none

This experiment was conducted to examine whether older adults are capable of developing attentional strategies to reduce interference from irrelevant information. Sixty young and 60 older adults were asked to name the ink color of a non-black neutral word, which was presented adjacent to a color word or a neutral word (Lowe & Mitterer, 1982). Twelve young and 12 older adults were assigned to 1 of 5 list compositions. The first list consisted of 100% congruent items (ink color of a neutral word compatible with the color word), and 0% incongruent items (ink color of a neutral word incompatible with the color word; 100C/0I). The remaining lists consisted of 75I/25C, 50I/50C, 25F75C and 0I/100C, respectively. Participants' interference and facilitation scores were computed. The results indicated that older adults experienced more interference on incongruent trials than did young adults, which is indicative of inhibitory decline. However, both young and older adults showed decreased interference as the proportion of incongruent trials increased suggesting that increasing age does not impair the ability to adapt to contextual demands of a task. Facilitation effects were greater for older adults than for young adults in the mostly congruent condition, indicating that they suffered no loss of activation ability. Overall, this study indicates that while older adults suffer from an inhibitory decline, they are capable of attentional control.

Past research on stereoscopic depth perception among the elderly has led to inconsistent findings. Some research on stereopsis and aging has found that younger and older adults are essentially the same in terms of their stereoscopic ability, while other research has found evidence of large differences. This past research has largely been limited to investigations of stereoacuity. The purpose of Experiment 1 was to extend this earlier research to compare how older and younger observers perceive the magnitude of stereoscopically defined depth intervals. Random-dot stereograms depicting sinusoidal surfaces were shown to seven younger (i.e., ages 30 and below) and six older (i.e., ages 60 and above) adults. These surfaces were defined by three levels of peak-trough image disparity, two spatial frequencies, and two densities of texture elements. The observers' task was to estimate the magnitude of the depth interval between the surfaces' peaks and troughs. It was found that the perceived depth intervals of the younger observers were closer to those predicted by the geometry of stereopsis: as disparity increased, so did the magnitudes of their perceived depth intervals. This finding was also true for the five out of the six older adults, but the magnitudes of their perceived depth intervals were less than their younger counterparts. The high frequency surfaces were more difficult to perceive for both groups, but were especially difficult for the elderly. In contrast, texture element density had essentially no effect upon the observers' performance for both groups. The results of this experiment showed that the elderly have a significant amount of stereoscopic functionality that is not qualitatively different from younger adults. Experiment 2 was designed to compare older and younger observers' ability to perceive the shape of stereoscopic surfaces. In this experiment, four different surfaces defined by disparity (i.e., bumps, saddles, vertical cylinders, and horizontal cylinders) were shown to five younger (i.e., 30 and below) and five older (i.e., 60 and above) observers. The random-dot stereograms varied in terms of their texture element density and amount of correspondence. The results showed that the older observers were less sensitive to stereoscopic depth and curvature. In all other respects, however, the results for the older observers were essentially identical to those of the younger observers. In particular, the reductions in density and correspondence led to nearly identical declines in performance for both age groups. In summary, the results of both experiments showed that, despite some reductions in perceptual sensitivity, older adults can effectively perceive and discriminate the shape and depth of stereoscopic surfaces.

