Spatial ability at different times of day

Three groups of approx. 30 Ss in each group of recruits drawn from the same sample were required to complete a test of spatial ability at three different times of day (morning 9.30; afternoon 13.30 and early evening 17.30). In accordance with predictions the morning group obtained a higher score than either the midday or evening group. Results are discussed in terms of chronobiological theories.     

Forgetting as a function of sleep at different times of day

The experiment studied the separate effects of sleep and time period of retention interval on forgetting. A free recall task was given to independent groups of subjects either at night or in the morning, and a second recall demanded 5 h later, after an intervening period of sleeping or waking activity. Oral body temperatures (BT) were measured at each session. The data were analysed in terms of (a) immediate recall at test 1, and (b) amount forgotten from test 1 to test 2. Immediate recall was higher for morning groups, in agreement with previous findings, serial position analysis indicating that the effect is confined to enhancement of the primary memory component. Long-term retention was higher over the night interval, irrespective of sleeping conditions, though having slept at night produced better retention than having stayed awake. Sleep during the morning was not effective in reducing forgetting. BT showed a marked drop for both night groups and rise for day groups over the retention interval. Alternative explanations for the classical sleep/memory findings are suggested in terms of (a) differential effects of sleep stages on memory, and (b) the underlying diurnal variation in BT and other processes.     

Text repetition and text integration

Two experiments explored the levels of text representation that mediate text repetition effects, following the Raney (2003) model. The magnitude of the repetition benefit in Experiment 1 supported predictions of Raney's model, indicating that the ease of forming a situation model contributed to the magnitude of the reprocessing benefit. In addition, representations organized around a good situation model were more sensitive to changes than were representations formed from reading without a good situation model. The results of Experiment 2 did not support the suggestion that the surface form and textbase are bound to a well-developed situation model, thereby limiting repetition effects to similar linguistic contexts. Rather, the nature of the repetition benefits in the present series of experiments are better explained by the degree o foverlap between passages at eachof the three levels of text representation.     

Discrepant integration times for upright and inverted faces

Judgments of upright faces tend to be more rapid than judgments of inverted faces. This is consistent with encoding at different rates via discrepant mechanisms, or via a common mechanism that is more sensitive to upright input. However, to the best of our knowledge no previous study of facial coding speed has tried to equate sensitivity across the characteristics under investigation (eg emotional expression, facial gender, or facial orientation). Consequently we cannot tell whether different decision speeds result from mechanisms that accrue information at different rates, or because facial images can differ in the amount of information they make available. To address this, we examined temporal integration times, the times across which information is accrued toward a perceptual decision. We examined facial gender and emotional expressions. We first identified image pairs that could be differentiated on 80% of trials with protracted presentations (1 s). We then presented these images at a range of brief durations to determine how rapidly performance plateaued, which is indicative of integration time. For upright faces gender was associated with a protracted integration relative to expression judgments. This difference was eliminated by inversion, with both gender and expression judgments associated with a common, rapid, integration time. Overall, our data suggest that upright facial gender and expression are encoded via distinct processes and that inversion does not just result in impaired sensitivity. Rather, inversion caused gender judgments, which had been associated with a protracted integration, to become associated with a more rapid process.     

Frontal cortex grafts have opposite effects at different postoperative recovery times

We studied the effect of different postoperative times on the behavioral recovery following brain implants. Adult male rats received cortical tissue grafts 2 weeks after aspiration of the medial frontal cortex. Either 2 (Immediate Group) or 28 (Delay Group) days after grafting, the performance of these rats on a behavioral battery, comprising the Morris water maze task, forepaw use, and grooming, was compared to that of rats with similar lesions and postoperative recovery times but no grafts. Rats tested immediately after receiving implants performed better on the spatial navigation task than rats with similar lesions but no grafts. This improvement, however, was less than that shown by rats with lesions but no grafts permitted to recover for 28 days before testing. In contrast, in the Delay Group, rats with grafts were more greatly impaired than were their operated controls. Neither lesions nor grafts affected grooming although the Immediate Group with grafts were significantly more impaired in using their forepaws during feeding than were any of the other groups. These results lead us to conclude that differing postoperative recovery times and task requirements may account for some of the inconsistent results of the influence of brain grafts on behavioral recovery reported in the literature. We also conclude that cortical tissue implants can have two effects with different time courses and opposite net behavioral effects.     

