Familiarity for Associations? A Test of the Domain Dichotomy Theory

Episodic recognition memory is mediated by functionally separable retrieval processes, notably familiarity (a general sense of prior exposure) and recollection (the retrieval of contextual details), whose relative engagement depends partly on the nature of the information being retrieved. Currently, the specific contribution of familiarity to associative recognition memory (where retrieval of the relationships between pairs of stimuli is required) is not clearly understood. Here we test domain dichotomy theory, which predicts that familiarity should contribute more to associative memory when stimuli are similar (within-domain) than when they are distinct (between-domain). Participants studied stimulus pairs, and at test, discriminated intact from rearranged pairs. Stimuli were either within-domain (name-name or image-image pairs) or between-domain (name-image pairs). Across experiments we employed two different behavioural measures of familiarity, based on ROC curves and a Modified Remember-Know procedure. Both experiments provided evidence that familiarity can contribute to associative recognition; however familiarity was stronger for between-domain pairs - in direct contrast to the domain dichotomy prediction

Characterising and measuring human episodic memory

Episodic memory, the ability to store and retrieve information from our past, is at the very heart of human experience, underpinning our identity and relationship with the world. Episodic memory is not a unitary phenomenon: in dual-process theory, researchers draw a distinction between familiarity, a rapid and automatic sense of oldness to a previously encountered stimulus ("I know that face"), and recollection, the reactivation of additional context from a particular episode ("We met at the York conference"). A fundamental objective in the study of human memory is to ground recollection and familiarity in neural terms. This requires accurately measuring the contribution of each from behavioural data, which in turn relies on an accurate characterisation of recollection. This thesis introduces a novel source retrieval task to demonstrate that recollection has two critical, and fiercely contested, properties: it is thresholded, i.e. it can fail completely, and successful recollection is graded, i.e. it varies in strength. The consequences of this characterisation are explored. Firstly, familiarity and recollection are functionally separable retrieval mechanisms. Secondly, the models currently used to measure the contribution of each are generally flawed, and a corrected model is described which better fits, and explains, the extant data. Finally, the frequency of recollection is shown to be dissociable from its strength, a result which links behavioural data more strongly than before to a neurocomputational account of episodic memory, and which suggests a relationship between the representational overlap of memory traces and their retrieval. This thesis necessitates a change in the way behavioural memory data is modelled, and consequently the interpretation of evidence underpinning neuroanatomical accounts of memory experience. Significantly, however, it also moves the field beyond a long-running debate and provides a deeper dual-process framework with which to address outstanding questions about the relationship between, and neural basis of, episodic memory processes

Discriminating famous from fictional names based on lifetime experience: evidence in support of a signal-detection model based on finite mixture distributions.

It is widely accepted that signal-detection mechanisms contribute to item-recognition memory decisions that involve discriminations between targets and lures based on a controlled laboratory study episode. Here, the authors employed mathematical modeling of receiver operating characteristics (ROC) to determine whether and how a signal-detection mechanism contributes to discriminations between moderately famous and fictional names based on lifetime experience. Unique to fame judgments is a lack of control over participants\u27 previous exposure to the stimuli deemed targets by the experimenter; specifically, if they pertain to moderately famous individuals, participants may have had no prior exposure to a substantial proportion of the famous names presented. The authors adopted established models from the recognition-memory literature to examine the quantitative fit that could be obtained through the inclusion of signal-detection and threshold mechanisms for two data sets. They first established that a signal-detection process operating on graded evidence is critical to account for the fame judgment data they collected. They then determined whether the graded memory evidence for famous names would best be described with one distribution with greater variance than that for the fictional names, or with two finite mixture distributions for famous names that correspond to items with or without prior exposure, respectively. Analyses revealed that a model that included a d\u27 parameter, as well as a mixture parameter, provided the best compromise between number of parameters and quantitative fit. Additional comparisons between this equal-variance signal-detection mixture model and a dual-process model, which included a high-threshold process in addition to a signal-detection process, also favored the former model. In support of the conjecture that the mixture parameter captures participants\u27 prior experience, the authors found that it was increased when the analysis was restricted to names in occupational categories for which participants indicated high exposure

