Kristi L. Lockhart is a Senior Lecturer and Research Scientist in the Department of Psychology at Yale University. A licensed clinical psychologist, her research focuses on children’s social cognition, particularly optimism, person perception, and beliefs about the potential for change in self and others.Frank C. Keil is the Charles C. & Dorathea S. Dilley Professor of Psychology, Linguistics, and Cognitive Science at Yale University and Chair of the Department of Psychology. Much of his research involves asking how intuitive explanations and understandings emerge in development and how they are related to notions of cause, mechanism, and agency.Karl S. Rosengren is a Professor of Psychology at the University of Wisconsin-Madison. His research focuses on cognitive and motor development.Matthew J. Jiang is a PhD candidate in Psychology at the University of Wisconsin-Madison. His research centers on how individuals conceptualize how to stay healthy, and whether these mental representations predict behavior.Charles W. Kalish is a Professor of Educational Psychology at the University of Wisconsin-Madison. His work focuses on the development of inductive inference and social cognition.David Menendez is a PhD candidate in Psychology at the University of Wisconsin-Madison. His research focuses on how cognitive constraints influence children’s biological reasoning.Iseli G. Hernandez is a PhD candidate in Psychology at the University of Wisconsin-Madison. She is interested in how parents transmit information about health and illness to their children and how this might vary across cultures.

• CONTENTSI. INTRODUCTION: UNDERSTANDING MEDICINES AND MEDICAL INTERVENTIONS...7Kristi L. Lockhart and Frank C. KeilII. THE PROPER REALMS OF MEDICINES AND THEIR ALTERNATIVES: WHAT COUNT AS CURES?...33Kristi L. Lockhart and Frank C. KeilIII. TIME COURSES OF ILLNESSES AND TREATMENTS...63Kristi L. Lockhart and Frank C. KeilIV. AGENCY AND SPATIAL PATTERNS OF ILLNESSES AND TREATMENTS...83Kristi L. Lockhart and Frank C. KeilV. REASONING ABOUT SIDE EFFECTS: INFLUENCES OF TEMPORAL AND SPATIAL EXPECTATIONS...100Kristi L. Lockhart and Frank C. KeilVI. TREATMENTS AND TRADEOFFS...123Kristi L. Lockhart and Frank C. KeilVII. FOLK MEDICINE AND FOLK CURES...140Kristi L. Lockhart and Frank C. KeilREFERENCES...159ACKNOWLEDGMENTS...174COMMENTARYCOMMENTARY: WHAT HEALS AND WHY? CHILDREN’S UNDERSTANDING OF MEDICAL TREATMENTS...175Karl S. Rosengren, Matthew J. Jiang, Charles W. Kalish, David Menendez, and Iseli G. HernandezCONTRIBUTORS...184SUBJECT INDEX...186

Kristi L. Lockhart is a Senior Lecturer and Research Scientist in the Department of Psychology at Yale University. A licensed clinical psychologist, her research focuses on children’s social cognition, particularly optimism, person perception, and beliefs about the potential for change in self and others.Frank C. Keil is the Charles C. & Dorathea S. Dilley Professor of Psychology, Linguistics, and Cognitive Science at Yale University and Chair of the Department of Psychology. Much of his research involves asking how intuitive explanations and understandings emerge in development and how they are related to notions of cause, mechanism, and agency.Karl S. Rosengren is a Professor of Psychology at the University of Wisconsin-Madison. His research focuses on cognitive and motor development.Matthew J. Jiang is a PhD candidate in Psychology at the University of Wisconsin-Madison. His research centers on how individuals conceptualize how to stay healthy, and whether these mental representations predict behavior.Charles W. Kalish is a Professor of Educational Psychology at the University of Wisconsin-Madison. His work focuses on the development of inductive inference and social cognition.David Menendez is a PhD candidate in Psychology at the University of Wisconsin-Madison. His research focuses on how cognitive constraints influence children’s biological reasoning.Iseli G. Hernandez is a PhD candidate in Psychology at the University of Wisconsin-Madison. She is interested in how parents transmit information about health and illness to their children and how this might vary across cultures.

