292 research outputs found
Age-related increases in false recognition: The role of perceptual and conceptual similarity
No full textOlder adults are more likely to falsely recognize novel events than young adults, and recent behavioral and neuroimaging evidence points to a reduced ability to distinguish overlapping information due to decline in hippocampal pattern separation. However, other data suggest a critical role for semantic similarity. Koutstaal et al. [(2003). False recognition of abstract versus common objects in older and younger adults: Testing the semantic categorization account, J. Exp Psychol. Learn, 29(4), 499-510] reported that older adults were only vulnerable to false recognition of items with pre-existing semantic representations. We replicated Koutstaal et al.’s (2003) second experiment and examined the influence of independently rated perceptual and conceptual similarity between stimuli and lures. At study, young and older adults judged the pleasantness of pictures of abstract (unfamiliar) and concrete (familiar) items, followed by a surprise recognition test including studied items, similar lures, and novel unrelated items. Experiment 1 used dichotomous ‘old/new’ responses at test, while in Experiment 2 participants were also asked to judge lures as ‘similar’, to increase explicit demands on pattern separation. In both experiments, older adults showed a greater increase in false recognition for concrete than abstract items relative to the young, replicating Koutstaal et al.’s (2003) findings. However, unlike in the earlier study, there was also an age-related increase in false recognition of abstract lures when multiple similar images had been studied. In line with pattern separation accounts of false recognition, older adults were more likely to misclassify concrete lures with high and moderate, but not low degrees of rated similarity to studied items. Results are consistent with the view that older adults are particularly susceptible to semantic interference in recognition memory, and with the possibility that this reflects age-related decline in pattern separation
The effects of age on the neural correlates of successful episodic retrieval: An ERP study
No full textThe neural correlates of successful episodic retrieval (recollection), as reflected in event-related potentials (ERPs), were investigated in young (ca. 20 years; n=18) and older (ca. 70 years; n=16) healthy individuals. Subjects classified a series of pictures according to whether each item was new or had been encountered at study in the context of an animacy or a size judgment task. By manipulating the number of times items were presented for study, subsets of test items were formed for which source accuracy did not differ according to age. Relative to ERPs elicited by unstudied pictures, ERPs elicited by items attracting equivalent levels of source accuracy showed marked age-related differences. Those from younger subjects demonstrated the positive-going left parietal and right frontal old/new effects described in several previous studies of source memory. By contrast, analogous ERPs from older subjects contained a large left-lateralized negative effect that overshadowed the positive-going effects evident in the young. No age-related differences in either parietal or frontal ERP old/new effects were detected at electrode sites overlying the right hemisphere. It is possible that the age-related ERP differences observed in this task primarily reflect the use of different kinds of information as a basis for source judgments
Age effects on the neural correlates of episodic retrieval: Increased cortical recruitment with matched performance
No full textFunctional neuroimaging investigations have revealed a range of age-related differences in the neural correlates of episodic memory retrieval. Typically, whereas activity is reduced in older compared with younger adults in some regions, other regions are engaged exclusively, or to a greater extent, in older adults. It is unclear whether such differences merely represent the neural correlates of the lower levels of memory performance and impaired recollection typical of older adults. This issue was addressed in the present event-related functional magnetic resonance imaging study. The level of recollection was matched between groups of healthy younger and older adults for a subset of picture items in a source memory task by manipulating the number of study presentations. Contrasts of the activity elicited by old items attracting correct source judgments and correctly identified new items revealed that the 2 groups recruited many of the same brain regions. However, a striking pattern of age-related differences was also observed. In older adults, retrieval-related increases in activity were more widespread and of greater magnitude than in the young. Moreover, regions demonstrating retrieval-related decreases in activity were almost absent in the older participants. These findings suggest an age-related decline in the efficiency with which neural populations support cognitive function.Functional neuroimaging investigations have revealed a range of age-related differences in the neural correlates of episodic memory retrieval. Typically, whereas activity is reduced in older compared with younger adults in some regions, other regions are engaged exclusively, or to a greater extent, in older adults. It is unclear whether such differences merely represent the neural correlates of the lower levels of memory performance and impaired recollection typical of older adults. This issue was addressed in the present event-related functional magnetic resonance imaging study. The level of recollection was matched between groups of healthy younger and older adults for a subset of picture items in a source memory task by manipulating the number of study presentations. Contrasts of the activity elicited by old items attracting correct source judgments and correctly identified new items revealed that the 2 groups recruited many of the same brain regions. However, a striking pattern of age-related differences was also observed. In older adults, retrieval-related increases in activity were more widespread and of greater magnitude than in the young. Moreover, regions demonstrating retrieval-related decreases in activity were almost absent in the older participants. These findings suggest an age-related decline in the efficiency with which neural populations support cognitive function
Mental reinstatement and selective recollection
No full textWhen trying to remember events, people are thought to be able to bias their memory search to selectively recollect the information they seek (Rugg and Wilding, 2000; Morcom, 2016). Long-standing cognitive theories propose that this memory selection involves mentally reinstating context that was present when the events were encoded, for example by visualising the location (Smith, 1979). In this fMRI study we will directly examine mental reinstatement using representational similarity analysis (RSA). We want to investigate the brain regions involved in mentally reinstating information about the scenes in which experimental events were encoded, and test whether this reinstatement is associated with successful memory performance and selection of targeted information. To do this we will use RSA measures of encoding-retrieval similarity, focusing on a priori scene-processing and object-processing ROIs, as well as domain-general ROIs. We will also conduct an exploratory searchlight of the whole-brain. We will use a similar RSA pipeline to a recent study from our lab (Naspi et al., 2021).
