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Effects of Hearing Acuity on Recall of Expository Prose Master’s Thesis Presented to The Faculty of the Graduate School of Arts and Sciences Brandeis University Department of Psychology Arthur Wingfield, D.Phil., Advisor In Partial Fulfillment of the Requirements for the Degree Master of Arts in Psychology by Heidi L. Sarles-Whittlesey May 2017 Copyright by Heidi L. Sarles-Whittlesey © 2017 ACKNOWLEDGEMENTS I would like to thank Art Wingfield, my advisor, for his wisdom, guidance, and this opportunity; Hannah Snyder, for her insightful advice and support throughout this process; Eriko Atagi for her endless patience and investment as a mentor; the entire Memory & Cognition Lab for their team effort; and my family for making all of this possible. iii ABSTRACT Effects of Hearing Acuity on Recall of Expository Prose A thesis presented to the Department of Psychology Graduate School of Arts and Sciences Brandeis University Waltham, Massachusetts By Heidi L. Sarles-Whittlesey The present study examined how memory processes may be impacted by uncorrected hearing loss and increased expenditure of cognitive resources during encoding of spoken prose in older adults (OAs). The effect of self-paced listening on the accuracy of recall was investigated, as well as the relationship between the order of propositions in a passage and the order in which they are recalled. 24 OAs were matched for cognitive ability, but differed in hearing acuity (12 had good hearing acuity (GH); 12 had mild to moderate poor hearing acuity (PH)). Expository passages were presented in a self-paced or continuous listening condition; as well as at +10 dB above each listener’s speech reception threshold (SRT) or at +25 dB above SRT. Results indicated a significant main effect of levels of detail on recall accuracy. Only the PH group’s recall accuracy was significantly impacted by pacing and presentation level. Self-pacing facilitated linear congruency of recall for the GH group only. Lag recency analysis suggested that the GH group formed stronger between-proposition associations than the PH group. Keywords: hearing acuity, effortful listening, free-recall, linear congruency, lag recency, memory, aging iv TABLE OF CONTENTS ACKNOWLEDGEMENTS………………………………………………………………………iii ABSTRACT……………………………………………………………………………………...iv LIST OF TABLES……………………………………………………………………………......vi LIST OF FIGURES...…………………………………………………………………………....vii LIST OF APPENDICES...……………………………………………………………………...viii INTRODUCTION.………………………………………………………………………………..1 METHODS..……………………………………………………………………………………....8 Participants………………………………………………………………………………...8 Cognitive Testing……………………………………………………………………….....8 Auditory Testing…………………………………………………………………………..9 Stimulus Materials……………………………………………………………………….10 Procedures………………………………………………………………………………..11 RESULTS..………………………………………………………………………………………13 Recall Accuracy………………………………………………………………………….13 Order of Recall…………………………………………………………………………...14 DISCUSSION..………………………………………………………………………………….17 REFERNCES...………………………………………………………………………………….23 TABLES………………………………………………………………………………………....25 FIGURES………………………………………………………………………………………..27 APPENDICES…………………………………………………………………………………...30 v LIST OF TABLES Participant characteristics………………………………………………………………………..25 Linear mixed-effects……………………………………………………………………………..26 vi LIST OF FIGURES Figure 1. Proportion of propositions recalled……………………………………………………27 Figure 2. Linear congruency of recall……………………………………………………………28 Figure 3. Lag recency plots………….…………………………………………………………...29 vii LIST OF APPENDICES Appendix A. Example of passage stimuli……………………………………………………….30 Appendix B. Sample of passage broken down into propositions………………………………..31 Appendix C. Sample scoring table for propositions, level of detail, and order of recall………..32 viii Effects of Hearing Acuity on Recall of Expository Prose The overall aim of this study is to assess how memory processes may be impacted by cognitive aging, specifically as they pertain to uncorrected hearing loss and increased expenditure of cognitive resources during encoding of spoken prose. It is common knowledge that as people age their ability to form new memories becomes compromised. Difficulties in remembering among older participants have been observed within the context of a variety of tasks and experimental settings, however much less is known about how these alterations are further impacted by changes co-occurring at the sensory level. The following study explores a number of factors related to episodic recall in older adulthood through a comparison of free-recall production between older adults matched for cognitive ability but differing in their level of hearing acuity. The impact of listening effort on free-recall production was assessed in terms of (1) presentation level (volume); (2) processing time (pacing); (3) the level of ideas recalled determined by hierarchical propositional analysis; and (4) the order in which ideas were recalled determined by their linear congruency to the original passage and their temporal proximity to each other. Effect of Listening Effort Increased cognitive demands associated with effortful listening have been shown to negatively impact the accuracy of recall. The effortful listening hypothesis put forth by Rabbitt (1968) suggests that increased cognitive effort expended on simply trying to hear the speech diverts mental resources away from encoding and storage processes necessary for later retrieval. Consistent with this hypothesis, recall of the associated information is reduced even when the 1 stimulus is presented at an audible level (supra-threshold)—i.e., where the individual is able to hear every word but the acoustic signal is below a comfortable listening volume, thus requiring extra