In this article, we apply the REM model (Shiffrin & Steyvers, 1997) to age differences in associative memory. Using Criss and Shiffrin's (2005) associative version of REM, we show that in a task with ...pairs repeated across 2 study lists, older adults' reduced benefit of pair repetition can be produced by a general reduction in the diagnosticity of information stored in memory. This reduction can be modeled similarly well by reducing the overall distinctiveness of memory features, or by reducing the accuracy of memory encoding. We report a new experiment in which pairs are repeated across 3 study lists and extend the model accordingly. Finally, we extend the model to previously reported data using the same task paradigm, in which the use of a high-association strategy introduced proactive interference effects in young adults but not older adults. Reducing the diagnosticity of information in memory also reduces the proactive interference effect. Taken together, the modeling and empirical results reported here are consistent with the claim that some age differences that appear to be specific to associative information can be produced via general degradation of information stored in memory. The REM model provides a useful framework for examining age differences in memory as well as harmonizing seemingly conflicting prior modeling approaches for the associative deficit.
Positive sequential dependencies occur when the response on the current trial n is positively correlated with the response on trial n−1. They are observed in a Judgment of Frequency (JOF) recognition ...memory task (Malmberg & Annis, 2012), and we developed a process model of them in the REM framework (Malmberg, Holden, & Shiffrin, 2004; Shiffrin & Steyvers, 1997) by assuming that features that represent the current test item in a retrieval cue carry over from the previous retrieval cue. We tested the model with data that distinguish between the number of times two given items were studied (frequency similarity) and the similarity between stimuli (item similarity), which was varied by presenting either landscape photos (high similarity), or photos of everyday objects such as shoes, cars, etc. (low similarity). Two models of item similarity were tested by assuming that the item representations share a proportion of features and that the exemplars from different stimulus classes vary in the distinctiveness or diagnosticity. A comprehensive exploration of several variants of these models directly was conducted comparing BIC and SBICR model selection statistics. The analyses establish the plausibility of the basic model of positive sequential dependencies, which assumes that differences in the similarity of the stimuli and differences in vigilance to the JOF task account for the pattern of sequential dependencies that we observed. They also indicate that different decision criteria are used to classify different stimuli on the JOF scale.
•A model of positive sequential dependencies was developed.•Several variants of the model were explored.•The modeling results suggest the plausibility of the basic model.
A relatively high percentage of Baltic corporations have already started their operations abroad, over 40% of the companies studied. It is surprising that the approaching EU membership docs not seem ...to be the driving force of the Baltic corporations' internationalization, though the EU is clearly the major export destination. The empirical evidence shows that the operations of the Baltic companies in foreign markets, have concentrated on the ex-CMEA countries, especially on the former USSR. The empirical data indicates that most of the operations abroad are related to marketing, such as the foundation of their own representative office or their own sales unit in a foreign market.
A relatively high percentage of Baltic corporations have already started their operations abroad, over 40% of the companies studied. It is surprising that the approaching EU membership docs not seem ...to be the driving force of the Baltic corporations’ internationalization, though the EU is clearly the major export destination. The empirical evidence shows that the operations of the Baltic companies in foreign markets, have concentrated on the ex‐CMEA countries, especially on the former USSR. The empirical data indicates that most of the operations abroad are related to marketing, such as the foundation of their own representative office or their own sales unit in a foreign market.
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