In the scanner, participants studied objects with scene backgrounds (context). At test, two scenes were designated as targeted events in each block. Participants viewed object names and were asked to judge objects as “targets” if these were studied with one of the two targeted scenes. We predict that participants mentally reinstated studied scenes before the retrieval cues are presented, and this reinstatement predicts recollection success on the upcoming trials. We also predict that recollection of targeted items will be prioritised over recollection of non-targeted items, so reinstatement of both scene and item information is greater for target trials at the time of recollection.
References:
Morcom AM (2016) Mind Over Memory: Cuing the Aging Brain. Curr Dir Psychol Sci 25.
Naspi, L., Hoffman, P., Devereux, B., & Morcom, A. M. (2021). Perceptual and semantic representations at encoding contribute to true and false recognition of objects. Journal of Neuroscience, 41(40), 8375-8389.
Rugg MD, Wilding EL (2000) Retrieval processing and episodic memory. Trends Cogn Sci 4:108; 115.
Smith SM (1979) Remembering in and out of context. J Exp Psychol Hum Learn Mem 5:460; 471
The construction of Karen Karnak: The multi-author-function
No full textThis thesis is situated within the comparatively recent developments of Web 2.0 and the emergence of interactive WikiMedia, and explores the mode of authorship within a Read/Write culture compared to that of a Read/Only tradition. The hypothesis of this study is that the role of the audience has become merged with the author, and as such, represents new functions and attributes, distinct from a more conventional concept of authorship, in which the roles of audience and author are more separate. Read/Write and participatory culture, as defined by this study, is focused on collaboration, and includes the influences of D.I.Y. culture, Open-Source practices and the production of text by multiple authors. Multi-authorship presents a re-thinking of several concepts which support the notion of the individual author, since the focus of multi-authorship is not on attribution and ownership of a finished text, but on the continued malleability of a text. Modes of multi-authorship, demonstrated in the use of the pseudonyms Alan Smithee and Karen Eliot, represent declarative authors whose names signify multiple origins, whilst concurrently indicating a distinct body of work. The function of these names form an important context to this study, since primary research involves the construction of an experimental mode of multi-authorship utilising WikiMedia technology and the interaction of thirty nine participants, who are invited to create a body of work under the collective pseudonym Karen Karnak. The data generated by this experiment is analysed using aspects of Michel Foucault's author-function to identify and determine power structures inherent in the WikiMedia context. The interplay of power structures, including concepts such as identity, ownership and the body of work, affect the resulting mode of authorship and contribute to the construction of Karen Karnak, suggesting further areas of research into the emerging multi-author
"Prime" Advertising Space: Measuring Implict Memory Online
No full textIn marketing literature, click-through-rates are generally employed to measure the success of banner advertisements online. This measure has led to the banner blindness hypothesis, which posits that internet users ignore banner advertisements. However, this measurement does not take into account the consumer action which may result from memory for advertised brands. This study illustrates that although there may not be explicit memory for these advertisements, consumers can be primed for advertised brands. This study includes two experiments, the first of which employs standard measures of memory in order to determine explicit recall (PR) and implicit memory (priming effects) for information included on banner ads under varying levels of attention during an encoding phase involving website viewing. The results of experiment 1 demonstrated that, there is explicit memory for banner ads when browsers attention is directed towards their presence. These results were in disparity with previous studies. However, there is no explicit memory for unattended advertisements. Additionally, there was a high measure of implicit memory throughout both attention conditions. These results are constant with mainstream memory literature and previous findings in the marketing domain (Yoo, 2008; Yang et al 2004). The second experiment measures two long-term effects of implicit memory which can produce familiarity for advertised brands: ‘the false fame effect’ and ‘the mere exposure effect’. It was demonstrated that there was long term familiarity for brand names. Therefore, this paper will argue that, in light of a wealth of marketing research which demonstrates that consumer action is driven by familiarity, the current measure of banner advertisement effectiveness is inadequate. The implications of these results for the processing of online advertisements are discussed.