effort on the part of the listener. Rabbitt (1991) later demonstrated that uncorrected hearing loss in older adults produces similar negative effects on memory. Likewise, Ward, Rogers, Van Engen, and Peelle (2016) observed a significant negative effect of effortful listening on the percentage of total details recalled by young and older listeners who were presented with spectrally degraded speech signals. Interestingly, this negative effect of effortful listening has the potential to be remediated by increasing the processing time available to the participant. In a study by Piquado, Benichov, Brownell and Wingfield (2012), young adults were presented with auditory passages that were either played continuously from beginning to end or paused periodically over the course of the passage, allowing the participant to initiate each following segment at their own pace. Researchers found that the extra processing time provided to the participants in the self-paced listening condition facilitated overall recall, increasing the number of details accurately recalled. Similarly, Titone, Prentice, and Wingfield (2000) found an effect of age on the amount of freely recalled details in continuous passages versus self-paced passages, with younger adults recalling more details overall and more minor details than the older adults. This gap in recall performance was exacerbated in the continuous listening condition where processing time was diminished, providing further support for the effortful listening hypothesis. The assumption underlying this “effortfulness” follows from the notion of limited attentional resources that must be allocated among simultaneous or closely successive perceptual or cognitive operations (e.g., Kahneman, 1973). Although “effort” in the cognitive literature remains poorly defined (e.g., McGarrigle et al., 2014), it is reasonable to predict that older adults 2 with age-related hearing loss and/or with speech presented at a challenging sound level would show poorer recall than age-matched participants with better hearing acuity and/or when speech is delivered at a higher sound level based on what is known about the effects of listening effort on recall. This prediction presupposes that the speech under all conditions is presented at a supra-threshold level for each participant. Self-pacing and Passage Recall In addition to declines in working memory, and executive resources, adult aging is also accompanied by a general slowing in a range of perceptual and cognitive operations (for reviews see McCabe, Roediger, McDaniel, Balota, & Hambrick, 2010; Salthouse, 1991; Wingfield, Amichetti, & Lash, 2015). This raises the question of whether allowing older adults extra time to encode an incoming speech passage will facilitate recall of that speech passage. One way to test this hypothesis is to allow listeners to self-pace their way through a passage using a so-called auditory moving window (AMW) technique (Fallon, Peelle, & Wingfield, 2006; Ferreira, Henderson, Anes, Weeks, & McFarlane, 1996). In this method, as a passage is presented via a computer sound file, and is interrupted after each sentence with listeners instructed to press a key when ready to hear the next sentence, with the goal of accurate recall of the entire passage when it has been completed. Using a within-participants design the recall accuracy for self-paced passages with recall of passages heard in a normal uninterrupted presentation will be contrasted between hearing groups. It is recognized that while the self-pacing task might differentially aid older adults’ passage recall, the dual-task nature of self-pacing (i.e., holding what has been heard in memory up to that point while making a decision as to when to initiate the next sentence) might hinder recall rather than help it. It is known, for example, that older adults are more susceptible to dual- 3 tasking than younger adults, and especially so for younger and older adults with reduced hearing acuity (e.g., Tun, McCoy, & Wingfield, 2009). A ‘Levels Effect’ in Passage Recall As a general rule, recall from both expository and narrative passages tends to show better representation of the main ideas within a passage relative to more minor details, with the effect of adult aging appearing to a differentially greater extent for details than for main ideas (Stine & Wingfield, 1987). My question is whether listening effort as determined by the sound level of passage presentations and participants’ audiometric classification will affect recall of passage details to a differentially greater extent than recall of main ideas. To answer this question, three levels of detail were determined for each passage based on a propositional analysis of sentence content (Ward, et al., 2016; van Dijk & Kintsch, 1983; Turner & Greene, 1977; see Methods). If listening effort reduces the cognitive resources needed to determine full coherence of a passage it may be that main ideas will suffer more than recall of passage details. Effects of Aging and Order of Recall Lag recency. Although an overall negative effect of cognitive aging on memory has been well established (Salthouse, 1991), much less is known about how aging impacts memory functions, especially the processes of encoding and retrieving information. For instance, researchers found no difference in the initiation of recall (which items were recalled first) between younger and older adults during free recall tasks of word lists, but found a significant difference in the lag recency effect between the two groups (Kahana, et al., 2002). Older adults’ recall transitions were much less influenced by the temporal context of the list items, demonstrating a reduced lag recency effect relative to the younger adults (Kahana, et al., 2002). These findings