Pilfering ravens, Corvus corax, adjust their behaviour to social context and identity of competitors

Like other corvids, food-storing ravens protect their caches from being pilfered by conspecifics by means of aggression and by re-caching. In the wild and in captivity, potential pilferers rarely approach caches until the storers have left the cache vicinity. When storers are experimentally prevented from leaving, pilferers first search at places other than the cache sites. These behaviours raise the possibility that ravens are capable of withholding intentions and providing false information to avoid provoking the storers' aggression for cache protection. Alternatively, birds may refrain from pilfering to avoid conflicts with dominants. Here we examined whether ravens adjust their pilfer tactics according to social context and type of competitors. We allowed birds that had witnessed a conspecific making caches to pilfer those caches either in private, together with the storer, or together with a conspecific bystander that had not created the caches (non-storer) but had seen them being made. Compared to in-private trials, ravens delayed approaching the caches only in the presence of storers. Furthermore, they quickly engaged in searching away from the caches when together with dominant storers but directly approached the caches when together with dominant non-storers. These findings demonstrate that ravens selectively alter their pilfer behaviour with those individuals that are likely to defend the caches (storers) and support the interpretation that they are deceptively manipulating the others' behaviour.This contribution is part of the special issue “Animal Logics” (Watanabe and Huber 2006).     

Evidence that baroreflex feedback influences long-term incidental visual memory in men

Sympathetic nervous system (SNS) activity at the time of acquisition is associated with human memory. However, rather than SNS activity per se, it may be afferent baroreflex feedback that is responsible for this effect. A pharmacological design was employed to unload (SNP, sodium nitro-prusside) and load (norepinephrine) baroreceptors. In addition to two placebo periods, epinephrine and esmolol (a peripherally acting beta1-blocker) served as control conditions for altered cardiac perception. During drug infusion blood pressure, heart rate, and perception of heartbeat were tested. Twenty-four healthy men were participated. The participants viewed emotional slides while their electromyographic eye blink responses to random noise bursts were measured (affective startle modulation paradigm) to determine potential drug impact on emotional processing. Subjects were not informed that memory testing would take place after 4 weeks. Drugs did not impact startle, thus indicating unbiased emotional processing at the time of acquisition. Norepinephrine had no effect on heartbeat perception, but improved (p = .002) recognition memory. SNP (p = .0001) increased heartbeat perception but impaired (p = .038) recognition memory. Epinephrine, on the other hand, increased heartbeat perception (p = .0001) yet did not impair but partially improve memory (effect on high arousing pictures only: p = .05). Heartbeat perception in the placebo condition did not correlate with recognition memory (p's > .5). We suggest that baroreflex unloading, with subsequent feedback activation of the SNS, impairs long-term incidental visual recognition memory in humans while baroreflex loading enhances it. Further, we propose that these memory effects are neither secondary to cardiac sensations that accompany SNS activation nor to altered emotional picture processing at the time of acquisition.     

Dissociation between extension of the sensitive period for avian vocal learning and dendritic spine loss in the song nucleus lMAN

Several instances of early learning coincide with significant rearrangements of neural connections in regions contributing to these behaviors. In fact developmentally restricted learning may be constrained temporally by the opportunity for experience to selectively maintain appropriate synapses amidst the elimination of exuberant connections. Consistent with this notion, during the normal sensitive period for vocal learning in zebra finches (Taenopygia guttata), there is a decline in the density of dendritic spines within a region essential for song development, the lateral magnocellular nucleus of the anterior nidopallium (lMAN). Moreover, in birds isolated from conspecific song shortly after hatching, both the closure of the sensitive period for vocal learning and the pruning of spines from lMAN neurons is delayed. Here, we employed a more subtle form of deprivation to delay the close of the sensitive period for song learning, and found that late song learning occurred without obvious alterations in the pruning of dendritic spines on lMAN neurons. At posthatch day (PHD) 65 (beyond the end of the normal sensitive period for song memorization in zebra finches), birds isolated from song beginning on PHD30 did not differ from normally reared birds in measures of dendritic spine density on Golgi-Cox stained lMAN neurons. Moreover, tutor exposure from PHD65 to 90 did not increase spine elimination in these isolates (who memorized new song material) relative to controls (who did not). Thus, we conclude that the extent of normally occurring lMAN spine loss is not sufficient to account for the timing of the sensitive period for zebra finch song learning.     

