Referential coding contributes to the horizontal SMARC effect

The present study tested whether coding of tone pitch relative to a referent contributes to the correspondence effect between the pitch height of an auditory stimulus and the location of a lateralized response. When left-right responses are mapped to high or low pitch tones, performance is better with the high-right/low-left mapping than with the opposite mapping, a phenomenon called the horizontal SMARC effect. However, when pitch height is task irrelevant, the horizontal SMARC effect occurs only for musicians. In Experiment 1, nonmusicians performed a pitch discrimination task, and the SMARC effect was evident regardless of whether a referent tone was presented. However, in Experiment 2, for a timbre-judgment task, nonmusicians showed a SMARC effect only when a referent tone was presented, whereas musicians showed a SMARC effect that did not interact with presence/absence of the referent. Dependence of the SMARC effect for nonmusicians on a reference tone was replicated in Experiment 3, in which judgments of the color of a visual stimulus were made in the presence of a concurrent high- or low-pitched pure tone. These results suggest that referential coding of pitch height is a key determinant for the horizontal SMARC effect when pitch height is irrelevant to the task.     

Exhausting attentional tracking resources with a single fast-moving object

Driving on a busy road, eluding a group of predators, or playing a team sport involves keeping track of multiple moving objects. In typical laboratory tasks, the number of visual targets that humans can track is about four. Three types of theories have been advanced to explain this limit. The fixed-limit theory posits a set number of attentional pointers available to follow objects. Spatial interference theory proposes that when targets are near each other, their attentional spotlights mutually interfere. Resource theory asserts that a limited resource is divided among targets, and performance reflects the amount available per target. Utilising widely separated objects to avoid spatial interference, the present experiments validated the predictions of resource theory. The fastest target speed at which two targets could be tracked was much slower than the fastest speed at which one target could be tracked. This speed limit for tracking two targets was approximately that predicted if at high speeds, only a single target could be tracked. This result cannot be accommodated by the fixed-limit or interference theories. Evidently a fast target, if it moves fast enough, can exhaust attentional resources.     

Multiple goals, writing strategies, and written outcomes for college students learning English as a second language

This study examined relations of achievement goals of writers who are speakers of English as a foreign language (EFL), the frequency of their writing strategy use, and the quality of their writing from a multiple goals perspective. The goal profiles of 57 EFL college students with similar writing proficiency were based on rating items of an unpublished scale; Group 1 had strong mastery and strong performance-approach goals, and two groups included students with only one strong mastery (Group 2) or performance (Group 3) goal. Think-aloud protocols indicated that the participants adopted 21 strategies in an argumentative writing task, classified into five categories. Group 1 was found to use writing strategies of monitoring or evaluating, revising, and compensating significantly more often than the other two groups, and produced better essays. Strong mastery and performance-approach goals might be beneficial for EFL college writers.     

The evolution of decision-making under risk: Framing effects in monkey risk preferences

When making choices between risky options, human decision-makers exhibit a number of framing effects. One of the most prominent framing effects is the tendency for decision makers to evaluate gambles relative to a reference point, and to act risk-seeking when prospects are framed as losses but risk-averse when identical prospects are framed as gains. This tendency for risk-preferences to reverse between loss and gain frames has been termed the reflection effect, and is one of the primary predictions of Prospect Theory. Here, we explore whether non-human primates exhibit a similar reflection effect. Using a token-trading task, we show that capuchin monkeys (Cebus apella) exhibit an analogous reversal of risk preferences depending on whether outcomes are presented as gains or losses, suggesting that similar framing effects also influence choice in non-human primates. This finding suggests that the mechanisms that drive framing effects in humans may be evolutionarily ancient, extending broadly across the primate order.     

Age differences in the automatic accessibility of emotional words from semantic memory

Using a speeded word fragment completion task, we assessed age differences in the automatic accessibility of emotional versus neutral words from semantic memory. Participants were instructed to complete a series of single-solution word fragments as quickly as possible. The results demonstrate that older adults are biased against accessing both positive and negative words relative to neutral words, whereas young adults are biased against accessing positive words only. These findings suggest an arousal-based accessibility bias favouring neutral stimuli in older adults coupled with a valence-based bias accessing negative and neutral stimuli for young adults.     

Cognitive impairment and whole brain diffusion in patients with neuromyelitis optica after acute relapse

The objective of this study investigated cognitive impairments and their correlations with fractional anisotropy (FA) and mean diffusivity (MD) in patients with neuromyelitis optica (NMO) without visible lesions on conventional brain MRI during acute relapse. Twenty one patients with NMO and 21 normal control subjects received several cognitive tests to assess cognitive function. Head diffusion tensor imaging (DTI) of all patients with NMO were collected with a 3-T MR system. Correlations of cognitive test scores and whole brain FA and MD were examined by voxel-based analysis. Region-of-interest analysis was applied to the significantly correlated regions which the most frequently appeared. We found that NMO patients without visible brain lesions had significantly impaired learning and memory, decreased information processing speed, and damaged attention compared with normal control subjects. These impaired cognitive domains were significantly correlated with FA and MD in local regions of corpus callosum, anterior cingulate and medial frontal cortex. In corpus callosum of NMO patients, mean FA was significantly lower and mean MD higher than normal control subjects. Our findings suggest that cognitive impairments in learning and memory, information processing speed and attention occur in NMO patients without visible brain lesions during acute relapse. The impairments in immediate and short-term memory in NMO patients may be due to information encoding deficits in the process of information acquisition. The corpus callosum of such patients may have local microscopic damages that play a role in cognitive impairments during acute relapse.     

Mechanism of isoflavone aglycone's effect on cognitive performance of senescence-accelerated mice

This study investigated the effect of isoflavone aglycone (IA) on the learning and memory performance of senescence-accelerated mice, and explored its neural protective mechanism. Results showed that SAM-P/8 senescence-accelerated mice treated with IA performed significantly better in the Y-maze cognitive test than the no treatment control (P<0.05). The cortex AchE activity, serum SOD and GSH-Px activities were notably higher (P<0.05). MDA concentration and the β-secretase activity in the hippocampal tissue were both lower (P<0.05). Additionally, the number of hippocampal neurons was increased and cell morphology was significantly improved. Data suggested that IA could indirectly increase concentration of the cholinergic neural transmitter Ach through regulation of AchE, therefore improving the central cholinergic function and enhancing the learning and memory ability. By reducing the β-secretase activity, IA could decrease the formation and deposition of insoluble Adebris, relieve the resulted toxicity and damage to neurons, and thereby effectively protect the nervous system.