The role of mental imagery in spontaneous thoughts of the past and future

Spontaneous thought refers to a mental state, or series of mental states, that are unconstrained by a specific task and move freely over time. Converging evidence suggests that spontaneous thoughts may contain mental imagery of scenes ('scene construction') when remembering the past and imagining the future ('mental time travel'). However, no research has directly examined the relationship between scene construction and mental time travel during spontaneous thought. We used experience sampling and multi-level modeling to obtain subjective reports from eighty participants during waking rest, and examined these reports along three dimensions: (1) freedom of movement (referring to the degree to which thoughts are deliberate or spontaneous), (2) mental imagery (including scene construction, inner speech, and isolated elements), and (3) temporal orientation (towards the past, present, and future). Our results showed that multiple types of mental imagery, including scene construction, inner speech, and isolated elements, were positively associated with spontaneous thoughts generated during waking rest. Furthermore, all forms of mental imagery were positively associated with past and future orientation. In contrast, deliberate thoughts generated during waking rest were negatively associated with mental imagery and present orientation. These data suggest that various forms of mental imagery, including scene construction, inner speech, and isolated elements, all support spontaneous thoughts of the past and future. This research advances our understanding of healthy, adaptive human thought patterns in everyday life, and provides a baseline for better understanding unhealthy, maladaptive thought patterns in clinical contexts.Arts, Faculty ofPsychology, Department ofGraduat

Test Expectation Enhances Memory Consolidation across Both Sleep and Wake

Citation: Wamsley EJ, Hamilton K, Graveline Y, Manceor S, Parr E (2016) Test Expectation Enhances Memory Consolidation across Both Sleep and Wake. PLoS ONE 11(10): e0165141. doi:10.1371/journal.pone.0165141 Abstract: Memory consolidation benefits from post-training sleep. However, recent studies suggest that sleep does not uniformly benefit all memory, but instead prioritizes information that is important to the individual. Here, we examined the effect of test expectation on memory consolidation across sleep and wakefulness. Following reports that information with strong “future relevance” is preferentially consolidated during sleep, we hypothesized that test expectation would enhance memory consolidation across a period of sleep, but not across wakefulness. To the contrary, we found that expectation of a future test enhanced memory for both spatial and motor learning, but that this effect was equivalent across both wake and sleep retention intervals. These observations differ from those of least two prior studies, and fail to support the hypothesis that the “future relevance” of learned material moderates its consolidation selectively during sleep. Here, we archive both the raw datafile (in SPSS format) used to generate these results, and the laboratory procedures manuals used as a guide during data collection. A separate SPSS syntax file contains the data exclusions used for analysis. Questions may be addressed to Dr. Erin Wamsely at Furman University: [email protected]

Comparing the phenomenological qualities of stimulus-independent thought, stimulusdependent thought, and dreams using experience sampling

Humans spend a considerable portion of their lives engaged in “stimulus-independent thoughts” (SIT), or mental activity that occurs independently of input from the immediate external environment. Although such SITs are, by definition, different from thoughts that are driven by stimuli in one’s external environment (i.e., stimulus-dependent thoughts; SDTs), at times, the phenomenology of these two types of thought appears to be deceptively similar. But how similar are they? We address this question by comparing the content of two types of SIT (dreaming and waking stimulus-independent thoughts) with the content of SDTs. In this seven-day, smartphonebased experience-sampling procedure, participants were intermittently probed during the day and night to indicate whether their current thoughts were stimulus dependent or stimulus independent. They then responded to content-based items indexing the qualitative aspects of their experience (e.g., My thoughts were jumping from topic to topic). Results indicate substantial distinctiveness between these three types of thought: significant differences between at least two of the three traits were found across every measured variable

Sleep Architecture.

<p>Sleep Architecture.</p

Experimental Group Characteristics at Baseline.

<p>Experimental Group Characteristics at Baseline.</p

Experimental Design.

<p>After training on two learning tasks, participants were retested following an 11hr delay filled with either wakefulness or sleep. Immediately after encoding, <i>test expected</i> groups were informed that they would be later tested on the same material, whereas <i>test unexpected</i> groups were not.</p

Effect of Expectation on Consolidation.

<p>The instruction to expect a future test enhanced performance on both the VMT and MST tasks. Error bars ±SEM. For clarity, this figure displays improvement from baseline. Statistical tests utilized an ANCOVA controlling for baseline performance.</p

Expectation Equivalently Affects Memory across Both Wake and Sleep.

<p>The effect of expectation on memory consolidation was expressed equally across wake and sleep delays. Error bars ±SEM. For clarity, this Fig displays improvement from baseline. Statistical tests utilized an ANCOVA controlling for baseline performance.</p