Recognition Memory For Scenes Research Articles

Subjective reports of mind wandering during encoding predict recognition memory for scenes

Subjective reports of mind wandering during encoding predict recognition memory for scenes

The extent and specificity of visual exploration determines the formation of recollected memories in complex scenes.

Our visual memories of complex scenes often appear as robust, detailed records of the past. Several studies have demonstrated that active exploration with eye movements improves recognition memory for scenes, but it is unclear whether this improvement is due to stronger feelings of familiarity or more detailed recollection. We related the extent and specificity of fixation patterns at encoding and retrieval to different recognition decisions in an incidental memory paradigm. After incidental encoding of 240 real-world scene photographs, participants (N = 44) answered a surprise memory test by reporting whether an image was new, remembered (indicating recollection), or just known to be old (indicating familiarity). To assess the specificity of their visual memories, we devised a novel report procedure in which participants selected the scene region that they specifically recollected, that appeared most familiar, or that was particularly new to them. At encoding, when considering the entire scene,subsequently recollected compared to familiar or forgotten scenes showed a larger number of fixations that were more broadly distributed, suggesting that more extensive visual exploration determines stronger and more detailed memories. However, when considering only the memory-relevant image areas, fixations were more dense and more clustered for subsequently recollected compared to subsequently familiar scenes. At retrieval, the extent of visual exploration was more restricted for recollected compared to new or forgotten scenes, with a smaller number of fixations. Importantly, fixation density and clustering was greater in memory-relevant areas for recollected versus familiar or falsely recognized images. Our findings suggest that more extensive visual exploration across the entire scene, with a subset of more focal and dense fixations in specific image areas, leads to increased potential for recollecting specific image aspects.

Amyloid pathology but not APOE ε4 status is permissive for tau-related hippocampal dysfunction.

We investigated whether the impact of tau-pathology on memory performance and on hippocampal/medial temporal memory function in non-demented individuals depends on the presence of amyloid pathology, irrespective of diagnostic clinical stage. We conducted a cross-sectional analysis of the observational, multicentric DZNE-Longitudinal Cognitive Impairment and Dementia Study (DELCODE). Two hundred and thirty-five participants completed task functional MRI and provided CSF (92 cognitively unimpaired, 100 experiencing subjective cognitive decline and 43 with mild cognitive impairment). Presence (A+) and absence (A−) of amyloid pathology was defined by CSF amyloid-β42 (Aβ42) levels. Free recall performance in the Free and Cued Selective Reminding Test, scene recognition memory accuracy and hippocampal/medial temporal functional MRI novelty responses to scene images were related to CSF total-tau and phospho-tau levels separately for A+ and A− individuals. We found that total-tau and phospho-tau levels were negatively associated with memory performance in both tasks and with novelty responses in the hippocampus and amygdala, in interaction with Aβ42 levels. Subgroup analyses showed that these relationships were only present in A+ and remained stable when very high levels of tau (>700 pg/ml) and phospho-tau (>100 pg/ml) were excluded. These relationships were significant with diagnosis, age, education, sex, assessment site and Aβ42 levels as covariates. They also remained significant after propensity score based matching of phospho-tau levels across A+ and A− groups. After classifying this matched sample for phospho-tau pathology (T−/T+), individuals with A+/T+ were significantly more memory-impaired than A−/T+ despite the fact that both groups had the same amount of phospho-tau pathology. ApoE status (presence of the E4 allele), a known genetic risk factor for Alzheimer’s disease, did not mediate the relationship between tau pathology and hippocampal function and memory performance. Thus, our data show that the presence of amyloid pathology is associated with a linear relationship between tau pathology, hippocampal dysfunction and memory impairment, although the actual severity of amyloid pathology is uncorrelated. Our data therefore indicate that the presence of amyloid pathology provides a permissive state for tau-related hippocampal dysfunction and hippocampus-dependent recognition and recall impairment. This raises the possibility that in the predementia stage of Alzheimer’s disease, removing the negative impact of amyloid pathology could improve memory and hippocampal function even if the amount of tau-pathology in CSF is not changed, whereas reducing increased CSF tau-pathology in amyloid-negative individuals may not proportionally improve memory function.

