How Much to Make and How Much to Buy: Explaining Plural Sourcing Strategies

While many theories of the firm seek to explain when firms make rather than buy, in practice firms often make and buy the same input- they engage in plural sourcing. We argue that explaining the mix of external procurement and internal sourcing for the same input requires a consideration of complementarities across and constraints within modes of procurement. We create analytical foundations for making empirical predictions about when plural sourcing is likely to be optimal and why the optimal mix of internal and external sourcing may vary across situations. Our framework also proves useful for assessing the possible estimation biases in transaction level make-or-buy studies arising from ignoring complementarities and constraints.

The left superior temporal gyrus is a shared substrate for auditory short-term memory and speech comprehension: evidence from 210 patients with stroke

Competing theories of short-term memory function make specific predictions about the functional anatomy of auditory short-term memory and its role in language comprehension. We analysed high-resolution structural magnetic resonance images from 210 stroke patients and employed a novel voxel based analysis to test the relationship between auditory short-term memory and speech comprehension. Using digit span as an index of auditory short-term memory capacity we found that the structural integrity of a posterior region of the superior temporal gyrus and sulcus predicted auditory short-term memory capacity, even when performance on a range of other measures was factored out. We show that the integrity of this region also predicts the ability to comprehend spoken sentences. Our results therefore support cognitive models that posit a shared substrate between auditory short-term memory capacity and speech comprehension ability. The method applied here will be particularly useful for modelling structure–function relationships within other complex cognitive domains

How Much to Make and How Much to Buy? Explaining Plural Sourcing Strategies

While many theories of the firm seek to explain when firms make rather than buy, in practice, firms often make and buy the same input—they engage in plural sourcing. We argue that explaining the mix of external procurement and internal sourcing for the same input requires a consideration of complementarities across and constraints within modes of procurement. We create analytical foundations for making empirical predictions about when plural sourcing is likely to be optimal and why the optimal mix of internal and external sourcing may vary across situations. Our framework also proves useful for assessing the possible estimation biases in transaction level make-or-buy studies arising from ignoring complementarities and constraints

Mode Identification from Combination Frequency Amplitudes in ZZ Ceti Stars

The lightcurves of variable DA stars are usually multi-periodic and non-sinusoidal, so that their Fourier transforms show peaks at eigenfrequencies of the pulsation modes and at sums and differences of these frequencies. These combination frequencies provide extra information about the pulsations, both physical and geometrical, that is lost unless they are analyzed. Several theories provide a context for this analysis by predicting combination frequency amplitudes. In these theories, the combination frequencies arise from nonlinear mixing of oscillation modes in the outer layers of the white dwarf, so their analysis cannot yield direct information on the global structure of the star as eigenmodes provide. However, their sensitivity to mode geometry does make them a useful tool for identifying the spherical degree of the modes that mix to produce them. In this paper, we analyze data from eight hot, low-amplitude DAV white dwarfs and measure the amplitudes of combination frequencies present. By comparing these amplitudes to the predictions of the theory of Goldreich & Wu, we have verified that the theory is crudely consistent with the measurements. We have also investigated to what extent the combination frequencies can be used to measure the spherical degree (ell) of the modes that produce them. We find that modes with ell > 2 are easily identifiable as high ell based on their combination frequencies alone. Distinguishing between ell=1 and 2 is also possible using harmonics. These results will be useful for conducting seismological analysis of large ensembles of ZZ Ceti stars, such as those being discovered using the Sloan Digital Sky Survey. Because this method relies only on photometry at optical wavelengths, it can be applied to faint stars using 4 m class telescopes.Comment: 73 pages, 22 figures, accepted in the Ap

Heterogeneity of Research Results: A New Perspective From Which to Assess and Promote Progress in Psychological Science

Heterogeneity emerges when multiple close or conceptual replications on the same subject produce results that vary more than expected from the sampling error. Here we argue that unexplained heterogeneity reflects a lack of coherence between the concepts applied and data observed and therefore a lack of understanding of the subject matter. Typical levels of heterogeneity thus offer a useful but neglected perspective on the levels of understanding achieved in psychological science. Focusing on continuous outcome variables, we surveyed heterogeneity in 150 meta-analyses from cognitive, organizational, and social psychology and 57 multiple close replications. Heterogeneity proved to be very high in meta-analyses, with powerful moderators being conspicuously absent. Population effects in the average meta-analysis vary from small to very large for reasons that are typically not understood. In contrast, heterogeneity was moderate in close replications. A newly identified relationship between heterogeneity and effect size allowed us to make predictions about expected heterogeneity levels. We discuss important implications for the formulation and evaluation of theories in psychology. On the basis of insights from the history and philosophy of science, we argue that the reduction of heterogeneity is important for progress in psychology and its practical applications, and we suggest changes to our collective research practice toward this end

If God Handed Us the Ground-Truth Theory of Memory, How Would We Recognize It?

What makes a scientific theory convincing? We have many formal models of human memory, but no agreement about which is the right one. If anything, we agree that they are all wrong. By analyzing the properties of successful theories in physics, I propose that we will be convinced by a theory of memory only when it is able to make precise point predictions for individual people’s behavior in any new memory task, manipulation, or paradigm we could construct, without refitting parameters to do so or only by estimating its parameters for each individual on an independent standardized battery of tests. Such a theory would not only be able to accurately describe lab-based empirical effects but would also be practically useful. I highlight how some of our current model development and evaluation practices might be holding us back and outline some important empirical steps necessary to evaluate theories by this standard

Making Ranking Theory Useful for Psychology of Reasoning

An organizing theme of the dissertation is the issue of how to make philosophical theories useful for scientific purposes. An argument for the contention is presented that it doesn’t suffice merely to theoretically motivate one’s theories, and make them compatible with existing data, but that philosophers having this aim should ideally contribute to identifying unique and hard to vary predictions of their theories. This methodological recommendation is applied to the ranking-theoretic approach to conditionals, which emphasizes the epistemic relevance and the expression of reason relations as part of the semantics of the natural language conditional. As a first step, this approach is theoretically motivated in a comparative discussion of other alternatives in psychology of reasoning, like the suppositional theory of conditionals, and novel approaches to the problems of compositionality and accounting for the objective purport of indicative conditionals are presented. In a second step, a formal model is formulated, which allows us to derive quantitative predictions from the ranking-theoretic approach, and it is investigated which novel avenues of empirical research that this model opens up for. Finally, a treatment is given of the problem of logical omniscience as it concerns the issue of whether ranking theory (and other similar approaches) makes too idealized assumptions about rationality to allow for interesting applications in psychology of reasoning. Building on the work of Robert Brandom, a novel solution to this problem is presented, which both opens up for new perspectives in psychology of reasoning and appears to be capable of satisfying a range of constraints on bridge principles between logic and norms of reasoning, which would otherwise stand in a tension

Neuroeconomics: Using Neuroscience to Make Economic Predictions

Neuroeconomics seeks to ground economic theory in detailed neural mechanisms which are expressed mathematically and make behavioural predictions. One finding is that simple kinds of economising for life-and-death decisions (food, sex and danger) do occur in the brain as rational theories assume. Another set of findings appears to support the neural basis of constructs posited in behavioural economics, such as a preference for immediacy and nonlinear weighting of small and large probabilities. A third direction shows how understanding neural circuitry permits predictions and causal experiments which show state-dependence of revealed preference – except that states are biological and neural variables