suggest a deficit in associative processes (Howard, Kahana, & Wingfield, 2006) 4 and impairment in the ability to employ temporal context as a retrieval strategy (Kahana, et al., 2002). Whereas the traditional recency effect relates the temporal proximity of recalled items to the time of the test, the lag recency effect relates the temporal proximity of recall to the item that was just recalled (Howard & Kahana, 1999; Kahana, 1996). Temporal proximity in this context refers to the number of items, or aggregate of distracting information, interfering between two items in the list. This method emphasizes the order of recall as a critical component in understanding the process of self-initiated memory retrieval as opposed to traditional models that focus almost exclusively on recall as a function of the order in which items were presented (Kahana, Howard, Zaromb, & Wingfield, 2002). Using lag recency, the associative process in free recall (Howard & Kahana, 1999; Kahana, 1996) and serial recall (Kahana & Caplan, 2002; Raskin & Cook, 1937) of word lists are found to be asymmetric, favoring forward associations over backward associations at approximately a 2:1 ratio (Kahana, et al., 2002). This is demonstrated in findings where positive lag tends to be greater than negative lag, indicating the formation of stronger forward associations during free recall and serial recall, and perhaps a facilitative effect of sequence on memory. To date, lag recency has been used exclusively with word lists. One might wonder if such methods could be applied to longer bodies of text and if similar patterns of recall could be observed. It turns out that canonically structured narratives, such as fairy tales, facilitate accurate recall (Myers, Pezdek, & Coulson, 1973; Wolfe, 2005). Researchers have postulated that the sequential order and recursive development of a story serves as a tool for recall by creating strong associative links between details where the recall of one detail triggers the recall of 5 another (Myers, et al., 1973). This facilitative effect of passage structure often results in greater total recall than that recalled from expository passages or bodies of text that primarily serve to deliver information and lack the sequentially dependent development of a storyline (Petros, Tabor, Cooney, & Chabot, 1983; Wolfe, 2005). One could postulate that associations formed between elements of a story are semantically more meaningful and therefore more robust (less vulnerable to interference) than those formed from lists of words, but that is beyond the scope of this thesis. Instead the lag recency effect will be employed here as a method to quantitatively represent the recall tendencies that emerge during the free recall of expository passages. Due to the inherent structure of a passage as opposed to lists of words, greater representation of the primacy effect is expected compared with previous research findings gathered from word-list recall, as well as a greater probability that the first items recalled will be among the first items presented in the passage, across participants. The Present Study In summary, based on prior research, one could expect to find poorer overall recall across groups when increased listening effort is required, (e.g., lower presentation amplitude and uninterrupted passage presentations) and poorer overall recall for older adults with impaired hearing compared to those with normal hearing, even when the stimuli are played at an audible level for each participant. Poorer recall for passage details compared with recall for main ideas in conditions of increased listening effort would be expected across groups, with increased level effects observed among participants with impaired hearing. Self-paced listening, as a method of increasing processing time, is expected to increase overall recall accuracy and reduce level effects across groups, but be differentially beneficial for those with impaired hearing. Finally, it is hypothesized that poorer linear congruency between recalled details and the original passage 6 reflected in both reduced lag recency effects and greater departure in the order of recalled details from the passage stimuli among older adults with impaired hearing, relative to older adults with normal hearing. In the self-pacing condition it is expected that linear congruency for those with impaired hearing will differentially benefit. 7 Methods Participants Participant characteristics are provided in Table 1. A total of 24 participants were recruited from the local community and were separated into two groups of 12 based on their pure tone threshold average (PTA): those with good hearing acuity (GH) (PTA < 20dB HL; see Auditory Testing), and those with mild to moderately poor hearing acuity (PH) (PTA ranging from 20 – 55 dB HL). GH participants (2 male) ranged in age from 65.2 to 78.5 years (M = 73.6, SD = 4.0); PH participants (5 male) ranged in age from 66.3 to 88.9 years, (M = 78.6, SD = 6.8. Groups differed significantly by age, t(17.89) = 2.15, p = .05. Participants did not differ in years of formal education, t(19.37) = .91, p = .37. All participants were self-reported native speakers of American English in good health with no reported history of neurologic or cognitive disorders that might interfere with their ability to perform the experimental tasks. Participants provided written informed consent prior to participating in the experiment in accordance with the protocol approved and overseen by the Brandeis University Institutional Review Board. Cognitive testing. Participants were further matched across working memory capacity, vocabulary knowledge, and verbal fluency, in order to insure that any differences found between the two hearing-level groups were not due to