David P. McCabe

The Relationship Between Working Memory Capacity and Executive Functioning: Evidence for a Common Executive Attention Construct

Attentional control has been conceptualized as executive functioning by neuropsychologists and as working memory capacity by experimental psychologists. We examined the relationship between these constructs using a factor analytic approach in an adult life span sample. Several tests of working memory capacity and executive function were administered to more than 200 subjects between 18 and 90 years of age, along with tests of processing speed and episodic memory. The correlation between working memory capacity and executive functioning constructs was very strong (r = .97), but correlations between these constructs and processing speed were considerably weaker (rs approximately .79). Controlling for working memory capacity and executive function eliminated age effects on episodic memory, and working memory capacity and executive function accounted for variance in episodic memory beyond that accounted for by processing speed. We conclude that tests of working memory capacity and executive function share a common underlying executive attention component that is strongly predictive of higher level cognition.

Effects of Healthy Aging and Early Stage Dementia of the Alzheimer's Type on Components of Response Time Distributions in Three Attention Tasks

OBJECTIVE The characteristics of response time (RT) distributions beyond measures of central tendency were explored in 3 attention tasks across groups of young adults, healthy older adults, and individuals with very mild dementia of the Alzheimers type (DAT). METHOD Participants were administered computerized Stroop, Simon, and switching tasks, along with psychometric tasks that tap various cognitive abilities and a standard personality inventory (NEO-FFI). Ex-Gaussian (and Vincentile) analyses were used to capture the characteristics of the RT distributions for each participant across the 3 tasks, which afforded 3 components: mu and sigma (mean and standard deviation of the modal portion of the distribution) and tau (the positive tail of the distribution). RESULTS The results indicated that across all 3 attention tasks, healthy aging produced large changes in the central tendency mu parameter of the distribution along with some change in sigma and tau (mean etap(2) = .17, .08, and .04, respectively). In contrast, early stage DAT primarily produced an increase in the tau component (mean etap(2) = .06). tau was also correlated with the psychometric measures of episodic/semantic memory, working memory, and processing speed, and with the personality traits of neuroticism and conscientiousness. Structural equation modeling indicated a unique relation between a latent tau construct (-.90), as opposed to sigma (-.09) and mu constructs (.24), with working memory measures. CONCLUSIONS The results suggest a critical role of attentional control systems in discriminating healthy aging from early stage DAT and the utility of RT distribution analyses to better specify the nature of such change.

Handedness Is Related to Memory via Hemispheric Interaction: Evidence From Paired Associate Recall and Source Memory Tasks

Strongly right (SR)-handedness is associated with poorer memory performance than nonstrongly right (nSR)-handedness (e.g., Propper, Christman, & Phaneuf, 2005). The hemispheric interaction theory states that the nSR memory advantage occurs because nSR handedness, compared with SR, is a behavioral marker for greater interaction of the cerebral hemispheres. The hemispheric interaction theory predicts that the nSR advantage should be observed exclusively on memory tasks that require hemispheric interaction. The authors tested that prediction by comparing middle-aged and older adults on two memory tasks thought to depend on hemispheric interaction (paired associate recall, source memory) and two thought not to (face recognition, forward digit span). An nSR advantage was more robust for middle-aged than older subjects and, consistent with the hemispheric interaction theory, was found only on the tasks that depend on hemispheric interaction.

Illusions of competence and overestimation of associative memory for identical items: Evidence from judgments of learning

The relation between subjects’ predicted and actual memory performance is a central issue in the domain of metacognition. In the present study, we examined the influence of item similarity and associative strength on judgments of learning (JOLs) in a cued recall task. We hypothesized that encoding fluency would cause a foresight bias, so that subjects would overestimate recall of identical pairs (scale-scale), as compared with strong associates (weight-scale) or unrelated pairs (mask-scale). In Experiment 1, JOLs for identical word pairs were higher than those for related and unrelated pairs, but later recall of identical pairs was lower than recall of related pairs. In Experiment 2, the effect of encoding fluency (inferred from self-paced study time) was examined, and a similar pattern of results was obtained, with subjects spending the least amount of time studying identical pairs. We conclude that overconfidence for identical pairs reflects an assessment of item similarity when JOLs are made, despite associative strength being a better predictor of later retrieval.

