Natural experiments to study the effects of early experience: Progress and limitations

2003 ◽  
Vol 15 (4) ◽  
pp. 837-852 ◽  
Author(s):  
THOMAS G. O'CONNOR
Keyword(s):  
Conceptual Models ◽  
Early Experience ◽  
Psychological Development ◽  
Natural Experiments ◽  
Long Term Effects ◽  
Testing Hypotheses ◽  
Research Designs ◽  
Experimental Approaches ◽  
Alternative Research

Questions concerning the long-term effects of early experience on psychological development in humans continue to stir up controversy. There are, at present, great diversity and contradictions among extant conceptual models and inadequate data to resolve these differences. Limited opportunities to use experimental approaches and the inherent restrictions of observational approaches in research on humans implies that alternative research designs are needed. This article examines the use of “natural experiments” as a method for testing hypotheses concerning the effects of early experience on psychological development. The benefits and limitations of using natural experiments are reviewed and several case illustrations are considered.

scholarly journals A Framework to Advance the Understanding of the Ecological Effects of Extreme Climate Events

2019 ◽  
Vol 11 (21) ◽  
pp. 5954 ◽  
Author(s):  
Carlos Sanz-Lazaro
Keyword(s):  
Climate Change ◽  
Extreme Events ◽  
Ecological Effects ◽  
Rocky Shores ◽  
Long Term Effects ◽  
Starting Point ◽  
Experimental Approaches ◽  
Key Aspects ◽  
Climate Events

Climate change is modifying disturbance regimes, affecting the severity and occurrence of extreme events. Current experiments investigating extreme events have a large diversity of experimental approaches and key aspects such as the interaction with other disturbances, the timing, and long-term effects are not usually incorporated in a standardized way. This lack of comparability among studies limits advances in this field of research. This study presents a framework that is comprised of two experimental approaches designed to test expected changes on disturbance regime due to climate change. These approaches test the effects of disturbances becoming more clustered and more extreme. They use common descriptor variables regardless of the type of disturbance and ecosystem. This framework is completed with a compilation of procedures that increase the realism of experiments in the aforementioned key aspects. The proposed framework favours comparability among studies and increases our understanding of extreme events. Examples to implement this framework are given using rocky shores as a case study. Far from being perfect, the purpose of this framework is to act as a starting point that triggers the comparability and refinement of these types of experiments needed to advance our understanding of the ecological effects of extreme events.

When Natural Experiments Are Neither Natural nor Experiments

2012 ◽  
Vol 106 (1) ◽  
pp. 35-57 ◽  
Author(s):  
JASJEET S. SEKHON ◽  
ROCÍO TITIUNIK
Keyword(s):  
Social Sciences ◽  
Unbiased Estimate ◽  
Causal Effect ◽  
Natural Experiments ◽  
Treatment Control ◽  
Causal Inferences ◽  
The Social ◽  
Research Designs ◽  
Alternative Research ◽  
Conceptual Difficulties

Natural experiments help to overcome some of the obstacles researchers face when making causal inferences in the social sciences. However, even when natural interventions are randomly assigned, some of the treatment–control comparisons made available by natural experiments may not be valid. We offer a framework for clarifying the issues involved, which are subtle and often overlooked. We illustrate our framework by examining four different natural experiments used in the literature. In each case, random assignment of the intervention is not sufficient to provide an unbiased estimate of the causal effect. Additional assumptions are required that are problematic. For some examples, we propose alternative research designs that avoid these conceptual difficulties.

scholarly journals Hemifacial Microsomia: A Mini Review

2019 ◽  
pp. 1-7
Author(s):  
Shilpa Ashok Sharma ◽  
Sayali Vikram Pagar Patil ◽  
Anupama Mudhol ◽  
Jyothi Shashidhar
Keyword(s):  
Well Being ◽  
Psychological Development ◽  
Facial Appearance ◽  
Hemifacial Microsomia ◽  
Long Term Effects ◽  
Medical Treatments ◽  
Mandibular Hypoplasia ◽  
Branchial Arches ◽  
Derivatives Of

Hemifacial Microsomia (HFM) is a congenital anomaly involving embryological derivatives of the first and second branchial arches and characterized mainly by mandibular hypoplasia and unilateral or bilateral microtia; although, other facial structures may be affected. It may have long-term effects on psychological development and social well-being, due to unaesthetic facial appearance, functional disturbances and complex medical treatments.