accidental differences in cognitive or verbal ability. Working memory. Working memory was assessed using the reading span task introduced by Daneman and Carpenter (1980), a common assessment of verbal working memory that 8 focuses on complex span tasks in which material must be held in memory while other operations, either related or unrelated to the information in memory, must be performed (Baddeley, 2012). In this task participants are exposed to increasingly larger sets of sentences presented on a computer screen with instructions to indicate after each sentence whether the statement in each sentence is true or false. Once a full set of sentences has been presented participants are asked to recall the last word of each of the sentences in the order in which the sentences were presented for that set. The task thus requires the participant to make a true-false decision about the statement in each sentence while simultaneously holding the final words of each of the prior sentences in memory. Scores were calculated based on McCabe et al.’s (2010) scoring procedure, in which participants receive three trials for any given number of sentences, with a working memory score calculated as the total number of trials in which all sentence-final words were recalled accurately and in the correct order. The maximum score on this test is 15. The reading span version of this test was used rather than its analogous listening span version to avoid performance being affected by differences in hearing acuity. GH reading span scores were not significantly different than PH reading span scores, t(21.11) = 1.66, p = .11, thus confirming participants were matched on working memory capacity. Vocabulary knowledge. Vocabulary knowledge was assessed using a 20-item version of the Shipley vocabulary test (Zachary, 1991). This is a written multiple choice test in which the participant is required to indicate which of four listed words is synonymous with the given target word. The vocabulary score was determined by summing the total number correct with no penalty for incorrect answers. GH Shipley vocabulary scores were not significantly different that PH Shipley vocabulary scores, t(16.94) = 1.92, p = .07, thus confirming participants were matched on vocabulary knowledge. 9 Verbal fluency. Participants were asked to name as many items as they could within a given semantic category (e.g. animals), without repetition, in 60 seconds (e.g., Ardila, OstroskySolís, & Bernal, 2006). A practice trial of 20 seconds using a different semantic category (e.g. fruits) was given prior to the actual assessment. Participants were scored based on the number of unique items generated within the allotted time with no penalty for repeated or out-of-category items. Scores were not significantly different between the two hearing groups, t(16.36) = .76, p = .46, with GH participants’ production ranging from 9 to 30 unique items and PH participants’ production ranging from 18 to 28 unique items. Auditory testing. Audiometric evaluation of each participant was carried out using a Grason-Stadler AudioStar Pro clinical audiometer (Grason-Stadler, Inc., Madison, WI, USA) by way of standard audiometric techniques in a sound-attenuated testing room. Individuals’ betterear pure tone threshold averages (PTA) were calculated across 500, 1000, 2000, and 4000 Hz (Katz, 2002). This value was used to assign participants to their hearing acuity groups. Speech Reception Thresholds (SRTs) were determined based on the lowest volume (dB) the participant could accurately repeat back two-syllable words. SRTs were gathered separately for both ears and the ear with the lower SRT was used as the base from which listening levels were set (described below). Stimulus Materials Stimuli consisted of four approximately 400-word expository passages recorded onto computer sound files by a male native speaker of American English using Sound Studio V2.2.4 (Macromedia, Inc., San Francisco, CA, USA) that digitizes (16-bit) at a sampling rate of 44.1 kHz. Root-mean-square (RMS) amplitude was equated across passages. Unlike passages that have a narrative structure (a set-up, plot, and resolution), expository passages are primarily 10 informative in nature. The passages used consisted of descriptions of topics not commonly known in order to limit potential effects of prior knowledge on recall. Topics included: (1) behaviors and characteristics of diving ducks, (2) the history of kites, (3) behaviors and characteristics of snakes found in the Smoky Mountains National Park, and (4) the history of bird banding (Spargo & Williston, 1980). See Appendix A for an example. Procedures Presentation conditions. Standard (uninterrupted) condition. In this condition the passages were heard as recorded, from beginning to end without interruption. Following each passage participants were asked to recall, as accurately as possible, as much of the speech passage as they could remember. Responses were audio recorded and later, manually transcribed and scored for accuracy and order (as described in Results). Following the recall of each passage, participants answered five written true/false questions that appeared visually on the computer screen as a check for comprehension. Self-pacing condition. The self-paced listening condition was based on the auditory moving window paradigm (Fallon, Peelle, & Wingfield, 2006; Ferreira et al., 1996; Wingfield, Kemtes, & Miller, 2001). In this condition participants were told that they were allowed to control the presentation rate of the passages themselves, with the goal of being able to provide as much accurate recall as possible after the full passage had been heard. For this purpose, passages automatically paused after each sentence, with the participant instructed to