Fixed-width output analysis for Markov chain Monte Carlo

Markov chain Monte Carlo is a method of producing a correlated sample in order to estimate features of a target distribution via ergodic averages. A fundamental question is when should sampling stop? That is, when are the ergodic averages good estimates of the desired quantities? We consider a method that stops the simulation when the width of a confidence interval based on an ergodic average is less than a user-specified value. Hence calculating a Monte Carlo standard error is a critical step in assessing the simulation output. We consider the regenerative simulation and batch means methods of estimating the variance of the asymptotic normal distribution. We give sufficient conditions for the strong consistency of both methods and investigate their finite sample properties in a variety of examples

Modeling age-related differences in immediate memory using SIMPLE

In the SIMPLE model (Scale Invariant Memory and Perceptual Learning), performance on memory tasks is determined by the locations of items in multidimensional space, and better performance is associated with having fewer close neighbors. Unlike most previous simulations with SIMPLE, the ones reported here used measured, rather than assumed, dimensional values. The data to be modeled come from an experiment in which younger and older adults recalled lists of acoustically confusable and nonconfusable items. A multidimensional scaling solution based on the memory confusions was obtained. SIMPLE accounted for the overall difference in performance both between the two age groups and, within each age group, the overall difference between acoustically confusable and nonconfusable items in terms of the MDS coordinates. Moreover, the model accounted for the serial position functions and error gradients. Finally, the generality of the model’s account was examined by fitting data from an already published study. The data and the modeling support the hypothesis that older adults’ memory may be worse, in part, because of altered representations due to age-related auditory perceptual deficits

Postmortem meat tenderization and associated biochemical factors ： comparative study on water buffalo meat and Brahman beef

Thesis (Ph. D. in Agricultural Science)--University of Tsukuba, (A), no. 4699, 2008.3.25Includes bibliographical references (leaves 80-90

Facial expression discrimination varies with presentation time but not with fixation on features: A backward masking study using eye-tracking

This is an Accepted Manuscript of an article published by Taylor & Francis in Cognition and Emotion on 23 Sep 2013, available online: http://www.tandfonline.com/10.1080/02699931.2013.812557.The current study investigated the effects of presentation time and fixation to expression-specific diagnostic features on emotion discrimination performance, in a backward masking task. While no differences were found when stimuli were presented for 16.67 ms, differences between facial emotions emerged beyond the happy-superiority effect at presentation times as early as 50 ms. Happy expressions were best discriminated, followed by neutral and disgusted, then surprised, and finally fearful expressions presented for 50 and 100 ms. While performance was not improved by the use of expression-specific diagnostic facial features, performance increased with presentation time for all emotions. Results support the idea of an integration of facial features (holistic processing) varying as a function of emotion and presentation time.This study was supported by the Canadian Institutes for Health Research (CIHR)the Canada Foundation for Innovation (CFI)the Ontario Research Fund (ORF)and the Canada Research Chair (CRC) program to RJI

Fixation to features and neural processing of facial expressions in a gender discrimination task

The final publication is available at Elsevier via http://dx.doi.org/10.1016/j.bandc.2015.05.007. © 2015. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Early face encoding, as reflected by the N170 ERP component, is sensitive to fixation to the eyes. Whether this sensitivity varies with facial expressions of emotion and can also be seen on other ERP components such as P1 and EPN, was investigated. Using eye-tracking to manipulate fixation on facial features, we found the N170 to be the only eye-sensitive component and this was true for fearful, happy and neutral faces. A different effect of fixation to features was seen for the earlier P1 that likely reflected general sensitivity to face position. An early effect of emotion (∼120 ms) for happy faces was seen at occipital sites and was sustained until ∼350 ms post-stimulus. For fearful faces, an early effect was seen around 80 ms followed by a later effect appearing at ∼150 ms until ∼300 ms at lateral posterior sites. Results suggests that in this emotion-irrelevant gender discrimination task, processing of fearful and happy expressions occurred early and largely independently of the eye-sensitivity indexed by the N170. Processing of the two emotions involved different underlying brain networks active at different times

A Remember-Know Analysis of the Semantic Serial Position Function

Did the serial position functions observed in certain semantic memory tasks (e.g., remembering the order of books or films) arise because they really tapped episodic memory? To address this issue, participants were asked to make "remember-know" judgments as they reconstructed the release order of the 7 Harry Potter books and 2 sets of movies. For both classes of stimuli, the "remember" and "know" serial position functions were indistinguishable, and all showed the characteristic U-shape with marked primacy and recency effects. These results are inconsistent with a multiple memory systems view, which predicts recency effects only for "remember" responses and no recency effects for "know" responses. However, the data were consistent with a general memory principle account: the relative distinctiveness principle. According to this view, performance on both episodic and semantic memory tasks arises from the same type of processing: Items that are more separated from their close neighbors in psychological space at the time of recall will be better remembered