In a typical useful field of view (UFOV) paradigm, an observer must correctly identify a center target while simultaneously localizing a peripheral target. Previous research has shown that many older adults have difficulty locating the peripheral target in the UFOV paradigm when compared to younger adults (Sekuler & Ball, 1986; Scialfa, Kline, & Lyman, 1987; Ball, Beard, Roenker, Miller, & Griggs, 1988; Ball, Roenker, & Bruni, 1990; Scialfa, Thomas, & Joffe, 1994). However, the reason for this difficulty is not clearly understood. The purpose of this study was to test two potential explanations for the difficulty that some older adults have in locating the peripheral target in the UFOV paradigm. The first explanation was based upon research using the gap paradigm (Fischer & Ramsperger, 1984; Mayfrank, Mobashery, Kimmig, & Fischer, 1986; Fischer, 1987; Fischer & Breitmeyer, 1987). This research has shown that a temporal gap between the offset of a fixation point and the onset of a peripheral stimulus helps to facilitate the disengagement of focal attention. This explanation of peripheral localization difficulties in older adults posited that some older adults have a slowing in the ability to disengage attention from the center target in the UFOV paradigm. Three hypotheses were tested based on this explanation. The second explanation was based upon the assumption that the inability of some older adults to locate the peripheral target in the UFOV paradigm is due to a slowing in parallel processing of the entire display, and posited that peripheral localization is highest when the peripheral target is presented for longer durations. Three hypotheses were also tested based on this explanation. In the present study, thirty-six older adults (age 60 or greater) were tested in a screening phase and testing phase. The screening phase permitted a determination of threshold in each of three subtests similar to those used by Ball and colleagues (Ball et al., 1988; Ball et al., 1990; Ball & Owsley, 1992) in their UFOV task. The threshold was designated as the fastest duration in each of the subtests where subjects could perform the task with 75% accuracy. The testing phase used four testing conditions where the center and peripheral target were manipulated in order to investigate the two potential explanations of peripheral localization difficulties in some older adults. The present study did not clearly support nor reject either of the explanations that were posited. The data did not demonstrate that some older adults are slower at disengaging attention from the center target because the conditions used to enhance disengagement yielded the lowest number of correct peripheral localizations. In addition, the data did not demonstrate that some older adults are slower at parallel processing of the entire display because the length of display time for peripheral targets did not systematically effect localization performance. Based on these findings, it is possible that a slowing in the disengagement of attention or a slowing in the parallel processing of the entire display remain potential explanations for the inability of some older adults to locate the peripheral target in the UFOV paradigm.

Two studies were performed to investigate the effects of age and practice on Stroop inhibition. The first experiment examined the influence of age on the ability to ignore the meaning of words on Stroop items. Fifteen younger and 15 older adults were asked to name the color of congruent, incongruent, and control items appearing on a computer screen. Participants' interference and facilitation scores, error rates, and color and word process dissociation estimates were computed. The results indicate that older adults experienced more interference and facilitation than the younger adults and produced more errors than the younger adults on items where the meaning of the word and the color of the item did not match. Likewise, the process dissociation measures showed higher word estimates for older adults. Altogether these findings are indicative of a breakdown in older adults' inhibitory processes. The second study examined the effects of practice on older and younger adults' ability to inhibit word reading in the Stroop. Twelve younger and 12 older adults were assigned to each of two list conditions. Participants in the mostly congruent list condition received 140 items, 100 of which were congruent, 20 of which were incongruent and 20 of which were control. Participants in the mostly incongruent condition also received 140 trials, 100 of which where incongruent, 20 of which were congruent and 20 of which were control. The mostly incongruent list thus provided more practice in ignoring word meaning. Once again Stroop facilitation and interference scores, error rates, and process dissociation measures were computed. The results indicated that the mostly congruent list produced more facilitation and interference than the mostly incongruent list and that older adults again had higher facilitation and interference scores than younger adults. However, there was no evidence in the latency data that older adults benefitted less from practice than their younger counterparts. The process dissociation estimates demonstrated that older adults had higher word process estimates than the younger participants but that their color process estimates were similar to those of the younger adults. In addition, the mostly incongruent list produced lower word estimates and higher color estimates than the mostly congruent list. Moreover, this pattern did not differ across list types from that of the younger adults, again suggesting a similar benefit from practice for the two age groups. Taken together, these two studies suggest that while older adults are poorer at inhibitory skills, they do benefit from practice.

