Age differences in fluid intelligence: contributions of general slowing and frontal decline

The current study examined the contributions of general slowing and frontal decline to age differences in fluid intelligence. Participants aged 20-89 years completed Block Design, Matrix Reasoning, simple reaction time, choice reaction time, Wisconsin Card Sorting, and Tower of London tasks. Age-related declines in fluid intelligence, speed of processing, and frontal function were observed. Hierarchical regression analyses showed that the processing speed and frontal function measures accounted for significant variance in fluid intelligence performance, but there was also a residual effect of age after controlling for each variable individually as well as both variables. An additional analysis showed that the variance in fluid intelligence that was attributable to processing speed was not fully shared with the variance attributable to frontal function. These findings suggest that the age-related decline in fluid intelligence is due to general slowing and frontal decline, as well as other unidentified factors.     

Strengthening encoding via implementation intention formation increases prospective memory commission errors

Prospective memory refers to the ability to remember to execute future intentions (e.g., taking medication with dinner). Although most prior research on prospective memory errors has focused on omission errors (i.e., failures to perform an intention in response to a target cue), there has been a recent surge in research on commission errors, the erroneous performance of a finished intention. Existing studies have examined factors at retrieval that lead to commission errors; the present study extends this research by investigating the impact of encoding strength. We found that relative to standard encoding, implementation intention encoding doubled the risk of commission errors in our laboratory paradigm for both young and older adults. This novel finding demonstrates the impact of encoding strength on commission errors and documents the potential challenges of deactivating the effects of implementation intentions upon completion of a prospective memory task.     

The strategic control of prospective memory monitoring in response to complex and probabilistic contextual cues

Participants use simple contextual cues to reduce deployment of costly monitoring processes in contexts in which prospective memory (PM) targets are not expected. This study investigated whether this strategic monitoring pattern is observed in response to complex and probabilistic contextual cues. Participants performed a lexical decision task in which words or nonwords were presented in upper or lower locations on screen. The specific condition was informed that PM targets (“tor” syllable) would occur only in words in the upper location, whereas the nonspecific condition was informed that targets could occur in any location or word type. Context was blocked such that word type and location changed every 8 trials. In Experiment 1, the specific condition used the complex contextual cue to reduce monitoring in unexpected contexts relative to the nonspecific condition. This pattern largely was not evidenced when the complex contextual cue was probabilistic (Experiment 2). Experiment 3 confirmed that strategic monitoring is observed for a complex cue that is deterministic, but not one that is probabilistic. Additionally, Experiments 1 and 3 demonstrated a disadvantage associated with strategic monitoring—namely, that the specific condition was less likely to respond to a PM target in an unexpected context. Experiment 3 provided evidence that this disadvantage is attributable to impaired noticing of the target. The novel findings suggest use of a complex contextual cue per se is not a boundary condition for the strategic, context-specific allocation of monitoring processes to support prospective remembering; however, strategic monitoring is constrained by the predictive utility of the complex contextual cue.     

List-wide control is not entirely elusive: Evidence from picture–word Stroop

Stroop interference is attenuated in mostly incongruent lists, as compared with mostly congruent ones. This finding is referred to as the list-wide proportion congruence effect. The traditional interpretation refers to the strategic biasing of attention via list-wide control. In mostly incongruent lists, attention is biased away from the irrelevant words, whereas in mostly congruent lists, words are more fully processed. According to the item-specific account, the list-wide proportion congruence effect reflects stimulus-driven mechanisms, and not list-wide control. The unambiguous evidence available to date strongly favors the item-specific account. Using a picture–word Stroop task, we demonstrate a list-wide proportion congruence effect for 50% congruent items that are embedded in mostly incongruent and mostly congruent lists. This novel finding illustrates that the list-wide proportion congruence effect is not entirely dependent on item-specific contributions and supports the list-wide control account. We discuss factors impacting the emergence of list-wide control in Stroop tasks.     