Serial position functions in general knowledge

Serial position functions with marked primacy and recency effects are ubiquitous in episodic memory tasks. The demonstrations reported here explored whether bow-shaped serial position functions would be observed when people ordered exemplars from various categories along a specified dimension. The categories and dimensions were: actors and age; animals and weight; basketball players and height; countries and area; and planets and diameter. In all cases, a serial position function was observed: People were more accurate to order the youngest and oldest actors, the lightest and heaviest animals, the shortest and tallest basketball players, the smallest and largest countries, and the smallest and largest planets, relative to intermediate items. The results support an explanation of serial position functions based on relative distinctiveness, which predicts that serial position functions will be observed whenever a set of items can be sensibly ordered along a particular dimension. The serial position function arises because the first and last items enjoy a benefit of having no competitors on 1 side and therefore have enhanced distinctiveness relative to mid-dimension items, which suffer by having many competitors on both sides

Neural processing of fearful and happy facial expressions during emotion-relevant and emotion-irrelevant tasks: A fixation-to-feature approach

The final publication is available at Elsevier via http://dx.doi.org/10.1016/j.biopsycho.2016.07.013. © 2016. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Research suggests an important role of the eyes and mouth for discriminating facial expressions of emotion. A gaze-contingent procedure was used to test the impact of fixation to facial features on the neural response to fearful, happy and neutral facial expressions in an emotion discrimination (Exp.1) and an oddball detection (Exp.2) task. The N170 was the only eye-sensitive ERP component, and this sensitivity did not vary across facial expressions. In both tasks, compared to neutral faces, responses to happy expressions were seen as early as 100-120ms occipitally, while responses to fearful expressions started around 150ms, on or after the N170, at both occipital and lateral-posterior sites. Analyses of scalp topographies revealed different distributions of these two emotion effects across most of the epoch. Emotion processing interacted with fixation location at different times between tasks. Results suggest a role of both the eyes and mouth in the neural processing of fearful expressions and of the mouth in the processing of happy expressions, before 350ms.This research was supported by grants from the Natural Sciences and Engineering Research Council of Canada (NSERC Discovery Grant #418431)the Ontario government (Early Researcher Award, ER11-08-172)the Canada Foundation for Innovation (CFI, #213322)and the Canada Research Chair (CRC, #213322 and #230407) program to RJIas well as by a doctoral NSERC grant to KNNT (PGS D Grant # 210825634)

Positional uncertainty in the Brown-Peterson paradigm

Since McGeoch’s (1932) influential article, no accounts of long-term memory have invoked decay as a cause of forgetting. In contrast, multiple accounts of short-term memory (STM) invoke decay, with many appealing to results from the Brown-Peterson paradigm as offering support. Two experiments are reported that used a standard Brown-Peterson task but which scored the data in 2 ways. With traditional scoring (was the entire 3-letter consonant trigram recalled?) performance decreased with increasing delay. With immediate serial recall scoring (e.g., was the first letter recalled first, was the second letter recalled second?), standard position error gradients (Experiment 1), and protrusion gradients (Experiment 2) were observed. That is, when the first letter of the consonant trigram was not recalled first, it was more likely to be recalled second than last. In addition, if a letter from a previous list was mistakenly recalled in a later list, it most likely retained its original position. The presence of such gradients is inconsistent with claims of decay but is predicted by SIMPLE, a local distinctiveness model of memory. Moreover, the presence of such gradients is consistent with the claim that forgetting in the Brown-Peterson paradigm follows the same principles observed in other memory tasks

Backward recall and benchmark effects of working memory

Working memory was designed to explain four benchmark memory effects: the word length effect, the irrelevant speech effect, the acoustic confusion effect, and the concurrent articulation effect. However, almost all research thus far has used tests that emphasize forward recall. In four experiments, we examine whether each effect is observable when the items are recalled in reverse order. Subjects did not know which recall direction would be required until the time of test, ensuring that encoding processes would be identical for both recall directions. Contrary to predictions of both the primacy model and the feature model, the benchmark memory effect was either absent or greatly attenuated with backward recall, despite being present with forward recall. Direction of recall had no effect on the more difficult conditions (e.g., long words, similar-sounding items, items presented with irrelevant speech, and items studied with concurrent articulation). Several factors not considered by the primacy and feature models are noted, and a possible explanation within the framework of the SIMPLE model is briefly presented