Key Words: Banner Advertisements, Memory, Implicit, Explicit, Familiarity, Memory Measures, False Fame, Mere Exposure, Attention, Banner Blindness
The Magazine Women Believed in: "Marriage Advice" 1950-1955
No full textIn the United States society, the 1950s is seen as a time of great conservatism where both men and women were placed into specific gender roles that dictated much of how they lived their lives. One institution that verified these gender roles and stereotypes to be true was women's magazines. These magazines contained sections such as fashion segments, helpful cooking guidelines, advertisements, and advice columns that seemed to target middle class, white, suburban married housewives. One advice column that seemed to particularly focus on the idea of a happy housewife and married life was the column Making Marriage Work, which appeared in the magazine Ladies Home Journal during this 1950s time period. The author of this column, Clifford R. Adams, idealized the 1950s perfect housewife existence and through his advice he encouraged women to strive for this lifestyle, while there were other sources demonstrating that this perceived notion of the perfect housewife did not exist during the 1950s time period
Author Correction: Hippocampal oxytocin receptors are necessary for discrimination of social stimuli
No full textThe original version of this Article contained an error in the spelling of the author Alexa H. Veenema, which was incorrectly given as Alexa Veenema. This has now been corrected in both the PDF and HTML versions of the Article.</jats:p
Re-engaging with the past: recapitulation of encoding operations during retrieval
No full textRecollection of events is accompanied by selective reactivation of cortical regions which responded to specific sensory and cognitive dimensions of the original events. This reactivation is thought to reflect the reinstatement of stored memory representations and therefore to reflect memory content, but it may also reveal processes which support both encoding and retrieval. The present study used event-related functional magnetic resonance imaging (fMRI) to investigate whether regions selectively engaged in encoding face and scene context with studied words are also re-engaged when the context is later retrieved. As predicted, encoding face and scene context with visually presented words elicited activity in distinct, context-selective regions. Retrieval of face and scene context also re-engaged some of the regions which had shown successful encoding effects. However, this recapitulation of encoding activity did not show the same context selectivity observed at encoding. Successful retrieval of both face and scene context re-engaged regions which had been associated with encoding of the other type of context, as well as those associated with encoding the same type of context. This recapitulation may reflect retrieval attempts which are not context-selective, but use shared retrieval cues to re-engage encoding operations in service of recollection
Cortical pattern separation and item-specific encoding
No full textPattern separation and pattern completion are fundamental brain processes thought to be critical for episodic memory encoding and retrieval, and for discrimination between similar memories. These processes are best understood in the hippocampus, but are proposed to occur throughout the brain, in particular in sensory regions. Cortical, as well as hippocampal, pattern separation may therefore support formation of event-unique memory traces. Using fMRI, we investigated cortical pattern separation and pattern completion and their relationship to encoding activity predicting subsequent item-specific compared to gist memory. During scanning, participants viewed images of novel objects, repeated objects, and objects which were both perceptually and conceptually similar to previously presented images, while performing a size judgement task. In a later surprise recognition test, they judged whether test items were ‘same’ ‘similar’ or ‘new’ relative to studied items. Activity consistent with pattern separation – responses to similar items as if novel – was observed in bilateral occipito-temporal cortex. Activity consistent with pattern completion – responses to similar items as if repeated – was observed in left prefrontal cortex and hippocampus. Curve fitting analysis further revealed that graded responses to change in image conceptual and perceptual similarity in bilateral prefrontal and right parietal regions met specific computational predictions for pattern separation for one or both of these similarity dimensions. Functional overlap between encoding activity predicting subsequent item-specific recognition and pattern separation activity was also observed in left occipital cortex and bilateral inferior frontal cortex. The findings suggest that extrahippocampal regions including sensory and prefrontal cortex contribute to pattern separation and pattern completion of visual input, consistent with the proposal that cortical pattern separation contributes to formation of item-specific memory traces, facilitating accurate recognition memory
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