Event-related auditory and visual potentials were recorded from 36 attention-deficit hyperactivity disorder (ADHD) and 35 normal 6-year-old subjects engaged in a two-choice discrimination task. When normal subjects attended to stimuli in a given modality, enhanced negative (N2) and positive (P3b) responses (as compared with responses to nonattended stimuli) were found for auditory and visual target stimuli. In contrast, when ADHD subjects attended, little or no enhanced negative responses were found in either modality, and enhanced positive P3b responses were found only in response to visual target stimuli. Auditory N1, N2, and P3b and visual N2 amplitudes to attended target stimuli were significantly reduced in ADHD subjects as compared with normal subjects. No between-group differences were found for responses to nonattended stimuli. Both amplitude and latency abnormalities indicate that ADHD boys suffer from deficient preferential processing of attended stimuli. P3b and N2 abnormalities found here suggest deficiencies in two independent cognitive processes thought to be crucial to what we perceive, learn, and remember.
We examine the golden age of U.S. innovation by undertaking a major data collection exercise linking historical U.S. patents to state and county-level aggregates and matching inventors to Federal Censuses between 1880 and 1940. We identify a causal relationship between patented inventions and long-run economic growth and outline a basic framework for analyzing key macro and micro-level determinants. We find a positive relationship between innovation and drivers of regional performance including population density, financial development and geographic connectedness. We also explore the impact of social structure measured by slavery and religion. We then profile the characteristics of inventors and their life cycle finding that inventors were highly educated, positively selected through exit early in their careers, made time allocation decisions such as delayed marriage, and tended to migrate to places that were conducive to innovation. Father's income was positively correlated with becoming an inventor, though not when controlling for the child's education. We show there were strong financial returns to technological development. Finally, we document an inverted-U shaped relationship between inequality and innovation but also show that innovative places tended to be more socially mobile. Our new data help to address important questions related to innovation and long-run growth dynamics.
Auditory evoked potentials were recorded from 19 electrode sites in 20 children with Attention Deficit Disorder with Hyperactivity and 20 normal subjects in a two‐choice discrimination task. N2 and Nd were found to be significantly smaller in subjects with Attention Deficit Disorder with Hyperactivity. The N2 abnormalities are discussed in relationship to the mismatch negativity component of the orienting response, poor discrimination of salient stimuli, neurotransmitter deficiency, and theories of “arousal.’Nd findings are related to findings from studies of cerebral blood flow in children diagnosed as having Attention Deficit Disorder with Hyperactivity. These results suggest a problem with both automatic (not under conscious control) and controlled (under voluntary control) processing in children with Attention Deficit Disorder with Hyperactivity.
(Tippie) and the Queen's University of Belfast for helpful comments. We thank the Division of Research and Faculty Development at Harvard Business School for funding. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research. NBER working papers are circulated for discussion and comment purposes. They have not been peerreviewed or been subject to the review by the NBER Board of Directors that accompanies official NBER publications.
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