Expert evidence by psychologists: Sometimes problematic and often premature

This article provides a critical review of two major types of expert evidence: (a) clinical assessments, and (b) generalizations drawn from psychological research. Strong arguments both for and against both types of testimony have been offered by legal experts and psychologists. These arguments are evaluated and the conclusion is drawn that there are two fundamental problems for psychologists in the role of expert. First, the types of assessments clinicians are asked to make (e.g., concerning the accused's mental state at the time of committing the offense) may exceed the capacity of the discipline; such assessments are problematic. Second, the research foundation that psychologists employ in court does not always apply to the court situation in the way experts imply; the application of laboratory research findings to real world contexts is sometimes premature. The article concludes with an admonition that psychologists should adopt a more conservative response to requests to provide expert evidence.     

Humean dispositionalism

Humean metaphysics is characterized by a rejection of necessary connections between distinct existences. Dispositionalists claim that there are basic causal powers. The existence of such properties is widely held to be incompatible with the Humean rejection of necessary connections. In this paper I present a novel theory of causal powers that vindicates the dispositionalist claim that causal powers are basic, without embracing brute necessary connections. The key assumptions of the theory are that there are natural types of causal processes, and that manifestations of powers are identified with certain kinds of causal processes. From these assumptions, the modal features of powers are explained in terms of internal relations between powers themselves and the process-types in which powers are manifested.     

Changes in verb meaning and the sentence context effect in children's PA learning

Two experiments are reported in which sentence context facilitation of paired associate learning was examined. The major purpose was to determine whether semantic changes in the verb connecting a pair of nouns affects the facilitation due to the verb connective. It was found that trial to trial changes in the connective had no effect, and facilitation was as great as when the verb remained the same on each trial. These results were interpreted in terms of imaginal coding in multitrial experiments.