Michelle Perry

Transitional knowledge in the acquisition of concepts

These studies explore children’s conceptual knowledge as it is expressed through their verbal and gestural explanations of concepts. We build on previous work that has shown that children who produce a large proportion of gestures that do not match their verbal explanations are in transition with respect to the concept they are explaining. This gesture/speech mismatch has been called “discordance.” Previous work discovered this phenomenon with respect to 5- to 7-yearold children’s explanations of conservation problems. Study 1 shows: (I) that older children (IO to 11 years old) exhibit gesture/speech discordance with respect to another concept, understanding the equivalence relationship in mathematical equations, and; (2) that children who produce many discordant responses in their explanations of mathematical equivalence are more likely to benefit from instruction in the concept than are children who produce few such responses. Studies 2 and 3 explore the properties and usefulness of discordance as an index of transitional knowledge in a child’s acquisition of mathematical equivalence. Under any circumstance in which new concepts are acquired, there exists a mental bridge connecting the old knowledge state to the new. The studies reported here suggest that the combination of gesture and speech may be an easily observable and significantly interpretable reflection of knowledge states, both static and in flux.

Learning and Transfer: Instructional Conditions and Conceptual Change

Abstract It is widely assumed that instruction plays a role in learning and in transfer. The present studies examine how type of instruction (containing principle-based vs. procedure-based information) influences learning and transfer in a mathematical concept. In the first study, both types of instruction led a comparable number of children to learn, but principle-based instruction led significantly more children to transfer their new knowledge. In the second study, the types of instruction were combined (i.e., children received both principle and procedure information). The results were virtually identical to the results obtained from the procedure-only instructions. This indicates that principle-based instruction may be crucial for transfer to occur and, when children also are exposed to procedures, few will transfer. It is hypothesized that children may ignore the conceptually rich information inherent in the principle when procedures are also provided.

Bias or responsivity? Sex and achievement-level effects on teachers' classroom questioning practices

The authors examined rates of both teacher responsiveness and student participation in the classroom question-asking context. Participants were 165 students and their teachers in 6 science classrooms. Teachers in 3 of the 6 classrooms called on male students to answer questions more often than would have been expected on the basis of the number of boys in the classroom. In none of the classrooms, however, did teachers call on boys more often than would be expected on the basis of the heightened volunteering rates of their male students. No systematic sex or achievement-level differences were found in the types of questions that students responded to. These findings suggest the need to focus on the role that both teachers and their students play in creating and maintaining sex differences in the teacher-student interaction context.

Divergent Role of Gamma Interferon in a Murine Model of Pulmonary versus Systemic Klebsiella pneumoniae Infection

ABSTRACT Klebsiella pneumoniae is a leading cause of both community-acquired and nosocomial gram-negative-bacterial pneumonia. A further clinical complication of pulmonary K. pneumoniae infection is dissemination of bacteria from the lung into the peripheral blood, resulting in bacteremia concurrent with the localized pulmonary infection. Here, we report studies detailing the divergent role of gamma interferon (IFN-γ) in pulmonary versus systemic K. pneumoniae infection. Intratracheal inoculation of IFN-γ knockout mice resulted in significantly increased mortality compared to that observed for wild-type infected animals. Increased mortality correlated with a 100-fold increase in pulmonary bacteria within 2 days postinfection and upregulation of lung-associated interleukin-10 (IL-10) mRNA. Interestingly, IFN-γ knockout mice had a twofold reduction in plasma aminospartate transferase activity, indicating diminished liver injury following peripheral blood bacterial dissemination. To study the host response towards blood-borne bacteria in the absence of the ongoing pulmonary infection, intravenous inoculation studies were initiated. IFN-γ knockout mice were no more susceptible to intravenous infection than their wild-type counterparts. The consistent observation in IFN-γ knockout mice was for improved survival correlating with increased clearance of blood- and liver-associated bacteria. Intravenous inoculation resulted in a two- to threefold increase in hepatic IL-10 production 24 and 48 h postinfection. Liver injury was also significantly reduced in IFN-γ knockout mice. These data indicate that IFN-γ secretion is a critical mediator in the resolution of localized gram-negative pulmonary pneumonia. Surprisingly, host responses towards systemic infection with the same bacteria appear to be IFN-γ independent.

Asking Questions in First-Grade Mathematics Classes: Potential Influences on Mathematical Thought.

