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.

The purpose of the study was to investigate relationships between teacher self-concept and pupil reading achievement at the first and second grade levels. Research has verified the relationship between teacher self-concept and pupil self-concept as well as between pupil self-concept and reading achievement. A logical extension would seem to be that teacher self-concept is related to pupil reading achievement. However, this assumption does not appear to have been thoroughly investigated. This study was designed to investigate that relationship.The subjects included 275 pupils and the thirty-two teachers to whom these pupils were assigned in first and second grades. The sample was drawn from four elementary schools in a large midwestern city. Criteria for selection of schools included random assignment of pupils to both first and second grade self-contained classrooms during the 1977-78 and 1978-79 school years.Instruments employed in the study included the Index of Adjustment and Values administered to assess global self-concept of teachers. The discrepancy score (Self-Ideal Self) was used as a basis for classifying teachers into groupings designating range of discrepancy from minimal to maximal. The SRA Assessment Survey Achievement Series, administered to pupils as part of the regular testing program within the school corporation, provided the data on reading achievement.After teacher discrepancy scores were computed, rank ordered, and subdivided into three sections for each grade, these were designated as minimal discrepancy score (Mi DS), medium discrepancy score (Me DS), or maximal discrepancy score (Mx DS). Nine groups representing the nine possible combinations of teachers grouped by discrepancy scores were devised. The reading achievement scores obtained by pupils at the end of second grade were then placed into the appropriate groups based on the designations of their first and second grade teachers. Mean reading achievement scores and standard deviations for pupils in each group were computed.The following null hypotheses were tested:1. No significant relationships exist between teacher self-concept and pupil reading achievement when pupils are identified on the basis of assignment in first and second grades to teachers manifesting varying degrees of discrepancy between self-concept and ideal self-concept.2. No significant differences exist in the reading achievement of pupils having had either a first or second grade Mi DS teacher and pupils who did not.3. No significant differences exist in the reading achievement of pupils having had either a first or second grade Mx DS teacher and pupils who did not.4. No significant differences exist in the reading achievement of pupils having had a Mi DS first grade teacher and pupils who did not.A one-way analysis of variance technique comparing the differences of the means within and between groups was employed. No significant differences were found. Therefore, none of the four null hypotheses was rejected.The most obvious conclusion to be drawn was that teacher self-concept, when assessed by the IAV which provides a global measure, revealed no significant relationship to pupil reading achievement. However, it is possible that several dimensions of self-concept exist and variables demonstrated in the classroom may not have been adequately measured by the self-concept instrument. Also, it is possible that the self-concept's of other, more significant adults such as parents exert a greater influence on children's reading achievement than the self-concept of the teacher. It was recommended that further studies be conducted to investigate these implications.

The purpose of this study was to investigate the effects of a cognitive self instruction-based career and life planning group intervention on the perception of locus of control. The null hypotheses pertained to the differences in perception of locus of control between treatment and control groups as measured by the Nowicki-Stricklard Locus of Control Scale for Children.Career and life planning is a concept that was designed to help people recognize themselves as active change agents in their own lives. Perception of locus of control has been shown to be influential in determining proactive as well as reactive behaviors. For example, people perceiving an internal rather than an external locus of control are more likely to actively engage in information gathering and use newly acquired information to aid in decision-making. Cognitive self-instruction has been used effectively with various groups to change behaviors. The emphasis of this intervention mode was on developing self-control through the awareness of alternative and more constructive self-talk.The subjects were pre-delinquent high school adolescents from a midwest residential treatment center. Eighty subjects were randomly selected by computer from a population of 131. Through computer randomization, half of the subjects were assigned to a treatment group and half to a control group. The treatment and control groups' experiences all occurred at the residential treatment center.The treatment group sessions were forty-five minutes long and were conducted every third day. A total of six sessions were held. The treatment material and approach emphasized role playing as a technique to examine self-talk that led to negative outcomes and explore alternative selftalk to achieve more satisfying results. The control group maintained their normal daily routine while the treatment group was dismissed to attend the group sessions.Immediately following the last treatment group session and again four weeks later all subjects were administered the Nowicki-Strickland Locus of Control Scale for Children. The instruments were scored and the differences between the average raw scores of the scale were subjected to two univariate analyses of variances, with differences considered significant at the .05 level.The computed F values for the treatment group effects relevant to the post and delayed post-test(F = .16, p < .6897 and F = .04, p < .8373, respectively) were not significant. Therefore, the null hypothesis-- there will be no significant difference between the treatment and control group subjects' mean scores on the Nowicki-Strickland Locus of Control Scale for Children immediately following and four weeks after treatment--was not rejected.Analysis of the data indicated that there was no significant difference in perception of locus of control between the treatment and control groups as measured by the locus of control scale. Therefore, it is concluded that using this six forty-five-minute group intervention mode, the cognitive self-instruction and career and life planning experience did not produce a significant change in perception of locus of control as measured by the aforementioned instrument scale.Comments by the subjects indicated that many positive relationships between the group leaders and the adolescents were established. Five of the six group leaders were completely inexperienced in working with pre-delinquent adolescents. Although they demonstrated the ability to relate well to the subjects, they did experience difficulty and some failure in keeping the group experience closely related to the specific treatment material. More intense training of group leaders regarding the use of the treatment material with this specific population could have been helpful.

