<p>The objectives of the present study were 1) to examine the effects of noise exposure on recall and recognition of orally presented text and 2) to examine the relation between working memory capacity and the performance of recall and recognition of orally presented text in noisy conditions. A total of 32 subjects, age 20-33, with no known hearing impairment, were paid to participate in the experiment. The hearing ability of all subjects was tested using recorded sentences with and without background noise. Their working memory capacity was tested using listening span, reading span and operation span tests measuring a) correctly recalled words of all three tests, b) the response latency in the reading span test and c) the processing time of the arithmetical operations in the operation span test. Finally all subjects took recall and recognition tests on texts presented orally with and without broadband background noise (white noise). The test results showed that 1) noise had no significant main effect on recall or recognition of the spoken texts, 2) ) the capacity of the central executive component of working memory, measured as the processing time of the arithmetical operations of the operation span test, correlated significantly with recall and recognition of the orally presented text in the noise condition, but not in the control condition, 3) noise exposure had a negative effect on the recognition performance of subjects with lower capacity of the central executive component of working memory.</p>

<p>Abstract</p><p>Title: Serial recall of two-voice lists: Words are not perceptually organized by voice.</p><p>The present study examined how voice affects the perceptual grouping of words in short-term memory that are auditory presented. Three different voice-lists were used: single-voice, alternating-voice and split-voice. In single-voice lists all words were presented in the same voice. In alternating-voice lists words were presented alternately in a male and a female voice. Finally, in split-voice lists words were presented grouped four and four in a male and a female voice. It was hypothesized that recall would be best for split-voice lists, especially at serial position 4 and 5. This was not confirmed. However, in line with earlier investigations, a recall advantage of single-voice lists was found in comparison with recall of alternating-voice lists at the beginning of the serial position curve. Taken together, these results suggest that words are not perceptually organized by voice in short-term memory. Like earlier studies this study found that recall of single-voice lists was better than alternating-voice lists at the first serial position, a result that yet has to be explained.</p><p>Keywords: Multi-voice lists, serial recall, short-term memory, perceptual organization</p>

<p>In many earlier investigations a recall advantage of auditory lists spoken in a single voice has been found over recall of lists spoken in two alternating voices. One explanation proposed is an organization strategy which makes recall of alternating-voice lists so difficult. The strategy implies sorting same-voice words into same-voice groups at encoding. Based on this proposition, it was assumed that voice-by-voice recall would be better than recall in order of presentation, as then the recall instruction and the organization of items in memory would be in concordance. The present experiment tested and was unable to support this hypothesis. However, an intriguing interaction between recall instruction and the sex of the participants was found, indicating that males perform worse in the voice-by-voice recall instruction than in serial recall while females’ performance did not differ between the two recall instructions. Implications of these results are discussed.</p>

This dissertation investigates the effect of endogenous and exogenous events on firm behavior and performance. These are fundamental questions in economics. The contribution of this study is threefold. First, it provides estimates of the impact of mergers on railroad efficiency, which has important antitrust implications. Second, it provides new estimates of the effect of negative events on the market value of Johnson & Johnson, Bridgestone, and Toyota, which is important to the understanding of how markets punish corporate errors. Third, it develops better ways to estimate these effects. Chapter 2 uses the event study approach to determine how product recalls due to exogenous and endogenous shocks affect the value of the firm. Three recalls from Johnson & Johnson, Bridgestone, and Toyota have been studied in this chapter. The traditional event study method assumes that markets are efficient, a questionable assumption in the short run. Thus, the current stock value of a firm may not reflect its true market value. To address this potential problem, frontier based methods are used, including data envelopment analysis, corrected ordinary least squares, and stochastic frontier regression analysis. Stochastic frontier methods are shown to be more appropriate when market behavior is not fully rational. The evidence shows that endogenous events due to firm errors are more detrimental to firm value than exogenous negative events that are beyond the control of the firm. That is, the market is more forgiving of negative shocks that the company cannot control. Chapter 3 studies the effects of merger activity on the efficiency and productivity growth of U.S. Class I railroads from 1983 to 2008. In this chapter, I assess the effects of merger activity on efficiency, and identify the major factors associated with productivity growth. Unlike previous research, I use data envelopment analysis with an attribute-incorporated Malmquist productivity index. This approach allows firm specific measures of efficiency and productivity to be calculated for firms with differences in technology. The approach allows a decomposition of the attribute-incorporated Malmquist productivity index into technical, efficient and attribute components, the impacts of railroads mergers, and the real source and change of productivity. I find that (1) the technology efficiency performance of the seven survivor firms has grown through time; (2) mergers overall do not lead significant technology and scale efficiency gains, but there are differences across mergers; (3) mergers in the 1980s do not have significant different effect on efficiency change compared to those in the 1990s; and (4) the productivity gains are mostly attributed to the network and operation attributes change and industry technology improvement. Overall, the mergers have no direct impact on the efficiency gains or losses during our study period. The application of these techniques to product recalls and railroad merger models demonstrates how they can provide superior estimates over traditional estimation techniques. It is hoped that these applications will motivate the use of these techniques in other settings. / Graduation date: 2012