Aging reduces veridical remembering but increases false remembering: neuropsychological test correlates of remember-know judgments.

In 1985 Tulving introduced the remember-know procedure, whereby subjects are asked to distinguish between memories that involve retrieval of contextual details (remembering) and memories that do not (knowing). Several studies have been reported showing age-related declines in remember hits, which has typically been interpreted as supporting dual-process theories of cognitive aging that align remembering with a recollection process and knowing with a familiarity process. Less attention has been paid to remember false alarms, or their relation to age. We reviewed the literature examining aging and remember/know judgments and show that age-related increases in remember false alarms, i.e., false remembering, are as reliable as age-related decreases in remember hits, i.e., veridical remembering. Moreover, a meta-analysis showed that the age effect size for remember hits and false alarms are similar, and larger than age effects on know hits and false alarms. We also show that the neuropsychological correlates of remember hits and false alarms differ. Neuropsychological tests of medial-temporal lobe functioning were related to remember hits, but tests of frontal-lobe functioning and age were not. By contrast, age and frontal-lobe functioning predicted unique variance in remember false alarms, but MTL functioning did not. We discuss various explanations for these findings and conclude that any comprehensive explanation of recollective experience will need to account for the processes underlying both remember hits and false alarms.

Memory Efficiency and the Strategic Control of Attention at Encoding: Impairments of Value-Directed Remembering in Alzheimer's Disease

Selecting what is important to remember, attending to this information, and then later recalling it can be thought of in terms of the strategic control of attention and the efficient use of memory. To examine whether aging and Alzheimers disease (AD) influenced this ability, the present study used a selectivity task, where studied items were worth various point values and participants were asked to maximize the value of the items they recalled. Relative to younger adults (N = 35) and healthy older adults (N = 109), individuals with very mild AD (N = 41), and mild AD (N = 13) showed impairments in the strategic and efficient encoding and recall of high value items. Although individuals with AD recalled more high value items than low value items, they did not efficiently maximize memory performance (as measured by a selectivity index) relative to healthy older adults. Performance on complex working memory span tasks was related to the recall of the high value items but not low value items. This pattern suggests that relative to healthy aging, AD leads to impairments in strategic control at encoding and value-directed remembering.

Are survival processing memory advantages based on ancestral priorities

Recent research has suggested that our memory systems are especially tuned to process information according to its survival relevance, and that inducing problems of “ancestral priorities” faced by our ancestors should lead to optimal recall performance (Nairne & Pandeirada, Cognitive Psychology,2010). The present study investigated the specificity of this idea by comparing an ancestor-consistent scenario and a modern survival scenario that involved threats that were encountered by human ancestors (e.g., predators) or threats from fictitious creatures (i.e., zombies). Participants read one of four survival scenarios in which the environment and the explicit threat were either consistent or inconsistent with ancestrally based problems (i.e., grasslands–predators, grasslands–zombies, city–attackers, city–zombies), or they rated words for pleasantness. After rating words based on their survival relevance (or pleasantness), the participants performed a free recall task. All survival scenarios led to better recall than did pleasantness ratings, but recall was greater when zombies were the threat, as compared to predators or attackers. Recall did not differ for the modern (i.e., city) and ancestral (i.e., grasslands) scenarios. These recall differences persisted when valence and arousal ratings for the scenarios were statistically controlled as well. These data challenge the specificity of ancestral priorities in survival-processing advantages in memory.