Scene memory and hippocampal volume in middle-aged women with early hormone loss

The present study explored whether early midlife bilateral salpingo-oophorectomy (BSO), a female-specific risk factor for dementia, is associated with reduced medial temporal lobe structure and function. Younger middle-aged women with the BRCA1/2 mutation and a BSO prior to spontaneous menopause (SM) were recruited. We determined the performance of women with BSO not taking estradiol-based hormone therapy (n = 18) on a task measuring object and scene recognition and quantified medial temporal lobe subregion volumes using manually segmented high-resolution T2-weighted MRI scans. Comparisons were made to those with BSO taking estradiol-based hormone therapy (n = 20), age-matched premenopausal controls (n = 28), and older women in SM not taking hormone therapy matched for duration of hormone deprivation (n = 17). Reduced hippocampal integrity specific to the BSO group not taking hormone therapy was observed, reflected by significantly smaller dentate gyrus/CA2/CA3 volumes and lower scene recognition memory performance. These findings show that hippocampal subfield volume may be useful for identifying early midlife changes in women at elevated risk for dementia.

Disturbed sleep and reduced hippocampal integrity at midlife: Implications for AD risk in women with early surgical menopause

AbstractBackgroundWomen bear the greatest burden of Alzheimer’s disease (AD), and early (<45y) ovarian hormone deprivation via surgical menopause further increases risk (Rocca et al., 2007). Given that sleep disturbance is implicated in AD progression (Lim et al., 2013), an important area of investigation is determining whether younger women with early surgical menopause demonstrate disturbed sleep at midlife, and whether this may confer additional risks by contributing to changes in hippocampal integrity. Thus, we investigated whether middle‐aged women with bilateral salpingo‐oophorectomy not taking hormone therapy demonstrate sleep disturbance, and reduced hippocampal volume and memory. Additionally, we assessed whether sleep and hippocampal volume predict memory performance.MethodWomen with an early BSO that were either taking estradiol‐based hormone therapy (BSO+ET: age=43y; n=22), or not taking ET (BSO: age=46y; n=18) were recruited to the study, and were compared to age‐matched premenopausal (AMC: n=24) and spontaneously postmenopausal women who were ∼10y older (SM: 55y; n=20). Sleep was assessed via portable polysomnography (Vitaport‐5/REMbo‐234, Temec Technologies) for 1‐3 nights, and sleep staging was acquired using automated scoring (Z3score, Neurobit technologies). High‐resolution T2‐weighted scans were acquired using a Siemens 3T Prisma scanner, and hippocampal subfields (CA1, Subiculum, combined region: DGCA23), were manually segmented (Olsen et al., 2017) in FSLView. The interference match‐to‐sample (IMTS) task was used to asses and recognition memory for scenes (Watson et al., 2013).ResultBoth hormone‐deprived groups demonstrated increased sleep latency (BSOvsAMC: p<.05, d= 0.74; SMvsAMC: d= 0.69) and decreased sleep efficiency (BSOvsAMC: p<.05, d= 0.79; SMvsAMC: p<.05, d= 0.67). Only the BSO group demonstrated reduced volume in the anterior CA1 and DGCA23 relative to AMC (p<.05, d= 0.96‐1.06) and BSO+ET (p<.05, d= 0.67‐0.84). Additionally, the BSO demonstrated reduced efficiency (accuracy/RTcorrect) on scene recognition memory (p<.05, d=0.70‐0.86). Multiple regression analyses show that DGCA23 volume and group membership predict scene recognition memory performance.ConclusionWhile both hormone‐deprived groups demonstrated disturbed sleep, women with early BSO also showed reduced hippocampal integrity, despite being ∼10 years younger than SM women. These findings are consistent with the elevated AD risk among women with BSO. It remains to be seen whether sleep disturbance at a younger age exacerbates risk.