It is sometimes necessary to make validity judgments about information with which we are unfamiliar, because we have no factual knowledge about the event. Under these circumstances, subjective evidence, such as whether the statement has been seen or heard in the past, may be used to judge validity. Previous research has shown that the repetition of unfamiliar, but plausible statements increases the judged validity of the statements. In other words, the more one hears a particular statement, the more one believes it to be true. The present study has been designed to explore this "truth effect." The first experiment examined the influence of increasing age on the truth effect and recognition of repeated statements. Younger and older adults were asked to rate a series of statements for validity. Two weeks later, the subjects rated a similar list containing some new statements along with statements repeated from the first session. Subjects were also given a task to assess their recognition of repeated statements. The results indicated that older adults demonstrated the truth effect to a greater extent than younger adults, despite the fact that their recognition scores were much less accurate. These results indicate that repetition and recognition have independent influences on perceived validity. A second experiment was conducted to examine the effect of feedback on the truth effect and recognition judgments. It was proposed that ratings for repeated items in the second session would increase in judged validity due to the unintentional influence of familiarity. If feedback information was deliberately recollected, this misattribution of familiarity to credibility could be checked for false statements. Subjects were asked to rate statements for validity, and feedback as to the actual truth value of some of the items was given in the first session. Subjects rated repeated and new items in the second session for validity, as well as performing a source recognition task. The results of the second experiment showed that, again, both young and older adults demonstrate the truth effect. For young subjects, true statements were rated the truest, followed by non-feedback, nonrepeated, and false statements. The same pattern was found for older subjects, except that the false and non-repeated statements were rated similarly. As in the first experiment, older subjects were less accurate than young subjects at recognizing the source of repeated statements. Again, repetition and recognition were found to influence the truth effect independently. The results of this study indicate that the effects of repetition may influence older adults more than young adults, due to their less efficient memory for source. This deficit in source memory would serve to make older individuals less skeptical about the credibility of their knowledge, and thus more susceptible to false beliefs.

Thesis--University of Wisconsin--Madison. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 185-199).

This thesis extends previous research on critical decision making and problem-solving by refining and validating a self-report measure designed to assess the use of critical decision making and problem solving in making life choices. The analysis was conducted by performing two studies, and therefore collecting two sets of data on the psychometric properties of the measure. Psychometric analyses included: item analysis, internal consistency reliability, interrater reliability, and an exploratory factor analysis. This study also included regression analysis with the Wonderlic, an established measure of general intelligence, to provide preliminary evidence for the construct validity of the measure.

Previous attempts to adequately evaluate orientation-specific colored aftereffects (Mccollough Effects) have thus far been unsuccessful in yielding quantitative measures of relative strengths of the effects. Similarly, little success has been shown in previous attempts to establish what level of illumination is necessary in order to evoke the aftereffects. The present study sought to determine (a) whether threshold measurements could serve as adequate, quantitative dependent variables of the Mccollough Effects, (b) whether photopic illumination was necessary in order to evoke the aftereffect. It was predicted that the greater the number of inspection trials, the dimmer the illumination level could be in order for the aftereffects to first be detected. In addition, it was· predicted that the appearance of the test pattern would change markedly near the rod-cone break. The strength of the McCollough Effects, as a function of the number of inspection trials, was examined on subsequent scotopic and photopic threshold measurements in normal color-visioned subjects. All subjects were measured alternately on 10 ascending and 10 descending trials at specific times after being conditioned in "short" (15 min) and "long" (30 min) inspection trials, counterbalanced across subjects, with a 7-day interval between test trials. Overall, statistically insignificant results were achieved for both predictions; possible explanation of the results and changes in experimental design were discussed.

<p>The ability to rapidly and continuously update phonological representations is critical to skilled reading. Denkla and Rudel (1976) first reported Rapid Naming impairments in poor readers, leading to a wide body of evidence supporting the Rapid Naming task as a reliable predictor of reading success. Despite a well-established correlation between Rapid Naming performance and reading achievement, the factors driving this relationship remain unclear. The present study was an exploratory investigation of the role of articulatory planning in Rapid Naming performance. Specifically, we explored the effects of phonological similarity and word length of the items to-be-named in the Rapid Naming task. Naming times were measured in 30 Undergraduate students with typical reading ability, and 10 poor reading high school students completing the standard Rapid Naming task, as well tasks manipulated for phonological similarity and word length. The results showed that phonologically similar words generated significantly longer naming times than the standard Rapid Naming task for both typical and poor readers. This finding suggests that when phonological representations are similar, it creates competition for the rapid updating of representations during motor planning for naming. Additionally, 3-syllable items for typical readers and 2-and 3-syllable items for poor readers produced significantly longer naming times than the standard Rapid Naming task, suggesting that larger phonological representations also create competition in motor planning. The results of the preset study suggest that phonological similarity and word length have a similar influence on Rapid Naming ability in typical and poor readers.</p> / Master of Science (MSc)