The spontaneous use of memory aids at different educational levels

Three groups of students in different educational levels: 8th–9th grade students (average age 15); 10th–11th grade students (average age 16); and college students (average age 21), completed a metamemory questionnaire on the use of external, general, and formal memory aids in everyday life and study situations. Short-term repetition, mental rehearsing, and summary elaboration were the most frequent aids. The least frequently used were those that require a special training to be used effectively (e.g. Digit-letters and method of loci). There were differences in the use of general memory aids due to education level, but not in the case of external and formal memory aids. Results showed also that women used memory aids more frequently than men.     

Multisensory integration affects visuo-spatial working memory

In the present study, we investigate how spatial attention, driven by unisensory and multisensory cues, can bias the access of information into visuo-spatial working memory (VSWM). In a series of four experiments, we compared the effectiveness of spatially-nonpredictive visual, auditory, or audiovisual cues in capturing participants' spatial attention towards a location where to-be-remembered visual stimuli were or were not presented (cued/uncued trials, respectively). The results suggest that the effect of peripheral visual cues in biasing the access of information into VSWM depend on the size of the attentional focus, while auditory cues did not have direct effects in biasing VSWM. Finally, spatially congruent multisensory cues showed an enlarged attentional effect in VSWM as compared to unimodal visual cues, as a likely consequence of multisensory integration. This latter result sheds new light on the interplay between spatial attention and VSWM, pointing to the special role exerted by multisensory (audiovisual) cues.     

Hope, pride, and processing during optimal and nonoptimal times of day

We examine the conditions under which the distinct positive emotions of hope versus pride facilitate more or less fluid cognitive processing. Using individuals' naturally occurring time of day preferences (i.e., morning vs. evening hours), we show that specific positive emotions can differentially influence processing resources. We argue that specific positive emotions are more likely to influence processing and behavior during nonoptimal times of day, when association-based processing is more likely. We show in three experiments that hope, pride, and a neutral state differentially influence fluid processing on cognitive tasks. Incidental hope facilitates fluid processing during nonoptimal times of day (compared with pride and neutral), improving performance on tasks requiring fluid intelligence (Experiment 1) and increasing valuation estimates on tasks requiring that preferences be constructed on the spot (Experiments 2 and 3). We also provide evidence that these differences in preference and valuation occur through a process of increased imagination (Experiment 3). We contribute to emotion theory by showing that different positive emotions have different implications for processing during nonoptimal times of day.     

Sleep strengthens integration of spatial memory systems

Spatial memory comprises different representational systems that are sensitive to different environmental cues, like proximal landmarks or local boundaries. Here we examined how sleep affects the formation of a spatial representation integrating landmark-referenced and boundary-referenced representations. To this end, participants (n = 42) were familiarized with an environment featuring both a proximal landmark and a local boundary. After nocturnal periods of sleep or wakefulness and another night of sleep, integration of the two representational systems was tested by testing the participant''s flexibility to switch from landmark-based to boundary-based navigation in the environment, and vice versa. Results indicate a distinctly increased flexibility in relying on either landmarks or boundaries for navigation, when familiarization to the environment was followed by sleep rather than by wakefulness. A second control study (n = 45) did not reveal effects of sleep (vs. wakefulness) on navigation in environments featuring only landmarks or only boundaries. Thus, rather than strengthening isolated representational systems per se, sleep presumably through forming an integrative representation, enhances flexible coordination of representational subsystems.