A randomised controlled trial of the effectiveness of writing as a self-help intervention for traumatic injury patients at risk of developing post-traumatic stress disorder

The study investigated the effects of writing and self-help information on severity of psychological symptoms in traumatic injury patients at risk for developing post-traumatic stress disorder (PTSD). Patients attending Accident and Emergency (A & E), were screened for Acute Stress Disorder and randomised to an information control group (n = 36) or a writing and information group (n = 31). Participants in both groups received an information booklet one-month post-injury. Participants in the writing group also wrote about emotional aspects of their trauma during three 20-min sessions, five to six weeks post-injury. Psychological assessments were completed within one month and at three and six months post-injury. There were significant improvements on measures of anxiety, depression and PTSD over time. Differences between groups on these measures were not statistically significant. However, subjective ratings of the usefulness of writing were high. In conclusion, the results do not currently support the use of writing as a targeted early intervention technique for traumatic injury patients at risk of developing PTSD.     

Context cue focality influences strategic prospective memory monitoring

Monitoring the environment for the occurrence of prospective memory (PM) targets is a resource-demanding process that produces cost (e.g., slower responding) to ongoing activities. However, research suggests that individuals are able to monitor strategically by using contextual cues to reduce monitoring in contexts in which PM targets are not expected to occur. In the current study, we investigated the processes supporting context identification (i.e., determining whether or not the context is appropriate for monitoring) by testing the context cue focality hypothesis. This hypothesis predicts that the ability to monitor strategically depends on whether the ongoing task orients attention to the contextual cues that are available to guide monitoring. In Experiment 1, participants performed an ongoing lexical decision task and were told that PM targets (TOR syllable) would only occur in word trials (focal context cue condition) or in items starting with consonants (nonfocal context cue condition). In Experiment 2, participants performed an ongoing first letter judgment (consonant/vowel) task and were told that PM targets would only occur in items starting with consonants (focal context cue condition) or in word trials (nonfocal context cue condition). Consistent with the context cue focality hypothesis, strategic monitoring was only observed during focal context cue conditions in which the type of ongoing task processing automatically oriented attention to the relevant features of the contextual cue. These findings suggest that strategic monitoring is dependent on limited-capacity processing resources and may be relatively limited when the attentional demands of context identification are sufficiently high.     

Whoops, I did it again: commission errors in prospective memory

Prospective memory research almost exclusively examines remembering to execute an intention, but the ability to forget completed intentions may be similarly important. We had younger and older adults perform a prospective memory task (press Q when you see corn or dancer) and then told them that the intention was completed. Participants later performed a lexical-decision task (Phase 2) in which the prospective memory cues reappeared. Initial prospective memory performance was similar between age groups, but older adults were more likely than younger adults to press Q during Phase 2 (i.e., commission errors). This study provides the first experimental demonstration of event-based prospective memory commission errors after all prospective memory tasks are finished and identifies multiple factors that increase risk for commission errors.     

Memory training interventions require a tailor-made approach: Commentary on McDaniel and Bugg

Memory training for older adults often produces gains that are limited to the particular memory tasks encountered during training. We suggest that memory training programs may be misguided by an implicit "generalist" assumption-memory training on a couple of memory tasks will have a positive benefit on memory ability in general. One approach to increase memory-training benefits is to target training for the everyday memory tasks for which older adults struggle. Examples include training retrieval strategies, prospective memory strategies, and strategies for learning and remembering names. Another approach is to design training to foster transfer. Possible elements to improve transfer are increasing the variation that is experienced during the course of training at the level of stimuli and tasks, incorporating "homework" that guides the older adult to become attuned to situations in which the strategies can be applied, and providing older adults with a better understanding of how memory works. Finally, incorporating aerobic exercise into memory training programs may potentiate the acquisition and maintenance of the trained cognitive strategies.     

Dissociative effects of orthographic distinctiveness in pure and mixed lists: an item-order account

We apply the item-order theory of list composition effects in free recall to the orthographic distinctiveness effect. The item-order account assumes that orthographically distinct items advantage item-specific encoding in both mixed and pure lists, but at the expense of exploiting relational information present in the list. Experiment 1 replicated the typical free recall advantage of orthographically distinct items in mixed lists and the elimination of that advantage in pure lists. Supporting the item-order account, recognition performances indicated that orthographically distinct items received greater item-specific encoding than did orthographically common items in mixed and pure lists (Experiments 1 and 2). Furthermore, order memory (input–output correspondence and sequential contiguity effects) was evident in recall of pure unstructured common lists, but not in recall of unstructured distinct lists (Experiment 1). These combined patterns, although not anticipated by prevailing views, are consistent with an item-order account.