Feasibility of mobile app‐based assessment of memory functions: Insights from a citizen science study

AbstractBackgroundMobile app‐based, high‐frequency monitoring of cognition holds the promise to facilitate the individual detection of cognitive change. However, there are several factors in everyday life that potentially influence estimates of cognitive performance in an unsupervised remote test setting. Characterizing these factors is critical to guide the interpretation of results from mobile app‐based studies of cognitive function in the future.MethodsWe conducted a Germany wide Citizen Science Project (after accreditation with the Citizen Science Portal of the German Ministry for Science and Education) with the goal to identify everyday life factors influencing cognitive performance estimates acquired via smartphone‐based assessments. To that end, every participant was pseudo‐randomly assigned to one of three memory tests: 1) pattern separation of objects and scenes (Berron et al., 2018, 2019); 2) complex (photographic) scene recognition memory (Düzel et al., 2011, 2018); 3) pattern completion of object‐in‐scene associations. Participants were asked to perform one test per week over a period of 15 weeks.Results1765 participants (70% female) completed 7900 weekly test sessions. The age‐range of participants was between 18 and 89 years of age. Mean age was 53 (SD=15). We found significant effects of age, time of the day of test performance, time between encoding and retrieval as well as the screen size of the mobile device. Further, our results indicate minor or even no practice effects with repeated tests and indicate that between 4‐5 test sessions are sufficient in order to define a measure of baseline performance.ConclusionOur results indicate several factors influencing cognitive measures in an unsupervised setting of remote smartphone‐based assessment of memory functions. While some factors were specific to only some tests, most factors were associated to all three tests suggesting that they are of general nature. Finally, several sets of different parallel test versions for each memory test resulted in marginal practice effects with repeated assessments.

Visual recognition memory for scenes in aerial photographs: Exploring the role of expertise

Aerial photographs depict objects from an overhead position, which gives them several unusual visual characteristics that are challenging for viewers to perceive and memorize. However, even for untrained viewers, aerial photographs are still meaningful and rich with contextual information. Such visual stimulus properties are considered appropriate and important when testing for expertise effects in visual recognition memory. The current experiment investigated memory recognition in expert image analysts and untrained viewers using two types of aerial photographs. The experts were better than untrained viewers at recognizing both vertical aerial photographs, which is the domain of their expertise, and oblique aerial photographs. Thus, one notable finding is that the superior memory performance of experts is not limited to a domain of expertise but extends to a broader category of large-scale landscape scenes. Furthermore, the experts' recognition accuracy remained relatively stable throughout the experimental conditions, illustrating the ability to use semantic information over strictly visual information in memory processes.

Visual search for changes in scenes creates long-term, incidental memory traces.

Humans are very good at remembering large numbers of scenes over substantial periods of time. But how good are they at remembering changes to scenes? In this study, we tested scene memory and change detection two weeks after initial scene learning. In Experiments 1-3, scenes were learned incidentally during visual search for change. In Experiment 4, observers explicitly memorized scenes. At test, after two weeks observers were asked to discriminate old from new scenes, to recall a change that they had detected in the study phase, or to detect a newly introduced change in the memorization experiment. Next, they performed a change detection task, usually looking for the same change as in the study period. Scene recognition memory was found to be similar in all experiments, regardless of the study task. In Experiment 1, more difficult change detection produced better scene memory. Experiments 2 and 3 supported a "depth-of-processing" account for the effects of initial search and change detection on incidental memory for scenes. Of most interest, change detection was faster during the test phase than during the study phase, even when the observer had no explicit memory of having found that change previously. This result was replicated in two of our three change detection experiments. We conclude that scenes can be encoded incidentally as well as explicitly and that changes in those scenes can leave measurable traces even if they are not explicitly recalled.

