Studies concerning tactile short-term memory (short-term memory or the sense of touch) have often been contradictory. Some of these studies support the existence of modality-specific tactile memory, a separate, independent storage system for tactile information. Other studies do not support such a system. Further, confusion has arisen regarding the tactile test materials, since many of them use common shapes which are easily labeled verbally. It is hypothesized that information which can be labeled is stored in material-specific verbal memory in the left hemisphere, while patterned or spatial information is stored in material-specific nonverbal memory in the right hemisphere. This paper reports two studies conducted to demonstrate both verbal and nonverbal material-specific memory using tactile test materials. The first experiment utilized the Seguin Formboard, which has wooden shapes that are easily labeled verbally. The test was administered to brain damaged patients and to normal controls. Results showed that the performance of the people with left hemisphere brain damage was significantly impaired relative to the normal controls. This was expected since verbal material is processed in the left hemisphere. People with damage in this area have difficulty naming objects and storing the names. The second experiment utilized wooden shapes that were presumed difficult to label. This test was again administered to brain damaged subjects as well us to normal controls. The results were not significant. This may have been because the test was too difficult or because it did not tap nonverbal spatial information. Thus, people with right hemisphere damage were expected to have difficulty processing this type of material. The right damaged group did tend to do more poorly than the other groups. It is not known if this difference would be significant were the test simplified, or if there were actually no group differences. The first study suggests that the Seguin Formboard, thought to be a nonverbal tactile memory test, is actually verbally mediated. The second study did not yield significant results, but suggests a line of further research into the area of nonverbal material-specific memory tested in the tactile modality. These experiments suggest the importance of carefully evaluating test materials to determine what abilities they actually measure in order to obtain a fine analysis of memory function.

