Relational memory generalization and integration in a transitive inference task with and without instructed awareness

Transitive inference and the testing effect: Retrieval practice impairs transitive inference

There is substantial interest in the extent to which the testing effect (the finding that retrieval practice enhances memory) extends to more complex forms of learning, especially those entailing greater element interactivity. Transitive inference (TI) requires just such interactivity, in which information must be combined across multiple learning elements or premises to extract an underlying structure. Picklesimer et al. provided preliminary evidence that retrieval practice fails to enhance, and actually disrupts, TI. This study assessed the generality of that result. The current experiments employed a seven- or eight-element TI paradigm in which participants initially learned a set of premise pairs (e.g., A > B, B > C, and C > D) and then engaged in either restudy or retrieval practice of the premise pairs before taking a final test that assessed memory for the original premise pairs and one's ability to make TIs (e.g., to infer that B > D). Experiments 1 and 2 used pictorial materials and simultaneous presentation of premises during learning, a form of presentation that has induced testing effects on other forms of inference. For TI, the results were unchanged from Picklesimer et al.-TI was worse for retrieval practice than restudy. Experiment 3 used verbal materials and likewise found worse TI for retrieval practice. A small-scale meta-analysis combining the current experiments with those of Picklesimer et al. revealed a significant negative testing effect on TI (d = -0.37). Although retrieval practice enhances many aspects of memory, this fundamental aspect of human reasoning may be impaired by retrieval practice.

Development of human hippocampal subfield microstructure and relation to associative inference

The hippocampus is a complex brain structure composed of subfields that each have distinct cellular organizations. While the volume of hippocampal subfields displays age-related changes that have been associated with inference and memory functions, the degree to which the cellular organization within each subfield is related to these functions throughout development is not well understood. We employed an explicit model testing approach to characterize the development of tissue microstructure and its relationship to performance on 2 inference tasks, one that required memory (memory-based inference) and one that required only perceptually available information (perception-based inference). We found that each subfield had a unique relationship with age in terms of its cellular organization. While the subiculum (SUB) displayed a linear relationship with age, the dentate gyrus (DG), cornu ammonis field 1 (CA1), and cornu ammonis subfields 2 and 3 (combined; CA2/3) displayed nonlinear trajectories that interacted with sex in CA2/3. We found that the DG was related to memory-based inference performance and that the SUB was related to perception-based inference; neither relationship interacted with age. Results are consistent with the idea that cellular organization within hippocampal subfields might undergo distinct developmental trajectories that support inference and memory performance throughout development.

The transitive inference task to study the neuronal correlates of memory-driven decision making: A monkey neurophysiology perspective

A vast amount of literature agrees that rank-ordered information as A>B>C>D>E>F is mentally represented in spatially organized schemas after learning. This organization significantly influences the process of decision-making, using the acquired premises, i.e. deciding if B is higher than D is equivalent to comparing their position in this space. The implementation of non-verbal versions of the transitive inference task has provided the basis for ascertaining that different animal species explore a mental space when deciding among hierarchically organized memories. In the present work, we reviewed several studies of transitive inference that highlighted this ability in animals and, consequently, the animal models developed to study the underlying cognitive processes and the main neural structures supporting this ability. Further, we present the literature investigating which are the underlying neuronal mechanisms. Then we discuss how non-human primates represent an excellent model for future studies, providing ideal resources for better understanding the neuronal correlates of decision-making through transitive inference tasks.

Advantage conferred by overnight sleep on schema-related memory may last only a day

Study Objectives

Sleep contributes to declarative memory consolidation. Independently, schemas benefit memory. Here we investigated how sleep compared with active wake benefits schema consolidation 12 and 24 hours after initial learning.

Methods

Fifty-three adolescents (age: 15-19 years) randomly assigned into sleep and active wake groups participated in a schema-learning protocol based on transitive inference (i.e. If B > C and C > D then B > D). Participants were tested immediately after learning and following 12-, and 24-hour intervals of wake or sleep for both the adjacent (e.g. B-C, C-D; relational memory) and inference pairs: (e.g.: B-D, B-E, and C-E). Memory performance following the respective 12- and 24-hour intervals were analyzed using a mixed ANOVA with schema (schema, no-schema) as the within-participant factor, and condition (sleep, wake) as the between-participant factor.

Results

Twelve hours after learning, there were significant main effects of condition (sleep, wake) and schema, as well as a significant interaction, whereby schema-related memory was significantly better in the sleep condition compared to wake. Higher sleep spindle density was most consistently associated with greater overnight schema-related memory benefit. After 24 hours, the memory advantage of initial sleep was diminished.

Conclusions

Overnight sleep preferentially benefits schema-related memory consolidation following initial learning compared with active wake, but this advantage may be eroded after a subsequent night of sleep. This is possibly due to delayed consolidation that might occur during subsequent sleep opportunities in the wake group.

Clinical Trial Information

Name: Investigating Preferred Nap Schedules for Adolescents (NFS5) URL: https://clinicaltrials.gov/ct2/show/NCT04044885. Registration: NCT04044885.

The Effect of Retrieval Practice on Transitive Inference

Abstract. Compared to restudying, retrieval practice has often been found to enhance memory (the testing effect). However, it has been proposed that materials with high element interactivity may not benefit from retrieval practice. Transitive inference (TI) requires just such interactivity, in which information must be combined across multiple learning elements or premises. The current study employed a 7-element TI paradigm in which participants initially learned a set of premises (e.g., A > B, B > C, C > D, etc.), then engaged in either restudy or retrieval practice with the premises, and then were given a final test that assessed memory for the original premises and one’s ability to make transitive inferences about them (e.g., to infer that B > D). Three experiments examined TI on final tests with retention intervals of a few minutes (Experiment 1), 2 days (Experiment 2), or up to a week (Experiment 3). Retrieval practice consistently failed to enhance transitive inference. Furthermore, retrieval practice significantly reduced TI in Experiment 1. Across experiments, TI was numerically worse in the retrieval-practice than restudy condition in 4 of 5 comparisons, and a small-scale meta-analysis revealed a significant negative effect of retrieval practice on TI.

Statistical Learning Creates Novel Object Associations via Transitive Relations

A remarkable ability of the cognitive system is to make novel inferences on the basis of prior experiences. What mechanism supports such inferences? We propose that statistical learning is a process through which transitive inferences of new associations are made between objects that have never been directly associated. After viewing a continuous sequence containing two base pairs (e.g., A-B, B-C), participants automatically inferred a transitive pair (e.g., A-C) where the two objects had never co-occurred before (Experiment 1). This transitive inference occurred in the absence of explicit awareness of the base pairs. However, participants failed to infer the transitive pair from three base pairs (Experiment 2), showing the limits of the transitive inference (Experiment 3). We further demonstrated that this transitive inference can operate across the categorical hierarchy (Experiments 4-7). The findings revealed a novel consequence of statistical learning in which new transitive associations between objects are implicitly inferred.

Memory integration: neural mechanisms and implications for behavior

Everyday behaviors require a high degree of flexibility, in which prior knowledge is applied to inform behavior in new situations. Such flexibility is thought to be supported in part by memory integration, a process whereby related memories become interconnected in the brain through recruitment of overlapping neuronal populations. Recent advances in cognitive and behavioral neuroscience highlight the importance of a hippocampal-medial prefrontal circuit in memory integration. Emerging evidence suggests that abstracted representations in medial prefrontal cortex guide reactivation of related memories during new encoding events, thus promoting hippocampal integration of related experiences. Moreover, recent work indicates that integrated memories are called upon during novel situations to facilitate a host of behaviors, from spatial navigation to imagination.