OBJECT AND SCENE MEMORY ARE DIFFERENTIALLY ASSOCIATED WITH CSF MARKERS OF ALZHEIMER’S DISEASE AND MRI VOLUMETRY

Alzheimer's Disease (AD) is characterized by progressive tau-pathology in perirhinal and entorhinal cortices (ErC), hippocampus, parahippocampal cortex and the retrosplenial/posterior cingulate region (RsC/PCC). The latter also shows early amyloid plaque accumulation. While these regions form a network for complex objects-in-scene memories, there is a segregation of object memory into a perirhinal-entorhinal and scene-layout memory into a RsC/PCC-parahippocampal-entorhinal pathway. Here we investigated whether complex objects-in-scene memory, as opposed to isolated object or scene-layout memory is correlated with CSF levels of Aß42 and phospho-tau and MR volume and thickness measures. 204 participants (cognitively healthy, subjective memory complaints, mild cognitive impairment or early AD) of the DELCODE study of the DZNE performed a complex scene recognition memory task. CSF samples were available from 80 participants. 78 participants also performed a second task on mnemonic discrimination of objects (in the absence of scenes) and scenes (in the absence of objects). Of these 28 CSF samples were available. MR thickness measures were obtained from T1 and T2-weighted images using Freesurfer 6. Objects-in-scene recognition memory correlated with right and left PCC volume (p=0.005; p=0.047), right and left hippocampal volume (p=0.002; p=0.001), Aß42, phospho-tau and their ratio (p=0.002; p=0.002; p=0.000). Isolated object and scene discrimination correlated with left and right hippocampal volume (Scene: p=0.039; p=0.006; Object: p=0.011; p=0.001); scene memory correlated with right and object memory with both left and right ErC thickness (Scene: p=0.027; Object: p=0.024; p=0.031). A scene-minus-object difference score correlated with Aß42 levels indicating that decreasing levels of Aß42 were associated with selective decline of scene discrimination (p=0.034). When considering only healthy older adults, object discrimination relatively selectively correlated with right and left hippocampal volume (n=57; rp=0.022; p=0.005), left entorhinal thickness (p=0.042) and with phospho-tau levels (n=19; p=0.052). These data suggest that complex object-in-scene recognition captures variance caused by both tau and amyloid pathology. A domain-specific breakdown, however, indicates that tau-related variance tends to be captured by object discrimination whereas amyloid pathology is captured by scene discrimination performance. The findings are compatible with the possibility that object and scene discrimination track different stages of disease progression in AD.

Effects of varying presentation time on long-term recognition memory for scenes: Verbatim and gist representations.

Konkle, Brady, Alvarez and Oliva (Psychological Science, 21, 1551-1556, 2010) showed that participants have an exceptional long-term memory (LTM) for photographs of scenes. We examined to what extent participants' exceptional LTM for scenes is determined by presentation time during encoding. In addition, at retrieval, we varied the nature of the lures in a forced-choice recognition task so that they resembled the target in gist (i.e., global or categorical) information, but were distinct in verbatim information (e.g., an "old" beach scene and a similar "new" beach scene; exemplar condition) or vice versa (e.g., a beach scene and a new scene from a novel category; novel condition). In Experiment 1, half of the list of scenes was presented for 1s, whereas the other half was presented for 4s. We found lower performance for shorter study presentation time in the exemplar test condition and similar performance for both study presentation times in the novel test condition. In Experiment 2, participants showed similar performance in an exemplar test for which the lure was of a different category but a category that was used at study. In Experiment 3, when presentation time was lowered to 500ms, recognition accuracy was reduced in both novel and exemplar test conditions. A less detailed memorial representation of the studied scene containing more gist (i.e., meaning) than verbatim (i.e., surface or perceptual details) information is retrieved from LTM after a short compared to a long study presentation time. We conclude that our findings support fuzzy-trace theory.

