Introduction: Older adults have been shown to be particularly vulnerable to the effects of mild traumatic brain injury (mTBI). However, limited research exists that examines the information and support received by older adults after a TBI, despite suggestions that input may be insufficient. We therefore aimed to evaluate the information and rehabilitative support received by individuals after mTBI, and to determine whether there were any age-related differences. Method: Adults (n = 250) who presented at the Christchurch Hospital Emergency Department over a 12 month period, with a diagnosis of mTBI were invited to participate in the study. Of these, 106 consented and 80 were able to be contacted for follow up. Participants were aged 18-85 years (M = 48) and evenly distributed into four age groups (18-30, 31-50, 51-65 and 66-85 years). Participants were interviewed over the phone using a questionnaire developed in a pilot study. Questions focussed on information and treatment received after the participants’ injury, as well as questions about cognitive and mood problems following the injury. Data was analysed both quantitatively and qualitatively. Results: There were no significant differences between age groups for the number of post-TBI symptoms reported by participants. However, as predicted, the post-injury information and assistance received were inconsistent and differed across groups: 25% of all participants did not receive any information after their TBI, and older adults were the least satisfied with the information received. Post-injury assistance was most commonly offered by friends, family and significant others, but this may not have been sufficient to encourage complete recovery. Participants made suggestions for assistance and support that they would have liked following their injury. Conclusions: The current study has significant implications for the treatment of mTBI as ill-informed and neglected patients are unlikely to return to pre-injury functioning and mental state. Furthermore, a rapidly increasing older population makes immediate attention to mTBI in older adults imperative.

Research shows that children often confuse facial expressions of fear with surprise and disgust with anger. According to the perceptual-attentional limitations hypothesis, facial expressions are confused because they share action units (Camras, 1980; Wiggers, 1982). Experiment 1 tested this hypothesis for the confusion between fear and surprise and Experiment 2 for the confusion between disgust and anger. Eye movements were monitored in both experiments. In experiment 1, the results showed that children were more accurate when two distinctive action units were presented than when the brow lowerer was the only distinctive action unit differentiating between fear and surprise. Furthermore, the results showed that participants spent more time fixating on the mouth than the eyebrows. They made more saccades when the only distinctive cue was in the eyebrows. In experiment 2, participants identified the emotion as anger when the mouth was open, and disgust when the mouth was closed, spending more time on the mouth when the mouth was open. These findings suggest that facial expressions are confused, not only because of the amount of visual similarities they share, but also because children do not allocate their attention to facial regions equally; they tend to focus on the mouth.

This dissertation investigated different factors contributing to age differences in working memory (WM) performance. Younger and older adults participated in five experiments, four on visuospatial WM (VSWM) and one on verbal WM. All addressed methodological issues that may differentially lower older adults’ performance. Experiments 1a and 1b manipulated the administration of a VSWM span task, with participants performing the task under either an ascending format (shortest sets presented first), or an interference-reducing descending format (longest sets presented first). Older adults’ performed significantly better in the descending compared to ascending format, consistent with an age-related susceptibility to proactive interference (PI). By contrast, younger adults did better in the ascending compared to descending condition, possibly due to their ability to benefit from practice and strategy use when easier trials are presented first. Experiment 2 considered how the similarity of task material influenced the build-up of PI and whether or not the combination of two PI-reducing manipulations (i.e., descending format and distinct trials) would further improve older adults’ performance. Distinctiveness helped older adults on the ascending format; however, combining distinct trials and a descending format provided no additional benefit. Experiment 3 considered whether or not synchronizing a VSWM task with an individual’s circadian arousal pattern would moderate interference effects, with the task administered at a peak or off-peak time of day. Peak-time administration improved older adults’ performance on the descending, but not the ascending, condition. Experiment 4 investigated the possibility that the serial order requirement of many WM tasks contributes to age differences in performance. Younger and older adults participated in a verbal WM span task – Operation Span - under either serial order or free recall instructions. Typical age differences were found when order but not free recall was required. Further analyses of the order condition data revealed that older adults were, in fact, recalling the items just as well as young adults, only not in the correct order. Taken together, the findings strongly suggest that age differences found on typical WM span tasks are influenced by numerous factors, such as task presentation, individual circadian arousal patterns, material similarity, and recall instructions.