Research on numerical cognition proposes that there are two systems for the perception of numerical quantity, a small-number system (1~3) invoking parallel individuation, or “subitizing”, and a large-number system (4+) that is based on Weberian magnitude estimation (Hyde, 2011). Many numerical cognitive neuroscientists have focused on studying how the magnitude of numerosities (small vs. large numbers) and numerical distance (close vs. far differences between numbers) are influential factors when processing numbers and change detection. However, is there a difference when numerosities are increasing or decreasing? The effects of direction on numerical change processing are lesser known. This 128-channel EEG study investigated the neurobehavioral basis of differentiation between small vs. large-number perception and effects of change directionality. During EEG data collection, participants were sequentially presented with stimulus arrays of 1 to 6 dots, with parameters like size and location controlled for, to minimize varying non-numerical visual cues during habituation. Participants were instructed to press a key whenever they detect a change in the number of dots presented. The current study adapts a dot-stimuli numerical change study design from Hyde and Spelke (2009, 2012). In their EEG study, the researchers examined event-related-potential (ERP) differences during the processing of small (1, 2, 3) and large (8, 16, 24) numbers. For this study, we chose to examine a narrower numerical range from 1~6, so that small (1, 2, 3) vs. large (4, 5, 6) contrasts were along a numerical continuum. In contrast to Hyde and Spelke (2009, 2012), where participants passively-viewed the sequential presentation of dot arrays, this study employed an active change detection paradigm, where participants’ reaction time (RT) and accuracy in detecting change in the number of dots were recorded. We investigated the effects of Direction and Size in numerical change detection, where Direction is operationally defined as Decreasing and Increasing change in numeric set size, while Size is divided into Small-to-Small, Large-to-Large and Crossovers. Numerical change conditions were categorized into six groups: “Increasing Small-to-Small” (e.g., 1-to-2, 2-to-3), “Decreasing Small-to-Small” (e.g., 2-to-1, 3-to-2), “Increasing Large-Large” (e.g., 4-to-6, 5-to-6), “Decreasing Large-Large” (e.g., 5-to-4, 6-to-5), Increasing Small-to-Large” (e.g., 2-to-4, 3-to-5, 3-to-6) and “Decreasing Large-to-Small” (e.g., 4-to-2, 5-to-2, 6-to-3), where the last two groups are operationally defined as Crossovers. There was also a “No Change” condition, where the number of dots remain the same for up to five presentations. ERP analyses were conducted for the N1 component (125-200 ms) over the left and right occipital-temporal-parietal (POT) junction and for the P3b component (435-535 ms) over the midline parietal area (Pz). During the No Change condition, results show that the N1 amplitude was modulated by the cardinal values of the habituated numbers 1~6. Within this continuous range, we found N1 amplitudes commensurate with cardinal values in the small range (1, 2, 3), but not in the large range (4, 5, 6), suggesting that numbers in the subitizing range are individuated as objects in working memory. Meanwhile, in the Change condition, there was a significant main effect of Direction on N1 peak latency, where the Increasing condition showed earlier peaks. In the Decreasing Small-to-Small condition, N1 amplitudes were the lowest (even lower than N1 peaks for No Change conditions), while the other five Change conditions all produced higher N1 negativities than No Change conditions. These results imply that when the number of dots get small enough to parallel individuate, instead of encoding items into visual short-term memory, the brain is “off-loading” items from our perceptual load. Intriguingly, although the Decreasing Small-to-Small condition had the lowest N1 negativities, it produced the highest P3b positivity. Distinctions in P3b waveforms reflect a clear categorical break between small vs. large numbers, where easier/small number change conditions have higher amplitudes than harder, large number conditions, suggesting more difficulty with updating the context in the latter. However, in contrast to the earlier N1, there was no main effect of Direction on P3b peak latency, but there was an interaction effect of Direction by Size. Interestingly, there was also a similar interaction effect of Direction by Size for reaction times, with similar trends showing that Decreasing conditions produced shorter reaction times for the Large-to-Large and Crossover conditions, yet this pattern was reversed in the Small-to-Small condition. This lends more support to the implication of the “off-loading” phenomenon when processing decreases of numerosities in the small range (1~3). Meanwhile, when it comes to context-updating at later stages, and a behavioral response is required for this change detection task, the Large-to-Large condition prove to be the most difficult, as there was lower accuracy, longer reaction times, later and lower P3b peaks. N1 and P3b amplitudes are complementary to each other, with the early N1 being more sensitive to Direction, and the later P3b being more sensitive to Size. This suggests that the posterior parietal cortex might encode Direction first, followed by Size. This study proposes a model that is an adaptation to the P3b context-updating model (Donchin, 1981), where the early, sensory N1 interplays with the later, cognitive P3b. These findings suggest a neurobehavioral basis for the differentiation of small vs. large number perception at early stages of processing that is sensitive to encoding vs. off-loading objects from perceptual load and visual short-term memory, as well as a later stage that involve higher-order cognitive processing on the magnitude of set size that is employed in numerical change detection tasks.

This dissertation investigated the impact of active stereoscopic 3-dimensional (3D) imagery equipment and individual differences in visuo-spatial working memory (VSWM) capacity on retention of a set of similar, novel objects (i.e., armored military vehicles). Seventy-one participants were assessed on their visuo-spatial working memory using the Visual Patterns Test (Della Sala, Gray, Baddeley, & Wilson, 1997). They were then assigned to one of four different conditions (3D high VSWM, 3D low VSWM, 2D high VSWM, 2D low VSWM) based upon their visuo-spatial working memory. Participants were then trained to identify military vehicles using a simulation that presented the training stimuli in one of two dimensionalities, i.e. two dimensional (2D) or active stereoscopic three-dimensional (3D). Testing consisted of a vehicle memory training assessment, which challenged participants to choose the correct components of each vehicle immediately after studying; a measure of retention for military vehicles which asked participants to categorize the alliance and identify previously studied vehicles; and a transfer measure using video footage of actual military vehicles. The latter measures depicted military vehicles in an array of combat situations, and participants were asked to decide on whether or not to shoot each vehicle, as well as identify the vehicles. Testing occurred immediately after training. The moderating, as well as main effects, of VSWM were assessed. The mediating/moderating effects of several experiential factors were measured as well, including: immersion, presence, engagement, flow state, and technology acceptance. Findings indicate that perceptions of the simulation experience and VSWM are strong positive predictors of performance, while 3D was not predictive, and in some instances, significantly worse than the 2D condition. These findings indicate that individual differences in visual memory and user experiences during the SBT both are predictive factors in memory tasks iv for confusable objects. The SBT designed in this study also led to robust prediction of training outcomes on the final transfer task.