press a key on a computer keyboard when he or she felt ready to hear the next sentence. In this way, the participant worked their way through the passage, sentence-by-sentence until it had finished. Following each passage recall was tested as described above. The critical feature of this condition is that participants’ pause-times in between sentences were automatically recorded by 11 the computer. Sound levels. Although always presented at a supra-threshold level, passages were heard at a lower sound level of 10 dB above the individuals’ better-ear SRT (i.e., 10 dB SRT) or a louder level of 25 dB above better-ear SRT (25 dB SRT). Counterbalancing control. Each participant heard all four passages, two uninterrupted, and two self-paced, with one passage in each condition heard at 10 dB SRT and one at 25 dB SRT. The order of passage presentation was rotated and the assignment of passage to listening/pacing condition was randomized. 12 Results Recall Accuracy Scoring. Each passage was divided into propositions (“idea units”) following Ward, et al. (2016; van Dijk and Kintsch 1983; Turner & Greene, 1977). Recall accuracy was scored as the proportion of propositions recalled. A participant received full credit (1 point) if they accurately recalled the idea, partial credit (1/2 point) if they partially recalled the idea, and no credit (0 points) if they failed to recall the idea. A sample of this process can be found in Appendix B. Determining levels of detail. An advantage of a propositional analysis of text is that it allows one to give independent accuracy scores for detail versus recall of general gist, referred to as levels of recall. Scoring procedures from Piquado et al., (2012) were used to score passage recall at three levels, with propositions representing main ideas (Level 1), secondary ideas (Level 2 details), or tertiary ideas (Level 3 details). The scoring procedure as described above was used to score the mean proportion of propositions recalled within each level of detail. Outcomes. The four panels in Figure 1 show the proportion of propositions recalled for self-paced and continuous presentation conditions for main ideas, mid-level ideas and details for the GH and PH groups when heard at 10 dB above SRT (“HARD”) or 25 dB above SRT (“EASY”). The most notable effect in these data is a levels effect (main ideas recalled better than more detailed information). This was confirmed by a significant main effect of levels of detail, F(1, 250) = 242.48, p < .001. Presumably because materials were in all cases presented suprathreshold, there was no main effect of hearing group, F(1,22) = 2.91, p = .10, and no significant 13 main effect of presentation level, F(1, 250) = .02, p = .89. A significant main effect of pacing condition on recall was found, F(1,250) = 4.35, p = .04, although the effect of self-pacing versus continuous presentation was small and not consistent across levels of detail. Interestingly, in a follow-up set of ANOVAs conducted for each hearing group, pace was only found to have a significant effect on recall accuracy for the PH group, F(1, 125) = 6.98, p < .01, with self-pacing facilitating overall recall accuracy compared to the continuous condition. Pacing conditions did not appear to have a significant effect on the GH group, F(1, 125) = .22, p = .64, There was a significant Hearing group X Presentation level interaction, F(1, 250) = 7.61, p < .01, with the “EASY” listening level producing greater overall recall compared to the “HARD” listening level. With follow-up comparisons, a significant within-group main effect of presentation level was found for the PH participants, F(1, 125) = 3.99, p = .05, and approached significance for the GH group, F(1, 125) = 3.68, p = .06, suggesting that the effect of presentation level had a greater facilitative effect on the PH group. No other interactions were significant. Order of Recall Scoring. To assess the order in which participants recalled details, the initial word of the recall output for each of the propositions the participant recalled was numbered based on the word order of their recall. That word number was then compared to the proposition index of the corresponding detail in the original passage. A sample of this procedure can be found in Appendix C. Figure 2 reflects the mean (across subjects) median-squared deviance from a perfectly linear recall (i.e. the order in which ideas were presented in the passage), calculated by normalizing each subject's recall to the total amount recalled (by number of words) and each passage by total number of propositions in the passage such that each recall word number and 14 each proposition is in terms of "serial proportion." Normalized recall then indicates how far into the recall an idea was recalled in proportion to the total number of words uttered during recall, and normalized proposition position reflects how far into the passage an idea was recalled in proportion to the entire length of the passage. The deviance score captures how far the subject's recall is from "perfect" recall, where the assumption is that in a perfectly ordered recall, an idea recalled 10% into the recall would have occurred 10% into the original passage. Outcomes. There was a significant main interaction between hearing group (GH, PH) and pacing condition (continuous, self-paced), F(1, 47) = 5.57, p =.02. None of the main effects or other interactions reached significance. These results indicate that the GH participants differentially benefitted from the self-pacing condition in terms of the linear congruency of their recall compared to the PH participants. The presentation level didn’t seem to have an effect, so the data were collapsed across presentation levels for the post-hoc analyses. The follow-up comparisons