Motor Development Research: Designs, Analyses, and Future Directions

2020 ◽  
Vol 8 (2) ◽  
pp. 410-437 ◽  
Author(s):  
Nancy Getchell ◽  
Nadja Schott ◽  
Ali Brian
Keyword(s):  
Motor Development ◽  
Motor Behavior ◽  
Developmental Change ◽  
Development Research ◽  
Cross Sectional ◽  
Future Directions ◽  
Research Designs ◽  
Experimental Approaches ◽  
Human Motor ◽  
Alternative Research

Throughout this special issue, different authors have discussed diverse aspects of past, present, and future motor development research. In such research, understanding how people move involves much more than studying motor behavior in individuals of different ages. Rather, empirical designs should embed some element of past, present, and future motor behavior into research questions, designs, methodologies, and interpretations. In this article, we provide an overview on the process of asking movement-related developmental questions and designing appropriate research studies that will answer them to provide a foundation for both new and returning investigators interested in studying human motor development. We compare descriptive and experimental approaches as well as longitudinal, cross-sectional, and alternative research designs, followed by a discussion of common statistical analyses suited for these designs. Through this discussion, we offer suggestions for the most appropriate ways in which to study developmental change. We finish with our thoughts on future directions for investigational methods within motor development research.

scholarly journals Plant responses to volcanically elevated CO<sub>2</sub> in two Costa Rican forests

2019 ◽  
Vol 16 (6) ◽  
pp. 1343-1360 ◽  
Author(s):  
Robert R. Bogue ◽  
Florian M. Schwandner ◽  
Joshua B. Fisher ◽  
Ryan Pavlick ◽  
Troy S. Magney ◽  
...  
Keyword(s):  
Elevated Co2 ◽  
Chlorophyll Concentration ◽  
Carbon Isotopic Composition ◽  
Tropical Trees ◽  
Ecological Impacts ◽  
Atmospheric Co2 ◽  
Natural Experiments ◽  
Long Term Effects ◽  
Active Volcanoes

Abstract. We explore the use of active volcanoes to determine the short- and long-term effects of elevated CO2 on tropical trees. Active volcanoes continuously but variably emit CO2 through diffuse emissions on their flanks, exposing the overlying ecosystems to elevated levels of atmospheric CO2. We found tight correlations (r2=0.86 and r2=0.74) between wood stable carbon isotopic composition and co-located volcanogenic CO2 emissions for two of three investigated species (Oreopanax xalapensis and Buddleja nitida), which documents the long-term photosynthetic incorporation of isotopically heavy volcanogenic carbon into wood biomass. Measurements of leaf fluorescence and chlorophyll concentration suggest that volcanic CO2 also has measurable short-term functional impacts on select species of tropical trees. Our findings indicate significant potential for future studies to utilize ecosystems located on active volcanoes as natural experiments to examine the ecological impacts of elevated atmospheric CO2 in the tropics and elsewhere. Results also point the way toward a possible future utilization of ecosystems exposed to volcanically elevated CO2 to detect changes in deep volcanic degassing by using selected species of trees as sensors.

Social Skills Training with Young Offenders: False Expectations and the “Failure of Treatment”

1984 ◽  
Vol 12 (4) ◽  
pp. 331-341 ◽  
Author(s):  
Clive R. Hollin ◽  
Monika Henderson
Keyword(s):  
Social Skills ◽  
Social Skills Training ◽  
Skills Training ◽  
Future Research ◽  
Young Offenders ◽  
Criminal Behaviour ◽  
Long Term Effects ◽  
Research Designs ◽  
Correctional Rehabilitation

Alongside the view that “nothing works” in correctional rehabilitation, the behavioural technique of social skills training (S.S.T.) has been singled out for use with offenders. The present paper critically reviews empirical evidence regarding the long-term effects of S.S.T. on young offenders with a view to examining the conceptual and methodological issues linking S.S.T. with criminal behaviour. It is concluded that S.S.T. has been shown to have only very limited effects on the future criminal behaviour of young offenders. Several explanations for this finding are considered, and it is concluded that re-offending is an inadequate measure of the efficacy of S.S.T. programmes as reported in the extant literature. Following criticism of research designs which produce false expectations by including unrealistic measures, several proposals for future research are made.