Visual search for changes in scenes creates long-term, incidental memory traces

Humans are very good at remembering large numbers of scenes over substantial periods of time. But how good are they at remembering changes to scenes? In this study, we tested scene memory and change detection two weeks after initial scene learning. In Experiments 1-3, scenes were learned incidentally during visual search for change. In Experiment 4, observers explicitly memorized scenes. At test, after two weeks observers were asked to discriminate old from new scenes, to recall a change that they had detected in the study phase, or to detect a newly introduced change in the memorization experiment. Next, they performed a change detection task, usually looking for the same change as in the study period. Scene recognition memory was found to be similar in all experiments, regardless of the study task. In Experiment 1, more difficult change detection produced better scene memory. Experiments 2 and 3 supported a depth-of-processing account for the effects of initial search and change detection on incidental memory for scenes. Of most interest, change detection was faster during the test phase than during the study phase, even when the observer had no explicit memory of having found that change previously. This result was replicated in two of our three change detection experiments. We conclude that scenes can be encoded incidentally as well as explicitly and that changes in those scenes can leave measurable traces even if they are not explicitly recalled.

A Novel Approach to Measuring the Useful Field of View in Simulated Real-World Environments Using Gaze Contingent Displays: The GC-UFOV.

The Useful Field of View (UFOV) task assesses attentional breadth within a single glance. The UFOV has successfully predicted changes in attention that have real-world consequences (e.g. automobile collision likelihood), however its design prevents it from being incorporated into simulated environments (e.g. driving/flight simulators). Additionally, the UFOV task and other attentional breadth measures (e.g. the peripheral detection task) do not disentangle attention from hard-wired perceptual properties that change with retinal eccentricity (e.g., spatial resolution via cortical magnification). We therefore developed an alternative method of measuring attentional breadth using gaze-contingent (GC) displays, the GC-UFOV. Thirteen participants completed four sessions of testing to determine the effect of a secondary task (auditory N-back) on Gabor patch orientation discrimination at four retinal eccentricities (0o, 3o, 6o, and 9o). Gabor patches were occasionally presented gaze-contingently for single eye fixations while participants completed a scene recognition memory task. Gabors were size-thresholded under single-task conditions to disentangle eccentricity-dependent acuity from changes in attention occurring between single and dual-task conditions, while N-back levels were thresholded to ensure that cognitive load was equivalent across participants. RESULTS showed a significant decrease in orientation sensitivity in the dual-task condition, but not as a function of retinal eccentricity. We conclude that interference with executive attention produces general interference with visual attention equally across retinal eccentricity. N-back sensitivity was only minimally impaired under dual-task conditions compared to single-task trials. Picture recognition memory was no different between N-back single and dual tasks, but was significantly better in the Gabor single task condition. Thus, the Gabor task did not interfere with processing picture information, making this method ideal for use in simulated real-world tasks. Furthermore, we propose that future adaptations of this method employ other ecologically valid sources of cognitive load (e.g., stress, traffic density) to observe their effects on attentional breadth. Meeting abstract presented at VSS 2015. Language: en

Blur Detection Is Unaffected By Cognitive Load, But Eye Movements and Scene Recognition Memory Are.

Blur Detection Is Unaffected By Cognitive Load, But Eye Movements and Scene Recognition Memory Are.

Relationships between Methods for Presenting Information on Navigation Tools and Users' Wayfinding Behavior

This study examines the effects of different methods for presenting navigational information on users' wayfinding behavior and spatial memory. In the first experiment, we examined tools that differed in the degree to which they induced the user to engage in deliberate route planning. We found that users of a tool that showed a route to the goal (the route tool) had a poor scene-recognition memory and simply followed the directed route, compared to users of a paper map which did not show a route. A tool that showed the direction toward the goal (the direction tool) was equivalent to the route tool with respect to users’ scene-recognition memory, but allowed users to take routes more varied than the route tool and as varied as the paper map did. The direction tool affected men and women differently, inducing the latter to make more turns. Our second experiment examined the effects of the size of the device screen, and found that the map’s advantage of allowing the user to attend to their surroundings diminished when the map was shown in small size. We discuss implications for designing effective navigational aids in different situations.

