When awareness gets in the way : reactivation aversion effects resolve the generality/specificity paradox in sensorimotor interference tasks

Interference tasks combining different distractor types usually find that between-trial adaptations (congruency sequence effects [CSEs]) do not interact with each other, suggesting that sensorimotor control is domain-specific. However, within each trial, different distractor types often do interact, suggesting that control is domain-general. The present study presents a solution to this apparent paradox. In 3 experiments, testing 130 participants in total, we (a) confirm the simultaneous presence of between-trial domain-specific (noninteracting) CSEs and within-trial “domain-general” interactions in a fully factorial hybrid prime-Simon design free of repetition or contingency confounds; (b) demonstrate that the within-trial interaction occurs with supraliminal, but not with subliminal primes; and (c) show that it is disproportionately enlarged in older adults. Our findings suggest that whereas interference (priming and Simon) effects and CSEs reflect direct sensorimotor control, the within-trial interaction does not reflect sensorimotor control but “confusion” at higher-level processing stages (reactivation aversion effect [RAE])

An internet study of prospective memory across adulthood

In an Internet study, 73,018 18-79-year-olds were asked to “remember to click the smiley face when it appears”. A smiley face was present/absent at encoding, and participants were told to expect it “at the end of the test”/“later in the test.” In all 4 conditions, it occurred after 20 min of retrospective memory tests. Prospective remembering benefited at all ages from both prior target exposure and temporal uncertainty; moreover, it resembled working memory in its linear decline from young adulthood. The study demonstrates the power of Internet methodology to reveal age-related deficits in a single-trial prospective memory task outside the laboratory

Speech errors across the lifespan

Dell, Burger, and Svec (1997) proposed that the proportion of speech errors classified as anticipations (e.g., " moot and mouth ") can be predicted solely from the overall error rate, such that the greater the error rate, the lower the anticipatory proportion (AP) of errors. We report a study examining whether this effect applies to changes in error rates that occur developmentally and as a result of ageing. Speech errors were elicited from 8- and 11-year-old children, young adults, and older adults. The error rate decreased and the AP increased from children to young adults, but neither error rate nor AP differed significantly between young and older adults. In cases where fast speech resulted in a higher error rate than slow speech, the AP was lower. Thus, there was overall support for Dell et al.'s prediction from speech error data across the lifespan

Similarity and attraction effects in episodic memory judgments

In the decision-making literature, it is known that preferences between two options can be influenced in different ways by the introduction of a third option. We investigated whether such influences could be demonstrated when making decisions about qualitative aspects of episodic memories. In a baseline condition, participants were asked which of two dissimilar events they remembered more vividly: (A) a well-known Olympic victory, or (B) the death of a well-known public figure. In two further conditions, a third event was added: (C) an Olympic victory similar and competitive to A, or (D) an Olympic victory similar but inferior to A. With the addition of C, participants were less likely to choose A than B (similarity effect), whereas with the addition of D, they were more likely to choose A than B (attraction effect), suggesting that effects known in decision-making can be generalised to relative judgments about episodic memories

Habitual prospective memory in schizophrenia

Background Prospective memory (PM), the act of remembering that something has to be done in the future without any explicit prompting to recall, provides a useful framework with which to examine problems in internal-source monitoring. This is because it requires distinguishing between two internally-generated processes, namely the intention to perform an action versus actual performance of the action. In habitual tasks, such as taking medicine every few hours, the same PM task is performed regularly and thus it is essential that the individual is able to distinguish thoughts (i.e., thinking about taking the medicine) from actions (i.e., actually taking the medicine). Methods We assessed habitual PM in patients with schizophrenia by employing a laboratory analogue of a habitual PM task in which, concurrently with maneuvering a ball around an obstacle course (ongoing activity), participants were to turn over a counter once during each trial (PM task). After each trial, participants were asked whether they had remembered to turn the counter over. Results Patients with schizophrenia made a disproportionate number of errors compared to controls of reporting that a PM response had been made (i.e., the counter turned over) after an omission error (i.e., the counter was not turned over). There was no group difference in terms of reporting that an omission error occurred (i.e., forgetting to turn over the counter) when in fact a PM response had been made. Conclusion Patients with schizophrenia displayed a specific deficit distinguishing between two internally-generated sources, attributable to either poor source monitoring or temporal discrimination

Associations between a one-shot delay discounting measure and age, income, education and real-world impulsive behavior

