First graders (n=280; 5.77 years) were assessed on 2 types of basic numerical cognition, 8 domain-general abilities, procedural calculations (PCs), and word problems (WPs) in fall and then reassessed on PCs and WPs in spring. Development was indexed via latent change scores, and the interplay between numerical and domain-general abilities was analyzed via multiple regression. Results suggest that the development of different types of formal school mathematics depends on different constellations of numerical versus general cognitive abilities. When controlling for 8 domain-general abilities, both aspects of basic numerical cognition were uniquely predictive of PC and WP development. Yet, for PC development, the additional amount of variance explained by the set of domain-general abilities was not significant, and only counting span was uniquely predictive. By contrast, for WP development, the set of domain-general abilities did provide additional explanatory value, accounting for about the same amount of variance as the basic numerical cognition variables.
Children with a mathematical learning disability (MLD, n = 19) and low achieving (LA, n = 43) chi... more Children with a mathematical learning disability (MLD, n = 19) and low achieving (LA, n = 43) children were identified using mathematics achievement scores below the 11th percentile and between the 11th and 25th percentiles, respectively. A control group of typically achieving (TA, n = 50) children was also identified. Number line and speed of processing tasks were administered in 1st and 2nd grade and a working memory battery in 1st grade. In both grades, the MLD children were less accurate in their number line placements and more reliant on a natural number-magnitude representational system to make these placements than were TA children. The TA children were more reliant on the school-taught linear system in both grades. The performance of the LA children was similar to that of the MLD children in first grade and to the TA children in second. The central executive component of working memory contributed to across-grade improvements in number line performance and to group differences in this performance. Several large-scale population-based, prospective studies and a number of smaller-scale studies have consistently found that between 5% and 10% of children and adolescents will experience a substantive learning deficit-not attributable to low cognitive ability-in at least one area of mathematics before graduating from high school (
In this volume, Ellis et al. have compiled a massive compendium of citations for reported sex dif... more In this volume, Ellis et al. have compiled a massive compendium of citations for reported sex differences. References cited are located on a compact disc that accompanies the book. Ellis et al. placed few constraints on the research they report, including human and nonhuman animal studies, as well as all age groups. Approximately 18,000 studies are cited, some of which report more than one sex difference, for a total of about 30,000 citations. These are condensed into 1,920 tables, organized with the intent of updating as new studies are published. Tables are divided into rows by the direction of the sex difference, or no significant difference, and into columns by age: ''infant'' (in humans,\1 year), ''toddler'' (in humans, 1-2 years), ''early childhood'' (in humans, 3-5 years), ''childhood'' (in humans, 6-12 years), ''adolescent'' (in humans, 13-18 years), and ''adult'' (in humans, 19 years or older). Citations are categorized within cells according to seven world regions (Africa, Asia, Europe, Latin America, Middle East, North America, and Oceania). Nonhuman species, which comprise 10% of the citations, are listed by species and approximate age in human years. Before each table is a brief introduction to the variables addressed in it. The book is organized into 13 chapters. Chapter 1, ''Basic Biological Factors,'' includes sex ratios at birth, weight, and sizes and functioning of various anatomical and physiological organs. Chapter 2, ''The Brain and Biochemistry,'' summarizes findings on neurological functioning, neuroanatomy, neurochemistry, hormones, neurotransmitter receptors, and so forth. Chapter 3, ''Health and Illness Factors,'' includes overall health and illness as determined by use of health care services
We contrasted the long-term mate preferences, reported developmental experiences, life history tr... more We contrasted the long-term mate preferences, reported developmental experiences, life history traits, and current personal traits of low-income women who reproduced with a single man (n = 222), two or more men (n = 145), or had not yet reproduced (n = 106). The mate preferences of the three groups were more similar than different, suggesting that group differences in reproductive strategy may be more strongly related to developmental experiences and current circumstances than to explicit preferences for one type of reproductive partner or another. Path analytic models revealed that the only direct predictor of number of reproductive mates was age of first reproduction, which in turn was predicted by level of education and age of first sexual intercourse. Age of first intercourse, in turn, was predicted by time spent with father. The pattern suggests paternal investment influences timing of adolescent sexual activity, and timing of this activity can set in motion a long-term reproductive trajectory.