Wilson and McNaughton (1994) reported that “… information acquired during active behavior is … reexpressed in hippocampal circuits during sleep….” This observation of experience-dependent neural replay activity in the brain during slow-wave sleep (for review, see O''Neill et al. 2010) forms a keystone in our current understanding of how sleep affects memory consolidation in an active system consolidation process that involves the redistribution of hippocampal memory to extrahippocampal regions (McClelland et al. 1995; Diekelmann and Born 2010; Klinzing et al. 2019). According to theory, the emerging extrahippocampal memory representations are essentially schematic, devoid of specific context-information, and lack minute detail (Lewis and Durrant 2011; Payne 2011; Sekeres et al. 2018). Simultaneously, hippocampal replay strengthens hippocampal memory traces in the short-term following Hebbian learning, leading to improved context memory immediately after sleep compared with wakefulness (van der Helm et al. 2011; Weber et al. 2014). In the present study, we sought to test sleep''s role in establishing higher-level memory representations drawing on the example of spatial memory processing.Inspired by the strong role of the hippocampal formation in human spatial memory (Burgess 2008; Hartley et al. 2014) a number of studies examined effects of sleep specifically on spatial memory consolidation (Peigneux et al. 2004; Orban et al. 2006; Ferrara et al. 2008; Rauchs et al. 2008; Wamsley et al. 2010; Nguyen et al. 2013; Noack et al. 2017). In these studies, participants explored a virtual environment during a learning phase before retention periods of sleep and wakefulness and, later on, engaged in specific retrieval tasks that required to reach a predefined goal location in the environment as fast as possible. Results were mixed with, some studies reporting positive effects of sleep on spatial navigation performance (e.g., Peigneux et al. 2004; Wamsley et al. 2010; Nguyen et al. 2013; Noack et al. 2017), whereas in others such sleep effect depended on the length of the retention interval (e.g., Ferrara et al. 2008), or was completely absent (Orban et al. 2006; Rauchs et al. 2008). Interestingly, in the latter studies—despite absent behavioral effects—using a 72-h retention interval between learning and retrieval testing, functional magnetic resonance imaging (fMRI) suggested that sleep favors a shift from activation of hippocampal areas toward preferential activation of striatal areas at retrieval of the relevant spatial representations.Indeed, spatial navigation can rely on two distinct representational systems that involve as key structures hippocampal and striatal circuitry, respectively, and are also linked to different spatial frames of reference (Burgess 2008; Hartley et al. 2014). Doeller et al. (2008) showed in humans that striatal activation is linked to the processing of single proximal landmarks whereas hippocampal activation is related to the processing of spatial boundaries, and that acquisition of representations in both systems may follow different learning rules (Doeller and Burgess 2008). The subject''s reliance on one or the other representation system depends on the specific navigational problem (Maguire et al. 1998; Hartley et al. 2003) as well as familiarity with the environment (Hartley et al. 2003; Iaria et al. 2003; Packard and McGaugh 1996), but both systems can also be activated in parallel and interact. For example, patients with hippocampal atrophy showed impaired memory performance not only for boundary-based but also for landmark-based navigation (Guderian et al. 2015) suggesting the presence of synergistic effects between the representational systems. The activation of the representational systems is presumably coordinated by the medial prefrontal cortex (Ragozzino et al. 1999; Doeller et al. 2008; Rich and Shapiro 2009), that is, a region that is not only involved in the abstraction of schema-like spatial representations (Tse et al. 2011; van Buuren et al. 2014) but, also shows neuronal reactivation during sleep (Euston et al. 2007; Peyrache et al. 2009).In fact, there is first evidence suggesting that sleep supports the formation of abstract representations of space in particular. We found, for example, that sleep benefitted the extraction of semantic structure (regions defined by semantic category of landmarks) in a virtual navigation task (Noack et al. 2017). To date, there is no study, however, to specifically test the interaction between landmark- and boundary-referenced representations of space and their integration during sleep. Here we sought to fill this gap. Drawing on the active systems consolidation concept of sleep (Dudai et al. 2015; Klinzing et al. 2019) and on the existing literature, we followed the hypothesis that, rather than benefiting a specific spatial representation, sleep via neuronal replay primarily supports the formation of an integrative schema-like spatial representation and, thereby, improves flexibility in the use of hippocampus-based and striatum-based representations.To this end, we conducted two experiments, a Main experiment and a Control experiment, using a virtual spatial environment with one proximal landmark and a local boundary (Fig. 1) to preferentially engage striatum and hippocampus-based representational systems, respectively (Doeller et al. 2008). The Main experiment was designed to test the effect of sleep on the integration of landmark-referenced and boundary-referenced representations of space. To this end, participants were first familiarized with an environment featuring both a landmark and a boundary, thereby encoding both hippocampal as well as striatal representations of the environment. In order to test whether sleep enhances the integration of these representations, participants either slept or remained awake on the night after the Familiarization phase. They then learned new objects in impoverished environments featuring the same spatial cues (landmark and boundary) at the same locations but only one at a time. At a final Test session, the integration of the combined environmental layout including landmark and boundary (as presented during Familiarization before sleep) was investigated by the participant''s flexibility to switch from landmark-based to boundary-based navigation in the environment, and vice versa, from boundary-based to landmark-based navigation (Fig. 1). In the Control experiment, we investigated the direct effect of postlearning sleep or wakefulness on the consolidation of spatial memory representation that were either merely boundary-referenced or landmark-referenced, thereby controlling for general effects of sleep on spatial memory performance.Open in a separate windowFigure 1.Task and general procedures. (A) Example views on the three different environments. (Panel i) landmark and boundary present, as used in the Familiarization phase of the Main experiment. Alpine environment (panel ii), and Desert environment (panel iii) as used in the Control experiment. (B) Task procedure: The task featured three different trial types in both experiments. (Panel i) Acquisition trials were presented at the start of Familiarization and Learning phases in both experiments. (Panel ii) Feedback and Test trials started with the presentation of an object on a gray screen. Participants were then placed in the experimental environment containing boundary (thick encirclement), landmarks (traffic cone) or both, and dropped the object at the location where they found it during acquisition. In Feedback trials feedback was given by presenting the object at its correct location. Participants navigated to it to collect it. (C) Design of Main experiment: Environment featured both landmark and boundary cues during Familiarization. The Test session comprised Learning phase and Retrieval phase. Only one spatial cue (landmark or boundary) was present during each trial of the Learning and Retrieval phase (three objects with landmark, three objects with boundary). Object reference switched from Learning to Retrieval phase: Objects presented together with the landmark during learning were presented with boundary during retrieval and vice versa. Note that a specific spatial cue was always at the same relative position when presented during Familiarization, Learning, and Test. (D) Design of Control experiment: Participants were randomly assigned to the Boundary or the Landmark group, whereas all participants performed in Wake and Sleep condition. Each of the two visits (sleep and wake) consisted of two sessions (learning: six Acquisition trials + four blocks and six feedback trials; retrieval: three blocks and six Test trials).To preview our results: Whereas there was no effect of sleep on landmark- and boundary-referenced spatial memory per se in the Control experiment, sleep indeed facilitated the flexible use of different spatial retrieval cues possibly based on a superior integrated spatial memory representation.     