We developed a novel approach that requires subjects to produce and finely tune ground reaction forces (GRFs) while standing. Using this method we were able to identify specific contributions of individual muscles and how these contributions change with the effects of age. One of the aims of this investigation was to determine whether electromyographic data in our findings was due to random muscle activation or representative of a neuromuscular control strategy. Ten healthy young adults (5 male, 5 female) with their dominant foot fixed within a boot mounted to a force platform participated twice in a target matching protocol, requiring subjects to control both the direction and magnitude of GRF along the horizontal plane while maintaining constant inferior-superior loads of 50% body-weight. Subjects were asked to manoeuvre a cursor with their dominant leg to match a series of targets projected on a screen. Targets appeared at random one at-a-time, separated by 30o around a circular trajectory. Subjects applied loads to the force platform in various horizontal directions to move the cursor while also controlling body weight. A successful target match required subjects to maintain 50% body weight and 30% of their peak horizontal load for one second. Electromyography (EMG) of eight muscles that cross the knee joint, ground reaction forces, and kinematic data were recorded for each successful match. EMG was normalized to percent maximum voluntary isometric contractions collected on an isokinetic dynamometer. Each target matching session was separated by two-three days. A random model, single measures intra-class correlation analysed the reliability for both test-retest and intra-day results, in addition to intersubject reliability. We observed moderate to high ICC values (0.60 – 0.993) for most muscles in most directions, indicating low within-subject variance. In addition, moderate to high between-subject reliability was observed in all eight muscle activation profiles, indicating subjects used similar neuromuscular control strategies to achieve the desired GRFs. Our findings support that groups who have undergone the same number of testing sessions can be compared, and that a single testing session is all that is required to compare neuromuscular control strategies used by a group to achieve target locations. The second aim of this investigation was to evaluate age related differences in neuromuscular control about the knee joint using our target match protocol. Thirty-three healthy adults (17 younger 24 years ±2, 16 older 59 years ±5), completed the same protocol evaluated above. The mean magnitude of muscle activity, specificity index, and mean direction of muscle activity were calculated in each target direction. Older adults presented with significantly lower strength in knee flexion and extension, hip abduction, and ankle plantar flexion. Significantly (p<0.25) higher mean activation magnitudes in the rectus femoris, vastus lateralis, vastus medialis, biceps femoris, semitendinosus, medial gastrocnemius, and tensor facia lata were also observed. Intraclass correlations (ICC) magnitudes indicate the percentage of global variance that can be explained by within subject and between trial variability. Muscle activation patterns were found to be similar in all muscles (ICC≤0.82). Similar patterns are supported by non-significant differences in mean direction of activation and muscle activation specificity. These results indicated that healthy older adults utilise different activation magnitudes for stabilising the knee while maintain similar muscle activation synergies in all muscles to younger adults.

