Object naming induces reliance on orientation-independent representations during longer-term, but not short-term, visual remembering

Naming novel objects with novel count nouns changes how the objects are drawn from memory, revealing that object categorisation induces reliance on orientation-independent visual representations during longer-term remembering, but not during short-term remembering. Serial position effects integrate this finding with a more established conceptualisation of short-term and longer-term visual remembering in which the former is identified as keeping an item in mind. Adults were shown a series of four novel objects in orientations in which they would not normally be drawn from memory. When not named ("Look at this object"), the objects were drawn in the orientations in which they had been seen. When named with a novel count noun (e.g., "Look at this dax"), the final object continued to be depicted in the orientation in which it had been seen, but all other objects were depicted in an unseen but preferred (canonical) orientation, even though participants could still remember the orientations in which they had been seen. Although orientation-dependent exemplar representations appear to be more accessible than orientation-independent generic representations during short-term remembering, the reverse is the case during longer-term remembering. How the theoretical framework emerging from these observations accommodates a broader body of evidence is discussed.     

On the foundations of beliefs in free will: intentional binding and unconscious priming in self-agency

The concept of an ability to make choices and to determine one's own outcomes fits well with experiences that most people have, and these experiences form the basis for beliefs in free will. However, the existence of conscious free will is challenged by modern research findings highlighting the unconscious origins of goal-directed behavior that gives rise to free-will beliefs. This report expands on these insights by revealing that both conscious and unconscious processes play an important role in free-will beliefs. Specifically, Experiment 1 demonstrates that free-will beliefs are strengthened when conscious intentions to produce action outcomes bind the perception of action and outcome together in time. Experiment 2 shows that these beliefs are strengthened when unconscious priming of action outcomes creates illusory experiences of self-agency when the primed outcomes occur. Together, these findings suggest that beliefs in free will are associated with self-agency and are enhanced by both conscious and unconscious information processing of goal-directed behavior.     

Travelling backwards and forwards in time: culture and gender in the episodic specificity of past and future events

There is considerable evidence that, when recalling past events, Westerners exhibit greater episodic specificity than East Asians and women exhibit greater episodic specificity than men. Yet it is unknown whether the same cultural and gender differences are true for future events. In the present study 209 European American and Chinese young adults were asked to recall past personal events and imagine future personal events occurring in varied time periods (i.e., 1 week, 1 year, 10-15 years). Regardless of time period, European Americans consistently produced more specific details than Chinese for future events than they did for past events, and women produced more specific details than men for both past and future events. These findings provide additional support for the constructive-episodic-simulation hypothesis, and shed new light on the influence of culture and gender on episodic thinking.     

马克思与虚无主义问题

马克思的目的是要说明人对价值的需要无须超越历史就能得到满足。认为善(good)内在于历史上与断言善是与历史相同的并非一回事。马克思并不是一个历史主义者——如罗森所使用的术语——因为他没有把善与"所发生之事"等同起来。罗森认为,马克思必定主张在历史中发生的任何事情都是可允许的。马克思的标准是人,而不是历史中在马克思的特定意义上算作人类的(行动)的所有行动。实际上在历史进程中,绝大多数个体是以一种非人的方式把自己对象化的。这就是马克思把前共产主义时期描述为"前历史"的原因,因为那是这样一段时间,在其中社会存在是人类活动的无意识的产物。只有当诸个体自觉地决定其生活并把物质世界置于合作性控制之下,恰当意义上的历史才真正开始。     

Long-lasting effects of inescapable-predator stress on brain tryptophan metabolism and the behavior of juvenile mice

The kynurenine (KYN) pathway, which is initiated by indoleamine 2,3-dioxygenase, is the main tryptophan (TRP) metabolic pathway. It shares TRP with the serotonin (5-HT) pathway. We investigated the influence of inescapable-predator (rat) stress on behavior and brain TRP metabolism in mice. Male ICR mice (4W) were exposed to 20-min inescapable-predator stress. Behavior on an elevated plus-maze, and TRP, KYN, and 5-HT levels in the prefrontal cortex, hippocampus, amygdala, and dorsal raphe nuclei were measured 1 and 4 weeks after stress exposure. Predator stress increased the number of open-arm entries (NOA) 4 weeks after stress exposure without altering the number of closed-arm entries (NCA). Thus, the open/closed-arm entry ratio (NOA/NCA) increased after stress exposure. Predator stress increased KYN levels in the prefrontal cortex (until 4 weeks after stress exposure) and dorsal raphe nuclei (for 1 week after stress exposure), decreased 5-HT levels in all brain regions (until 4 weeks after stress exposure). Thus, predator stress increased the KYN/5-HT ratio in all regions, in particular in the prefrontal cortex and hippocampus until 4 weeks after stress exposure. Predator stress shifted the balance between the KYN and 5-HT pathways to the KYN pathway, and induced behavioral disinhibition.     