were run on this collapsed data (across presentation levels) within each group. Results show that there was a significant difference between self-paced and continuous pacing for the GH group, t(33.22) = 2.11, p = .04, but not for the PH group t(29.96) = -.89, p = .38, suggesting that the GH participants benefitted from self-pacing, but the PH did not, in terms of producing more linearly congruent recall. Lag recency. Kahana (1996) demonstrated the strong influence interitem associations within a list exert on the output order of free-recall. These temporally defined associations were inferred from participants’ tendency to successively recall items from proximal list positions rather than from distal list positions. To quantify this phenomenon Kahana proposed the conditional response probability as a function of lag (lag-CRP). If a participant has just recalled an item from Serial Position i and the next recalled item is from Serial Position j, the relationship 15 between recall probability and the lag (separation, in items) can be used to measure the distribution of successive recalls as a function of lag, or lag-CRP (Kahana, 1996). Within this model, positive values of lag = (i – j) indicate forward recalls and negative values of lag indicate backward recalls; large absolute values correspond to list items spaced widely apart and small absolute values correspond to list items close together (Kahana, 1996). Results from the lag recency analysis can be found in Figure 3. The lag recency appears to suggest that forward-going recall occurred with greater frequency than backwards-going recall for both groups. The GH participants seem to be overall more likely to recall positions immediately after or before an idea than PH participants indicated by the greater lag-CRP values for the GH group across pacing and presentation conditions. Findings suggest that the GH participants as a group formed stronger between-proposition associations than the PH group. Age To examine the relative contribution of age and hearing acuity to proportion recalled, a linear mixed effects model with age, PTA, levels of detail, and presentation level as factors was fit. This model revealed a significant main effect of levels of detail, as well as a significant interaction between PTA and presentation level. The main effect of age and PTA were not significant (Table 2). 16 Discussion Memory changes in older adulthood are widely acknowledged, but less is known about how these changes are impacted by reductions in hearing acuity. By age 70, 83% of the population will have some degree of hearing loss (Cruickshanks, Wiley, Tweed, Klein, MaresPerlman, & Nondahl, 1998), the third most common physical condition after arthritis and heart disease (Lethbridge-Cejku, Schiller, & Bernadel, 2004). In recent years hearing loss has also been linked with the development of Alzheimer Disease and other dementias (Lin, Metter, O’Brien, Resnick, Zonderman, & Ferucci, 2011), adding to the concern for public health implications. Recall Accuracy Despite differences in hearing acuity, there were no differences observed in the overall recall accuracy between groups. This suggests that presenting both sound levels at a level above each participant’s audiometric threshold matched the two hearing groups on their overall recall accuracy, in addition to the cognitive matching measures, enabling interpretation of significant results in the context of differences in recall behavior. A significant main effect of pace (self-pacing vs. continuous) on overall recall was found suggesting that the two pacing conditions impacted recall outcomes differently, with self-pacing generally resulting in greater recall accuracy than continuous listening. This finding supports previous research on the effortful listening hypothesis and the benefit of increased processing time on memory. As effort increases, cognitive resources normally available for encoding and 17 storage processes are diminished and memory ability is impacted. Increasing the time available to process effortful stimuli mitigates the strain and improves memory. However, in a follow-up set of ANOVAs conducted for each hearing group, pace was only found to have a significant effect on recall accuracy for the PH group with inconsistent effects across levels of detail. Contrary to predictions, there was no main effect of presentation level suggesting that presentation level (volume) did not significantly impact recall accuracy overall. However, in the follow-up within group comparisons, a significant effect of presentation level was found for the PH group, with the “EASY” (louder) listening level generally producing greater recall accuracy compared to the harder (lower) listening level. These findings are interesting as they support the notion that effortful listening may impact hearing groups differently, with PH participants differentially affected by “HARDER” listening levels. Even though presentation levels for both hearing groups were always presented suprathreshold and based on the individual’s SRTs, the “HARDER” condition appears to have required greater effort on the part of the PH listeners than GH listeners, resulting in reduced recall performance. Similarly, there was a significant interaction between group and presentation level, further suggesting that the GH and PH groups were differentially impacted by the two presentation levels. Results show that PH participants as a group experienced greater gains in recall accuracy from the “EASY” listening level compared to the “HARD” listening level than the GH participants, suggesting greater remediation benefits for the PH group when volume was increased. It is important to keep in mind that for all participants, listening levels were determined based on individual hearing thresholds, so playing the stimuli 10 dB louder in the easy condition should be the same for all participants. Nonetheless, this increase had a greater effect on the PH group. 