The level of subjective visibility at different stages of memory processing

Recent research suggests that the content of iconic memory (IM) and fragile visual short-term memory could be associated with a similar level of conscious accessibility as working memory (WM). The results of our studies, in which we used a subjective visibility scale in a partial-report change detection paradigm, indicate that it is possible to distinguish separate stages of memory based on both discriminative accuracy and conscious accessibility. The highest scores were associated with IM and the lowest with WM, while somewhere in the middle there was fragile memory. Based on classical assumptions, WM accessibility should be greater than the other two types of memory; however, our study showed that this might not always be the case. We discuss the potential sources of this outcome, of which one may be the task construction, as we only tested items that were directly in the focus of attention.     

Distinct neural mechanisms mediate olfactory memory formation at different timescales

Habituation is one of the oldest forms of learning, broadly expressed across sensory systems and taxa. Here, we demonstrate that olfactory habituation induced at different timescales (comprising different odor exposure and intertrial interval durations) is mediated by different neural mechanisms. First, the persistence of habituation memory is greater when mice are habituated on longer timescales. Second, the specificity of the memory (degree of cross-habituation to similar stimuli) also depends on induction timescale. Third, we demonstrate a pharmacological double dissociation between the glutamatergic mechanisms underlying short- and long-timescale odor habituation. LY341495, a class II/III metabotropic glutamate receptor antagonist, blocked habituation only when the induction timescale was short. Conversely, MK-801, an N-methyl-D-aspartate (NMDA) receptor antagonist, prevented habituation only when the timescale was long. Finally, whereas short-timescale odor habituation is mediated within the anterior piriform cortex, infusion of MK-801 into the olfactory bulbs prevented odor habituation only at longer timescales. Thus, we demonstrate two neural mechanisms underlying simple olfactory learning, distinguished by their persistence and specificity, mediated by different olfactory structures and pharmacological effectors, and differentially utilized based solely on the timescale of odor presentation.     

