How does background information improve memory for text content?

In two experiments, we investigated whether reading background information benefits memory for text content by influencing the amount of content encoded or the organization of the encoded content. In Experiment 1, half of the participants read background information about the issues to be discussed in the text material, whereas half did not. All the participants were then tested for free recall and cued recall of text content. Free recall was greater for individuals who read issue information than for those who did not. The groups did not differ on cued recall, suggesting that background information did not facilitate the encoding of more text content. Measures of representational organization indicated that increased recall in the issue information group resulted from better organization of content in memory. Experiment 2 extended these findings, using background information about text sources, demonstrated that the efficacy of background information depends on the semantic relationship between that information and text content.     

Recognition memory for source and occurrence: The importance of recollection

Previous recognition memory studies indicate that when both recollection and familiarity are expected to contribute to recognition performance (e.g., discriminating studied items from nonstudied items) the dual-process and the unequal-variance signal detection models provide comparable accounts of performance. When familiarity is not expected to be useful (e.g., when items from two equally familiar sources are discriminated between), the dual-process model provides a significantly better account of performance. In the present study, source recognition was tested under conditions in which familiarity could have been used to perform a list-discrimination task; participants were required to discriminate between strong studied items, weak studied items, and new items. The dual-process model provided a better account of performance than did the unequal-variance model. Moreover, the results indicated that the unequal-variance assumption in a single-process signal detection model was not a valid substitution for recollection and that recollection was used to make recognition judgments even when assessments of familiarity were useful.     

Strong cues are not necessarily weak: Thomson and Tulving (1970) and the encoding specificity principle revisited

Performance on tests in which there is control over reporting (e.g., cued recall with the option to withhold responses) can be characterized by four parameters: free- and forced-report retrieval (correct responses retrieved from memory when the option to withhold responses is exercised and when it is not, respectively), monitoring (discrimination between correct and incorrect potential responses), and report bias (willingness to report responses). Typically, researchers do not examine all these components in cued-test performance; blanks are sometimes counted the same as errors, meaning that the (free-report) performance index is contaminated with report bias and monitoring ability. In this research, a two-stage testing procedure is described that allows measures of free- and forced-report retrieval, monitoring, and bias to be derived from the original encoding specificity experiments (Thomson & Tulving, 1970). The results show that their cue-reinstatement manipulation affected free-report retrieval, but once report bias and monitoring effects were removed by forcing output, retrieval was unaffected.     

The effect of category learning on sensitivity to within-category correlations

A salient property of many categories is that they are not just sets of independent features but consist of clusters of correlated features. Although there is much evidence that people are sensitive to between-categories correlations, the evidence about within-category correlations is mixed. Two experiments tested whether the disparities might be due to different learning and test tasks. Subjects learned about categories either by classifying items or by inferring missing features of items. Their knowledge of the correlations was measured with classification, prediction, typicality, and production tests. The inference learners, but not the classification learners, showed sensitivity to the correlations, although different tests were differentially sensitive. These results reconcile some earlier disparities and provide a more complete understanding of people's sensitivities to within-category correlations.     

Personally familiar proper names are relatively successfully processed in the human right hemisphere; or, the missing link

Responding to our abstract in Brain and Language (Ohnesorge & Van Lancker, 1999), which proposed that famous proper nouns are successfully processed in both cerebral hemispheres, Schweinberger, Landgrebe, Mohr, and Kaufmann (2001) claimed that the "link" between personal names and the right hemisphere is "illusory." Ohnesorge and Van Lancker (2001) further described six experimental studies in which LVF/RH recognition of famous proper nouns was influenced by task conditions and stimulus familiarity. Here presenting two more experiments performed to explore the refutation presented by Schweinberger et al., this article confirms an ability of the right hemisphere to recognize famous proper nouns and explains why appropriate stimulus development and task conditions are essential in furthering our understanding of the role of the right hemisphere in processing personal relevance.     

Effect of speech task on intelligibility in dysarthria: a case study of Parkinson's disease

This study assessed intelligibility in a dysarthric patient with Parkinson's disease (PD) across five speech production tasks: spontaneous speech, repetition, reading, repeated singing, and spontaneous singing, using the same phrases for all but spontaneous singing. The results show that this speaker was significantly less intelligible when speaking spontaneously than in the other tasks. Acoustic analysis suggested that relative intensity and word duration were not independently linked to intelligibility, but dysfluencies (from perceptual analysis) and articulatory/resonance patterns (from acoustic records) were related to intelligibility in predictable ways. These data indicate that speech production task may be an important variable to consider during the evaluation of dysarthria. As speech production efficiency was found to vary with task in a patient with Parkinson's disease, these results can be related to recent models of basal ganglia function in motor performance.     

Variability in aphasic patients' response times

Response time studies of acquired language disorders are plagued by tremendous variability in patients' response times. In this brief report we demonstrate how variability itself may provide informative data. Lexical decision response times, generated by nine patients, illustrate how within-patient variability may estimate stability in cognitive dynamics.     

The influence of word frequency on recency effects in directed free recall

Leading theoretical explanations of recency effects are designed to explain the reported absence of a word frequency effect on recall of words from recency serial positions. The present study used a directed free-recall procedure (J. J. Dalezman, 1976) and manipulated the frequency composition of the word lists (pure and mixed). Overall, with pure lists, a greater proportion of high-frequency (HF) words were recalled than low-frequency (LF) words, and with mixed lists, a greater proportion of LF words were recalled than HF words. Of importance, this recall advantage for one frequency over the other as a function of list composition was evident across the last three serial positions, indicating an influence of word frequency on recency effects that is dependent on the frequency composition of the lists. These results challenge one of the major assumptions on which several theories of recency effects have been based.