Modeling cyclic variations in sustained human performance as measured by reaction time and the flash visual evoked potential-P2.

Recent research suggests that sustained attention is punctuated by periodic lapses that produce cyclic variations in sustained human performance. Research conducted by our laboratory (Arruda, Zhang, Amoss, Coburn, & Aue, 2009) and by the laboratories of others (Aue, Arruda, Kass, & Stanny, 2009; Smith, Valentino, & Arruda, 2003) suggests that sustained human performance cycles approximately every 1.5 and 5.2min. Further, it has been suggested that a norepinephrine based arousal system may be responsible for these variations. Unfortunately, both cholinergic and noradrenergic pathways are known to mediate attention and it is unclear from previous research whether one or both of the identified cycles is related to cholinergic functioning. Consequently, the purpose of the present investigation was to assess the validity of the 1.5 and the 5.2mincycles using both reaction time and a cortical marker of cholinergic activity-the flash visual evoked potential P2 (FVEP-P2). Twenty-seven participants performed a 15-min continuous performance task. A spectral analysis procedure was used to detect the prevalence of the 1.5 and 5.2mincycles in both performance and cortical activity. While the results of these analyses support the validity of the 1.5 and 5.2mincycles in sustained human performance, only the 5.2mincycle was detected in cortical activity (i.e., the FVEP-P2 amplitudes) using model fitting. Consequently, the results of the present investigation support the validity of the 1.5 and 5.2mincycles and extend the findings of previous research by implicating acetylcholine in the 5.2mincycle.

Age-related differences in recall for words using semantics and prosody.

The positivity effect is a developmental shift seen in older adults to be increasingly influenced by positive information in areas such as memory, attention, and decision-making. This study is the first to examine the age-related differences of the positivity effect for emotional prosody. Participants heard a factorial combination of words that were semantically positive or negative said with either positive or negative intonation. Results showed a semantic positivity effect for older adults, and a prosody positivity effect for younger adults. Additionally, older adults showed a significant decrease in recall for semantically negative words said in an incongruent prosodically positive tone.

From Brown-Peterson to continual distractor via operation span: A SIMPLE account of complex span.

Three memory tasks-Brown-Peterson, complex span, and continual distractor-all alternate presentation of a to-be-remembered item and a distractor activity, but each task is associated with a different memory system, short-term memory, working memory, and long-term memory, respectively. SIMPLE, a relative local distinctiveness model, has previously been fit to data from both the Brown-Peterson and continual distractor tasks; here we use the same version of the model to fit data from a complex span task. Despite the many differences between the tasks, including unpredictable list length, SIMPLE fit the data well. Because SIMPLE posits a single memory system, these results constitute yet another demonstration that performance on tasks originally thought to tap different memory systems can be explained without invoking multiple memory systems.

Comparison of interstimulus intervals on change detection in nondriving and driving scenarios.

Change detection across disruptions of visual scenes is typically studied using brief durations of the interstimulus interval (ISI) (i.e., up to 300 ms). We investigated change detection across durations that approximate longer, voluntary glances away from a visual scene (i.e., 500-2,000 ms), which are often actualized in driving situations. Experiment 1 found that in nondriving scenarios, change detection performance, as measured by accuracy and response time, decreased as ISI increased. Experiment 2 found that in driving scenarios, change detection for plausible changes also decreased as the ISI increased, but there was no similar decrease in performance for implausible changes. Both Experiments 1 and 2 showed that the necessary number of exposures to the change decreased as ISIs approximated voluntary glances, suggesting that change detection strategies may be modified at longer ISI durations.

Does working memory change with age? The interactions of concurrent articulation with the effects of word length and acoustic confusion.

The effects of acoustic confusion (phonological similarity), word length, and concurrent articulation (articulatory suppression) are cited as support for Working Memory's phonological loop component (e.g., Baddeley, 2000 , Psychonomic Bulletin and Review, 7, 544). Research has focused on younger adults, with no studies examining whether concurrent articulation reduces the word length and acoustic confusion effects among older adults. In the current study, younger and older adults were given lists of similar and dissimilar letters (Experiment 1) or long and short words (Experiment 2) for immediate serial reconstruction of order. Items were presented visually or auditorily, with or without concurrent articulation. As expected, younger and older adults demonstrated effects of acoustic confusion, word length, and concurrent articulation. Further, concurrent articulation reduced the effects of acoustic confusion and word length equally for younger and older adults. This suggests that age-related differences occur in overall performance, but do not reflect an age-related deficiency in the functioning of the phonological loop component of working memory.

The effect of perceptual cues on inhibiting irrelevant information in older adults using a list-learning method.

UNLABELLED: BACKGROUND/STUDY CONTEXT: The inhibitory deficit hypothesis (Hasher & Zacks, 1988 , The Psychology of Learning and Motivation: Advances in Research and Theory, 22, 193-225) suggests that older adults are more susceptible to interference from irrelevant information because of age-related declines in inhibitory ability. Reading comprehension tasks have found that this deficit can be overcome by salient perceptual cues used to accentuate relevant information (Carlson, Hasher, Connelly, & Zacks, 1995 , Psychology and Aging, 10, 427-436). This study examined the ability of older adults to use perceptual cues to aid inhibition in list-learning tasks. METHODS: Sixteen younger (18-24 years of age) and sixteen older (62-79 years of age) adults were asked to remember/ignore presented items based on a pre- or posttrial perceptual cue (i.e., red or green font designated item relevance before or after each trial). The to-be-ignored stimuli could be pseudo-words or words taken from the same word pool as the relevant items. A repeated measures analysis of variance (ANOVA) was done to examine age-related differences in recognition of to-be-remembered items. RESULTS: As expected, younger adults showed better performance than older adults when item relevance was designated posttrial. Most importantly, pretrial perceptual cues eliminated age-related differences in performance when the task-irrelevant stimuli were pseudo-words, but not when they were words from the same word pool as the task-relevant stimuli. CONCLUSION: The results suggest that perceptual cues are not reliably sufficient to overcome inhibitory deficits in older adults, and that older adults may continue to process irrelevant information, leading to declines in task performance. This warrants further investigation regarding the extent to which relevant and irrelevant items must be distinguishable, perceptually or semantically, in order to aid inhibitory ability in older adults.