Michael J. O’Brien

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The reporting of colorectal cancer is facilitated by the provision of a checklist giving the features required for good patient care. However, the practicalities of applying such a checklist may not be straightforward. Familiar examples include finding the prescribed number of lymph nodes, distinguishing mesenteric tumor deposits from replaced lymph nodes,(More)
Using data on auctions of companies, we estimate valuations (maximum willingness to pay) of strategic and financial bidders from their bids. We find that a typical target is valued higher by strategic bidders. However, 22.4% of targets in our sample are valued higher by financial bidders. These are mature, poorly performing companies. We also find that (i)(More)
is how to explain spatial and temporal patterns observed in the archaeological record. Why is a particular artifact found in one region but not in another region? Why does an artifact type differ in shape or size between two sites? Why do some artifacts change rapidly, whereas others remain stable over long periods of time? In THE CULTURAL TRANSMISSION OF(More)
Niche construction is the process whereby organisms, through their activities and choices, modify their own and each other’s niches. By transforming naturalselection pressures, niche construction generates feedback in evolution at various different levels. Niche-constructing species play important ecological roles by creating habitats and resources used by(More)
Modeling work suggests that population size affects cultural evolution such that larger populations can be expected to have richer and more complex cultural repertoires than smaller populations. Empirical tests of this hypothesis, however, have yielded conflicting results. Here, we report a study in which we investigated whether the subsistence toolkits of(More)
The appearance of the bow and arrow in North America as a weapon-delivery system is predicted to have prompted an increase in variation among antecedent projectile points that tipped darts propelled by atlatls. Attributes of dart points are expected to display greater variation with the appearance of the bow as prehistoric artisans experimentally sought(More)
Many modern studies of cultural innovation and demographic change rest on the proposition that social learning is a key process in the spread of novel variants. We agree with this proposition, but we also suggest that the selectivity of social learning, with respect to a skill or knowledge, has largely been overlooked in considering how the tempo of(More)