Metacognitive awareness of event-based prospective memory

This study examined people’s ability to predict and postdict their performance on an event-based prospective memory task. Using nonfocal cues, one group of participants predicted their success at finding animal words and a different group predicted their ability to find words with a particular syllable in it. The authors also administered a self-report questionnaire on everyday prospective and retrospective memory failures. Based on the different strategies adopted by the two groups and correlations among the dependent variables, the authors concluded that people do have a basic awareness of their prospective memory abilities, but that this awareness is far from accurate. The importance of metamemory concerning one’s prospective memory is discussed in terms of how it influences the strategies that people might choose for actually completing their various everyday intentions.     

Is the mind inherently forward looking? Comparing prediction and retrodiction

It has been suggested that prediction may be an organizing principle of the mind and/or the neocortex, with cognitive machinery specifically engineered to detect forward-looking temporal relationships, rather than merely associating temporally contiguous events. There is a remarkable absence of behavioral tests of this idea, however. To address this gap, we showed subjects sequences of shapes governed by stochastic Markov processes, and then asked them to choose which shape reliably came after a probe shape (prediction test) or before a probe shape (retrodiction test). Prediction was never superior to retrodiction, even when subjects were forewarned of a forward-directional test.     

New objects can capture attention without a unique luminance transient

Recent evidence has suggested that new objects capture attention solely because they are typically accompanied by a unique luminance transient. In the present study, we presented a stationary pattern mask after an array of placeholders but before a subsequent search display. This allowed all of the search elements to be presented simultaneously, thereby eliminating the unique luminance transient associated with the appearance of any new objects. Under these circumstances, new objects still captured attention. In another experiment, we jiggled the mask. This caused new objects to lose their advantage. We discuss implications for the importance of new objects, and the attentional consequences of motion.     

Methylene blue facilitates the extinction of fear in an animal model of susceptibility to learned helplessness

The objectives were to (1) extend previous findings on fear extinction deficits in male congenitally helpless rats (a model for susceptibility to learned helplessness) to female congenitally helpless rats, and (2) attempt a therapeutic intervention with methylene blue, a metabolic enhancer that improves memory retention, to alleviate the predicted extinction deficits. In the first experiment, fear acquisition (four tone-shock pairings in operant chamber) was followed by extinction training (60 tones in open field). Congenitally helpless rats showed fear acquisition similar to controls but had dramatic extinction deficits, and did not display the gradual extinction curves observed in controls. Congenitally helpless rats demonstrated greater tone-evoked freezing as compared to controls in both the acquisition and extinction contexts one week after extinction training, and also in the extinction probe conducted one month later. In the second experiment (which began one month after the first experiment) congenitally helpless subjects were further exposed to tones for 5 days, each followed by 4 mg/kg methylene blue or saline IP, and had a fear renewal test in the acquisition context. Methylene blue administration improved retention of the extinction memory as demonstrated by significant decreases in fear renewal as compared to saline-administered congenitally helpless subjects. The impaired ability to extinguish fear to a traumatic memory in congenitally helpless rats supports the validity of this strain as an animal model for vulnerability to post-traumatic stress disorder, and this study further suggests that methylene blue may facilitate fear extinction as an adjunct to exposure therapy.     

Drink alcohol and dim the lights: The impact of cognitive deficits on medial frontal cortex function

Scalp electroencephalogram (EEG) recordings indicate that regions in the medial frontal cortex (MFC) are active following errors. Alcohol consumption reduces this error-related activity, perhaps suggesting that alcohol disrupts the operation of an error-monitoring system in the MFC. However, it could also be that alcohol consumption affects the MFC only indirectly, by impairing stimulus processing and thus making errors harder to detect. This interpretation leads to the prediction that stimulus degradation should likewise reduce error-related activity in the MFC. To test this hypothesis, behavioral and EEG data were collected as participants performed a speeded response task with either bright or very dim stimuli. The results using dim stimuli replicated the observed effects of alcohol consumption—with slowed responses accompanied by reduced error-related MFC activity. The sensitivity of the MFC to disrupted processing elsewhere in the brain suggests complications in interpreting evidence of disturbed MFC function. This research was supported by the National Institutes of Health Conte Center for Neuroscience Research (Grant P50-MH62196 to N.Y.) and by the Netherlands Organization for Scientific Research (to S.N.).     

