Various processing principles have been suggested to be governing the resolution of quantifier scope ambiguities in sentences such as Every kid climbed a tree. This paper investigates structural principles, that is, those which refer to the syntactic or semantic positions of the quantified phrases. To test these principles, the preferred interpretations for three grammatical constructions were determined in a task in which participants made speeded judgments of whether a sentence following a doubly quantified sentence was a reasonable discourse continuation of the quantified sentence. The observed preferences cannot be explained by any single structural principle, but point instead to the interaction of several principles. Contrary to many proposals, there is little or no effect of a principle that assigns scope according to the linear order of the phrases. The interaction of principles suggests that alternative interpretations of the ambiguity may be initially considered in parallel, followed by selection of the single interpretation that best satisfies the principles. These results are discussed in relation to theories of ambiguity resolution at other levels of linguistic representation.

Clinical practice guidelines (CPGs) are intended to improve mental, behavioral, and physical health by promoting clinical practices that are based on the best available evidence. The American Psychological Association (APA) is committed to generating patient-focused CPGs that are scientifically sound, clinically useful, and informative for psychologists, other health professionals, training programs, policy makers, and the public. The Institute of Medicine (IOM) 2011 standards for generating CPGs represent current best practices in the field. These standards involve multidisciplinary guideline development panels charged with generating recommendations based on comprehensive systematic reviews of the evidence. The IOM standards will guide the APA as it generates CPGs that can be used to inform the general public and the practice community regarding the benefits and harms of various treatment options. CPG recommendations are advisory rather than compulsory. When used appropriately, high-quality guidelines can facilitate shared decision making and identify gaps in knowledge.

We measured the size of visual fields within which actual and imagined circular patterns could be resolved, as the patterns varied in both area and relative contrast. As pattern area increased, imagery fields increased in size at the same rate as perceptual fields. However, as the relative contrast between parts of the patterns was reduced, perceptual fields diminished in size, while imagery fields did not. For all variations of pattern area and contrast, fields in imagery were roughly the same shape as fields in perception. A control experiment provided no support for the possible criticism that these results might be explained on the basis of subjects' expectations for the size and shape of the imagery fields, especially since control subjects falsely believed that reductions in contrast would reduce considerably the size of these fields. Although these findings suggest that images and physical objects are functionally equivalent at pattern-processing levels of the visual system, they demonstrate that images and objects are not functionally equivalent at certain levels of the visual system where information about relative contrast is processed.

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We describe a simple psychophysical technique for measuring the size and shape of visual fields in mental imagery, and use this technique to compare fields in imagery and perception within which bar gratings of various spatial frequencies can be resolved. The first experiment demonstrates that the size of fields of resolution obtained when bar gratings are imagined decreases with increasing spatial frequency of the gratings, in the same way that the size of fields obtained when the gratings are actually observed decreases. This experiment also shows that imagery and perceptual fields are very similar in shape, both being elongated horizontally and extending farther below the point to which one's gaze is directed than above. The second experiment shows that experimental subjects are not able to anticipate the more subtle characteristics of these fields, such as the precise rate at which field size decreases with increasing spatial frequency--characteristics that most clearly reveal the very close correspondence between the imagery and perceptual fields. The third experiment shows that the size of the imagery fields can serve to discriminate between vivid and nonvivid imagers when the task of imagining the gratings is made sufficiently difficult. We interpret these findings as evidence that visual imagery involves the activation of mechanisms in the visual system that are specifically designed to process information about spatial frequency. In particular, we claim that constraints that these mechanisms impose on the resolution of high spatial frequencies in perception are also imposed in mental imagery, restricting how well fine details of an object can be imagined. We then discuss implications of these findings for theories about spatial-frequency analysis in vision and for the general issue of the functional value of mental imagery.