We developed a novel approach that requires subjects to produce and finely tune ground reaction forces (GRFs) while standing. Using this method we were able to identify specific contributions of individual muscles and how these contributions change with the effects of age. One of the aims of this investigation was to determine whether electromyographic data in our findings was due to random muscle activation or representative of a neuromuscular control strategy. Ten healthy young adults (5 male, 5 female) with their dominant foot fixed within a boot mounted to a force platform participated twice in a target matching protocol, requiring subjects to control both the direction and magnitude of GRF along the horizontal plane while maintaining constant inferior-superior loads of 50% body-weight. Subjects were asked to manoeuvre a cursor with their dominant leg to match a series of targets projected on a screen. Targets appeared at random one at-a-time, separated by 30o around a circular trajectory. Subjects applied loads to the force platform in various horizontal directions to move the cursor while also controlling body weight. A successful target match required subjects to maintain 50% body weight and 30% of their peak horizontal load for one second. Electromyography (EMG) of eight muscles that cross the knee joint, ground reaction forces, and kinematic data were recorded for each successful match. EMG was normalized to percent maximum voluntary isometric contractions collected on an isokinetic dynamometer. Each target matching session was separated by two-three days. A random model, single measures intra-class correlation analysed the reliability for both test-retest and intra-day results, in addition to intersubject reliability. We observed moderate to high ICC values (0.60 – 0.993) for most muscles in most directions, indicating low within-subject variance. In addition, moderate to high between-subject reliability was observed in all eight muscle activation profiles, indicating subjects used similar neuromuscular control strategies to achieve the desired GRFs. Our findings support that groups who have undergone the same number of testing sessions can be compared, and that a single testing session is all that is required to compare neuromuscular control strategies used by a group to achieve target locations. The second aim of this investigation was to evaluate age related differences in neuromuscular control about the knee joint using our target match protocol. Thirty-three healthy adults (17 younger 24 years ±2, 16 older 59 years ±5), completed the same protocol evaluated above. The mean magnitude of muscle activity, specificity index, and mean direction of muscle activity were calculated in each target direction. Older adults presented with significantly lower strength in knee flexion and extension, hip abduction, and ankle plantar flexion. Significantly (p<0.25) higher mean activation magnitudes in the rectus femoris, vastus lateralis, vastus medialis, biceps femoris, semitendinosus, medial gastrocnemius, and tensor facia lata were also observed. Intraclass correlations (ICC) magnitudes indicate the percentage of global variance that can be explained by within subject and between trial variability. Muscle activation patterns were found to be similar in all muscles (ICC≤0.82). Similar patterns are supported by non-significant differences in mean direction of activation and muscle activation specificity. These results indicated that healthy older adults utilise different activation magnitudes for stabilising the knee while maintain similar muscle activation synergies in all muscles to younger adults.

The career anchors concept is an approach to understanding career orientation and motivation. The original career anchor model was introduced by Schein in 1974. Several investigators have created revisions of the model to make it more useful. This dissertation is a continuation of the quest to evaluate the original model and the revised models with respect to empirical support. This study is the first of two studies in which measurement methods are devised to solve the psychometric problems of previous measures. In this study we create and test an "economic exchange" model to correct the problem of acquiescent bias. We test five career anchor models and this new scaling method against two sets of data. The first consists of data from 330 participants we collect in the present study, and the other is a set of correlation matrices from Barclay's dissertation meta-analysis of six previous studies from the literature. We find that the economic exchange method creates greater variances in the ratings (both within each person and across persons) as predicted, but the hypothesis of predicted increase in the range of correlation coefficients for this method is not supported. In its present form the economic exchange method is not found to be superior to the standard Likert scale method. In addition, the oppositionality of career anchor choices does not increase for older respondents as expected. From a confirmatory factor analysis test of goodness of fit of the five models against the six datasets of this dissertation and the six studies from Barclay's meta-analysis, we find no evidence for one best career anchors model. That is, the five competing theoretical models seem to each be "best" in some situations or populations.

Age differences in metamemory accuracy obtained for episodic memory – new information – compared to semantic memory – general knowledge information were compared in this study. Younger and older adults with no known cognitive impairments viewed pictures of famous faces for semantic memory and nonamous faces for episodic memory. Participants then viewed the faces again and had to provide the name for either semantic or episodic memory. After attempting recall for each face, participants made a Feeling-of-Knowing prediction about future recognition. Finally, each face was presented with the correct answer and three alternative answers. A gamma correlation was used to calculate prediction accuracy. Younger and older adults were equally accurate at predicting their recognition for semantic and episodic memory. The findings demonstrate that using the same materials and a within-subjects design, older adults do not show deficits in metamemory accuracy, even when predicting a type of memory that is typically impaired with age.