This study investigated the types of questions that are asked in 1st-grade addition and subtraction lessons in Japan, Taiwan, and the United States. Some researchers have argued that knowledge is, in part, constructed through questions and that these may be used differently in U.S. than in Asian classrooms. Thus, each question about addition or subtraction in 311 observed lessons was coded as 1 of 6 types of questions. Analyses revealed that the Asian teachers asked significantly more questions about conceptual knowledge and about problem-solving strategies than did U.S. teachers. In addition, Chinese teachers asked significantly more questions that were embedded in a concrete context than did U.S. teachers

How Many Do You See? The Use of Nonspoken Representations in First-Grade Mathematics Lessons

Not all relevant instructional information comes in the form of spoken words. In the present study, the authors examine multiple modalities of nonspoken forms of representatio n—specifically gestures, pictures, objects, and writing—used by 3 teachers in 3 years of lst-grade math lessons. Teachers frequently used visually based modalities of representatio n and tended to produce combinations of representational forms rather than isolated representations. There were individual differences in their preference for representation types. Teachers used representations to accompany important spoken terms and to respond to student confusion. With nonspoken representations, teachers conveyed information critical to the explanation of mathematical concepts. Students must attend to the visual as well as vocal means of expressing information to gain access to all of the information presented in mathematics

An Examination of Stereotype Threat Effects on Girls' Mathematics Performance

Stereotype threat has been proposed as 1 potential explanation for the gender difference in standardized mathematics test performance among high-performing students. At present, it is not entirely clear how susceptibility to stereotype threat develops, as empirical evidence for stereotype threat effects across the school years is inconsistent. In a series of 3 studies, with a total sample of 931 students, we investigated stereotype threat effects during childhood and adolescence. Three activation methods were used, ranging from implicit to explicit. Across studies, we found no evidence that the mathematics performance of school-age girls was impacted by stereotype threat. In 2 of the studies, there were gender differences on the mathematics assessment regardless of whether stereotype threat was activated. Potential reasons for these findings are discussed, including the possibility that stereotype threat effects only occur in very specific circumstances or that they are in fact occurring all the time. We also address the possibility that the literature regarding stereotype threat in children is subject to publication bias.

Learning Mathematics in First-Grade Classrooms: On Whose Authority?.

Integral to knowing mathematics is an understanding of how mathematical ideas are generated and validated. In mathematics classrooms, teachers socialize this understanding by establishing discourse patterns and participatory structures in which various sources—the teacher, the text, the discipline of mathematics, or the community of learners—are implicitly and explicitly credited with the authority to develop and validate mathematical ideas. In the present investigation, the authors focused on classroom discourse processes and participatory structures that grant sources of mathematical authority in 6 first-grade classrooms. In general, teachers firmly and with few exceptions positioned themselves as the sole mathematical authority in their classrooms. Yet, the authors found significant exceptions in 1 teacher’s lessons, with these exceptions inspiring possibilities in accomplishing the shift from a formal to a growth-and-change tradition of socializing students into the discipline of mathematics. Mathematical ideas, although oftentimes presented in textbooks, originate from human experience. Still, many of us turn to texts and to human experts to verify our ideas. Although there is nothing wrong with checking our ideas and formulations against those presented in books or by experts, this practice potentially hides the fact that these ideas and formulations originated from people. The fact that mathematics is a human invention (albeit, invented by extraordinary humans) may seem obvious, but it is not obvious to young students in American schools. Most students act as if mathematical ideas are predetermined and unarguable truths, which they either do or do not understand, but not ideas to which they could possibly contribute to or question (Schoenfeld, 1992; Stodolsky, 1988). Why would this be the case? In other words, why would students act as if they have no say in either the creation or verification of mathematical ideas? And, if we are to take recent reforms in mathematics education seriously, to have students vitally involved in conducting mathematical inquiry, how can we change this and promote students to take an active role in the creation and verification of mathematical ideas? These questions guide the study presented here.

Is gesture-speech mismatch a general index of transitional knowledge?

Abstract When asked to explain their beliefs about a concept, some children produce gestures that convey different information from the information conveyed in their speech (i.e., gesture-speech mismatches). Moreover, it is precisely the children who produce a large proportion of gesture-speech mismatches in their explanations of a concept who are particularly “ready” to benefit from instruction in that concept, and thus may be considered to be in a transitional state with respect to the concept. Church and Goldin-Meadow (1986) and Perry, Church and Goldin-Meadow (1988) studied this phenomenon with respect to two different concepts at two different ages and found that gesture-speech mismatch reliability predicts readiness to learn in both domains. In an attempt to test further the generality of gesture-speech mismatch as an index of transitional knowledge, Stone, Webb, and Mahootian (1991) explored this phenomenon in a group of 15-year-olds working on a problem-solving task. On this task, however, gesture-speech mismatch was not found to predict transitional knowledge. We present here a theoretical framework, which makes it clear why we expect gesture-speech mismatch to be a general index of transitional knowledge, and then use this framework to motivate our methodological practices for establishing gesture-speech mismatch as a predictor of transitional knowledge. Finally, we present evidence suggesting that, if these practices had been used by Stone et al., they too would have found that gesture-speech mismatch predicts transitional knowledge.

Indexing Transitional Knowledge.

Various indexes have been proposed to mark when a child is on the verge of acquiring new knowledge. This article described a new method for indexing this point of transition, which is based on the specificity of childrens verbal explanations. The degree to which children were specific in their verbal explanations was related to whether they benefited from instruction. In particular, children who were vague in their explanations (i.e., less specific) benefited from instruction more than children who were explicit in their explanations (i.e., more specific). This index provides insights into the childs mental state prior to acquiring new knowledge