When facts go down the rabbit hole: contrasting features and objecthood as indexes to memory

People will often look to empty, uninformative locations in the world when trying to recall spoken information. This spatial indexing behaviour occurs when the information had previously been associated with those locations. It remains unclear, however, whether this behaviour is an example of a simple association across perceptual and cognitive systems, or whether location information plays a role in memory retrieval. In the current study, we investigate whether higher-level cognitive processes, such as object-based attention, are involved in spatial indexing. Participants saw creatures burrowing around the screen, appearing from underground to tell them facts. They saw the same creature in two locations, or two identical creatures in two locations, depending on spatiotemporal cues conveyed by a burrowing animation. While answering questions, we found that participants relied on these spatiotemporal cues, fixating the previous locations of the creature associated with the relevant fact, rather than the location of an identical creature. We interpret these findings in terms of an object-based attentional mechanism that is common to semantic memory and scene perception, and allows 'external memory' to be exploited in a dynamic environment.     

The spacing effect in children's memory and category induction

The spacing effect describes the robust phenomenon whereby memory is enhanced when learning events are distributed, instead of being presented in succession. We investigated the effect of spacing on children's memory and category induction. Three-year-old children were presented with two tasks, a memory task and a category induction task. In the memory task, identical instances of an object were presented and then tested in a multiple choice test. In the category induction task, different instances of a category were presented and tested in a multiple choice test. In both tasks, presenting the instances in a spaced sequence resulted in more learning than presenting the instances in a massed sequence, despite the difficulty created by the spaced sequence. The spaced sequence increased the difficulty of the task by allowing children time to forget the previous instance during the spaced interval.     

Rumor mongering and remembering: how rumors originating in children's inferences can affect memory

This study examined how rumors originating in 3- to 6-year-olds' causal inferences can affect their own and their peers' memories for a personally experienced event. This was accomplished by exposing some members of classrooms to contextual clues that were designed to induce inferences about the causes of two unresolved components of the event. After a 1-week delay, a substantial number of children who were exposed to the clues misremembered their inferences as actual experiences. Causal inferential memory errors were most pronounced among 5- and 6-year-olds. Also, many of the children whose classmates were exposed to the clues mistakenly incorporated their classmates' causal inferences into their own accounts, with 3- and 4-year-olds being most likely to make this error.     

The development of metamemory monitoring during retrieval: the case of memory strength and memory absence

This research examined the development of the ability to monitor memory strength and memory absence at retrieval. In two experiments, 7-year-olds, 10-year-olds, and adults enacted and imagined enacting a series of bizarre and common actions. Two weeks later, they completed a memory test in which they were asked to determine whether each action had been enacted, had been imagined, or was novel and to provide a confidence judgment for each response. Results showed that participants across age groups successfully monitored differences in strength between memories for enacted actions and memories for imagined actions. However, compared with 10-year-olds and adults, 7-year-olds exhibited deficits in monitoring of differences in memory strength among imagined actions as well as deficits in monitoring memory absence. Results underscore metamemory developments that have important implications for memory accuracy.     

When generating answers benefits arithmetic skill: the importance of prior knowledge

People remember information better if they generate the information while studying rather than read the information. However, prior research has not investigated whether this generation effect extends to related but unstudied items and has not been conducted in classroom settings. We compared third graders’ success on studied and unstudied multiplication problems after they spent a class period generating answers to problems or reading the answers from a calculator. The effect of condition interacted with prior knowledge. Students with low prior knowledge had higher accuracy in the generate condition, but as prior knowledge increased, the advantage of generating answers decreased. The benefits of generating answers may extend to unstudied items and to classroom settings, but only for learners with low prior knowledge.     

How young children judge whether a word is one they know: a dual criterion account

Word familiarity judgment may be important for word learning, yet little is known about how children make this judgment. We hypothesized that preschool-age children differ in the judgment criteria that they use and that this difference derives from individual differences in basic memory processes. Those who have superior phonological working memory, but who retrieve less semantic information than their peers, base the judgment on whether they recognize a word’s sound form. Those who show the opposite memory profile base the judgment on whether they retrieve a word’s meaning. The results of two studies of 3- and 4-year-olds were consistent with these claims. Among those performing poorly on one memory measure, judgment accuracy was directly related to performance on the other memory measure. These memory-judgment relations were also found to be highly specific. This is the first investigation to demonstrate the usefulness of an individual differences approach for identifying relations between linguistic judgment processes and basic memory processes during early childhood.     