Underreporting in dietary assessment has been linked to dietary restraint (DR) and social desirability (SD). Thus, this study investigated accuracy of reporting energy intake (EI) of a laboratory meal during a 24-hour dietary recall (24HR) in 38 healthy, college-aged (20.3 +/- 1.7 years), normal-weight women (22.4 +/- 1.8 kg/m2), categorized as high or low in DR and SD. Participants consumed a meal (sandwich wrap, chips, fruit, and ice cream) and completed a telephone 24HR. Accuracy of reported intake = (((reported intake - measured intake)/measured intake) x 100) [positive numbers = overreporting]. Overreporting of EI was found in all groups (meal accuracy rate = 43.1 +/- 49.9%). An interaction of SD x individual foods (p < 0.05) occurred. SD-High as compared to SD-Low more accurately reported EI of chips (19.8 +/- 56.2% vs. 117.1 +/- 141.3%, p < 0.05) and ice cream (17.2 +/- 78.2% vs. 71.6 +/- 82.7%, p < 0.05). An effect of SD occurred, where SD-High as compared to SD-Low more accurately reported meal EI (29.8 +/- 48.2% vs. 58.0 +/- 48.8%, p < 0.05). For measured meal EI, an effect of DR occurred where DR-High consumed less than DR-Low (437 +/- 169 kcals vs. 559 +/- 207 kcals, p < 0.05). An interaction of DR x food type (p < 0.05) occurred where DR-High as compared to DR-Low consumed less sandwich wrap (156 +/- 63 kcals vs. 210 +/- 76 kcals, p < 0.05) and ice cream (126 +/-73 kcals vs. 190 +/- 106 kcals, p < 0.05). For reported meal EI, an effect of DR occurred where DR-High reported consuming less than DR-Low (561 +/- 200 kcals vs. 818 +/- 362 kcals, p < 0.05). An interaction of DR x individual foods (p < 0.05) occurred where DR-High reported consuming less ice cream than DR-Low (145 +/- 91 kcals vs. 302 +/- 235 kcals, p < 0.05). Overreporting EI from a laboratory meal was prevalent. However, those high in SD were more accurate in reporting intake, particularly of high-fat foods. Future research is needed to investigate factors that contribute to overreporting.

Verbal information has predominantly been the to-be-remembered materials in human memory research for more than a century. In recent years some interesting deviations from the established rules of verbal memory have been observed in subjects who have been asked to motorically self-perform (enact) action sentences at the encoding phase of the memory task, instead of only hearing or reading them as in a traditional verbal task (VT). Marked enhancements in recall were also consistently demonstrated in such studies and the effect was named the subject-performed task (SPT) effect. Presently, the body of SPT research is large but little agreement has been reached regarding the mechanism at work in producing the SPT phenomenon. The present thesis addresses two major issues in SPT research. The enhancement of associative information and the significance of the motor component are evaluated. In Study A, the SPT effect was studied in two cued-recall tasks that relied on item-specific association and relational association, respectively. The results showed that SPT encoding interacts with item-specific associative cues at recall to produce a larger SPT effect as compared to free recall. This supports the notion that part of the SPT effect is due to enhanced item-specific association. In Study B, the associative effect in SPT was studied amongst age cohorts comprised of subjects between 40 and 85 years old. Normal age-related decline in episodic memory has elsewhere been suggested to be caused mainly by associative deficits connected with ageing. The results of Study B indicate that the item-specific associative effect in SPT was more age sensitive than recall of VT and the relational associative effect in SPT. In Study C, the question over whether the SPT effect is dependent on motor modality or not was addressed. Self-produced sign language encoding was argued to be qualitatively the same as self-produced oral/verbal encoding, with the motor modality component being the only exception. It was also argued that the motor modality component was the main similarity to performing SPT. Since the signing subjects performed at the same level as the SPT condition at recall, and better than the control conditions (e.g., VT), the conclusion was made that motor activation per se can contribute to memory enhancement in SPT. Whether SPT encoding results in qualitatively different memory traces is discussed as well as the effect of SPT on other types of associative information. The results are also briefly related to other controversies in SPT research. It is concluded, finally, that enactment produces differential effects on different types of associations. The association between verb and noun is clearly enhanced by SPT encoding. Moreover, it is concluded that overt motor activation is necessary for obtaining a full SPT effect. To explore these interactions further and to build upon these conclusions, an increased focus on motor processes and their relation to verbal processes is called for in future cognitive research.

