Image memorability influences memory for where the item was seen but not when.

Observers can determine whether they have previously seen hundreds of images with more than 80% accuracy. This "massive memory" for WHAT we have seen is accompanied by smaller but still massive memories for WHERE and WHEN the item was seen (spatial & temporal massive memory). Recent studies have shown that certain images are more easily remembered than others (higher "memorability"). Does memorability influence spatial massive memory and temporal massive memory? In two experiments, viewers saw 150 images presented twice in random order. These 300 images were sequentially presented at random locations in a 7 × 7 grid. If an image was categorized as old, observers clicked on the spot in the grid where they thought they had previously seen it. They also noted when they had seen it: Experiment 1-clicking on a timeline; Experiment 2-estimating the trial number when the item first appeared. Replicating prior work, data show that high-memorability images are remembered better than low-memorability images. Interestingly, in both experiments, spatial memory precision was correlated with image memorability, while temporal memory precision did not vary as a function of memorability. Apparently, properties that make images memorable help us remember WHERE but not WHEN those images were presented. The lack of correlation between memorability and temporal memory is, of course, a negative result and should be treated with caution.

The influence of semantics on long-term visual memory capacity in children and adults.

Human visual memory capacity has a rapid developmental progression. Here we examine whether image semantics modulate this progression. We assessed the performance of children (6-14 years) and young adults (19-36 years) on a visual memory task using real-world (or meaningful) as well as abstract image sets, which were matched in low-level image attributes. For real images, we find comparable performance across the two age groups, consistent with previously reported results. However, for abstract images, we find a clear age-related difference indicating greater reliance of children's memory processes on semantics, suggesting that strategies for encoding abstract patterns keep improving even into late childhood. We complemented these studies with computational experiments designed to examine the role of increasing experience with real-world images on real and abstract image encoding, to examine whether the observed age-related differences, as well as the general privilege of real over abstract images, can emerge directly through experience with meaningful images. Our results provide support for this possibility and set the stage for a finer-grained investigation of the timeline along which children's memory capacity for abstract images reaches adult levels.

The effect of survival processing on memory for pictures depends on how memory is tested.

ABSTRACTTwo experiments investigated the effects of survival processing on memory for pictures of objects. In experiment 1, participants were presented with 32 pictures of common objects and rated them for their relevance to a survival scenario, a moving home scenario, or for pleasantness. In a surprise recall test, participants in the survival condition recalled more of the verbal labels of the objects than participants in the moving and pleasantness conditions. In experiment 2, participants rated 64 pictures of objects in survival, moving home, or pleasantness conditions. Memory for visual detail was assessed using a forced-choice recognition test in which participants had to decide which of two highly similar pictures was the one they rated at study. In contrast to the results of experiment 1, correct recognition scores were highest in the pleasantness condition and lowest in the survival condition. This pattern suggests that survival processing enhances memory for objects but not for precise visual detail. The findings are consistent with the view that rating objects for their survival value directs attention to the potential uses of the objects. They also emphasise the importance of the match between encoding and retrieval processes in the survival processing paradigm.

Multi-domain Cognitive Testing: A Biomarker for Classifying the Cognitive Status of Mild Cognitive Impairment and Alzheimer's Disease.

Context: Cognition is impaired in Alzheimer's disease (AD) and patients with mild cognitive impairment (MCI) with varying levels of magnitude. Aim: The present study aimed to identify a biomarker for classifying MCI and AD using multi-domain cognitive testing. Settings and Design: This was a cross-sectional study. Methods and Materials: 26 AD patients, 28 MCI patients and 25 controls were recruited. Cognitive assessment of different domains was done using standard questionnaires and cognitive function tests. Statistical Analysis Used: Cognitive task scores were compared between the groups using multivariate analysis of variance (MANOVA). Results: Patients with AD had significantly lower MMSE, CDR, cognitive task scores compared to controls and MCI. Cognitive scores of all tasks for MCI were significantly less than controls, except MMSE and digits forward score. ROC analysis showed that picture memory had 100% sensitivity, 91.6% specificity for AD and 88.4% sensitivity, 92.5% specificity for MCI. Word memory had 92.3% specificity, 100% specificity for AD and 80.7% specificity, 84.6% specificity for MCI. Conclusions: The global cognitive tools are less specific in bringing out the differences especially between MCI and control. Limitation of MMSE, heterogeneity of MCI and differential impairment of various domains of cognition, demands the inclusion of multi-domain cognitive evaluation especially picture and word memory tasks with high sensitivity and specificity into the existing diagnostic protocol. ROC results also suggested the continuum of cognitive impairment and MCI as a transitional stage leaving more scope on the quantum of research required for intervention to halt the structural and functional decline.

Levels-of-processing effects on context and target recollection for words and pictures.

The effects of levels of processing (LoP) on memory performance have been extensively studied in cognitive psychology for about half a century. The initial observation of superior memory for words studied under a semantic orienting task rather than a perceptual orienting task elicited a theoretical debate about the underlying mechanisms of this effect. Next, research on LoP effects was extended to pictorial stimuli and connected with analyses of recollection and familiarity processes of recognition memory. The main aim of the current study was to explore the effects of LoP on two distinct components of recollection memory: context recollection, and target recollection-processes recently differentiated in dual-recollection theory. Verbal and pictorial materials were used in several experiments and the participants were asked to remember the study context defined by the kind of orienting task performed. LoP effects were confirmed for context and target recollection when words were used as stimuli. However, reversed LoP effects for context recollection were found in experiments using pictures as the to-be-remembered material. The function of the distinctiveness of pictorial material and the role of the effortfulness of cognitive operations for recollection were analysed and discussed from the perspective of the sensory-semantic model and the source monitoring framework.

Functional brain networks during picture encoding and recognition in different odor contexts.

Contextual odors can serve as retrieval cues when applied during encoding and recall/recognition of information. To investigate the neuronal basis of these observations, we collected functional MRI data while participants (n=51) performed an encoding and recognition memory task during which odors (congruent: CO or incongruent: IO) were presented as contextual cues. Recognition performance was not influenced by odor, but there was increased activation in the piriform cortex during successful encoding in the CO group, possibly indicating enhanced retrieval of information previously integrated with an olfactory percept. Moreover, group-independent component analysis revealed a stronger task-modulation of subcortical networks for IO versus CO during the recognition task, pointing to differences in olfactory processing. These observations provide a deeper understanding of the involvement of functional neuronal networks in memory tasks and a basis for further evaluation of the impact of odor contexts.

Recognition and memory for briefly presented scenes.

Three times per second, our eyes make a new fixation that generates a new bottom-up analysis in the visual system. How much is extracted from each glimpse? For how long and in what form is that information remembered? To answer these questions, investigators have mimicked the effect of continual shifts of fixation by using rapid serial visual presentation of sequences of unrelated pictures. Experiments in which viewers detect specified target pictures show that detection on the basis of meaning is possible at presentation durations as brief as 13 ms, suggesting that understanding may be based on feedforward processing, without feedback. In contrast, memory for what was just seen is poor unless the viewer has about 500 ms to think about the scene: the scene does not need to remain in view. Initial memory loss after brief presentations occurs over several seconds, suggesting that at least some of the information from the previous few fixations persists long enough to support a coherent representation of the current environment. In contrast to marked memory loss shortly after brief presentations, memory for pictures viewed for 1 s or more is excellent. Although some specific visual information persists, the form and content of the perceptual and memory representations of pictures over time indicate that conceptual information is extracted early and determines most of what remains in longer-term memory.