This thesis examines the effects of prosody on serial recall. Serial recall is an experimental task commonly used to evaluate the capacity of short-term memory. The Working Memory model by Baddeley and Hitch is a theoretical framework that describes the inner operation of short-term memory. Its hierarchies are supported by empirical evidence, but details of the core mechanisms remain unclear. In an attempt to refine the framework, this thesis investigated prosody as a factor in serial recall accuracy. Two behavioural experiments were conducted on native speakers of Canadian English. In the first experiment, the explicit awareness of word stress was examined. Results showed a main effect of word stress type, where iambic words received higher stress identification scores compared to trochaic words. In the second experiment, an immediate serial recall task was used to examine serial recall of word lists. The lists consisted of disyllabic words from Canadian English sources. The lists had mixed or uniform stress patterns. A main effect of list stress patterns was found, where mixed lists elicited better recall of the order of list items compared to uniform lists. Overall, the present thesis offers a new interpretation on how word stress is represented in the short-term memory. It adds support to the proposed interaction between short-term and long-term memory. / Thesis / Master of Science (MSc) / Many daily experiences require us to remember a list of items, such as drafting a grocery list and reciting phone numbers. How well we can remember a list can be influenced by various characteristics of the list. This thesis looks at a seldom studied characteristic: prosody. Prosody in the English language can be realized via word stress, which is the amount of emphasis we place on certain parts of a word. This thesis explores the impact of word stress on our ability to remember a list of common English words. It reports data from an online survey and a laboratory experiment. Results show that mixed word stress patterns in a list lead to better memory for said list. Overall, this thesis offers new suggestions on the role of prosody in memory. As well, it offers a novel set of data that supports current theories in memory.

No description available.

There is evidence that language ability is related to a number of cognitive processes, including memory. As children become more proficient language-users, they develop the ability to use language as a memory attribute. This study used EEG coherence to investigate the extent to which verbal encoding strategies account for individual differences in two short-term recognition memory tasks in 50 3-year-olds. Children with better expressive and receptive language performed better on the picture memory task (which contains stimuli that can easily be labeled) but not the abstract memory task, indicating that language may support memory processes for some types of stimuli more than for others. Analyses of EEG coherence at the hypothesized electrode pairs (F7-T3 and F8-T4) at baseline and encoding were not significant, indicating that verbal encoding does not account for individual differences in short-term memory performance. When these electrode pairs were examined at baseline and retrieval for the picture memory task, EEG coherence analyses indicated that it may be the use of language as a retrieval cue rather than an encoding strategy that explains individual differences in short-term recognition memory. / Ph. D.

No description available.

Recent research suggests that increased demands placed upon working memory elicit elevated symptoms of hyperactivity in children diagnosed with ADHD. Such findings suggest that demands placed on working memory processing may influence motor activity. To investigate this relationship further, 43 undergraduate students from the University of Central Florida were given three versions of a visuo-spatial working memory task (including low, moderate, and high demand conditions). As the participants were engaged in these tasks, activity level was measured and recorded using 3-axis accelerometers. Participants also were given a continuous performance task (CPT) and the Conners' Adult ADHD Rating Scale Self Report, Screening Version (CAARS-S:SV) to assess symptoms of ADHD. Activity level of participants was found to increase as visuo-spatial working memory demands were increased. When those participants who reported symptoms of ADHD were statistically removed from the sample, a significant increase in activity between tasks remained. However, participants who reported elevated ratings of ADHD symptoms showed significantly more activity than those participants who did not report elevated ratings of ADHD as visuo-spatial working demands were increased. Implications for these findings are discussed.

