Thesis advisor: Elizabeth A. Kensinger / A key feature of human memory is the ability to remember not only discrete pieces of information but also to form novel associations between them. A special type of association, called an "integration", can be formed when the pieces are encoded as a single representation in memory (Wollen, Weber and Lowry, 1972; Murray and Kensinger, 2012). The work presented here investigates what neural mechanisms underlie the formation and subsequent retrieval of integrated mental images in younger adulthood (individuals aged 18-30), whether those mechanisms differ based on the emotional content of the integration, and whether older and younger adults generate and remember emotional integrations differently from one another. I show that younger adults utilize two different routes to form integrations, depending on their emotional content: a rapid, perceptually-supported route that allows for fast integration of emotional pairs but that leads to poor downstream memory for the associates, and a slow, conceptually-supported route for neutral pairs that takes more time but that leads to strong downstream memory. Conversely, older adults utilize slow, controlled processing of emotional integrations that leads to strong memory, but they fail to produce durable memory for non-emotional pairs due to age-related associative deficits. Together, these results highlight differences both within and between age groups in the formation and retrieval of emotional and non-emotional integrations, and suggest a circumstance - integration of emotional pairs - in which older adults can overcome previously reported age-related deficits. / Thesis (PhD) — Boston College, 2013. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Psychology.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1953. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 68-69).

Young adults often outperform older adults on tests of associative memory, however, the source of this age-related associative memory deficit is still under debate. There are two main non-mutually exclusive hypotheses: 1) impaired binding processes (i.e. creating and retrieving links between units of information) and; 2) impaired strategic processes (i.e. cognitive control processes that support encoding and retrieval). Although both components are thought to contribute uniquely and interact to support associative memory, they have rarely been studied together. The primary goal of this dissertation is to further characterize associative memory deficits in healthy aging by measuring and controlling binding and strategic processes. Specifically, in this series of three experiments, we studied these two components concurrently by varying the level of demands on binding (i.e. comparing memory for different types of associations) and strategic processes (i.e. varying demands on self-initiated processes). A total N of 97 young adults and 94 older adults studied lists of object-pairs and object-location pairs under intentional encoding conditions. Demands on self-initiated processes were manipulated by increasing the number of foils at test (Experiment 1: 4 alternative forced-choice (AFC), vs. Experiment 2 & 3: 20AFC), and by providing strategy instructions in Experiment 3. We measured the production of strategies with trial-by-trial self-report. In all three experiments, we found that young adults outperformed older adults on object-object memory, but not on object-location memory. Older adults were just as proficient as young adults in generating strategies at study. This remained true even when demands on self-initiated processes increased. However, we found in all three experiments that young adults had greater strategy effectiveness (i.e. accuracy on pairs encoded with a strategy) on the object-object test. In contrast, performance on the object-location task was found to be less related to strategies. Our findings suggest that not all associations are equally affected by aging and that even when strategy production is equivalent between age groups older adults can still be impaired on associative memory. The secondary goal of this dissertation was to explore the contribution of individual variability in age, general cognitive functioning, meta-memory and executive functioning on object-object and object-location memory, strategy production, and strategy effectiveness. Our results highlight the important contribution of executive functioning over and above any effects of age in explaining age-related associative memory decline.

An associative, or content-addressable, memory, one in which data may he retrieved "by its value rather than by real address, has always been an attractive idea. Although such a memory has not yet proven practical for files of respectable size, much interesting work has been done on the subject, for example, Minsky (1972), Slotnick (1970) and Parker (1970, 1971). This thesis is concerned with the device proposed by Slotnick and Parker, called 'Logic Per Track Device'. After briefly reviewing the design and capabilities of their device, the thesis proceeds to propose some modifications to the design which not only lead to greatly enhanced performance, but also establish its practical application for files of respectable size. In the device of Slotnick and Parker, there is a fairly sophisticated logic chip attached directly to each non-movable read-write head. This allows all logic heads to search simultaneously for information matching a given key, so that any desired record could be located within one revolution. However, reading and writing will require a second revolution because part of the record will have passed the head before the match is recognized. Moreover, if more than one record matches the search key, the extra bookkeeping will be needed if matching records on different tracks should partially overlap. These problems have been ignored in the retrieval system developed by Parker (1970, 1971). The following four additional features of the device have been proposed: 1. Two logic heads on each track has been introduced. The leading head will continue to have the primary responsibility for simultaneous searching. The additional second head, trailing a fixed distance behind will do the actual reading and writing of records. 2. A delay register whose length is the distance between logic heads on the same track, has been added to the read-write head. The function of the delay bit is to tell the read-write head partner where to start reading (or writing) a record whenever a match is recognized so that retrieving (or writing) a single record can always be performed in the same revolution. 3. Another major design change will give the new device the ability to keep track of all records which may be retrieved within a single revolution by parallel search. To this end, the monitor, which synchronizes the activities of all logic head couples, will be provided with a record counter, and a mark entity will be prefixed to every record on the disk itself. A file identification mechanism has been established for the associative memory. Functions of such a mechanism are (a) to manage file names, and (b) to manipulate data on the storage device. Next step is to explore the use of such a modified device for file-oriented problems. 'Hierarchical search' for records possessing a specified combination of keys can be performed directly on the key part of records without the intermediate step of transmitting records into the main computer memory. In an application requiring chain processing, the chain pointer can he a key of the record because each record in the associative memory is accessed by content rather than by real address. The chain key can be generated from the key if the record it points to by a simple and reversible procedure. Such a chain technique has a number of advantages: (a) any chain is in fact a two-way chain, (b) each record in the chain can be retrieved by following the chain key, or directly by the key of the record if it is known, and (c) the tangle of actual physical addresses in the chain processing can be avoided. The storage organization for more complex data structure such as tree structures presents another unique feature of the modified memory. In a tree structure, indexes to the subordinate records may be kept with each parent record, or each subordiante recoEdsnjaays^tDreaaniaindsx to its parent record. Both data structures take the same amount of storage space. Comparison <3f its performance to the convent tional counterpart shows that significant improvements in access times can be achived. / Science, Faculty of / Computer Science, Department of / Graduate