Recurrent stress has been found to impair brain structures essential to memory. The cognitive reserve model suggests that physical activity supplies protection against memory decline in neuropathologies. The purpose of the present study was to explore whether leisure physical activity modifies the predicted negative effect stress has on memory. A sub-sample derived from the Betula Study comprised 267 participants between 50 and 65 years. Memory was assessed by a SPT free recall and stress by a self-report. Low and High frequency exercisers were analyzed separately. After age, sex and education were controlled for in hierarchical regression, results showed that stress significantly improved memory performance in Low exercisers but no significant effect in High exercisers. Thus, frequency of physical activity did not explain variation in memory performance. However, higher age did not have a negative influence on memory performance for the High exercisers.

The objectives of the present study were 1) to examine the effects of noise exposure on recall and recognition of orally presented text and 2) to examine the relation between working memory capacity and the performance of recall and recognition of orally presented text in noisy conditions. A total of 32 subjects, age 20-33, with no known hearing impairment, were paid to participate in the experiment. The hearing ability of all subjects was tested using recorded sentences with and without background noise. Their working memory capacity was tested using listening span, reading span and operation span tests measuring a) correctly recalled words of all three tests, b) the response latency in the reading span test and c) the processing time of the arithmetical operations in the operation span test. Finally all subjects took recall and recognition tests on texts presented orally with and without broadband background noise (white noise). The test results showed that 1) noise had no significant main effect on recall or recognition of the spoken texts, 2) ) the capacity of the central executive component of working memory, measured as the processing time of the arithmetical operations of the operation span test, correlated significantly with recall and recognition of the orally presented text in the noise condition, but not in the control condition, 3) noise exposure had a negative effect on the recognition performance of subjects with lower capacity of the central executive component of working memory.

Abstract Title: Serial recall of two-voice lists: Words are not perceptually organized by voice. The present study examined how voice affects the perceptual grouping of words in short-term memory that are auditory presented. Three different voice-lists were used: single-voice, alternating-voice and split-voice. In single-voice lists all words were presented in the same voice. In alternating-voice lists words were presented alternately in a male and a female voice. Finally, in split-voice lists words were presented grouped four and four in a male and a female voice. It was hypothesized that recall would be best for split-voice lists, especially at serial position 4 and 5. This was not confirmed. However, in line with earlier investigations, a recall advantage of single-voice lists was found in comparison with recall of alternating-voice lists at the beginning of the serial position curve. Taken together, these results suggest that words are not perceptually organized by voice in short-term memory. Like earlier studies this study found that recall of single-voice lists was better than alternating-voice lists at the first serial position, a result that yet has to be explained. Keywords: Multi-voice lists, serial recall, short-term memory, perceptual organization

In many earlier investigations a recall advantage of auditory lists spoken in a single voice has been found over recall of lists spoken in two alternating voices. One explanation proposed is an organization strategy which makes recall of alternating-voice lists so difficult. The strategy implies sorting same-voice words into same-voice groups at encoding. Based on this proposition, it was assumed that voice-by-voice recall would be better than recall in order of presentation, as then the recall instruction and the organization of items in memory would be in concordance. The present experiment tested and was unable to support this hypothesis. However, an intriguing interaction between recall instruction and the sex of the participants was found, indicating that males perform worse in the voice-by-voice recall instruction than in serial recall while females’ performance did not differ between the two recall instructions. Implications of these results are discussed.