Mindfulness training modifies subsystems of attention

Mindfulness is defined as paying attention in the present moment. We investigate the hypothesis that mindfulness training may alter or enhance specific aspects of attention. We examined three functionally and neuroanatomically distinct but overlapping attentional subsystems: alerting, orienting, and conflict monitoring. Functioning of each subsystem was indexed by performance on the Attention Network Test (ANT; Fan, McCandliss, Sommer, Raz, & Posner, 2002). Two types of mindfulness training (MT) programs were examined, and behavioral testing was conducted on participants before (Time 1) and after (Time 2) training. One training group consisted of individuals naive to mindfulness techniques who participated in an 8-week mindfulness-based stress reduction (MBSR) course that emphasized the development of concentrative meditation skills. The other training group consisted of individuals experienced in concentrative meditation techniques who participated in a 1-month intensive mindfulness retreat. Performance of these groups was compared with that of control participants who were meditation naive and received no MT. At Time 1, the participants in the retreat group demonstrated improved conflict monitoring performance relative to those in the MBSR and control groups. At Time 2, the participants in the MBSR course demonstrated significantly improved orienting in comparison with the control and retreat participants. In contrast, the participants in the retreat group demonstrated altered performance on the alerting component, with improvements in exogenous stimulus detection in comparison with the control and MBSR participants. The groups did not differ in conflict monitoring performance at Time 2. These results suggest that mindfulness training may improve attention-related behavioral responses by enhancing functioning of specific subcomponents of attention. Whereas participation in the MBSR course improved the ability to endogenously orient attention, retreat participation appeared to allow for the development and emergence of receptive attentional skills, which improved exogenous alerting-related process.     

The Nature of Preschool Phonological Processing Abilities and Their Relations to Vocabulary, General Cognitive Abilities, and Print Knowledge

The development of reading-related phonological processing abilities (PPA) represents an important developmental milestone in the process of learning to read. In this cross-sectional study, confirmatory factor analysis was used to examine the structure of PPA in 129 younger preschoolers (M = 40.88 months, SD = 4.65) and 304 older preschoolers (M = 56.49 months, SD = 5.31). A 2-factor model in which phonological awareness and phonological memory was represented by one factor and lexical access was represented by a second factor provided the best fit for both samples and was largely invariant across samples. Measures of vocabulary, cognitive abilities, and print knowledge were significantly correlated with both factors, but phonological awareness/memory had unique relations with word reading. Despite significant development of PPA across the preschool years and into kindergarten, these results show that the structure of these skills remains invariant.     

Probing the human brain with stimulating electrodes: The story of Roberts Bartholow’s (1874) experiment on Mary Rafferty

Roberts Bartholow’s 1874 experiment on Mary Rafferty is widely cited as the first demonstration, by direct application of stimulating electrodes, of the motor excitability of the human cerebral cortex. The many accounts of the experiment, however, leave certain questions and details unexamined or unresolved, especially about Bartholow’s goals, the nature and quality of the evidence, and the experiment’s role in the history of theory and research on localisation of function. In this article, we try to fill these gaps and to tell the full story. We describe Bartholow’s career up to 1874, review the theoretical and empirical background for the experiment, and present Bartholow’s own account of the experiment as well as those of his supporters and critics. We then present our own analysis, assess the experiment’s influence on contemporaneous scientific opinion about cortical excitability, and trace its citation record into our own time. We also review and assess ethical criticisms of Bartholow and their effects on his career, and we close by discussing the role we think the experiment deserves to play in the history of theory and research on cortical excitability.