Time of day affects episodic memory in older adults

The neuropsychological test scores of 2030 cognitively normal older adults were examined to evaluate performance patterns as they related to time of day (TOD) at which testing was initiated. Multiple regression analyses were used to examine the association of TOD with scores on seven neuropsychological tests used in the clinical evaluation of dementia. Episodic memory performance was significantly related to TOD, while memory span and verbal fluency were not. Best performance occurred during early morning hours and late afternoon; worst performance occurred mid-day (i.e., noon). These findings may have implications for clinical assessment, the design of research on dementia, and the daily functioning of older adults.     

Time of day affects implicit memory for unattended stimuli

We investigated whether circadian arousal affects perceptual priming as a function of whether stimuli were attended or ignored during learning. We tested 160 participants on- and off-peak with regards to their circadian arousal. In the study phase, they were presented with two superimposed pictures in different colours. They had to name the pictures of one colour while ignoring the others. In the test phase, they were presented with the same and randomly intermixed new pictures. Each picture was presented in black colour in a fragment completion task. Priming was measured as the difference in fragmentation level at which the pictures from the study phase were named compared to the new pictures. Priming was stronger for attended than ignored pictures. Time of day affected priming only for ignored pictures, with stronger priming effects off-peak than on-peak. Thus, circadian arousal seems to favour the encoding of unattended materials specifically at off-peak.     

The integration of family therapy in a psychiatric day hospital

The clients, who present themselves at our psychiatric day hospital in Amsterdam, often have long-standing problems. These problems are usually of a complex nature, and the age of the clients plays an imporant role in this. Their age varies from seventeen to forty, with an average of twenty-eight.
Efforts were made over a long period to facilitate solutions to the clients' family conflicts. During this time an extensive range of problems within the family were presented of which the symptoms of the client represent just a part.
Working as a family therapist in a psychiatric day hospital, where clients are admitted individually, places the family therapist in a number of dilemmas, especially when many working in the hospital see the problems only as individual ones.     

Personality,time of day and delayed memory for tv news

An experiment was conducted to test the effects of time of day on delayed memory for televised news stories. Three groups received the same sequence of 6 news stories at 09.30, 13.30 and 16.30, respectively. Unexpected tests of free recall, cued recall and recognition were given about 2 hr after news presentation. Results showed that memory performance improved slightly across the day on tests of recall, and significantly so on recognition. Personality differences were also examined. In general, introverts remembered more than extraverts and differences between them were most marked during the late-afternoon session especially on free recall and when minimal cuing was provided. The results support previous time-of-day findings for delayed retention of complex learning materials. Personality differences observed here are consistent with predicted introvert-extravert differences in memory performance predicted by Eysenck's modified action-decrement hypothesis.     

Investigating the structure of autobiographical memory using reaction times

The study investigated the structure of autobiographical memory using reaction time measures. A total of 18 participants took photographs over their summer holidays and then reacted to pairs of these photographs displayed via a computer. They also subsequently sorted their photographs according to the autobiographical themes and events with which they were associated. When photographic sequence and the physical similarities in the photographs were controlled for by considering the results of “stranger” participants who were unfamiliar with the photographs, reaction times were significantly faster to pairs of photographs from the same theme or event. The results are consistent with currently held assumptions about the structure of autobiographical memory. Furthermore, the results suggest that reaction time measures may provide a valuable means by which aspects of autobiographical memory can be explored.     

Trait memory and behavior memory: the effects of alternative pathways on impression judgment response times

Carlston (1980a) and Lingle (1983) argued that remembered behaviors, previous trait inferences, or both may be accessed and used in making new trait inferences, depending on a variety of factors. In this article we relate this argument to a spreading activation model of memory and suggest factors that should affect the relative accessibility of inferences and behaviors during trait judgment processes. In our study we varied several of these factors and assessed accessibility, using response-time methods. The results of this study strongly support the model's prediction that prompting inference formation facilitates subsequent trait judgment response times, but only when relevant behavior memories have not been recently primed. We theorize that the inference manipulations used in this study strengthened the direct pathway to a relevant trait concept, but that the strength of this pathway was immaterial to judgment response times when a "proximal prime" directed retrieval efforts along an alternative "behavioral" route to the trait information. The results also suggest that the proximal behavior prime facilitated trait responses among subjects who had not been induced to make trait inferences, but slowed trait responses among subjects who had previously been induced to make trait inferences.