Why do older adults have difficulty with semantic fluency?

Aging involves many cognitive declines, particularly in fluid intelligence, with relative maintenance of crystallized intelligence. This paradox is evident in the language domain: lexical retrieval becomes slower and less accurate, despite well preserved vocabularies. Verbal fluency assesses both crystallized and fluid aspects of language. Semantic fluency hypothetically reflects semantic knowledge, while letter fluency putatively reflects executive functioning, which would predict a greater impact of aging on the latter. However, the opposite is typically observed.

To investigate factors contributing to such asymmetries, we examined verbal fluency in 86 adults (30-89 years). Multiple regression analyses indicated that semantic fluency depends largely on lexical retrieval speed, as well as visualization strategies to support controlled retrieval, skills which may disproportionately decline with age. By contrast, letter fluency relies heavily on vocabulary knowledge, providing some protection against age-related declines. These findings contribute to our understanding of the mechanisms of typical age-related declines in word retrieval.     

Learning and growing from ‘communities of practice’: autoethnographic narrative vignettes of an aspiring educational researcher’s experience

This is an autoethnographic study that inquiries into my own journey as an aspiring educational researcher throughout the second course of my Master’s Program at the University of Gothenburg in Sweden. My experiences take place in the context of a group of real educational researchers and their on-going research project at the faculty of education called ‘Beyond Plant Blindness: Seeing the importance of plants for a sustainable world’ (BPB). All of the experiences included in this study are expressed in the form of chronologically ordered narrative vignettes. In order to bring theoretical meaning to these experiences, the vignettes were critically reflected upon and interpreted through the concept Communities of Practice (CoP), which is central to situated learning theory. Through this conceptual lens, my experiences revealed that an aspiring educational researcher may feel emotional and intellectual growth as a newcomer who is granted legitimate peripheral participation in the ‘real’ researcher CoP. Consequently, this study sheds light on ways that real researchers may play a part in shaping the identities of aspiring educational researchers through learning experiences. However, more generally, this study may facilitate fresh conversations about the complexities of learning, identity, and inclusion in the field of educational research.     

Correction to: Continuous flash suppression and monocular pattern masking impact subjective awareness similarly

Attention, Perception, & Psychophysics - There is an error in Fig. 4, part A. In the “continuous flash suppression” box, the labels “non-dominant eye” and...     

American Indian methamphetamine and other drug use in the Southwestern United States

To investigate the extent of methamphetamine and other drug use among American Indians (AIs) in the Four Corners region, we developed collaborations with Southwestern tribal entities and treatment programs in and around New Mexico. We held nine focus groups, mostly with Southwestern AI participants (N = 81) from three diverse New Mexico communities to understand community members, treatment providers, and clients/relatives views on methamphetamine. We conducted a telephone survey of staff (N = 100) from agencies across New Mexico to assess perceptions of methamphetamine use among people working with AI populations. We collected and analyzed self-reported drug use data from 300 AI clients/relatives who completed the Addiction Severity Index (ASI) in the context of treatment at three diverse addiction treatment programs. Each focus group offered a unique perspective about the effect of drugs and alcohol on each respective community. Though data from the phone surveys and ASIs suggested concerning rates of methamphetamine use, with women more adversely affected by substance use in general, alcohol was identified as the biggest substance use problem for AI populations in the Southwest. There appears to be agreement that methamphetamine use is a significant problem in these communities, but that alcohol is much more prevalent and problematic. There was less agreement about what should be done to prevent and treat methamphetamine use. Future research should attend to regional and tribal differences due to variability in drug use patterns, and should focus on identifying and improving dissemination of effective substance use interventions.     

Changing the rate and hippocampal dependence of trace eyeblink conditioning: slow learning enhances survival of new neurons

Trace eyeblink conditioning in which a conditioned stimulus and unconditioned stimulus are separated by a gap, is hippocampal dependent and can rescue new neurons in the adult dentate gyrus from death (e.g., Beylin et al., 2001; Gould et al., 1999). Tasks requiring more training trials for reliable expression of the conditioned response are most effective in enhancing survival of neurons (Waddell & Shors, 2008). To dissociate hippocampal dependence from acquisition rate, we facilitated hippocampal-dependent trace eyeblink conditioning in two ways: a shorter trace interval and signaling the intertrial interval with a post-US cue. Trace conditioning with a shorter trace interval (250ms) requires an intact hippocampus, and acquisition is faster relative to rats trained with a 500ms trace interval (e.g., Weiss et al., 1999). Using excitotoxic hippocampal lesions, we confirmed that eyeblink conditioning with the 250 or 500ms trace interval is hippocampal dependent. However, training with the post-US cue was not hippocampal dependent. The majority of lesion rats in this condition reached criterion of conditioned responding. To determine whether hippocampal dependence is sufficient to rescue adult-generated neurons in the dentate gyrus, rats were injected with BrdU and trained in one of the three trace eyeblink arrangements one week later. Of these training procedures, only the 500ms trace interval enhanced survival of new cells; acquisition of this task proceeded slowly relative to the 250ms and post-US cue conditions. These data demonstrate that rate of acquisition and not hippocampal dependence determines the impact of learning on adult neurogenesis.     

Affiliation Goals and Health Behaviors

People are inherently driven by the need to form and maintain relationships, and these affiliation goals can influence health behaviors in two ways: (a) indirectly, by increasing a person's attention to others and subsequently leaving them more likely to emulate the health behaviors of others (social contagion); (b) directly, by leading people to be more likely to engage in health behaviors they perceive as helping them to form and maintain relationships with others (self-initiated behavioral engagement). In this review, we discuss the evidence for the catalyzing role of affiliation goals in these two processes for a variety of positive (e.g., exercising, smoking-cessation) and detrimental health behaviors (e.g., binge drinking and eating, needle sharing). Additionally, we discuss individual difference factors that may temporarily or chronically activate affiliation goals and ultimately impact health behaviors. Affiliation goals hold many implications for future work, and for improving interventions.     

Comparative analysis of movement characteristics during dead-reckoning-based navigation in humans and rats

Human and rat movement organization was investigated as they searched for randomly located rewards without access to visual information. Under dark conditions, rats foraged for randomly located food pellets (Experiment 1). Blindfolded humans were instructed to search for an ostensible hidden coin using a metal detector (Experiment 2). After locating the food pellet, rats carried it back to the refuge, and after a designated searching time, humans were instructed to return to the start location. Although both species exhibited a high degree of similarity in searching path movement organization and ability to return to the start location, disruption of human searching path organization was associated with impairments in returning to the start location. These results support the vestibular "gain" account of movement organization during dead-reckoning-based navigation.     

Comparing observational software with paper and pencil for time-sampled data: A field test of Interval Manager (INTMAN)

In this article, we describe the Interval Manager (INTMAN) software system for collecting timesampled observational data and present a preliminary application comparing the program with a traditional paper-and-pencil method. INTMAN is a computer-assisted alternative to traditional paper-and-pencil methods for collecting fixed interval time-sampled observational data. The INTMAN data collection software runs on Pocket PC handheld computers and includes a desktop application for Microsoft Windows that is used for data analysis. Standard analysis options include modified frequencies, percent of intervals, conditional probabilities, and kappa agreement matrices and values. INTMAN and a standardized paper-and-pencil method were compared under identical conditions on five dimensions: setup time, duration of data entry, duration of interobserver agreement calculations, accuracy, and cost. Overall, the computer-assisted program was a more efficient and accurate data collection system for time-sampled data than the traditional method.