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- Hellmer, Kahl, et al.
(author)
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The eye of the retriever : Developing episodic memory mechanisms in preverbal infants assessed through pupil dilation
- 2018
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In: Developmental Science. - : Wiley. - 1363-755X .- 1467-7687. ; 21:2
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Journal article (peer-reviewed)abstract
- Studying memory in infants can be challenging, as they cannot express their subjective recollection verbally. In this study we use a novel method with which we can assess episodic recognition memory through pupillometry, using identical procedures and stimuli for infants and adults. In three experiments of 4- and 7-month-old infants, and adults we show that the adult pupillary response is larger to previously seen than to never seen items (old/new effect). Pupil dilations index subjective memory experience in adults, producing distinct pupil dilations to items judged as remembered, familiar, and new, regardless of actual previous exposure (Experiment 1). Seven-month-old infants demonstrate a clear pupillary old/new effect, very similar to that of adults (Experiment 2), whereas 4-month-olds do not demonstrate such an effect (Experiment 3). Our findings suggest that the mnemonic mechanisms that serve infants' and adults' episodic recognition memory are more similar than previously asserted: they are not fully developed at 4 months of age but that there is contiguity in human episodic memory development from 7 months of age.
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- Kubik, Veit, 1981-, et al.
(author)
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Individual and Combined Effects of Enactment and Testing on Memory for Action Phrases
- 2014
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In: Experimental psychology (Göttingen). - : Hogrefe Publishing Group. - 1618-3169 .- 2190-5142. ; 61:5, s. 347-355
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Journal article (peer-reviewed)abstract
- We investigated the individual and combined effects of enactment and testing on memory for action phrases to address whether bothstudy techniques commonly promote item-specific processing. Participants (N = 112) were divided into four groups (n = 28). They eitherexclusively studied 36 action phrases (e.g., ‘‘lift the glass’’) or both studied and cued-recalled them in four trials. During study trials participantsencoded the action phrases either by motorically performing them, or by reading them aloud, and they took final verb-cued recall tests over 18-min and 1-week retention intervals. A testing effect was demonstrated for action phrases, however, only when they were verbally encoded, andnot when they were enacted. Similarly, enactive (relative to verbal) encoding reduced the rate of forgetting, but only when the action phraseswere exclusively studied, and not when they were also tested. These less-than-additive effects of enactment and testing on the rate of forgetting,as well as on long-term retention, support the notion that both study techniques effectively promote item-specific processing that can only bemarginally increased further by combining them.
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- Lindskog, Marcus, 1980-
(author)
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The Lazy Intuitive Statistician : Influence of Data Representation and Retrieval Processes on Intuitive Statistical Judgment
- 2012
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Licentiate thesis (other academic/artistic)abstract
- Intuitive statistical judgments are an integral part of people’s everyday life and a long line of research has investigated the extent to which man lives up to the norms of statistical theory when performing such judgments. A recent account of intuitive statistical judgments, summarized in the metaphor of the naïve intuitive statistician (K. Fiedler & P. Juslin, 2006), has suggested that people base judgments on small samples, which they have an ability to veridically record but an inability to evaluate the representativeness of. The present thesis builds on research concerning the naïve intuitive statistician and investigates how representation and memory retrieval of numerical information influences intuitive statistical judgments. Two studies were conducted. Study I introduced two possible accounts of how numerical information is represented and retrieved. The first possibility suggests that information is stored as exemplars and that estimates of statistical properties are calculated on small samples drawn from memory at the time of a query. The second possibility suggests that numerical information is stored as abstract summary statistics calculated at the time of exposure. The distinction was summarized in the metaphor of a lazy vs. an eager intuitive statistician. Study II extended the findings of Study I by investigating how point estimates of unknown quantities are formed from knowledge of statistical properties of a numerical variable. More specifically, a model of naïve point estimation based on the naïve sampling model (P., Juslin, A., Winman, & P., Hansson, 2007) was introduced to predict participants’ distribution of point estimates. In general, the results from both studies support the idea that people spontaneously act as lazy intuitive statisticians that record numerical information in a raw format during exposure and postpone evaluation of statistical properties until they are requested to do so. Under certain fairly predictable and limited circumstances, however, participants were able to form abstract representations of statistical properties. The results of Study II support the predictions by the model of naïve point estimation, including a novel phenomenon where participants give point estimates which they know, when probed otherwise, have a low probability of occurring. The findings of the two studies extend previous research concerning people’s ability to be intuitive statisticians by not only measuring how accurate the knowledge of properties of numerical variable is but by also describing how such knowledge is represented. The model of naïve point estimation contributes to the existing body of research by describing how people perform one type of intuitive statistical inference, point estimation, and shows how statistical properties of the underlying distribution influences the pattern of responses. The model also suggests novel explanations to results showing that people seem to have implicit expectations that distributions are normal.
