Grapheme–colour synaesthesia yields an ordinary rather than extraordinary memory advantage: Evidence from a group study

In synaesthesia, the input of one sensory modality automatically triggers an additional experience, not normally triggered by the input of that modality. Therefore, compared to non-synaesthetes, additional experiences exist and these may be used as retrieval cues when memory is tested. Previous case studies have suggested that synaesthesia may yield even extraordinary memory abilities. However, group studies found either a task-specific memory advantage or no performance advantage at all. The aim of the present study was to test whether grapheme–colour synaesthesia gives rise to a general memory benefit using a standardised memory test (Wechsler Memory Scale). The synaesthetes showed a performance advantage in episodic memory tests, but not in short-term memory tests. However, performance was still within the ordinary range. The results support the hypothesis that synaesthesia provides for a richer world of experience and as a consequence additional retrieval cues may be available and beneficial but not to the point of extraordinary memory ability.     

The effects of free recall testing on subsequent source memory

The testing effect is the finding that prior retrieval of information from memory will result in better subsequent memory for that material. One explanation for these effects is that initial free recall testing increases the recollective details for tested information, which then becomes more available during a subsequent test phase. In three experiments we explored this hypothesis using a source-monitoring test phase after the initial free recall tests. We discovered that memory is differentially enhanced for certain recollective details depending on the nature of the free recall task. Thus further research needs to be conducted to specify how different kinds of memorial details are enhanced by free recall testing.     

Imagining novel futures: The roles of event plausibility and familiarity

The constructive episodic simulation hypothesis suggests that episodic memory supports the simulation of future events through extraction and recombination of stored information. The current study explicitly investigated the use of past episodic thought in the simulation of future scenarios. Participants simulated one of three possible scenarios, differing in plausibility and participants’ prior experience of similar events. Participants recorded related memories and whether they were explicitly used during future event simulation. Memories were rated for source (self-experienced, other-experienced, or media). Findings suggest prior experience and event plausibility did not impact upon ease of future event simulation or the extent of memory usage during simulations. Differences emerged in the source of information used to assist future event simulation. These findings provide support for the hypothesis that episodic memories from a variety of sources are recombined when generating future simulations of novel events.     

Time of Day Affects Episodic Memory in Older Adults*

ABSTRACT

The neuropsychological test scores of 2,030 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.     

Parallel interactive retrieval of item and associative information from event memory

Memory contains information about individual events (items) and combinations of events (associations). Despite the fundamental importance of this distinction, it remains unclear exactly how these two kinds of information are stored and whether different processes are used to retrieve them. We use both model-independent qualitative properties of response dynamics and quantitative modeling of individuals to address these issues. Item and associative information are not independent and they are retrieved concurrently via interacting processes. During retrieval, matching item and associative information mutually facilitate one another to yield an amplified holistic signal. Modeling of individuals suggests that this kind of facilitation between item and associative retrieval is a ubiquitous feature of human memory.     

Children's reasoning about the temporal order of past and future events

Four- and five-year-olds completed two sets of tasks that involved reasoning about the temporal order in which events had occurred in the past or were to occur in the future. Four-year-olds succeeded on the tasks that involved reasoning about the order of past events but not those that involved reasoning about the order of future events, whereas 5-year-olds passed both types of tasks. Individual children who failed the past-event tasks were not particularly likely to fail the more difficult future-event tasks. However, children's performance on the reasoning tasks was predictive of their performance on a task assessing their comprehension of the terms “before” and “after.” Our results suggest that there may be a developmental change over this age range in the ability to flexibly represent and reason about the before-and-after relationships between events.     

Effects of saccadic bilateral eye movements on memory in children and adults: an exploratory study

The effects of saccadic bilateral (horizontal) eye movements on true and false memory in adults and children were investigated. Both adults and children encoded lists of associated words in the Deese-Roediger-McDermott paradigm followed by a test of recognition memory. Just prior to retrieval, participants were asked to engage in 30s of bilateral vs. vertical vs. no eye movements. For studied information, the results for adults replicated previous work; bilateral eye movements were demonstrated to increase the accuracy of memory by increasing the hit rate and reducing the false alarm rate for related and unrelated recognition test lures. The results for children also indicated an improvement in memory accuracy, and like adults, was due to both an increase in the hit rate and a reduction in the false alarm rate. In spite of these similarities, the effects of bilateral eye movements differed between adults and children for critical unstudied words; i.e., those associated with the theme of the list. Only in adults did, bilateral eye movements reduce associative false memories; children did not show a reduction in false memory for critical associates. This produced a dissociation between the effects of eye movements on associative false memory as a function of age. The results are discussed from a developmental perspective in terms of potential mechanisms underlying true and false memory.     

Autonoetic consciousness: Reconsidering the role of episodic memory in future-oriented self-projection

Following the seminal work of Ingvar (1985. “Memory for the future”: An essay on the temporal organization of conscious awareness. Human Neurobiology, 4, 127–136), Suddendorf (1994. The discovery of the fourth dimension: Mental time travel and human evolution. Master's thesis. University of Waikato, Hamilton, New Zealand), and Tulving (1985. Memory and consciousness. Canadian Psychology/PsychologieCanadienne, 26, 1–12), exploration of the ability to anticipate and prepare for future contingencies that cannot be known with certainty has grown into a thriving research enterprise. A fundamental tenet of this line of inquiry is that future-oriented mental time travel, in most of its presentations, is underwritten by a property or an extension of episodic recollection. However, a careful conceptual analysis of exactly how episodic memory functions in this capacity has yet to be undertaken. In this paper I conduct such an analysis. Based on conceptual, phenomenological, and empirical considerations, I conclude that the autonoetic component of episodic memory, not episodic memory per se, is the causally determinative factor enabling an individual to project him or herself into a personal future.     

Children's temporal judgments for autobiographical past and future events

We compared the performance of twenty 5-7-year-olds on two spatial-temporal judgment tasks. In a semantic task, children located temporal distances from today that were described using conventional, temporal terms on a spatial timeline. In an autobiographical task, children judged temporal distances on the same spatial timeline for events that they had experienced, or were going to experience, presented without explicit temporal references. Six-year-olds were equally accurate in judging temporal distances in the semantic and autobiographical tasks, but 7-year-olds were more accurate in the semantic task. Older children were more accurate than younger children in the semantic task, but no significant age differences were found for autobiographical events. Surprisingly, children were equally accurate in locating past and future events in time. Children at both ages were more accurate judging temporal distances up to one week away (both past and future) as compared to distances of two to four weeks across both tasks. Results suggest that knowledge of recurring time patterns and conventional time measurement systems is necessary, but not sufficient, for locating autobiographical events in time, and temporal distance plays an important role in children's temporal judgments.     

Question format shifts bias away from the emphasised response in tests of recognition memory

The question asked to interrogate memory has potential to influence response bias at retrieval, yet has not been systematically investigated. According to framing effects in the field of eyewitness testimony, retrieval cueing effects in cognitive psychology and the acquiescence bias in questionnaire responding, the question should establish a confirmatory bias. Conversely, according to findings from the rewarded decision-making literature involving mixed incentives, the question should establish a disconfirmatory bias. Across three experiments (ns = 90 [online], 29 [laboratory] and 29 [laboratory]) we demonstrate a disconfirmatory bias – “old?” decreased old responding. This bias is underpinned by a goal-driven mechanism wherein participants seek to maximise emphasised response accuracy at the expense of frequency. Moreover, we demonstrate that disconfirmatory biases can be generated without explicit reference to the goal state. We conclude that subtle aspects of the test environment influence retrieval to a greater extent than has been previously considered.