Accessing distant premise information: how memory feeds reasoning

According to current psychological models of deduction, people can draw inferences on the basis of information that they receive from different sources at different times. In 3 reading-comprehension experiments, the authors demonstrated that premises that appear far apart in a text (distant) are not accessed and are therefore not used as a basis for logical inferences (Experiment 1), unless the premises are reinstated by a contextual cue (Experiment 2). In Experiment 3, the authors investigated whether these deductions are then integrated into the reader's situation model of the text. The results are interpreted in terms of a collaboration between memory-based text processing and higher level schema-driven logical reasoning.     

An asymmetry between memory encoding and retrieval. Revelation, generation, and transfer-appropriate processing

Transfer-appropriate-processing accounts of memory emphasize the similarity of encoding and retrieval processes, and imply that experimental manipulations should have similar effects on encoding and retrieval. Exceptions to this expectation are thus of great interest, but extant exceptions (produced by studies using divided attention, alcohol, and benzodiazepines) are debatable, single dissociations between encoding and retrieval. The present experiments demonstrate a reversed dissociation, in which the same variable produced opposite effects when implemented at encoding and retrieval. At encoding, participants either solved anagrams of study words or read intact study words. At retrieval, participants likewise solved anagrams or read intact words prior to making recognition memory judgments. Compared with reading intact words, solving anagrams at encoding enhanced later recognition accuracy, whereas solving anagrams at test impaired accuracy. These results were obtained with old/new decisions (Experiment 1) and with confidence ratings (Experiment 2).     

Word frequency and memory: effects on absolute versus relative order memory and on item memory versus order memory

Word frequency can produce opposite effects on recognition and order memory: Low-frequency words produce greater recognition accuracy, whereas high-frequency words produce superior order memory. The present experiments further delineate the relationship between word frequency and order memory. Experiment 1 indicates that low-frequency words produce worse performance on a measure of absolute order memory but not on a test of relative order, which is consistent with the idea that different forms of information underlie different types of order judgments (Greene, Thapar, & Westerman, 1998). Experiment 2 contrasted high-, low-, and very low-frequency words on recognition memory and absolute order memory. In comparison with high-frequency words, low-frequency words enhanced recognition, whereas very low-frequency words did not. Both low- and very low-frequency words, however, produced worse memory for absolute order. Thus, the relationship between frequency and item memory is an inverted U-shaped function, whereas the relationship between frequency and absolute order memory is direct. This implies that the item-enhancing effects of lower word frequency may be dissociated from its order-disrupting effects.     

Image processing for improved eye-tracking accuracy

Video cameras provide a simple, noninvasive method for monitoring a subject’s eye movements. An important concept is that of the resolution of the system, which is the smallest eye movement that can be reliably detected. While hardware systems are available that estimate direction of gaze in real time from a video image of the pupil, such systems must limit image processing to attain real-time performance and are limited to a resolution of about 10 arc minutes. Two ways to improve resolution are discussed. The first is to improve the image processing algorithms that are used to derive an estimate. Offline analysis of the data can improve resolution by at least one order of magnitude for images of the pupil. A second avenue by which to improve resolution is to increase the optical gain of the imaging setup (i.e., the amount of image motion produced by a given eye rotation). Ophthalmoscopic imaging of retinal blood vessels provides increased optical gain and improved immunity to small head movements but requires a highly sensitive camera. The large number of images involved in a typical experiment imposes great demands on the storage, handling, and processing of data. A major bottleneck had been the real-time digitization and storage of large amounts of video imagery, but recent developments in video compression hardware have made this problem tractable at a reasonable cost. Images of both the retina and the pupil can be analyzed successfully using a basic toolbox of image-processing routines (filtering, correlation, thresholding, etc.), which are, for the most part, well suited to implementation on vectorizing supercomputers.     

Perceptual interference improves explicit memory but does not enhance data-driven processing.

Nairne (1988) has recently demonstrated that interfering with the perceptual processing of an item at study improves later memory for that item. Nairne hypothesized that interfering with perceptual processes induces a data-driven generation process that enhances the representation of visual information. Using a variant of Nairne's procedure, we both replicated his original findings and tested his hypothesis that enhanced data-driven processing causes the current effect. The results of studies using free recall and perceptual identification tests were inconsistent with Nairne's hypothesis. We consider several alternative interpretations in the General Discussion.     

Assessing a retrieval account of the generation and perceptual-interference effects

A number of memory phenomena are modulated by experimental design, with the effect (e.g., of bizarreness, generation, or perceptual interference) occurring in recall for mixed-list, but not pure-list designs. These effects have other similarities and have been treated in common theoretical frameworks, some focusing on encoding and others on retrieval. The typical paradigm for examining design effects confounds encoding and retrieval contexts, making it difficult to compare these accounts. Using a new paradigm, McDaniel, Dornburg, and Guynn (2005) concluded that retrieval processes contribute to the bizarreness effect. We applied this paradigm to the related perceptual-interference and generation effects. Participants were presented with two pure study lists and later recalled the lists separately (inducing pure retrieval sets) or together (inducing a combined or mixed retrieval set) in a single test. In four experiments, the combined recall condition consistently failed to enhance the size of the generation or perceptual-interference effect. Two additional experiments verified that perceptual interference and generation enhanced recognition memory, as predicted by the standard encoding accounts. The results provide no support for the retrieval account of these two variables but generally are consistent with an encoding locus.