Irrelevant Tapping and the Acoustic Confusion Effect

When items in a to-be-remembered list sound similar, recall performance is worse than when items are acoustically distinct, what is known as the acoustic confusion effect (ACE). When participants are asked to tap a syncopated rhythm during list presentation, the difference between the acoustically similar and dissimilar conditions is abolished; however, simple temporal and simple spatial tapping tasks have no effect. The objective of the present study is to examine whether spatial complexity is a property of the tapping task that interferes with the ACE. Participants were asked to tap a simple (Experiment 1) or a complex spatial pattern (Experiment 2) at a regular pace during a verbal serial recall task in which acoustic similarity was manipulated. The results showed that simple spatial tapping had no effect on the ACE, whereas complex spatial tapping significantly reduced the effect. Implications for three theories of memory are discussed.

Mobile Findex: Facilitating Information Access in Mobile Web Search with Automatic Result Clustering

Designing an effective mobile search user interface is challenging, as interacting with the results is often complicated by the lack of available screen space and limited interaction methods. We present Mobile Findex, a mobile search user interface that uses automatically computed result clusters to provide the user with an overview of the result set. In addition, it utilizes a focus-plus-context result list presentation combined with an intuitive browsing method to aid the user in the evaluation of results. A user study with 16 participants was carried out to evaluate Mobile Findex. Subjective evaluations show that Mobile Findex was clearly preferred by the participants over the traditional ranked result list in terms of ease of finding relevant results, suitability to tasks, and perceived efficiency. While the use of categories resulted in a lower rate of nonrelevant result selections and better precision in some tasks, an overall significant difference in search performance was not observed.

Old-Fashioned Responses in an Updating Memory Task

Errors in a running memory task are analysed. Participants were presented with a variable-length list of items and were asked to report the last four items. It has been proposed (Morris & Jones, 1990) that this task requires two mechanisms: the temporal storage of the target set by the articulatory loop and its updating by the central executive. Two implicit assumptions in this proposal are (a) the preservation of serial order, and (b) participants’ capacity to discard earlier items from the target subset as list presentation is running, and new items are appended. Order preservation within the updated target list and the inhibition of the outdated list items should imply a relatively higher rate of location errors for items from the medial positions of the target list and a lower rate of intrusion errors from the outdated and inhibited items from the pretarget positions. Contrary to these expectations, for both consonants (Experiment 1) and words (Experiment 2) we found recency effects and a relatively high rate of intrusions from the final pretarget positions, most of them from the very last. Similar effects were apparent with the embedded four-item lists for catch trials. These results are clearly at odds with the presumed updating by the central executive.

Phonological Information in Immediate and Delayed Sentence Recall

Potter and Lombardi (1990) state in their conceptual regeneration hypothesis that immediate sentence recall is only based on conceptual and lexical information; phonological information does not contribute. As experimental evidence for this hypothesis, they reported that if a sentence is followed by a word list that included a lure word similar to one of the content words of the sentence (target word), the lure word frequently intrudes into sentence recall. We demonstrated that Potter and Lombardi did not observe any influence of phonological information because list presentation followed sentence presentation, and phonological information was discarded. We observed that phonological information influenced the intrusion rate if recall was not delayed by the subsequent presentation of a word list. With immediate recall, the lure intrusion effect disappeared in auditorily presented sentences. This shows that, if available, phonological information contributes to sentence recall.

Amnesic patients' impaired category exemplar production priming

This study examined the effect of varying the number of potential target words on amnesic patients' category exemplar production performance. In Experiment 1, 4 words from each of 6 categories were presented to amnesic patients and normal control participants. This was followed by an indirect task in which each participant produced the first 8 words that came to mind when presented with a category cue. On this task the amnesic patients were impaired. This outcome stands in sharp contrast to most other category exemplar production tasks that have been reported. However, these other paradigms tend to restrict participants' processing during target item presentation while our procedure allowed them to analyze the target words as they chose. Our procedure may have allowed the control participant more opportunity to “cluster” target words from the same category during list presentation and this, in turn, may have given them an advantage at the time of category exemplar production. Therefore, in Experiment 2, only 1 word per category was presented in the target list and only 2 words per category were requested during category exemplar production. Surprisingly, the amnesic patients still exhibited impaired performance. Therefore, it was suggested that perhaps amnesic patients' known inability to perform semantic levels of processing during individual target word presentation may have resulted in impaired priming for categorical features for these patients. (JINS, 1998, 4, 576–583.)

Creating False Memories of Words With or Without Recognition of List Items: Evidence for Nonconscious Processes

Subjects exposed to lists of semantically related words falsely remember nonstudied words that are associated with the list items (e.g., Deese, 1959; Roediger & McDermott, 1995). To determine if subjects would demonstrate this false memory effect if they were unable to recognize the list items, we presented lists of semantically related words with or without a concurrent memory load at rates of 2 s, 250 ms, or 20 ms per word (Experiment 1, between-subjects design) and 2 s or 20 ms per word (Experiment 2, within-subjects design). We found that the subjects falsely recognized semantically related nonstudied words in all conditions, even when they were unable to discriminate studied words from unrelated nonstudied words. Recognition of list items was unnecessary for the occurrence of the false memory effect. This finding suggests that this memory illusion can be based on the nonconscious activation of semantic concepts during list presentation.