Source attributions for detected new items: Persistent evidence for schematic guessing

Performance in source-monitoring tests is not only determined by source memory but also by source guessing. Source guessing is not random as it is informed by two distinct mechanisms. (1) People may show a schema-based guessing bias and rely on cross-situationally stable world knowledge. (2) They may apply probability matching and rely on the specific item-source contingency experienced at encoding. According to probability matching theory, source guessing is based on probability matching when a specific contingency representation is available. This conclusion is derived from a source-monitoring paradigm in which no source judgements for detected new items are required. Here, we extend this paradigm to examine source guessing not only for detected old items but also for detected new items. The results suggest that participants take the old–new recognition status of the items into account when making source attributions. Probability matching is used only for detected old items: Source guessing sensitively reflects the item-source contingency for these items. For detected new items, participants resort to schema-based guessing. Using schema-based guessing rather than probability matching when judging detected new items may have the advantage that a newly acquired contingency representation that may only be locally valid is not generalised too readily at the expense of a schematic expectation that reflects a larger and more comprehensive learning history.

What is relative plausibility?

Allen and Pardo’s explanation of Relative Plausibility as a theory of evidence and proof in litigation is ambiguous and underspecified. Their account suggests at least three different interpretations of what they mean. They might be advocating “anti-halfism,” which tracks the “conventional account” but merely rejects >0.5 as the proper standard of proof. Or they might be advocating “probabilistic holism,” in which trial decision-makers apply probability to whole claims but not elements – in which case it remains to be explained how such an approach is internally coherent. Or they might be endorsing “total anti-probabilism,” in which “plausibility” obeys rules and axioms different from those of probability – rules and axioms that Allen and Pardo have yet to identify. To date, Allen and Pardo have side-stepped criticisms by shifting from one interpretation to another, strategically. Aside from presenting a theory too formless to determine how well it fits actual jury behavior, Allen and Pardo have not presented any robust empirical observations about how juries actually decide cases (despite their claims to do so). Before we can really assess whether Relative Plausibility is a new paradigm for understanding the structure of evidence and proof in litigation, Allen and Pardo must tell us much more about what it actually is.

Great Lakes Ore-Carrier Economics and Preliminary Design

Based on factual data from many sources the author has derived a compendium of information useful in the preliminary design of Great Lakes bulk carriers. The paper explains facile methods for estimating speed and power, weights, building costs, and operating costs for ore carriers ranging up to the 1000-footers allowed by the new lock at Sault Ste. Marie. The author uses this information to derive a parametric study of optimum design characteristics. He concludes that the biggest possible ship is not necessarily the most economic unless particular attention is paid to expediting its port turnaround. The Appendixes explain how to apply probability theory to estimating weights, building costs, and annual transport capability. This material can be applied to any sort of ship and is of interest to the entire profession, not just to engineers in the Great Lakes area.