Generalization of Habituation and Intrinsic Sensitization in the Leech

Using the shortening reflex of the medicinal leech Hirudo medicinalis we examined stimulus generalization of habituation learning. Preparations received mechanosensory stimulus at two positions on the leech body wall, one site used to carry out habituation training and a second novel site to test for generalization of habituation. After training, the specific mechanosensory neurons activated by each stimulus were assessed using intracellular recordings. As expected, the closer the two sites were to each other, the greater the degree of generalization of habituation at the novel site and the more sensory cells were shared. However, a form of behavioral facilitation was observed at the trained site that resembled behavioral sensitization, but differed from the standard sensitization process in several respects. (1) Facilitation was induced by stimulation of the novel site before habituation training at the trained site, although the stimulus intensity at the novel site was equivalent to the training stimuli and was not the strong, noxious stimuli that normally induce sensitization. (2) The magnitude of the facilitating effect was proportional to the proximity of the novel and trained stimulation sites. (3) Although behavior at the trained site was facilitated, behavior at the novel site was habituated, indicating that the induced behavioral facilitation did not generalize throughout the animal, as normally occurs during sensitization, but was limited to a single stimulus–response pathway.     

Self-Control Depletion Does Not Diminish Attitudes About Being Prosocial But Does Diminish Prosocial Behaviors

In three studies, ego-depleted participants reported the same level of affective/cognitive concern for others as control participants, but behaved less prosocially. In Study 1, participants had to sustain cooperation to increase the joint payout to themselves and another player. In Study 2, participants had to restrict their use of a shared resource. In Study 3, ego-depletion failed to produce effects on several measures of concern for others despite large effects found with other manipulations. Results suggest ego-depletion influences behavior by reducing one's ability or motivation to overcome egotistic desires when helping others comes at a cost to the self.     

Dexamethasone Does Not Prevent Seven-Day ADX-Induced Apoptosis in the Dentate Gyrus of the Rat Hippocampus

Long-term adrenalectomy (ADX) is known to result in apoptosis within the dentate gyrus of the rat hippocampus. While the underlying mechanism is still unclear, adrenal steroids appear to play a pivotal role in granule cell survival, as administration of the mineralocorticoid receptor (MR) agonists, corticosterone and aldosterone, to ADX rats results in protection against the ADX-induced effect. The consequence of administration of the glucocorticoid receptor (GR) agonists, dexamethasone and RU28362, however, is less clear, and either complete or only partial protection for the ADX animal has been reported. This study investigated further the role played by GR in the degenerative process. After establishing the characteristics of seven-day ADX-induced apoptosis in the young male Wistar rat, the effect of chronically-implanted, subcutaneous pellets containing various doses of dexamethasone and corticosterone, on ADX-induced apoptosis was studied. Both high and low doses of corticosterone were found to be protective. In contrast to some other studies, however, neither dose of dexamethasone had any obvious protective effect and rather seemed to increase apoptosis in dentate gyrus of intact animals. Intracerebroventricular infusion of dexamethasone for seven days was also found to be ineffective in preventing apoptosis, demonstrating that it is occupation of MR, rather than GR, which is crucial to dentate gyrus granule cell survival.     

Toward a Non-memory Misinformation Effect: Accessing the Original Source Does Not Prevent Yielding to Misinformation

The misinformation effect is regarded by many to be fully memory-related. The paper presents results demonstrating that it may occur without memory distortions or source monitoring errors. Three experiments were conducted, in which the participants were allowed to access the original and post-event source while answering. All experiments used a discrepancy detection test in order to see whether participants aware of discrepancies and having access to the original source, still provide answers consistent with misinformation. In Experiments 2 and 3, the participants’ actions in the modified procedure were recorded, ensuring that subjects actively access the original source. A misinformation effect was obtained in all experiments. Moreover, awareness of discrepancies did not fully protect against the misinformation effect. Results demonstrate that existing memory-related explanations of the misinformation effect, including source misattribution, may not be enough to fully understand it.     