Previous research on stereotyping has focused on perceptions of and negative consequences for individuals who activate stereotypes based on their membership in one stigmatized group. In contrast, relatively little research has examined stereotyping following categorization of targets into more than one stigmatized group. This dissertation focuses on perceptions of individuals who activate more than one set of stereotypes. In particular, I focused on the combination of stereotypes associated with the older adult age group and the Black racial group - two stereotype sets which contain elements that directly contradict one another. To examine the interaction of these two sets of stereotypes, I examined perceptions of four types of targets: young Black men, young White men, old Black men, and old White men. In Chapter 1, I examine perceptions of anger and happiness on the faces of young and old Black and White men. These perceptions are examined among young (Study 1a) and old (Study 1b) perceivers. In Chapter 2, I attempt to bias these perceptions of facial emotion in line with race or age stereotypes using a categorization priming procedure. The final three studies examine more basic perceptions of these targets of interest. I examine current and projected trait-related perceptions of novel (Chapter 3) and famous (Chapter 4) young and old Black and White men at various points across the lifespan. Finally, in Chapter 5, I directly compare these four targets on a number of traits using a forced-choice comparison task for both current and projected ratings. Overall, the results of this dissertation suggest that race-based and age-based stereotypes combine via a process of selective inhibition. Specifically, old Black and White men are characterized according to the old age stereotypes which most strikingly contrast them against their younger counterparts. Compared with their corresponding young targets, this pattern results in relatively positive evaluations of older Black men, but relatively negative evaluations of older White men.

My thesis is a collection of philosophical essays on the sense of touch. I argue first that touch is much like vision in being unisensory. (This has often been denied). But it is unlike vision in displaying a duality of the proximal and the distal, since it informs us both of the condition of our own bodies, and of the properties of external things. My account of this duality is unorthodox, since I argue that we do not sense distant objects in virtue of sensing the condition of our own bodies. Both forms of touch involve exploratory action—both are forms of haptic perception—but the nature of this involvement is unclear. I defend the view that haptic perceptions are haptic explorations. I first clarify this thesis, then distinguish it from other views, like those of Alva Noë and Susan Hurley, that posit a strong link between action and perception. Despite this interactive nature, touch may seem more constrained than vision and audition in requiring direct bodily contact with objects in the world. I argue against this view, and show that through touch we are capable of sensing objects that are not, and are not perceived as being, in direct contact with our bodies. Here again, touch is somewhat like vision. The development of this account requires conceptual analysis of a range of important issues in the philosophy of perception, including the nature of multisensory experience, the role of bodily awareness in perception, the relation between action and perception, and the structure of non-visual spatial perception. For instance, because touch involves both coordinated bodily movements and a range of distinct sensory receptors in the skin, it is often thought to be a multisensory form of awareness (especially by psychologists). However, this view relies on an implausible conception of multisensory interaction. In its place, I develop a nuanced hierarchy of multisensory involvement according to which touch is a single modality. This is because the various systems involved in touch all predicate or assign sensory properties to the same tangible objects: when we grasp a mug, for instance, many different tactual properties—shape, warmth, texture, etc.—are all felt to belong to the mug. This is similar to what happens in vision with visual objects: when we see an object, a range of different visual properties, largely processed in functionally-distinct systems—are seen as belonging to it. Another unique aspect of my view is the claim that through touch we can experience distal objects—objects not in direct or even apparent contact with our bodies. I develop a positive account of such touch, arguing that distal touch requires (1) a strong interactive connection between our bodies and the distal object (through tools or other such intermediaries) and (2) that distal objects are represented in touch as located in peripersonal space, the space immediately surrounding our bodies, defined by the limits of our exploratory engagement (by how far we can reach or move). This positive account allows for a more robust account of our embodied experience, and shows that touch—at least in some respects—is more like the other senses than typically supposed.

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.

Phonetic perception becomes native-like by 10 months of age. A potential mechanism of change, distributional learning, affects the perception of 6-8-month-old infants (Maye et al., 2002). However, it was anticipated that perception may be more difficult to change by 10 months of age, after native categories have developed. In fact, some evidence suggests that by this age, the presence of social interaction may be an important element in infants’ phonetic change (Kuhl et al., 2003). The current work advances the hypothesis that infants’ level of attention, which tends to be higher with social interaction, may be a salient factor facilitating phonetic change. Three experiments were designed to test infants’ phonetic plasticity at 10 months, after phonetic categories have formed. A non-social distributional learning paradigm was chosen, and infants’ attention was monitored to probe whether a facilitating role would be revealed. In Experiment 1, 10-month-old English-learning infants heard tokens from along a continuum that is no longer discriminated at this age that formed a distribution suggestive of a category boundary (useful distinction). The results failed to reveal evidence of discrimination, suggesting that the distributional information did not have any effect. A second experiment used slightly different sound tokens, ones that are farther from the typical English pronunciation and are heard less frequently in the language environment. Infants still failed to discriminate the sounds following the learning period. However, a median split revealed that the high attending infants evinced learning. Experiment 3 increased the length of the learning phase to allow all infants to become sufficiently high attending, and revealed phonetic change. Thus, after phonetic categories have formed, attention appears to be important in learning.

There is no abstract available for this dissertation.