[Truncated abstract] Various capabilities such as the ability to read or conduct a conversation rely on our ability to maintain and recall information in the correct order. Research spanning more than a century has been devoted to understanding how units of information are retained in order in short-term memory. The nature of the mechanisms that code the positions of items in serial short-term verbal recall can be investigated by examining a set of phenomena that can be termed temporal grouping effects. Inserting extended pauses to break a list of verbal items into sub-lists (e.g. SHD-QNR-BJF, where the dashes represents the pauses) improves the accuracy of serial recall relative to performance observed without this temporal grouping. In addition, two other effects are linked to temporal grouping. One of these effects is a shift in the shape of the serial position function, which changes from a single bowed function to a multiple-bowed function. That is, the serial position curve for ungrouped sequences is typically characterized by better performance for the beginning and ending items compared to the mid-list items. For grouped lists, the multiple-bowed function comprises better recall for the beginning and ending items within each group. Another effect associated with temporal grouping is a change in the patterns of order errors. For ungrouped sequences (e.g. SHDQNRBJF), order errors often involve the swapping of items in neighbouring positions, such as exchanging D for Q or R for B. By contrast, grouped sequences (such as SHD-QNR-BJF) show a reduction in order errors that cross group boundaries such as exchanging items D and Q or R and B; instead, there tend to be an increased incidence of exchanging items that share similar within-group positions such as swapping H and N or Q and B. According to several current models of short-term memory, items are retained by associating them with extra-list information such as contextual information. ... This was done by unconfounding temporal position (time from group onset) and ordinal position (number of items from group onset) for certain key items in sequences comprising two groups of four consonants. The critical manipulation was to vary the SOAs within and across the two groups. Errors that involve items migrating across groups should preserve within-group temporal position according to oscillator models, but should preserve within-group ordinal position according to non-oscillator models. Results from the intergroup errors strongly favored preservation of ordinal rather than temporal position. Finally, the Appendix reports an unpublished experiment that examined patterns of errors in recalling sequences of nine visually presented letters, where the letters were grouped into threes using temporal gaps. A critical manipulation was the insertion of a tobe- ignored item (an asterisk) between the first and second letters of selected groups. Inclusion of this item failed to alter the patterns of errors observed, indicating that the coding of serial position is based on only those events represented for recall. The central conclusion based on all the studies is that serial order for verbal items is retained using contextual positional codes that change with each presentation of a tobe- remembered item, are influenced by large temporal gaps that lead to grouping, but otherwise are not dependent on the timing of events.

The current thesis has two aims to further the understanding of the cognitive underpinnings that are involved in word-learning and language processing. One aim is to understand how individuals are able to make temporary phonological and serial order representations of new words in language and non-language domains. The second aim is to investigate whether the mechanisms involved in maintaining temporary nonverbal and serial order representations are related to verbal short-term abilities. We created four behavioural tasks to determine the processing of phonological short-term memory information, nonverbal short-term memory information, serial order short-term memory information and rhythmic short-term memory. We used 30 adult Spanish-English bilinguals as the target population to also investigate whether individual language abilities in two spoken languages affect the learning of words in a foreign language with distinct prosody and phonology. The first correlational analysis revealed that performance on a serially ordered verbal short-term memory task that involved a language of unfamiliar prosody and phonology was strongly predicted by performance on two serially ordered verbal short-term memory tasks that involved languages of familiar prosody and phonology. A second correlational analysis showed that tasks that tapped into individuals’ memory for serial order in the verbal, nonverbal and rhythmic domains were weakly associated with one another. In a third correlational analysis, it was shown that individuals’ lexical knowledge of Spanish was not a predictor of their performance on a measure of their serially ordered verbal short-term memory abilities. Multiple linear regression analyses found that none of the tasks that were used to measure individuals’ abilities for processing serial order information in the verbal, nonverbal and rhythmic domain were strong predictors for foreign-word learning. Overall, the results show promising findings for the tasks that tapped into serial order short-term memory for verbal information. However, they also suggest that the nonverbal and rhythm tasks may not be reliable measures of the constructs we were hoping to study. Future work should adjust the tasks to ensure we are properly tapping into individuals’ serial order abilities in the nonverbal and rhythm domains. / Thesis / Master of Science (MSc)