18 Levels Effect An overall, main effect of level of detail on proposition recall was observed for both groups under all conditions. The fact that an effect of levels was observed within both groups, and in previous studies, supports the robustness of this phenomenon. Although there were minor differences in self-pacing versus continuous presentation these differences were not consistent across all levels of detail or across groups. Order of Recall In the assessment of linear congruency of recall to the presentation order of the passage, a significant main interaction between group and pacing condition was observed. However, none of the main effects or other interactions reached significance. Within-group analyses indicate that the GH participants differentially benefitted from the self-pacing condition in terms of the linear congruency of their recall compared to the PH participants. The increased linear congruency observed in the recall output by the GH group in the self-paced condition suggests that increased processing time was effective in enhancing the saliency of the associative links, or temporal context, of the ideas presented in the passages. This can be seen in Figures 2 and 3. Figure 2 shows the increase in linear congruency of recall in the self-paced condition compared to the continuous condition within the GH group, along with the relatively unchanged linear congruency of recall for the PH group in the self-paced condition. Figure 3 depicts the increase in GH participant use of the temporal context within the self-paced condition (discussed further below). No effects of significance were observed on linear congruency within the PH group suggesting they did not benefit from the self-pacing condition in terms of linearly congruent recall. 19 One possible explanation for this is the increased effects dual-tasking impose on people with hearing impairment (Tun et al., 2009). The self-pacing condition involved the participant pressing a key to initiate the next sentence in the passage. Although a seemingly benign task, its successful execution involved not only the target task of listening to the passage and trying to remember as much as possible, but also simultaneously remembering to press the button after each sentence, essentially diverting attentional resources away from the target task. The fact that PH participants performed similarly across pacing conditions (self-pacing vs. continuous presentation) suggests that any benefits they may have incurred from the increased processing time were effectively eliminated from the dual-task nature of the experimental design. The significant benefit gained by the GH participants combined with the fact that the PH did not perform worse in the self-paced condition suggests that future experiments could expect to see memory gains in both groups if processing time is increased in the absence of additional tasks or attentional diversions. One way this could be achieved is by imposing a pause during the interrupted (self-pacing) condition, where the recording automatically pauses after each sentence. The pause times could be determined by averaging the pause times already collected for each individual sentence in order to reflect participants’ pausing behavior without requiring them to attend to anything other than the target task. The lag recency effect appears to suggest that people, regardless of hearing group, have a greater tendency to recall events in a forward-going direction as opposed to backwards-going recall, at least for word lists and, in this case, for expository texts. This finding supports the idea of a facilitative effect of sequence on memory, favoring forward over reverse sequences. The GH participants appeared to be overall more likely to recall positions immediately after or before an idea than PH participants suggesting that their recall was contextually bound to a greater extent 20 than the PH participants. This finding is interesting as the GH participants did not recall with significantly greater accuracy than the PH participants. Presumably, if you recall more, you’re also more likely to recall the ideas that occur immediately after or before it. But since the two groups were not significantly different in the amount recalled, the lag recency would seem to suggest that the GH participants are recalling more “associatively,” that is employing temporal context as a strategy for recall to a greater extent, compared to the PH group. It is important to note that the lag recency only assessed main ideas as the hierarchical nature of the propositional analysis did not lend the level 2 or level 3 details to this approach. This could potentially explain some of the differences observed as the GH group recalled main ideas with greater accuracy than the PH group did. Conclusions Overall, the present study yielded both expected and unexpected findings. As expected, propositions more important to the gist of the passages were better recalled than propositions representing more minor details. Moreover, these effects were seen to be very robust, appearing in a similar manner for both continuous and self-paced conditions, and for both listening levels. Unexpectedly, the easier presentation level and self-pacing condition only benefitted the PH group on recall accuracy, while only the self-pacing condition benefitted the GH for linearly congruent recall. Removing the dual-task nature of the self-paced condition along with increasing the number of participants tested may produce expected results. The demonstration of the lag recency effect in free-recall of unrelated word lists (Kahana et al., 2002) raises the question of whether a similar effect would be found for recall of meaningful extended speech passages. To my knowledge this is the first attempt to test this 21 possible extension. As seen, the lag recency data, showing stronger forward associations, yields similar lag recency curves as those observed by Kahana and colleagues. 