scholarly journals Plant responses to volcanically-elevated CO<sub>2</sub> in two Costa Rican forests

2018 ◽  
Author(s):  
Robert R. Bogue ◽  
Florian M. Schwandner ◽  
Joshua B. Fisher ◽  
Ryan Pavlick ◽  
Troy S. Magney ◽  
...  
Keyword(s):  
Elevated Co2 ◽  
Chlorophyll Concentration ◽  
Carbon Isotopic Composition ◽  
Tropical Trees ◽  
Ecological Impacts ◽  
Atmospheric Co2 ◽  
Natural Experiments ◽  
Long Term Effects ◽  
Active Volcanoes

Abstract. We explore the use of active volcanoes to determine the short- and long-term effects of elevated CO2 on tropical trees. Active volcanoes continuously but variably emit CO2 through diffuse emissions on their flanks, exposing the overlying ecosystems to elevated levels of atmospheric CO2. We found tight correlations (r2 = 0.86 and r2 = 0.74) between wood stable carbon isotopic composition and co-located volcanogenic CO2 emissions for two species, which documents the long-term photosynthetic incorporation of isotopically heavy volcanogenic carbon into wood biomass. Measurements of leaf fluorescence and chlorophyll concentration suggest that volcanic CO2 also has measurable short-term functional impacts on select species of tropical trees. Our findings indicate significant potential for future studies to utilize ecosystems located on active volcanoes as natural experiments to examine the ecological impacts of elevated atmospheric CO2 in the tropics and elsewhere. Results also point the way toward a possible future utilization of ecosystems exposed to volcanically elevated CO2 to detect changes in deep volcanic degassing by using selected species of trees as sensors.

scholarly journals Measuring the Impacts of Teachers: Reply

2017 ◽  
Vol 107 (6) ◽  
pp. 1685-1717 ◽  
Author(s):  
Raj Chetty ◽  
John N. Friedman ◽  
Jonah E. Rockoff
Keyword(s):  
North Carolina ◽  
Missing Data ◽  
Los Angeles ◽  
Empirical Evidence ◽  
Replication Study ◽  
Long Term Effects ◽  
Research Designs ◽  
Using Data

Rothstein (2017) successfully replicates Chetty, Friedman, and Rockoff's (2014a, b)—henceforth, CFR's—results using data from North Carolina, but raises concerns about CFR's methods. We show that Rothstein's methodological critiques are invalid by presenting simulations and supplementary empirical evidence which show that (i) his preferred imputation of missing data generates bias; (ii) his “placebo test” rejects valid research designs; and (iii) his method of controlling for covariates yields inconsistent estimates of teachers' long-term effects. Consistent with the conclusions of Bacher-Hicks, Kane, and Staiger (2016) using data from Los Angeles, we conclude that Rothstein's replication study ultimately reinforces CFR's methods and results. (JEL H75, I21, J45)

Natural Experiments and Causality in Economic History: On Their Relations to Theory and Temporality

2017 ◽  
Vol 72 (4) ◽  
pp. 699-728
Author(s):  
Sacha Bourgeois-Gironde ◽  
Éric Monnet
Keyword(s):  
Economic History ◽  
Historical Analysis ◽  
Natural Experiments ◽  
Long Term Effects ◽  
The Many ◽  
Definition Of ◽  
Implicit And Explicit ◽  
Common Understanding

A recent and influential research methodology, mainly endorsed by economists, proposes to renew historical analysis based on the notions of natural experiment and causality. It has the dual ambition of unifying various disciplines around a common understanding of causality in order to tackle major historical questions (such as the role of colonization, political regimes, or religion in economic development) and of making the analysis of history more scientific. The definition of causality it promotes—of the “interventionist” type—tends to liken historical events to laboratory experiments. This is articulated with a neo-institutionalist perspective aimed at measuring the long-term effects of past institutional changes, which are considered exogenous. In the first part of this article, we present the ambitions, contributions, methods, and hypotheses (implicit and explicit) of this approach, showing how it differs from more traditional quantitative economic history and placing it in the context of the recent empirical and neo-institutionalist “turns” of the economic discipline. In a second stage, we consider the criticism—often scathing—voiced by historians or economists against this method and its objectives. Finally, we emphasize the many difficulties posed by this approach when it comes to taking into account the historicity of phenomena, to producing general statements based on particular cases, and to providing a complete and coherent definition of causality in history.

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