Blur detection is unaffected by cognitive load

Blur detection is affected by retinal eccentricity, but is it also affected by attentional resources? Research showing effects of selective attention on acuity and contrast sensitivity suggests that allocating attention should increase blur detection. However, research showing that blur affects selection of saccade targets suggests that blur detection may be pre-attentive. To investigate this question, we carried out experiments in which viewers detected blur in real-world scenes under varying levels of cognitive load manipulated by the N-back task. We used adaptive threshold estimation to measure blur detection thresholds at 0°, 3°, 6°, and 9° eccentricity. Participants carried out blur detection as a single task, a single task with to-be-ignored letters, or an N-back task with four levels of cognitive load (0, 1, 2, or 3-back). In Experiment 1, blur was presented gaze-contingently for occasional single eye fixations while participants viewed scenes in preparation for an easy picture recognition memory task, and the N-back stimuli were presented auditorily. The results for three participants showed a large effect of retinal eccentricity on blur thresholds, significant effects of N-back level on N-back performance, scene recognition memory, and gaze dispersion, but no effect of N-back level on blur thresholds. In Experiment 2, we replicated Experiment 1 but presented the images tachistoscopically for 200 ms (half with, half without blur), to determine whether gaze-contingent blur presentation in Experiment 1 had produced attentional capture by blur onset during a fixation, thus eliminating any effect of cognitive load on blur detection. The results with three new participants replicated those of Experiment 1, indicating that the use of gaze-contingent blur presentation could not explain the lack of effect of cognitive load on blur detection. Thus, apparently blur detection in real-world scene images is unaffected by attentional resources, as manipulated by the cognitive load produced by the N-back task.

A Potential Spatial Working Memory Training Task to Improve Both Episodic Memory and Fluid Intelligence

One current challenge in cognitive training is to create a training regime that benefits multiple cognitive domains, including episodic memory, without relying on a large battery of tasks, which can be time-consuming and difficult to learn. By giving careful consideration to the neural correlates underlying episodic and working memory, we devised a computerized working memory training task in which neurologically healthy participants were required to monitor and detect repetitions in two streams of spatial information (spatial location and scene identity) presented simultaneously (i.e. a dual n-back paradigm). Participants’ episodic memory abilities were assessed before and after training using two object and scene recognition memory tasks incorporating memory confidence judgments. Furthermore, to determine the generalizability of the effects of training, we also assessed fluid intelligence using a matrix reasoning task. By examining the difference between pre- and post-training performance (i.e. gain scores), we found that the trainers, compared to non-trainers, exhibited a significant improvement in fluid intelligence after 20 days. Interestingly, pre-training fluid intelligence performance, but not training task improvement, was a significant predictor of post-training fluid intelligence improvement, with lower pre-training fluid intelligence associated with greater post-training gain. Crucially, trainers who improved the most on the training task also showed an improvement in recognition memory as captured by d-prime scores and estimates of recollection and familiarity memory. Training task improvement was a significant predictor of gains in recognition and familiarity memory performance, with greater training improvement leading to more marked gains. In contrast, lower pre-training recollection memory scores, and not training task improvement, led to greater recollection memory performance after training. Our findings demonstrate that practice on a single working memory task can potentially improve aspects of both episodic memory and fluid intelligence, and that an extensive training regime with multiple tasks may not be necessary.