• CONTENTSI. INTRODUCTION: UNDERSTANDING MEDICINES AND MEDICAL INTERVENTIONS...7Kristi L. Lockhart and Frank C. KeilII. THE PROPER REALMS OF MEDICINES AND THEIR ALTERNATIVES: WHAT COUNT AS CURES?...33Kristi L. Lockhart and Frank C. KeilIII. TIME COURSES OF ILLNESSES AND TREATMENTS...63Kristi L. Lockhart and Frank C. KeilIV. AGENCY AND SPATIAL PATTERNS OF ILLNESSES AND TREATMENTS...83Kristi L. Lockhart and Frank C. KeilV. REASONING ABOUT SIDE EFFECTS: INFLUENCES OF TEMPORAL AND SPATIAL EXPECTATIONS...100Kristi L. Lockhart and Frank C. KeilVI. TREATMENTS AND TRADEOFFS...123Kristi L. Lockhart and Frank C. KeilVII. FOLK MEDICINE AND FOLK CURES...140Kristi L. Lockhart and Frank C. KeilREFERENCES...159ACKNOWLEDGMENTS...174COMMENTARYCOMMENTARY: WHAT HEALS AND WHY? CHILDREN’S UNDERSTANDING OF MEDICAL TREATMENTS...175Karl S. Rosengren, Matthew J. Jiang, Charles W. Kalish, David Menendez, and Iseli G. HernandezCONTRIBUTORS...184SUBJECT INDEX...186

Kristi L. Lockhart is a Senior Lecturer and Research Scientist in the Department of Psychology at Yale University. A licensed clinical psychologist, her research focuses on children’s social cognition, particularly optimism, person perception, and beliefs about the potential for change in self and others.Frank C. Keil is the Charles C. & Dorathea S. Dilley Professor of Psychology, Linguistics, and Cognitive Science at Yale University and Chair of the Department of Psychology. Much of his research involves asking how intuitive explanations and understandings emerge in development and how they are related to notions of cause, mechanism, and agency.Karl S. Rosengren is a Professor of Psychology at the University of Wisconsin-Madison. His research focuses on cognitive and motor development.Matthew J. Jiang is a PhD candidate in Psychology at the University of Wisconsin-Madison. His research centers on how individuals conceptualize how to stay healthy, and whether these mental representations predict behavior.Charles W. Kalish is a Professor of Educational Psychology at the University of Wisconsin-Madison. His work focuses on the development of inductive inference and social cognition.David Menendez is a PhD candidate in Psychology at the University of Wisconsin-Madison. His research focuses on how cognitive constraints influence children’s biological reasoning.Iseli G. Hernandez is a PhD candidate in Psychology at the University of Wisconsin-Madison. She is interested in how parents transmit information about health and illness to their children and how this might vary across cultures.

• CONTENTSI. INTRODUCTION: UNDERSTANDING MEDICINES AND MEDICAL INTERVENTIONS...7Kristi L. Lockhart and Frank C. KeilII. THE PROPER REALMS OF MEDICINES AND THEIR ALTERNATIVES: WHAT COUNT AS CURES?...33Kristi L. Lockhart and Frank C. KeilIII. TIME COURSES OF ILLNESSES AND TREATMENTS...63Kristi L. Lockhart and Frank C. KeilIV. AGENCY AND SPATIAL PATTERNS OF ILLNESSES AND TREATMENTS...83Kristi L. Lockhart and Frank C. KeilV. REASONING ABOUT SIDE EFFECTS: INFLUENCES OF TEMPORAL AND SPATIAL EXPECTATIONS...100Kristi L. Lockhart and Frank C. KeilVI. TREATMENTS AND TRADEOFFS...123Kristi L. Lockhart and Frank C. KeilVII. FOLK MEDICINE AND FOLK CURES...140Kristi L. Lockhart and Frank C. KeilREFERENCES...159ACKNOWLEDGMENTS...174COMMENTARYCOMMENTARY: WHAT HEALS AND WHY? CHILDREN’S UNDERSTANDING OF MEDICAL TREATMENTS...175Karl S. Rosengren, Matthew J. Jiang, Charles W. Kalish, David Menendez, and Iseli G. HernandezCONTRIBUTORS...184SUBJECT INDEX...186