Programming of expected and unexpected movements: effects on the onset of the lateralized readiness potential

When participants utilize prime information to prepare some or all aspects of the forthcoming movement, reaction time (RT) costs are obtained when the imperative response signal demands an unexpected rather than an expected movement. Longer RT in trials for which primes are invalid rather than valid, i.e., the response validity effect, are taken to reflect prolonged motoric processing time. The present study was designed to test this assumption by using the lateralized readiness potential (LRP) in order to reveal influences of response validity at motoric processes, pre-motoric processes, or both. In two response priming experiments LRP onset latency was examined when valid and invalid advance information about direction (Experiment 1) or about direction and hand (Experiment 2) was provided. RT revealed large response validity effects in both experiments. Analysis of LRP onsets provided strong evidence against the common assumption of a motoric locus of the RT increase in invalid trials. Rather, the present results suggest a pre-motoric locus of the response validity effect within information processing.     

《结构存在论》引论

罗姆巴赫的结构现象学思想与东方哲学有着绝妙的契合。在其核心著作《结构存在论》一开篇,罗姆巴赫就明确地通过对老子哲学的阐释来说明他的“结构”概念。无论在艺术,伦理学和宗教信仰还是在科学活动中,结构的构造状态都被视为普全的基本形式;而这种向分支领域扩展的基础在于对现象学视域内存在论的结构分析。同时,他也强调结构只能在活的历史关联中被描述,不存在最终有效的静态结构范畴。     

When language gets emotional: Irony and the embodiment of affect in discourse

Although there is increasing evidence to suggest that language is grounded in perception and action, the relationship between language and emotion is less well understood. We investigate the grounding of language in emotion using a novel approach that examines the relationship between the comprehension of a written discourse and the performance of affect-related motor actions (hand movements towards and away from the body). Results indicate that positively and negatively valenced words presented in context influence motor responses (Experiment 1), whilst valenced words presented in isolation do not (Experiment 3). Furthermore, whether discourse context indicates that an utterance should be interpreted literally or ironically can influence motor responding, suggesting that the grounding of language in emotional states can be influenced by discourse-level factors (Experiment 2). In addition, the finding of affect-related motor responses to certain forms of ironic language, but not to non-ironic control sentences, suggests that phrasing a message ironically may influence the emotional response that is elicited.     

Decomposing sources of response slowing in the PRP paradigm

The mechanism underlying the reaction time (RT2) slowing to the 2nd of 2 successively presented stimuli (S1 and S2) in the psychological refractory period paradigm was investigated. Stimulus onset synchrony (SOA) between S1 and S2, contrast of S2, and Task 2 set-level compatibility was manipulated. Specifically, the authors used a psychophysiological approach to examine RT2 slowing in trials in which the reaction time to S1 (RT1) was shorter than the SOA. For trials with RT1 < SOA, the clear decrease in RT2 with increasing SOA was underadditive with the S2 contrast effect, but additive with compatibility. Electrophysiological measures revealed an exclusively premotoric locus of RT2 slowing. These findings indicate that a central bottleneck stage is occupied for some period after response to S1 execution, consistent with an extended response selection bottleneck account.     

Stress modulates the use of spatial versus stimulus-response learning strategies in humans

Animal studies provided evidence that stress modulates multiple memory systems, favoring caudate nucleus-based "habit" memory over hippocampus-based "cognitive" memory. However, effects of stress on learning strategy and memory consolidation were not differentiated. We specifically address the effects of psychosocial stress on the applied learning strategy in humans. We designed a spatial learning task that allowed differentiating spatial from stimulus-response learning strategies during acquisition. In 13 subsequent trials, participants (88 male and female students) had to locate a "win" card out of four placed at a fixed location in a 3D model of a room. Relocating one cue in the last trial allowed inferring the applied learning strategy. Half of them participated first in the "Trier Social Stress Test." Salivary cortisol and heart rate measurements were taken. Stressed participants used a stimulus-response strategy significantly more often than controls. Subsequent verbal report revealed that spatial learners had a more complete awareness of response options than stimulus-response learners. Importantly, learning performance was not affected by stress. Taken together, stress prior to learning facilitated simple stimulus-response learning strategies in humans-at the expense of a more cognitive learning strategy. Depending on the context, we consider this as an adaptive response.