Kindergarten to 3 rd grade mathematics achievement scores from a prospective study of mathematica... more Kindergarten to 3 rd grade mathematics achievement scores from a prospective study of mathematical development were subjected to latent growth trajectory analyses (n = 306). The four corresponding classes included children with mathematical learning disability (MLD, 6% of sample), and low (LA, 50%), typically (TA, 39%) and high (HA, 5%) achieving children. The groups were administered a battery of intelligence (IQ), working memory, and mathematical-cognition measures in 1 st grade. The children with MLD had general deficits in working memory and IQ, and potentially more specific deficits on measures of number sense. The LA children did not have working memory or IQ deficits, but showed moderate deficits on these number sense measures and for addition fact retrieval. The distinguishing features of the HA children were a strong visuospatial working memory, a strong number sense, and frequent use of memory-based processes to solve addition problems. Implications for the early identification of children at risk for poor mathematics achievement are discussed. About 7% of children and adolescents will experience a substantive learning deficit in at least one area of mathematics (MLD) before graduating from high school (Barbaresi, Katusic,
Children's gains in problem-solving skills during the elementary school years are characteriz... more Children's gains in problem-solving skills during the elementary school years are characterized by shifts in the mix of problem-solving approaches, with inefficient procedural strategies being gradually replaced with direct retrieval of domain-relevant facts. We used a well-established procedure for strategy assessment during arithmetic problem solving to investigate the neural basis of this critical transition. We indexed behavioral strategy use by focusing on the retrieval frequency and examined changes in brain activity and connectivity associated with retrieval fluency during arithmetic problem solving in second- and third-grade (7- to 9-year-old) children. Children with higher retrieval fluency showed elevated signal in the right hippocampus, parahippocampal gyrus (PHG), lingual gyrus (LG), fusiform gyrus (FG), left ventrolateral PFC (VLPFC), bilateral dorsolateral PFC (DLPFC), and posterior angular gyrus. Critically, these effects were not confounded by individual differen...
This commentary focuses on one of the many issues raised in Geary's target article: the impor... more This commentary focuses on one of the many issues raised in Geary's target article: the importance of gender differences in spatial ability to gender differences in mathematics. I argue that the evidence for the central role of spatial ability in mathematical ability, or in gender differences in it, is tenuous at best.
Using strict and lenient mathematics achievement cutoff scores to define a learning disability, r... more Using strict and lenient mathematics achievement cutoff scores to define a learning disability, respective groups of children who are math disabled (MLD, n 5 15) and low achieving (LA, n 5 44) were identified. These groups and a group of typically achieving (TA, n 5 46) children were administered a battery of mathematical cognition, working memory, and speed of processing measures (M 5 6 years). The children with MLD showed deficits across all math cognition tasks, many of which were partially or fully mediated by working memory or speed of processing. Compared with the TA group, the LA children were less fluent in processing numerical information and knew fewer addition facts. Implications for defining MLD and identifying underlying cognitive deficits are discussed.
