S ir Arthur Stanley Eddington said, " We used to think that if we knew one, we knew two, because one and one are two. We are finding that we must learn a great deal more about 'and'. " Combining multiple materials with desirable properties is an oft-pursued route to achieve artificial composite materials with functionalities superior to any of their parts. When the dimensions at which the const...

The ability to allow for flexible forms of unobserved heterogeneity is an essential ingredient in modern microeconometrics. In this paper we extend the application of instrumental variable (IV) methods to a wide class of problems in which multiple values of unobservable variables can be associated with particular combinations of observed endogenous and exogenous variables. In our Generalized In...

The vigor with which a participant performs actions that produce valuable outcomes is subject to a complex set of motivational influences. Many of these are believed to involve the amygdala and the nucleus accumbens, which act as an interface between limbic and motor systems. One prominent class of influences is called pavlovian-instrumental transfer (PIT), in which the motivational characteris...

The aim of this paper is to present the concept of an ‘instrumental’ obstacle. In French agricultural education, the spreadsheet is often used as a tool or “artefact” in statistics teaching. Some obstacles to learning appear due to the use of this instrument. Difficulties appear during the learning of analysis of variance by students, who are not trained mathematicians. The concept of average h...

This article deals with the concept of instrumental gesture, specifically the gestures of bowed string instruments. These reflections are an extension of my compositional and research work at Institute for Research and Coordination in Acoustics and Music (IRCAM). The idea of gesture will be explored from many angles, from the simple gesture of a performer bowing a violin to produce a sound, to ...

We develop averaged instrumental variables estimators as a way to deal with many weak instruments. We propose a weighted average of the preliminary k-class estimators, where each estimator is obtained using different subsets of the available instrumental variables. The averaged estimators are shown to be consistent and to satisfy asymptotic normality. Furthermore, its approximate mean squared e...