Educators and researchers who study college alcohol use have explored shaping the campus environment as a method to positively influence college students' decisions regarding alcohol use. Existing literature has suggested that the interaction between the college students and the campus environment affects students' behavior (Goree & Szalay, 1996; Strange & Banning, 2001). The purpose of this study was to analyze how college and university viewbooks appeal to the different underlying dispositions of college students (non drinker vs. frequent drinker dispositions). The present study was also intended to identify whether college and university viewbooks are a part of the campus environment that affects students' behavioral decisions. The purposive sample included 51 college and university viewbooks from four different regions, six Carnegie Classifications, and an over-sampling of historically Black institutions. The findings revealed that college and university viewbooks appeal more to the non drinker dispositions than to the frequent drinker disposition. The findings also call into question previous scholarship suggesting that university recruitment materials have an influence on college student behaviors. / Master of Arts

No description available.

Let G be a finite group. Given a contravariant, product preserving functor F:G-sets → AB, we construct a Green-functor A(F):G-sets → CRNG which specializes to the Burnside ring functor when F is trivial. A(F) permits a natural addition and multiplication between elements in the various groups F(S), S ∈ G-sets. If G is the Galois group of a field extension L/K, and SEP denotes the category of K-algebras which are isomorphic with a finite product of subfields of L, then any covariant, product preserving functor ρ:SEP → AB induces a functor Fᵨ:G → AB, and thus the Green-functor Aᵨ may be obtained. We use this observation for the case ρ = Br, the Brauer group functor, and show that Aᵦᵣ(G/G) is free on K-algebra isomorphism classes of division algebras with center in SEP. We then interpret the induction theory of Mackey-functors in this context. For a certain class of functors F, the structure of A(F) is especially tractable; for these functors we deduce that (DIAGRAM OMITTED), where the product is over isomorphism class representatives of transitive G-sets. This allows for the computation of the prime ideals of A(F)(G/G), and for an explicit structure theorem for Aᵦᵣ, when G is the Galois group of a p-adic field. We finish by considering the case when G = Gal(L/Q), for an arbitrary number field L.

published_or_final_version / Mathematics / Doctoral / Doctor of Philosophy

Previous research has shown that causal attributions can be made from patterns of covariation (Cheng, 1997). While the study of how humans learn contingencies goes back decades (e.g., Ward & Jenkins, 1965), cue interaction effects, involving covariations with two or more cues, have taken on particular importance (e.g., Shanks, 1985), due to their rich potential for theoretical insights. One such effect is causal discounting (Goedert & Spellman, 2005): People believe a cue is less contingent if they learned about it in the presence of a more contingent cue. Using a new method for investigating covariation detection, the steamed-trial technique (Allen et al., 2008), Art Markman, Kelly Goedert and I (Laux et al., 2010) have established that differences in bias underlie causal discounting. We argued that this implies discounting is an effect of a process employed to make causal judgments after learning has occurred. Analyses of how different theories account for discounting, especially simulations of associative models, establishes that this is not necessarily correct; several learning models can reproduce our data. However, model and data explorations show that the key feature of those data is that they track relative, not absolute, magnitudes. My dissertation extends this work establishing the plausibility of a comparative judgment process as the locus of causal discounting. I replicate the finding that responding tracks relative magnitudes. By conducting experiments that parametrically manipulate the contingency of the alternative cue (and thereby the relative contingency of the cues), I show that causal discounting is due to responding to contingencies as a linear function of their relative magnitude. I further verify that discounting manifests identically in response to contingencies presented via summary tables. Because summary tables do not afford the series of experiences necessary to build an association, this enhances the credibility of the theory that discounting is due to a shared process employed subsequent to learning—namely, a judgment process. These investigations reveal that discounting is not a cue interaction effect at all, but rather is a manifestation of a fundamental aspect of the systems that subserve covariation detection. / text

<p>Human learning and memory relies on a broad network of neural substrates, and is sensitive to a range of environmental factors and behaviors. The present studies are designed to investigate the modulation of active exploration behaviors in humans. In the current work, we operationalize exploration in two ways: participants’ spatial navigation (using a computer mouse) in environments containing rewarding and informative stimuli, and participants’ eyegaze activity while viewing images on a computer screen. The study described in Study 1 investigates the relationship between spatial exploration and reward, using participants’ reported anxiety levels to predict between-subject variability in vigor and information-seeking. The study described in Study 2 investigates the relationship between cue-outcome predictive validity and eyegaze behavior during learning; additionally, we test the extent to which differing states of expectation drive differences in eyegaze behavior to novel images. The study described in Study 3 expands on the questions raised in Study 2: using functional imaging and eyetracking, we investigate the relationship between predictive validity, gaze, and the neural systems supporting active exploration. Taken together, the findings in the present study suggest that emerging certainty in reward outcomes, rather than uncertainty, drives exploration and associative learning for events and their outcomes as well as encoding into long-term memory.</p> / Dissertation