A particular field in research on judgment and decision making (JDM) is concerned with realism of confidence in one’s knowledge. An interesting finding is the so-called format dependence effect, which implies that assessment of the same probability distribution generates different conclusions about over- or underconfidence depending on the assessment format. In particular, expressing a belief about some unknown continuous quantity (e.g., a stock value) in the form of an intuitive confidence interval is severely prone to overconfidence as compared to expressing the belief as an assessment of a probability judgment. This thesis gives a tentative account of this finding in terms of a Naïve Sampling Model, which assumes that people accurately describe their available information stored in memory, but they are naïve in the sense that they treat sample properties as proper estimators of population properties (Study 1). The effect of this naivety is directly investigated empirically in Study 2. A prediction that short-term memory is a constraining factor for sample size in judgment, suggesting that experience per se does not eliminate overconfidence is investigated and verified in Study 3. Age-related increments in overconfidence were observed with intuitive confidence interval but not for probability judgment (Study 4). This thesis suggests that no cognitive processing bias (e.g., Tversky &amp; Kahneman, 1974) over and above naivety is needed to understand and explain the overconfidence “bias” with intuitive confidence interval and hence the format dependence effect.

Este trabalho investigou processos metamnemônicos de monitoramento e controle, bem como conhecimento e desempenho de memória em diversas condições. O Capítulo I apresenta um paradigma experimental de aprendizado associativo de pares de palavras para avaliação da metamemória. No Capítulo II observou-se que julgamentos de aprendizagem (JOL) tardios foram mais precisos do que imediatos, porém apenas para adultos jovens, em comparação a adultos de idade intermediária. Adultos jovens contaram mais com seus JOLs e seu desempenho de memória prévios para alocação de tempo de estudo (STA), porém apenas na condição JOLs tardios. No Capítulo III, os grupos de pacientes pós-acidente vascular cerebral e controles não se diferenciaram significativamente quanto ao funcionamento metamnemônico. Contudo, uma análise de séries de casos revelou heterogeneidade dos casos e associações e dissociações funcionais entre memória e metamemória, além de uma dissociação dupla entre monitoramento e controle de memória, indicando que lesões à esquerda comprometem o monitoramento, enquanto lesões à direita o controle. / This work investigated metamemory processes of memory monitoring, control, as well as memory knowledge and performance in several conditions. Chapter I presents a paired-words associative learning experimental paradigm to assess metamemory. In Chapter II we observed that delayed judgements of learning (JOLs) were more accurate than immediate JOLs, however only for young adults compared to intermediate age adults. Young adults relied more on theirs previous JOLs and memory performance for the allocation of study-time (STA), though only in the delayed JOLs condition. In Chapter III a group analysis showed no significant differences for metamnemônic measures between stroke patients and controls. Nevertheless, a case series analysis revealed inter-case heterogeneity and functional associations and dissociations between memory and metamemory, in addition to a double dissociation between memory monitoring and control, which suggested that left hemisphere lesions impair the monitoring while right hemisphere lesions impair the control.

This mixed-method study investigated the correlation of sound symbolic associations with age and gender by analyzing data from a national survey of 292 American English speakers. Subjects used 10 semantic differential scales to rate six artificial brand names that targeted five phonemes. Subjects also described the potential products they imagined these artificial brand names to represent. Quantitative analysis alone provided insufficient evidence to conclude that age or gender affect sound symbolism in American English. While 26 out of 60 scales showed a monotonic shift among the means of the three age groups, only three were statistically significant. The evidence of differences between genders was similarly weak; only five scales out of 60 showed a statistically significant difference when comparing genders. Analysis of the qualitative data, however, suggested both monotonic generational shifts as well as generational blips in sound-symbolic associations. Of particular interest is the possible influence of pop culture, fashions, and fads, and society's shifting focus from broadcast to narrowcast media. The implications of this research are relevant for both theory (empirical evidence for iconicity in language) and application (e.g., devising brand names that communicate particular attributes to specific demographics).