停表错觉的机制：注意是否为决定因素

通过两个实验探讨了注意是否影响停表错觉（chronostasis）。实验一要求被试在注视时或眼跳后,估计处于眼跳目标或其附近位置的刺激的持续时间;实验二要求被试在眼跳条件下辨别眼跳目标或其附近位置的刺激,以考查两种位置的注意水平。结果表明,眼跳目标位置的注意水平高于其附近位置,而两种位置均可产生停表错觉,且两者的错觉量近似相等。从而说明注意并不影响停表错觉,停表错觉的机制可能是眼跳目标及其附近刺激的知觉提前。     

Reversing Arrows in Mediation Models Does Not Distinguish Plausible Models

Reversing arrows in the classic tri-variate X-M-Y mediation models as a test to check whether one mediation model is superior to another is inadmissible. Presenting evidence that one tri-variate mediation model yields a significant indirect effect, whereas one with some reversed arrows does not, is not proof or even evidence that one model should be preferred. In fact, the significance of the indirect or any other effect can never be used to infer whether one model should be preferred over another, if the models are in the same so-called equivalence class. The practice of running several mediation models with reversed arrows to decide which model to prefer should be abandoned. The only way to choose among equivalent models is through assumptions that are either fulfilled by design features or invoked based on theory. Similar arguments about reversing arrows in mediation models have been made before, but this current work is the first to derive this result analytically for the complete (Markovian) equivalence class of the tri-variate mediation model.     

Not all ideals are equal: Intrinsic and extrinsic ideals in relationships

The ideal standards model suggests that greater consistency between ideal standards and actual perceptions of one's relationship predicts positive relationship evaluations; however, no research has evaluated whether this differs across types of ideals. A self‐determination theory perspective was derived to test whether satisfaction of intrinsic ideals buffers the importance of extrinsic ideals. Participants (N = 195) in committed relationships directly and indirectly reported the extent to which their partner met their ideal on two dimensions: intrinsic (e.g., warm, intimate) and extrinsic (e.g., attractive, successful). Relationship need fulfillment and relationship quality were also assessed. Hypotheses were largely supported, such that satisfaction of intrinsic ideals more strongly predicted relationship functioning, and satisfaction of intrinsic ideals buffered the relevance of extrinsic ideals for outcomes.     

Parafoveal Magnification: Visual Acuity Does Not Modulate the Perceptual Span in Reading

ABSTRACT— Models of eye guidance in reading rely on the concept of the perceptual span—the amount of information perceived during a single eye fixation, which is considered to be a consequence of visual and attentional constraints. To directly investigate attentional mechanisms underlying the perceptual span, we implemented a new reading paradigm—parafoveal magnification (PM)—that compensates for how visual acuity drops off as a function of retinal eccentricity. On each fixation and in real time, parafoveal text is magnified to equalize its perceptual impact with that of concurrent foveal text. Experiment 1 demonstrated that PM does not increase the amount of text that is processed, supporting an attentional-based account of eye movements in reading. Experiment 2 explored a contentious issue that differentiates competing models of eye movement control and showed that, even when parafoveal information is enlarged, visual attention in reading is allocated in a serial fashion from word to word.     

SHORT REPORT Rhyme Attenuates the Auditory Suffix Effect: Alliteration Does Not

Two experiments are reported in each of which subjects were required to recall spoken consonant-vowel-consonant (CVC) syllable lists serially. Both experiments contrasted the effects of a rhyming suffix and an alliterative suffix on recall of the terminal list item. A rhyming suffix reliably attenuated the normally robust suffix effect; an alliterative suffix did not. The finding points to the importance of the location rather than the quantity of phonological repetition in determining the size of the suffix effect. In line with Treiman and Danis (1988), it is argued that the onset (C) and rime (VC) components of CVC syllables may exist as separate entites within short-term acoustic memory. This, coupled with the superior durability of the rime component within acoustic memory, affords the subject a greater probability of recalling correctly the terminal list item in the rhyming suffix condition.     