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- Mårtensson, Johanna, et al.
(author)
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Diffusion tensor imaging and tractography of the white matter in normal aging : The rate-of-change differs between segments within tracts
- 2018
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In: Magnetic Resonance Imaging. - : Elsevier BV. - 0730-725X .- 1873-5894. ; 45, s. 113-119
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Journal article (peer-reviewed)abstract
- Knowledge concerning the normal aging of cerebral white matter will improve our understanding of abnormal changes in neurodegenerative diseases. The microstructural basis of white matter maturation and aging can be investigated using diffusion tensor imaging (DTI). Generally, diffusion anisotropy increases during childhood and adolescence followed by a decline in middle age. However, this process is subject to spatial variations between tracts. The aim of this study was to investigate to what extent age-related variations also occur within tracts. DTI parameters were compared between segments of two white matter tracts, the cingulate bundle (CB) and the inferior fronto-occipital fasciculus (IFO), in 257 healthy individuals between 13 and 84years of age. Segments of the CB and the IFO were extracted and parameters for each segment were averaged across the hemispheres. The data was analysed as a function of age. Results show that age-related changes differ both between and within individual tracts. Different age trajectories were observed in all segments of the analysed tracts for all DTI parameters. In conclusion, aging does not affect white matter tracts uniformly but is regionally specific; both between and within white matter tracts.
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- Nilsson, Lars-Göran, et al.
(author)
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Cognitive test battery of CASCADE : Tasks and data.
- 2005
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In: Aging, Neuropsychology and Cognition. - 1382-5585. ; 12:1, s. 32-56
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Journal article (peer-reviewed)abstract
- This paper presents the cognitive test battery used in the CASCADE Study (Cardiovascular Determinants of Dementia) for examining the consequences of cerebral white matter lesions and atrophy. The test battery includes nine different tasks assessing memory, executive function, and global cognitive function. Three episodic memory tasks were used in combinations to assess the role of attention and speed on encoding. Estimates of short- and long-term memory capacity were also derived from these three memory tasks. Semantic memory production / frontal lobe functions were assessed by means of a word fluency test. The Letter Digit Substitution test and the Stroop test were used to assess speed of processing and attention. Motor speed was measured with the Purdue Pegboard test, and global cognitive function was assessed by the Mini Mental State Examination. Overall performance data for the whole CASCADE sample and for each of eight study centers are presented for each test. Possible reasons for performance differences among study centers are discussed.
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- Nordin, Kristin, et al.
(author)
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Age-related hippocampal resting-state connectivity shows axis-dependent associations with memory
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Other publication (other academic/artistic)abstract
- Functional connectivity across large-scale brain networks alters in older age and changes are often associated with memory decline. Studies assessing hippocampal resting-state functional connectivity (rsFC), however, rarely consider the anterior and posterior hippocampus separately, although evidence suggests they are part of two distinct networks differentially supporting memory. While only a limited number of studies have considered age effects on axis-related hippocampal connectivity, findings suggest that rsFC of the two regions display differential effects of age. Reports on the link between such effects and memory are however inconclusive, and previous findings mainly concern episodic memory, ignoring spatial memory also dependent on the hippocampus. Here, we therefore assessed age effects on axis-related hippocampal rsFC, accounting for associations with both episodic and spatial memory in young, middle-aged and older adults (n=194). The anterior and posterior hippocampus showed different age-related decreases in connectivity assessed across middle and older age, but common to the regions was a decreased coupling with the medial orbitofrontal cortex. Only connectivity between the posterior hippocampus and the lingual gyrus increased as a function of age, displaying negative associations with episodic memory. In contrast, the region’s connectivity with the insula, decreasing with age, was positively related to spatial memory. Consistent with previous reports, our findings indicate that hippocampal rsFC vary with age in an axis-dependent manner, and further add to the knowledge on this differentiation’s relevance to memory by showing that age-related rsFC of the anterior and posterior hippocampus is differentially associated with episodic and spatial memory.
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