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Recent psychophysical research supports the notion that horizontal information of a face is primarily important for facial identity processes. Even though this has been demonstrated to be valid for young adults, the concept of horizontal information as primary informative source has not yet been applied to older adults’ ability to correctly identify faces. In the current paper, the role different filtering methods might play in an identity processing task is examined for young and old adults, both taken from student populations. Contrary to most findings in the field of developmental face perception, only a near-significant age effect is apparent in upright and un-manipulated presentation of stimuli, whereas a bigger difference between age groups can be observed for a condition which removes all but horizontal information of a face. It is concluded that a critical feature of human face perception, the preferential processing of horizontal information, is less efficient past the age of 60 and is involved in recognition processes that undergo age-related decline usually found in the literature.
From age 5 to 7, there are remarkable improvements in children’s cognitive abilities (“5–7 shift”). In many countries, including Germany, formal schooling begins in this age range. It is, thus, unclear to what extent exposure to formal schooling contributes to the “5–7 shift.” In this longitudinal study, we investigated if schooling acts as a catalyst of maturation. We tested 5-year-old children who were born close to the official cutoff date for school entry and who were still attending a play-oriented kindergarten. One year later, the children were tested again. Some of the children had experienced their first year of schooling whereas the others had remained in kindergarten. Using 2 functional magnetic resonance imaging tasks that assessed episodic memory formation (i.e., subsequent memory effect), we found that children relied strongly on the medial temporal lobe (MTL) at both time points but not on the prefrontal cortex (PFC). In contrast, older children and adults typically show subsequent memory effects in both MTL and PFC. Both children groups improved in their memory performance, but there were no longitudinal changes nor group differences in neural activation. We conclude that successful memory formation in this age group relies more heavily on the MTL than in older age groups.
Deferred imitations assess declarative memory in infants. Many cross-sectional and a few longitudinal studies revealed that, with development, infants learn faster,and retain more target actions over longer retention intervals. Longitudinal stabilities are modest and increase through the second year. To date, there are only few multivariate deferred imitation studies pointing to interactions between declarative memory, language and self-development. However, as these studies applied variable-centered data analysis approaches, the individual stance was not taken into account.Therefore, the present dissertation focuses on the explanation of inter-individual differences of deferred imitation through the second year. In the multivariate, longitudinal Frankfurt Memory Study (FRAMES), declarative memory (deferred imitation), non-declarative memory (train task), as well as cognitive, language, motor, social, emotional and body self-awareness development (Developmental Test for 6-month- to 6-year-olds, ET6-6) were assessed on three measurement occasions (12-, 18- and 24-month-olds). From a psychometric perspective, sound tests for the assessment of deferred imitation in the respective age groups were developed (Paper 1 & 2). Reliability analyses (Paper 3) indicated relatively high short-term-stability for the deferred imitation test (12-month-olds). The co-development of declarative and nondeclarative memory in 12- and 18-month-olds provided evidence for discriminative validity (Paper 4). Longitudinally, deferred imitation performance tremendously increased throughout the second year, and performance was moderately stable between 12 and 18 months and stability increased between 18 and 24 months. Using a person-centered analysis approach (relative difference scores; cluster analysis), developmental subgroups were extracted out of the total sample. These groups differed in terms of mean growth and stability. However, between the first and second measurement occasion, the groups did not differ with respect to motor, cognitive and language development (Paper 5). Using the data of three measurement occasions, subgroups were extracted showing significant differences with respect to language, motor and body self-awareness development (Paper 6). The results are discussed against the background of infancy development theories.
Mnemonic but not contextual feedback signals defy dedifferentiation in the aging early visual cortex
(2024)
Perception is an intricate interplay between feedforward visual input and internally generated feedback signals that comprise concurrent contextual and time-distant mnemonic (episodic and semantic) information. Yet, an unresolved question is how the composition of feedback signals changes across the lifespan and to what extent feedback signals undergo age-related dedifferentiation, that is, a decline in neural specificity. Previous research on this topic has focused on feedforward perceptual representation and episodic memory reinstatement, suggesting reduced fidelity of neural representations at the item and category levels. In this fMRI study, we combined an occlusion paradigm that filters feedforward input to the visual cortex and multivariate analysis techniques to investigate the information content in cortical feedback, focusing on age-related differences in its composition. We further asked to what extent differentiation in feedback signals (in the occluded region) is correlated to differentiation in feedforward signals. Comparing younger (18–30 years) and older female and male adults (65–75 years), we found that contextual but not mnemonic feedback was prone to age-related dedifferentiation. Semantic feedback signals were even better differentiated in older adults, highlighting the growing importance of generalized knowledge across ages. We also found that differentiation in feedforward signals was correlated with differentiation in episodic but not semantic feedback signals. Our results provide evidence for age-related adjustments in the composition of feedback signals and underscore the importance of examining dedifferentiation in aging for both feedforward and feedback processing.