Distinguishing between the success and precision of recollection

Recollection reflects the retrieval of complex qualitative information about prior events. Recently, Harlow and Donaldson developed a method for separating the probability of recollection success from the precision of the mnemonic information retrieved. In the current study, we ask if these properties are separable on the basis of subjective reports-are participants aware of these two aspects of recollection and can they reliably report on them? Participants studied words paired with a location on a circle outline, and at test recalled the location for a given word as accurately as possible. Additionally, participants provided separate subjective ratings of recollection confidence and recollection precision. The results indicated that participants either recollected the target location with considerable (but variable) precision or retrieved no accurate location information at all. Importantly, recollection confidence reliably predicted whether locations were recollected, while precision ratings instead reflected the precision of the locations retrieved. The results demonstrate the experimental separability of recollection success and precision, and highlight the importance of disentangling these two different aspects of recollection when examining episodic memory

Characterising and measuring human episodic memory

Episodic memory, the ability to store and retrieve information from our past, is at the very heart of human experience, underpinning our identity and relationship with the world. Episodic memory is not a unitary phenomenon: in dual-process theory, researchers draw a distinction between familiarity, a rapid and automatic sense of oldness to a previously encountered stimulus ("I know that face"), and recollection, the reactivation of additional context from a particular episode ("We met at the York conference"). A fundamental objective in the study of human memory is to ground recollection and familiarity in neural terms. This requires accurately measuring the contribution of each from behavioural data, which in turn relies on an accurate characterisation of recollection. This thesis introduces a novel source retrieval task to demonstrate that recollection has two critical, and fiercely contested, properties: it is thresholded, i.e. it can fail completely, and successful recollection is graded, i.e. it varies in strength. The consequences of this characterisation are explored. Firstly, familiarity and recollection are functionally separable retrieval mechanisms. Secondly, the models currently used to measure the contribution of each are generally flawed, and a corrected model is described which better fits, and explains, the extant data. Finally, the frequency of recollection is shown to be dissociable from its strength, a result which links behavioural data more strongly than before to a neurocomputational account of episodic memory, and which suggests a relationship between the representational overlap of memory traces and their retrieval. This thesis necessitates a change in the way behavioural memory data is modelled, and consequently the interpretation of evidence underpinning neuroanatomical accounts of memory experience. Significantly, however, it also moves the field beyond a long-running debate and provides a deeper dual-process framework with which to address outstanding questions about the relationship between, and neural basis of, episodic memory processes.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

A pre-registered naturalistic observation of within domain mental fatigue and domain-general depletion of self-control

<div><p>Self-control is often believed to operate as if it were a finite, domain-general resource. However, recent attempts to demonstrate this under transparent conditions have failed to yield positive results. In the current study, we monitor two groups of students (N1 = 8,867, N2 = 8,754) over separate 17-week intervals with 24-hour coverage, as they engage in voluntary learning and self-testing using an online program. We use daily behavior to assess whether time-of-day effects support domain-general theories of self-control. Additionally, we assess whether mental fatigue emerges within task during prolonged persistent effort. Results reveal within-task fatigue emerges within an hour on-task. However, there is a negligible effect on ability throughout the day. Additionally, time-of-day has no detrimental effect on motivation; rather there is a strong tendency to increase learning time at night. Results are consistent with theories indicating people lose motivation within a specific task, but at odds with theories that argue for a domain-general self-control resource.</p></div

Example images from the website http://www.cerego.com.

<p>Example screens from a user’s session on Cerego. (A) When users log on, they see a visual summary of information they have learned on Cerego. (B) Learning trials involve paired information, in this case the name and visual representation of an osteoclast paired with its definition. (C) On a test trial, users will be asked to either freely recall information, or select correct options from a set. In this case the user must identify the correct name and representation after having been given the definition. Printed under a CC BY license, with permission from Cerego, original copyright 2017.</p

Deviance of session length data from theoretical models of daily session length fluctuations.

<p>Deviance of session length data from theoretical models of daily session length fluctuations.</p