There has been discussion over the extent to which delay discounting – as prototypically shown by a preference for a smaller-sooner sum of money over a larger-later sum – measures the same kind of impulsive preferences that drive non-financial behavior. To address this issue, a dataset was analyzed containing 42,863 participants’ responses to a single delay-discounting choice, along with self-report behaviors that can be considered as impulsive. Choice of a smaller-sooner sum was associated with several demographics: younger age, lower income, and lower education; and impulsive behaviors: earlier age of first sexual activity and recent relationship infidelity, smoking, and higher body mass index. These findings suggest that at least an aspect of delay discounting preference is associated with a general trait influencing other forms of impulsivity, and therefore that high delay discounting is another form of impulsive behavior

When distraction holds relevance : a prospective memory benefit for older adults

Evidence is accumulating to show that age-related increases in susceptibility to distracting information can benefit older more than young adults in several cognitive tasks. Here we focus on prospective memory (i.e., remembering to carry out future intentions) and examine the effect of presenting distracting information that is intention-related as a function of age. Young and older adults performed an ongoing 1-back working memory task to a rapid stream of pictures superimposed with to-be-ignored letter strings. Participants were additionally instructed to respond to target pictures (namely, animals) and, for half of the participants, some strings prior to the targets were intention-related words (i.e., animals). Results showed that presenting intention-related distracting information during the ongoing task was particularly advantageous for target detection in older compared to young adults. Moreover, a prospective memory benefit was observed even for older adults who showed no explicit memory for the target distracter words. We speculate that intention-related distracter information enhanced the accessibility of the prospective memory task and suggest that when distracting information holds relevance to intentions it can serve a compensatory role in prospective remembering in older adults

Enumeration in Alzheimer's disease and other late life psychiatric syndromes

Previous studies suggest that visual enumeration is spared in normal aging but impaired in abnormal aging (late stage Alzheimer's disease, AD), raising the task's potential as a marker of dementia. Experiment 1 compared speeded enumeration of 1–9 random dots in early stage AD, vascular dementia (VAD), depression, and age-matched controls. Previous deficits were replicated but they were not specific to AD, with the rate of counting larger numerosities similarly slowed relative to controls by both AD and VAD. Determination of subitizing span was complicated by the surprisingly slower enumeration of one than of two items, especially in AD patients. Experiment 2 showed that AD patients’ relative difficulty with one item persisted with further practice and extended to the enumeration of targets among distractors. However, it was abolished when pattern recognition was possible (enumerating dots on a die). Although an enumeration test is unlikely to help differentiate early AD from other common dementias, the unexpected pattern of patients’ performance challenges current models of enumeration and requires further investigation

Heart rate variability predicts older adults’ avoidance of negativity

Objectives The ability to produce situation-appropriate cognitive and emotional responses is dependent on autonomic nervous system (ANS) functionality. Heart rate variability (HRV) is an index of ANS functionality, and resting HRV levels have been associated with cognitive control and inhibitory capacity in young adults, particularly when faced with emotional information. As older adults’ greater preference for positive and avoidance of negative stimuli (positivity effect) is thought to be dependent on cognitive control, we hypothesized that HRV could predict positivity-effect magnitude in older adults. Method We measured resting-level HRV and gaze preference for happy and angry (relative to neutral) faces in 63 young and 62 older adults. Results Whereas young adults showed no consistent preference for happy or angry faces, older adults showed the expected positivity effect, which predominantly manifested as negativity avoidance rather than positivity preference. Crucially, older but not young adults showed an association between HRV and gaze preference, with higher levels of HRV being specifically associated with stronger negativity avoidance. Discussion This is the first study to demonstrate a link between older adults’ ANS functionality and their avoidance of negative information. Increasing the efficiency of the cardiovascular system might selectively improve older adults’ ability to disregard negative influences

Food for happy thought : glucose protects age-related positivity effects under cognitive load

Older adults show a preference for positive information, which disappears under high task demands. We examined whether glucose can help older adults preserve their positivity effect (PE) under high cognitive load. One hundred and twenty-two adults (40 young and 42 older in Experiment 1; 40 older in Experiment 2) consumed a glucose (25 g) or a taste-matched placebo drink and completed an immediate recall task of emotional word-lists presented under high- and low-load conditions. Older adults showed PEs for low-load lists. Whereas PEs disappeared for older-placebo participants for high-load lists, older-glucose participants retained their positive preference. Providing the brain with extra energy resources can help older adults achieve PEs even under demanding conditions