Examining the basis for illusory recollection: The role of remember/know instructions

Curiously, studies using the remember/know paradigm to measure recollective experience show that people often vividly remember events that never occurred, a phenomenon referred to asillusory recollection. Two experiments tested the hypothesis that false remember responses in the converging associates, or Deese/Roediger-McDermott (DRM) paradigm, reflect accurate memory for the study episode, rather than false recollection of critical lures. To test this hypothesis, we used standard remember instructions that emphasized recollection of the study context by allowing participants to use memory of surrounding list items as evidence for recollection, or we used modified instructions that did not include memory for surrounding list items as a basis for recollection. Results showed that, as compared with the standard instruction condition, the modified instructions selectively reduced reports of false remember responses to critical lures, but did not affect remember responses to studied items. By contrast, remember responses to critical lures were unaffected by an instruction condition that excluded the use of voice information as evidence for remembering. These results suggest that remember responses to falsely recognized items are driven partly by retrieval of studied items, rather than illusory recollection of the critical lures themselves. They further point to the importance of instructions in influencing subjective reports.

The Dark Side of Expertise: Domain-Specific Memory Errors

Expertise in a specific domain can lead to exceptional memory performance, such that experts can typically encode and retrieve large amounts of domain-related information. For example, chess experts can reproduce the exact locations of chess pieces from a game that is in progress (Chase & Simon, 1973; de Groot, 1966), baseball experts can recall large amounts of baseball-related information (Voss, Vesonder, & Spilich, 1980), and a college student used extensive knowledge of track and field to accurately recall long strings of rapidly presented digits (Chase & Ericsson, 1982). However, there are some costs associated with expertise, such that memory accuracy may actually decline in certain situations. For example, although doctors are more accurate than 3rd-year interns at making diagnoses, they are worse at recalling the exact information they used to make a diagnosis (Patel & Groen, 1991; Schmidt & Boshuizen, 1993). Arkes and Freedman (1984) found that on a recognition task, baseball experts made more false alarms to domain-relevant distractors compared with nonexperts, and Baird (2003) found that business majors displayed more domain-relevant intrusions than other students when recalling esoteric business terms. One potential explanation for the benefits and costs of expertise is based on organizational principles of knowledge. Specifically, these benefits and costs may be due to incoming information being incorporated with existing schemata and easily accessed later (e.g., Bédard & Chi, 1992). Van Overschelde, Rawson, Dunlosky, and Hunt (2005) found that participants with high levels of knowledge about American football (i.e., the National Football League) were more likely than lowknowledge participants to recall an ‘‘isolate’’ (i.e., a college football team that was included in a list of professional teams). Although high domain knowledge enhances access to and recall of domain-relevant information, this type of enhanced activation can also lead to increases in memory errors (Roediger & McDermott, 1995; Smith, Ward, Tindell, Sifonis, & Wilkenfeld, 2000). In the present study, we examined whether the organizational processing that benefits experts’ memory performance and leads to a rich encoding context can also increase intrusions during recall. Individuals with high and low levels of knowledge about American football (football experts and nonexperts) studied a list of familiar animal names, all of which were also names of football teams (e.g., lions, broncos, and bears), as well as a control list of body parts. Thus, all of the stimuli were familiar to participants, but the animal names were likely processed differently depending on level of football expertise. We expected football experts to recall more animal names than nonexperts because these names were also names of football teams and thus fit a well-organized schema, but we also expected that activation of this schema would increase intrusions of nonpresented animal names that represented football teams. We expected no differences between groups in performance for the control list.

The influence of instructions and terminology on the accuracy of remember–know judgments

The remember-know paradigm is one of the most widely used procedures to examine the subjective experience associated with memory retrieval. We examined how the terminology and instructions used to describe the experiences of remembering and knowing affected remember-know judgments. In Experiment 1 we found that using neutral terms, i.e., Type A memory and Type B memory, to describe the experiences of remembering and knowing reduced remember false alarms for younger and older adults as compared to using the terms Remember and Know, thereby increasing overall memory accuracy in the neutral terminology condition. In Experiment 2 we found that using what we call source-specific remember-know instructions, which were intended to constrain remember judgments to recollective experiences arising only from the study context, reduced remember hits and false alarms, and increased know hits and false alarms. Based on these data and other considerations, we conclude that researchers should use neutral terminology and source-specific instructions to collect the most accurate reports of the experiences of remembering and knowing arising from the study context.