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Journal of Experimental Psychology: Learning, Memory, and Cognition, 31(2), 359-364. Zachary R. A. (1991). Shipley Institute of Living Scale: Revised Manual. Los Angeles, CA: Western Psychological Services. 24 Table 1. Participant characteristics Characteristics Good Hearing n 12 Age (years) 73.6(4.0) Years of education 17.38(1.9) Shipley Vocabulary 17.3(2.4) Reading Span (total score) 8.7(3.1) Verbal Fluency (total score) 23.08(6.11) Better ear PTA (dB HL) 15.1(4.2) Better ear SRT (dB HL) 15.4(3.3) Note: Data are mean (SD). Poor Hearing 12 78.6(6.8) 16.5(2.8) 16.3(1.3) 6.8(2.5) 21.58(3.12) 26.8(5.2) 23.3(8.1) 25 Table 2. Linear Mixed-Effects Results Estimates Std.Error df t-value p-value age -0.002 0.003 21 -0.670 0.510 PTA -0.008 0.004 21 -1.939 0.066 level of detail -0.115 0.034 255 -3.340 0.001** presentation level -0.054 0.105 255 -0.509 0.611 level of detail * pres. level -0.021 0.049 255 -0.424 0.672 age * levels of detail 0.000 0.001 255 -0.286 0.775 age * pres. level -0.002 0.002 255 -0.825 0.410 PTA * levels of detail 0.002 0.001 255 1.658 0.099 PTA * pres. level 0.008 0.004 255 1.996 0.047* age * level of detail *pres. level 0.002 0.001 255 1.332 0.184 PTA * level of detail *pres. level -0.003 0.002 255 -1.566 0.119 Note: The main effect of age and Pure Tone Average (PTA) were not significant. *p < .05, **p < .01, ***p < .001 26 Proportion of Propositions Recalled Proportion of Propositions Recalled Proportion of Propositions Recalled Proportion of Propositions Recalled Figure 1. Proportion of propositions recalled for each level of detail by pace and listening level. Error bars indicate standard error of the mean. 27 Figure 2. Linear congruency of recall compared to passage by group and pace. Smaller “Deviance Score” signifies less congruency. Error bars indicate standard error of the mean. 28 Figure 3. Lag-recency plots for group, pace, and listening level. Error bars indicate standard error of the mean. 29 Appendix A The marking of birds was carried on during the days of the Roman Empire to identify the falcons of the emperor. Modern bird banding really had its beginning with Hans Christian Mortensen, a schoolteacher of Viborg, Denmark. In 1890, he began putting metal bands on the legs of teal, pintails, storks, starlings, and two or three kinds of hawks. These bands had his name and address inscribed on them. As his banded birds began to appear in many places in Europe, other bird students became interested in bird “ringing,” as it is called in Europe. In a short time, more and more people began to band birds in the United States. Banding birds has revealed many things about the individual bird as well as about the species or group to which it belongs. Banding has shown that many birds live as long as ten years, and some live even longer. For example, a red-winged blackbird that was banded in New York was shot 14 years later in North Carolina, and a black duck banded on Cape Cod was taken by a hunter 17 years later in Newfoundland. Some Canadian geese live to be more than 20 years old. The longest a North American bird has been known to live in the wild is 36 years. The holder of this record was a herring gull, banded off the coast in Maine in 1930 while still in the nest and found dead along the shore of northern Lake Michigan in 1966. If banded birds are captured, released alive, and recaptured, the migration routes they were following can be reconstructed. Or, when large numbers of birds are banded, one can form a general picture of the pathways used by these birds between nesting and wintering grounds. From banding information, we have learned that some birds, such as the golden plover, do not return north in the spring over the same route they took south in the fall. Many ducklings and goslings are banded each summer on their nesting grounds. Hunters who return the bands they find on these birds during the hunting season are helping to ensure their own hunting in the future. From the bands that are turned in from hunting areas, wildlife biologists can determine how many waterfowl there will be along the various migration routes during the following autumn. Appendix A. An example of one of the four passages in its entirety (Spargo & Williston, 1980). 30 Appendix B T3 In 1890, he began putting metal bands on the legs of teal, pintails, storks, starlings, and two or three kinds of hawks. 0 1 He put metal bands on birds 0 0 0 0 0 0 0 2 2 3 3 3 3 3 0 2 some birds on the legs teal pintails storks starlings two or three kinds of hawks {8} in 1890 Number of sentences in Section 1: Number of propositions in Section 1: Section 1 score (raw): Section 1 score (proportion of propositions): 3 19 0 0.0 Appendix B. Sample of passage text broken down into propositions and arranged for initial scoring. 31 Appendix C Sentence in passage: In early March, diving ducks migrate. They leave the coastal waters and head north to their breeding grounds. Example recall: “The diving ducks will migrate north around March… for a mating season.” Recall Score Level 1 1 1 2 0 3 0 1 0 2 1 1 0.5 1 Proposition (“Idea Unit”) Recall Word # Passage Index Diving ducks migrate 2 1 in March 8 2 0 3 0 4 0 5 5 6 10 7 early March They leave the waters coastal waters they head north to their breeding grounds Appendix C. Sample scoring table for propositions, level of detail, and order of recall. 32