Mental time travel to the future might be reduced in sleep.

We present a quantitative study of mental time travel to the future in sleep. Three independent, blind judges analysed a total of 563 physiology-monitored mentation reports from sleep onset, REM sleep, non-REM sleep, and waking. The linguistic tool for the mentation report analysis is based on established grammatical and cognitive-semantic theories and has been validated in previous studies. Our data indicate that REM and non-REM sleep must be characterized by a reduction in mental time travel to the future, which would support earlier physiological evidence at the level of brain function.

As we fall asleep we forget about the future: A quantitative linguistic analysis of mentation reports from hypnagogia.

We present a quantitative study of mental time travel to the past and future in sleep onset hypnagogia. Three independent, blind judges analysed a total of 150 mentation reports from different intervals prior to and after sleep onset. The linguistic tool for the mentation report analysis grounds on established grammatical and cognitive-semantic theories, and proof of concept has been provided in previous studies. The current results indicate that memory for the future, but not for the past, decreases in sleep onset - thereby supporting preliminary physiological evidence at the level of brain function. While recent memory research emphasizes similarities in the cognitive and physiological processes of mental time travel to the past and future, the current study explores a state of consciousness which may serve to dissociate between the two.

Decreased mental time travel to the past correlates with default-mode network disintegration under lysergic acid diethylamide.

This paper reports on the effects of LSD on mental time travel during spontaneous mentation. Twenty healthy volunteers participated in a placebo-controlled crossover study, incorporating intravenous administration of LSD (75 µg) and placebo (saline) prior to functional magnetic resonance imaging (fMRI). Six independent, blind judges analysed mentation reports acquired during structured interviews performed shortly after the functional magnetic resonance imaging (fMRI) scans (approximately 2.5 h post-administration). Within each report, specific linguistic references to mental spaces for the past, present and future were identified. Results revealed significantly fewer mental spaces for the past under LSD and this effect correlated with the general intensity of the drug's subjective effects. No differences in the number of mental spaces for the present or future were observed. Consistent with the previously proposed role of the default-mode network (DMN) in autobiographical memory recollection and ruminative thought, decreased resting-state functional connectivity (RSFC) within the DMN correlated with decreased mental time travel to the past. These results are discussed in relation to potential therapeutic applications of LSD and related psychedelics, e.g. in the treatment of depression, for which excessive reflection on one's past, likely mediated by DMN functioning, is symptomatic.

The impact of change in stimulus format on the electrophysiological indices of recognition.

The present study investigated the impact of changes in stimulus format between study and test on the event-related potential (ERP) correlates of recognition. To this end subjects studied the names and pictures of common objects. At retrieval, subjects were presented with old items for which the presentational format had changed (from picture to name or vice versa), old items that were shown in the same format as at study, and new items. ERPs revealed three temporally, spatially and functionally dissociable memory-related effects: an early bilateral frontal effect, which was sensitive to the perceptual similarity between study and test stimulus; a left temporo-parietal effect, which was sensitive to the type of stimulus that was encoded; and a late frontal effect, which was largest over right electrode sites and appeared to be sensitive to the type of test stimulus. The results provide further evidence for a functional dissociation between the early bilateral frontal and the later temporo-parietal old/new effect, suggesting an interpretation in terms of processes contributing to a perceptually-driven familiarity or novelty assessment and recollection, respectively.

Age-related differences in recognition memory: effects of materials and context change.

The study explored age-related differences in the effects of context change on recognition memory by presenting object names (Expt. 1A) or their pictures (Expt. 1B) on background scenes. Participants later attempted to recognize previously presented items on background scenes that were original, switched, blank, or new. Older adults recognized fewer word stimuli than did younger adults, and context effects were larger for older adults. With pictures, however, the age-related decrement was eliminated and context effects were reduced. The beneficial effect of context reinstatement in older adults occurs despite the finding that they are less able to recall or recognize such contexts (Experiment 2). Older adults can use context information in recognition memory at least as efficiently as younger adults when suitable materials and conditions are provided.

Person perception across the menstrual cycle: hormonal influences on social-cognitive functioning.

Women's reactions to men shift during the menstrual cycle. For example, during the phase of high conception risk, women prefer men with masculinized facial features. A favored explanation for this effect is that women display an enhanced sensitivity to stimuli that have significant reproductive relevance during the phase of the menstrual cycle in which conception risk is high. Consistent with this viewpoint, the present research demonstrated that women's cycle-dependent attentiveness to "maleness" also extends to basic aspects of the person-perception process. Specifically, during the phase of high conception risk, women displayed an enhanced ability both to categorize men and to access associated category-related (i.e., stereotypic) material from semantic memory. The implications of these findings for contemporary treatments of person perception are considered.

Remembering or knowing others? Person recognition and recollective experience.

Using Tulving's (1985) remember/know procedure, the present research investigated the experiential concomitants of person recognition. Noting basic differences in the manner in which the mind processes expectancy-related material, it was anticipated that facial typicality would be a critical determinant of people's recollective experiences (i.e., remembering vs knowing). In particular, it was expected that whereas remember responses would be more prevalent for distinctive than typical faces, know responses would reflect the opposite pattern. The results of two experiments provided general support for these predictions. In addition, the recollective advantage for distinctive faces was traced to the availability of attentional resources at encoding. These results are considered in the context of contemporary issues in person recognition and social cognition.

Creating memory illusions: expectancy-based processing and the generation of false memories.

The present research investigated the generation of memory illusions. In particular, it attempted to delineate the conditions under which category-based thinking prompts the elicitation of false memories. Noting fundamental differences in the manner in which expected and unexpected person-related information is processed and represented in the mind, it was anticipated that, via gist-based recognition, participants would display a pronounced propensity to generate expectancy-consistent false memories. The results of three experiments supported this prediction. In addition, the research revealed that participants' false memories were accompanied by the subjective experience of knowing (Expt. 2) and that false recognition was exacerbated under conditions of executive dysfunction (Expt. 3). We consider the theoretical implications of these findings for recent treatments of memory illusions and social cognition.