Fear-related pictures deteriorate the performance of university students with high fear of snakes or spiders

Despite research regarding emotional processing, it is still unclear whether fear-evoking stimuli are processed when they are irrelevant and when attention is oriented elsewhere. In this study, 63 healthy university students with high fear from snakes or spiders participated in two different experiments. In an emotional modification of the spatial cueing task, 31 subjects (5 males) were asked to detect a target letter while ignoring a neutral or fear-related distracting picture. The distribution of attention was independently manipulated by a spatial cue that preceded the appearance of the picture and the target letter. In an emotional modification of the cognitive load paradigm, 32 subjects (4 males) were asked to discriminate between two target letters, while ignoring a central neutral or fear-related picture, and additional 1, 3, or 5 distracting letters that created a varied attentional load. Fear-related pictures interfered with the performance of highly fearful participants, even when the pictures were presented outside the focus of attention and when the task taxed attentional resources. We suggest that highly fearful individuals process fear-related information automatically, either inattentively or with prioritized attention capture over competing items, leading to deteriorated cognitive performance. Different results were shown in healthy individuals while processing negative--but not phobic--pictures, suggesting that emotional processing depends on the fear value of the stimulus for a specific observer.     

The ease of lying

Brain imaging studies suggest that truth telling constitutes the default of the human brain and that lying involves intentional suppression of the predominant truth response. By manipulating the truth proportion in the Sheffield lie test, we investigated whether the dominance of the truth response is malleable. Results showed that frequent truth telling made lying more difficult, and that frequent lying made lying easier. These results implicate that (1) the accuracy of lie detection tests may be improved by increasing the dominance of the truth response and that (2) habitual lying makes the lie response more dominant.     

Contrasting cue-density effects in causal and prediction judgments

Many theories of contingency learning assume (either explicitly or implicitly) that predicting whether an outcome will occur should be easier than making a causal judgment. Previous research suggests that outcome predictions would depart from normative standards less often than causal judgments, which is consistent with the idea that the latter are based on more numerous and complex processes. However, only indirect evidence exists for this view. The experiment presented here specifically addresses this issue by allowing for a fair comparison of causal judgments and outcome predictions, both collected at the same stage with identical rating scales. Cue density, a parameter known to affect judgments, is manipulated in a contingency learning paradigm. The results show that, if anything, the cue-density bias is stronger in outcome predictions than in causal judgments. These results contradict key assumptions of many influential theories of contingency learning.     

A mechanism for the formation of hippocampal neuronal firing patterns that represent what happens where

The association of specific events with the context in which they occur is a fundamental feature of episodic memory. However, the underlying network mechanisms generating what-where associations are poorly understood. Recently we reported that some hippocampal principal neurons develop representations of specific events occurring in particular locations (item-position cells). Here, we investigate the emergence of item-position selectivity as rats learn new associations for reward and find that before the animal's performance rises above chance in the task, neurons that will later become item-position cells have a strong selective bias toward one of two behavioral responses, which the animal will subsequently make to that stimulus. This response bias results in an asymmetry of neural activity on correct and error trials that could drive the emergence of particular item specificities based on a simple reward-driven synaptic plasticity mechanism.     

Basolateral amygdala inactivation impairs learned (but not innate) fear response in rats

Numerous studies have suggested that the amygdala is involved in the formation of aversive memories, but the possibility that this structure is merely related to any kind of fear sensation or response could not be ruled out in previous studies. The present study investigated the effects of bilateral inactivation of the amygdaloid complex in rats tested in the plus-maze discriminative avoidance task. This task concomitantly evaluates aversive memory (by discrimination of the two enclosed arms) and innate fear (by open-arm exploration). Wistar rats (3-5 months-old) were implanted with bilateral guide cannulae into basolateral amygdala. After surgery, all subjects were given 1 week to recover before behavioral experiments. Afterwards, in experiment 1, 15 min prior to training, 0.5 μl of saline or muscimol (1 mg/ml) was infused in each side via microinjection needles. In experiment 2 the animals received injections immediately after the training session and in experiment 3 rats were injected prior to testing session (24 h after training). The main results showed that (1) pre-training muscimol prevented memory retention (evaluated by aversive arm exploration in the test session), but did not alter innate fear (evaluated by percent time in open arms); (2) post-training muscimol impaired consolidation, inducing increased percent in aversive arm exploration in the test session and (3) pre-testing muscimol did not affect retrieval (evaluated by aversive enclosed arm exploration in the test session). The results suggest that amygdala inactivation specifically modulated the learning of the aversive task, excluding a possible secondary effect of amygdala inactivation on general fear responses. Additionally, our data corroborate the hypothesis that basolateral amygdala is not the specific site of storage of aversive memories, since retention of the previously learned task was not affected by pre-testing inactivation.