Transparency for the Public Good: When Feeling Powerful Does and Does Not Affect Willingness to Sacrifice for the Environment

In two studies, we tested the hypothesis that the effect of feeling powerful on willingness to sacrifice for the preservation of shared resources depends on whether such willingness is expressed publically or privately. Participants were randomly assigned to either a power priming condition or a control condition and then completed measures assessing their attitudes, future intentions, and willingness to sacrifice for environmental conservation. Consistent with our hypothesis, the psychological experience of power decreased people's environmental attitudes and willingness to sacrifice for the environment, but only when these responses were made privately. These findings suggest that a sense of power, when experienced in private, influences the way individuals feel about and intend to engage in pro-environmental sacrifice. The findings also suggest that this effect may be eliminated when judgments are made transparently, in public view.     

Time Cues Block the CS, but the CS Does Not Block Time Cues

Analysis of conditioned defensive freezing in rats revealed that prior pairings of a tone conditioned stimulus (CS) and footshock in Context 1 at Time 1 failed to give that tone CS the power to block conditioning to Context 2 at Time 2. This failure of an excitatory CS to block conditioning of time cues was not reciprocal. When the stimulus roles were reversed, excitatory time cues blocked conditioning to the tone CS. This asymmetry in blocking is best explained by the notion that time cues have special access to the association-formation mechanism.     

Timing Precision in Circle Drawing Does Not Depend on Spatial Precision of the Timing Target

The authors manipulated the width of a timing target in continuous circle drawing to determine whether a more stringent spatial-timing criterion would produce an increase in participants' (N = 30) temporal variability. They also examined the effect of the computational method of determining cycle duration. There was no effect of spatial precision on temporal variability in circle drawing, and tapping and circle drawing were found to use the same criterion. Those findings lend strong support to the earlier view of R. B. Ivry, R. M. Spencer, H. N. Zelaznik, and J. Diedrichsen (2002), who argued that continuous tasks such as circle drawing are timed differently from discrete-like tasks such as tapping. Therefore, the results of the present study provide support for the event and emergent timing frameworks.     

Simulated Visual Field Loss Does Not Alter Turning Coordination in Healthy Young Adults

Turning, while walking, is an important component of adaptive locomotion. Current hypotheses regarding the motor control of body segment coordination during turning suggest heavy influence of visual information. The authors aimed to examine whether visual field impairment (central loss or peripheral loss) affects body segment coordination during walking turns in healthy young adults. No significant differences in the onset time of segments or intersegment coordination were observed because of visual field occlusion. These results suggest that healthy young adults can use visual information obtained from central and peripheral visual fields interchangeably, pointing to flexibility of visuomotor control in healthy young adults. Further study in populations with chronic visual impairment and those with turning difficulties are warranted.     

Surprise! An Unexpected Color Singleton Does Not Capture Attention in Visual Search

The existence of a pure form of stimulus-driven attentional control has been aligned exclusively with the existence of attentional capture. Unfortunately, there has been little evidence provided in support of attentional capture. The present study investigated whether the repeated failure to observe attentional capture might be due to the way in which attentional capture has been measured. A new visual search procedure was used to investigate whether attention would be captured by an initial and unexpected encounter with a color singleton. Despite this important change in procedure, the color singleton still did not capture attention. Further evidence showed that visual search for the color singleton could be highly efficient, but only after its relevance became established, and that the failure to observe capture in the present experiment was not due to other potentially detrimental effects of surprise. The present results suggest that new conceptions of stimulus-driven attentional control are required.     

Why the Non-Identity Problem Does Not Undermine our Obligations to the Future under Real-World Conditions

Philosophia - When Derek Parfit in Reasons and Persons, examined whether the Non-Identity Problem could be solved with the Impersonal Total Principle, he assumed perfect equality in the future...