Neural correlates of contextual cueing are modulated by explicit learning

Contextual cueing refers to the facilitated ability to locate a particular visual element in a scene due to prior exposure to the same scene. This facilitation is thought to reflect implicit learning, as it typically occurs without the observer's knowledge that scenes repeat. Unlike most other implicit learning effects, contextual cueing can be impaired following damage to the medial temporal lobe. Here we investigated neural correlates of contextual cueing and explicit scene memory in two participant groups. Only one group was explicitly instructed about scene repetition. Participants viewed a sequence of complex scenes that depicted a landscape with five abstract geometric objects. Superimposed on each object was a letter T or L rotated left or right by 90°. Participants responded according to the target letter (T) orientation. Responses were highly accurate for all scenes. Response speeds were faster for repeated versus novel scenes. The magnitude of this contextual cueing did not differ between the two groups. Also, in both groups repeated scenes yielded reduced hemodynamic activation compared with novel scenes in several regions involved in visual perception and attention, and reductions in some of these areas were correlated with response-time facilitation. In the group given instructions about scene repetition, recognition memory for scenes was superior and was accompanied by medial temporal and more anterior activation. Thus, strategic factors can promote explicit memorization of visual scene information, which appears to engage additional neural processing beyond what is required for implicit learning of object configurations and target locations in a scene.

Sleep deprivation and its effects on object-selective attention

Sleep deprivation (SD) affects attention but it is an open question as to whether all subtypes of attention are similarly affected. We investigated the effects of 24 h of total SD on object-selective attention. 26 healthy, young adults viewed quartets of alternating faces or place scenes and performed selective judgments on faces only, scenes only or both faces and scenes. Volunteers underwent fMRI following a normal night of sleep and again following approximately 24 h of total sleep deprivation in a counterbalanced fashion. Sleep deprivation resulted in slower and less accurate picture classification as well as poorer recognition memory for scenes. Attention strongly modulated activation in the Parahippocampal Place Area (PPA). Task-related activation in the fronto-parietal cortex and PPA was reduced in SD, but the relative modulation of PPA activation by attention was preserved. Psychophysiological interaction between the left intra-parietal sulcus and the PPA that was clearly present after a normal night of sleep was reduced below threshold following SD suggesting that PPI may be a more sensitive method of detecting change in selective attention. Sleep deprivation may affect object-selective attention in addition to exerting a task-independent deficit in attention.

Content-specific source encoding in the human medial temporal lobe.

Although the medial temporal lobe (MTL) is known to be essential for episodic encoding, the contributions of individual MTL subregions remain unclear. Data from recognition memory studies have provided evidence that the hippocampus supports relational encoding important for later episodic recollection, whereas the perirhinal cortex has been linked with encoding that supports later item familiarity. However, extant data also strongly implicate the perirhinal cortex in object processing and encoding, suggesting that perirhinal processes may contribute to later episodic recollection of object source details. To investigate this possibility, encoding activation in MTL subregions was analyzed on the basis of subsequent memory outcome while participants processed novel scenes paired with 1 of 6 repeating objects. Specifically, encoding activation correlating with later successful scene recognition memory was evaluated against that of source recollection for the object paired with the scene during encoding. In contrast to studies reporting a link between perirhinal cortex and item familiarity, it was found that encoding activation in the right perirhinal cortex correlates with successful recollection of the paired object. Furthermore, other MTL subregions also exhibited content-specific source encoding patterns of activation, suggesting that MTL subsequent memory effects are sensitive to stimulus category.

Processes of scene recognition memory in young children and adults

The study presented here investigates Mandler's (1983) claim that memory for scenes is qualitatively similar in children and adults. We assessed 5- to 7-year-olds' and adults' memory for inventory information in scenes as assessed by type changes, in which one object is replaced by a conceptually different object. We tested for effects of three schema-related processes on scene memory. Results showed that both children and adults used two of those processes, which we have called the added unexpected object effect and the congruency effect. In the added unexpected object effect viewers tended to correctly reject any distractor scenes in which a new unexpected object was added. In the congruency effect viewers tended to correctly reject distractor scenes that contained a new unexpected object if each of the original scenes that they had viewed had contained all expected objects, and vice versa. There was no evidence at either age for what we have called the deleted unexpected object effect, in which viewers would notice that an unexpected object in the original scene was now missing in the distractor scene. The only developmental difference was that adults appeared to give relatively greater weight to the added unexpected object effect than to the congruency effect, whereas children weighted them equally. We conclude by speculating on the role of metacognitive awareness in the developmental trend toward greater influence from the added unexpected object effect in memory for scenes.