The collection of articles in this special issue and related studies over the past decade provide... more The collection of articles in this special issue and related studies over the past decade provides a fine example of the substantial progress that has been made in our understanding and remediation of mathematical learning disabilities and difficulties since 1993 (Geary, 1993). The originally proposed procedural and retrieval deficits have been supported and a number sense deficit has been identified. There is evidence for visuospatial contributions to some aspects of mathematical learning, but identification of a core visuospatial deficit underlying some forms of mathematics learning disabilities and difficulties has been elusive. The contributions of working memory to the development and expression of these deficits is more nuanced than I originally proposed as are the brain systems supporting mathematical learning. Although much has been learned about children's difficulties in learning mathematics, but there is just as much and likely more than remains to be discovered. Cirino and Berch asked me to reflect on the articles in this special issue with respect to my 1993 review of what was then known about mathematical learning disabilities (MLD; Geary, 1993). At the time of my 1993 review, there were less than a score of cognitively-motivated studies of MLD and LA (low achievement), a somewhat richer literature in neuropsychology, and only a few behavioral genetic analyses of individual differences in mathematics achievement. The revolution in brain imaging technology was just underway and thus there were few such studies on mathematical processing and even fewer randomized control studies of cognitively-motivated interventions for MLD. In fact, there was no agreed upon criterion for diagnosing MLD. Substantial progress has been made in all of these areas, and the set of articles in this issue provides a fine illustration of how far our understanding of MLD and mathematical difficulties associated with LA has come since 1993. I reflect on some of these gains following the organization of the 1993 review; specifically, cognitive, neuropsychological, and genetic components of MLD. Unless otherwise noted, hereafter MLD refers to both MLD and LA children, as these groups were conflated in much of the earlier research. COGNITIVE COMPONENT With the early cognitively-motivated studies, the methods and theories used in the study of typical development were adopted to better understand the achievement deficits of children
Groups of first-grade (mean age=82 months), third-grade (mean age=107 months), and fifth-grade (m... more Groups of first-grade (mean age=82 months), third-grade (mean age=107 months), and fifth-grade (mean age=131 months) children with a learning disability in mathematics (MD, n=58) and their normally achieving peers (n=91) were administered tasks that assessed their knowledge of counting principles, working memory, and the strategies used to solve simple (4 + 3) and complex (16 + 8) addition problems. In all grades, the children with MD showed a working memory deficit, and in first grade, the children with MD used less sophisticated strategies and committed more errors while solving simple and complex addition problems. The group differences in strategy usage and accuracy were related, in part, to the group difference in working memory and to group and individual differences in counting knowledge. Across grade-level and group, the switch from simple to complex addition problems resulted in a shift in the mix of problem-solving strategies. Individual differences in the strategy mix and...
First- to fifth-grade mathematics and word reading achievement were assessed for children with ma... more First- to fifth-grade mathematics and word reading achievement were assessed for children with mathematical learning disability (MLD, n = 16), persistent low achievement (LA, n = 29), and typical achievement (n = 132). Intelligence, working memory, processing speed, and in-class attention were assessed in 2 or more grades, and mathematical cognition was assessed with experimental tasks in all grades. The MLD group was characterized by low school-entry mathematics achievement and poor word reading skills. The former was mediated by poor fluency in processing or accessing quantities associated with small sets of objects and corresponding Arabic numerals, whereas the latter was mediated by slow automatized naming of letters and numbers. Both the MLD and LA groups showed slow across-grade growth in mathematics achievement. Group differences in growth were mediated by deficits or delays in fluency of number processing, the ability to retrieve basic facts from long-term memory and to deco...
Kindergarten to 3 rd grade mathematics achievement scores from a prospective study of mathematica... more Kindergarten to 3 rd grade mathematics achievement scores from a prospective study of mathematical development were subjected to latent growth trajectory analyses (n = 306). The four corresponding classes included children with mathematical learning disability (MLD, 6% of sample), and low (LA, 50%), typically (TA, 39%) and high (HA, 5%) achieving children. The groups were administered a battery of intelligence (IQ), working memory, and mathematical-cognition measures in 1 st grade. The children with MLD had general deficits in working memory and IQ, and potentially more specific deficits on measures of number sense. The LA children did not have working memory or IQ deficits, but showed moderate deficits on these number sense measures and for addition fact retrieval. The distinguishing features of the HA children were a strong visuospatial working memory, a strong number sense, and frequent use of memory-based processes to solve addition problems. Implications for the early identification of children at risk for poor mathematics achievement are discussed. About 7% of children and adolescents will experience a substantive learning deficit in at least one area of mathematics (MLD) before graduating from high school (Barbaresi, Katusic,
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Papers by Dave Geary