Transfer of old ‘reactivated’ memory retrieval cues in rats

The present studies examined whether the retrieval of an old ‘reactivated’ memory could be brought under the control of new contextual cues. In Experiment 1 rats trained in one context were exposed to different contextual cues either immediately, 60 or 120 min after a cued reactivation of the training memory. When tested in the shifted context, subjects exposed shortly after reactivation treated the shifted context as the original context. This transfer diminished with longer post-reactivation delays. Experiment 2 replicated the basic finding and demonstrated that the transfer of the old retrieval cues was specific to the contextual cues present during exposure. These findings are consistent with previous research [i.e., Briggs, J. F., Fitz, K. I., & Riccio, D. C. (in press). Transfer of memory retrieval cues in rats. Psychonomic Bulletin & Review] showing the transfer of retrieval cues for a new memory, and demonstrating a similarity (in this case) between newly acquired and old reactivated memories.     

Cognitive Development in Young-old Type-2 Diabetes Patients: A Longitudinal Analysis From The “Interdisciplinary Longitudinal Study of Aging”

In the present study, we investigated cognitive status and cognitive development in young-old Type-2 diabetes patients. Extending previous research, using the sample of the ILSE study (“Interdisciplinary Longitudinal Study of Aging”), we applied a comprehensive cognitive test battery to 38 Type-2 diabetes patients (mean age at T1: 63 years) and 421 control participants and tested both cognitive status and longitudinal changes after four years in several cognitive domains (crystallized intelligence, verbal memory, visual memory, executive functioning, psychomotor speed, and fluid intelligence). Results revealed no cross-sectional group differences in any cognitive domain at T1 nor at T2. However, testing group differences in intraindividual change over time, reliable group differences in the change of crystallized intelligence and fluid intelligence were revealed. While controls improved in crystallized intelligence as well as in fluid intelligence over time, diabetes patients’ performance decreased. The results demonstrate that in young-old adults the effects of diabetes on cognition may only be detected by analyzing within-person changes instead of mean level differences.

Nicotinic acetylcholine receptors of the ventral tegmental area are involved in mediating morphine-state-dependent learning

In the present study, the possible role of nicotinic acetylcholine (nACh) receptors of the ventral tegmental area (VTA) on morphine-state-dependent learning was studied in adult male Wistar rats. As a model of memory, a step-through type passive avoidance task was used. All animals were bilaterally implanted with chronic cannulae in the VTA, trained using a 1 mA foot shock, and tested 24 h after training to measure step-through latency. Post-training subcutaneous (s.c.) injection of morphine (0.5–5 mg/kg) dose-dependently reduced the step-through latency, showing morphine-induced amnesia. Amnesia induced by post-training morphine was significantly reversed by pre-test administration of morphine (2.5–5 mg/kg, s.c.) and induced morphine-state-dependent learning. Pre-test injection of nicotine (0.25–1 μg/rat) into the VTA plus an ineffective dose of morphine (0.5 mg/kg) significantly restored the memory retrieval. It should be noted that pre-test intra-VTA injection of the same doses of nicotine (0.25–1 μg/rat) alone cannot affect memory retention. Furthermore, pre-test intra-VTA injection of the nicotinic acetylcholine receptor antagonist, mecamylamine (1–3 μg/rat) 5 min before the administration of morphine (5 mg/kg, s.c.) dose-dependently inhibited morphine-state-dependent learning. Pre-test injection of the higher dose of mecamylamine (3 μg/rat) into the VTA by itself decreased the step-through latency and induced amnesia. On the other hand, mecamylamine (0.5 and 1 μg/rat, intra-VTA) reversed the effect of nicotine on morphine response. The results indicate that nACh receptors in the VTA participate in the modulation of morphine-induced recovery of memory, on the test day.     

Fragile X syndrome: Neural network models of sequencing and memory

A comparative framework of memory processes in males with fragile X syndrome (FXS) and typically developing (TYP) mental age-match children is presented. Results indicate a divergence in sequencing skills, such that males with FXS recall sequences similarly to TYP children around five and a half years of age, but the males with FXS recall significantly worse when compared to TYP children around seven and a half years of age. Performance on one working memory measure, an n-back Card Task, is modeled with a neural network. To date, no network models explicate the sequencing and memory processes in those with FXS. Noise was added to various levels (weight matrices) in the FXS model and outputs approximated human FXS performance. Three models were compared: (1) FXS; (2) younger mental age-TYP matches; (3) older reading level-TYP matches. Modeling can help to reify conceptualizations of deficits and to guide in the creation of more valid, science-based remediations. The FXS model suggested that the levels of phonological representation and sequencing in memory were candidates for targeted therapies in males with FXS.