Top-down contingencies in peripheral cuing: The roles of color and location.

According to contingent-processing accounts, peripheral cuing effects are due to the cues' inadvertent selection for processing by control settings set up for targets (e.g., C. L. Folk, R. W. Remington, & J. C. Johnston, 1992). Consequently, cues similar to targets should have stronger effects than do dissimilar cues. In the current study, this prediction is confirmed for cue-target combinations similar or dissimilar in the static features of color (Experiments 1-3) and location (Experiment 4), even when both cues and targets share the dynamic feature of abrupt onset. Perceptual priming (Experiment 2) and reallocation of attention did not account for similar-dissimilar differences (Experiments 3 and 4). The results are best explained by top-down-contingent attentional effects of the similar cues. Implications for bottom-up accounts of peripheral cuing effects are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dynamic Aspects of Stimulus-Response Correspondence: Evidence for Two Mechanisms Involved in the Simon Effect.

It has been recently proposed that the time course of the Simon effect may vary across tasks, which might reflect different types of stimulus-response (S-R) transmissions (E. Wascher, U. Schatz, T. Kuder, & R. Verleger, 2001). The authors tested this notion in 4 experiments by comparing Simon effects evoked by horizontal and vertical S-R arrangements. The temporal properties of the effect, as well as lateralized readiness potential-difference waves, indicated a fast and transient influence of the horizontal, but a slow and sustained influence of the vertical spatial stimulus feature on performance. Additional evidence for this temporal dissociation was obtained in experiments that induced a shortening or lengthening of the mean response time. Thus, the data strongly indicate that there are 2 temporally dissociable mechanisms involved in generating the Simon effect for horizontal and vertical S-R relations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Task Switching in a Hierarchical Task Structure: Evidence for the Fragility of the Task Repetition Benefit.

This study examined how task switching is affected by hierarchical task organization. Traditional task-switching studies, which use a constant temporal and spatial distance between each task element (defined as a stimulus requiring a response), promote a flat task structure. Using this approach, Experiment 1 revealed a large switch cost of 238 ms. In Experiments 2-5, adjacent task elements were grouped temporally and/or spatially (forming an ensemble) to create a hierarchical task organization. Results indicate that the effect of switching at the ensemble level dominated the effect of switching at the element level. Experiments 6 and 7, using an ensemble of 3 task elements, revealed that the element-level switch cost was virtually absent between ensembles but was large within an ensemble. The authors conclude that the element-level task repetition benefit is fragile and can be eliminated in a hierarchical task organization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence of a Time-Dependent Long-Term Stage of Memory for a Spatial Learning Task in the Chick (Callus gallus).

The generalizability of temporal parameters of memory formation previously observed for a passive avoidance task was investigated in a spatial task with day-old chicks (Callus gallus). The percentage improvement in completion time over 2 separate trials was measured, and chicks were found to complete the second trial faster at all times tested up to 2 hr, except at 55 min posttraining. In addition, retention at 120 min, but not at 30 min, posttraining was found to be impaired by protein synthesis inhibition. These findings are consistent with the timing of a long-term stage of memory formation following passive avoidance training, implying that there may be some hardwiring to the temporal characteristics of memory formation in this species. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Involvement of the entorhinal cortex in a process of attentional modulation: Evidence from a novel variant of an IDS/EDS procedure.

Novel behavioral assays were used to assess the role of the entorhinal cortex in modulating attention to components of stimulus compounds. In Stage 1, rats received discrimination training with compounds constructed from 3 dimensions (auditory, visual, and tactile); in each compound the combination of components from 2 dimensions (e.g., auditory and visual) were relevant to the solution of the discrimination, and the remaining dimension (e.g., tactile) was irrelevant. In Stage 2, rats received a different discrimination in which the relevant dimensions were either congruent (auditory and visual) or incongruent (auditory and tactile) with those that were relevant in Stage 1. Sham-operated rats acquired the congruent discrimination more rapidly than the incongruent discrimination—a finding indicative of a process of attentional modulation—whereas rats with excitotoxic lesions of the entorhinal cortex acquired both discriminations equally readily. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Taking a bright view of negative priming in the light of dim stimuli: Further evidence for memory confusion during episodic retrieval.

A same–different letter-matching task was used to examine the effects of stimulus intensity on negative priming, which is poorer performance when target letters have been presented as distractor letters on the immediately preceding trial. In Exp 1, with 68 college students, stimulus intensity was manipulated between-participants, whereas in Exp 2, with 32 college students, it varied randomly from trial-to-trial within-participants. In Exp 1, negative priming was equivalent for both stimulus intensities. In Exp 2, negative priming effects were larger for repeated intensity stimuli than for nonrepeated intensity stimuli, when stimulus intensity was dim. Furthermore, for repeated intensity stimuli, negative priming effects were enhanced when the overt response required to the stimulus was repeated from prime to probe trial. These results are consistent with the hypothesis that negative priming may be due to memory confusion, rather than to inhibition of the distractor stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence for a shift from place navigation to directional responding in one variant of the Morris water task.

Previous work from our laboratory has demonstrated that rats display a preference for directional responding over place navigation in a wide range of procedural variants of the Morris water task (Hamilton, Akers, Weisend, & Sutherland, 2007; Hamilton et al., 2008). A preference for place navigation has only been observed when the pool is reduced as a cue by filling it with water. Studies using dry land mazes have suggested that rats place navigate early in training and later switch to other forms of responding (e.g., motor). The present study evaluated whether rats switch from place navigation to directional responding in the “full-pool” variant of the water task. Rats were given 12, 24, or 36 hidden platform training trials. Probe trials with the pool repositioned in the room revealed a preference for place navigation in rats given 12 trials, an equal division of response preferences in rats given 24 trials, and a preference for directional responding in rats given 36 trials. These results indicate that the early preference for place navigation in the full-pool water task is transient and yields to a preference for directional responding with continued training. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the additive effects of stimulus quality and word frequency in lexical decision: Evidence for opposing interactive influences revealed by RT distributional analyses.

The joint effects of stimulus quality and word frequency in lexical decision were examined in 4 experiments as a function of nonword type (legal nonwords, e.g., BRONE, vs. pseudohomophones, e.g., BRANE). When familiarity was a viable dimension for word-nonword discrimination, as when legal nonwords were used, additive effects of stimulus quality and word frequency were observed in both means and distributional characteristics of the response-time distributions. In contrast, when the utility of familiarity was undermined by using pseudohomophones, additivity was observed in the means but not in distributional characteristics. Specifically, opposing interactive effects in the underlying distribution were observed, producing apparent additivity in means. These findings are consistent with the suggestion that, when familiarity is deemphasized in lexical decision, cascaded processing between letter and word levels is in play, whereas, when familiarity is a viable dimension for word-nonword discrimination, processing is discrete. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Effect of Age of Acquisition in Visual Word Processing: Further Evidence for the Semantic Hypothesis.

The authors investigated whether the meaning of visually presented words is activated faster for early-acquired words than for late-acquired words. They addressed the issue using the semantic Simon paradigm. In this paradigm, participants are instructed to decide whether a stimulus word is printed in uppercase or lowercase letters. However, they have to respond with a verbal label ("living" or "nonliving") that is either congruent with the meaning of the word (e.g., saying "living" to the stimulus DOG) or incongruent (e.g., saying "nonliving" to the stimulus dog). Results showed a significant congruency effect that was stronger for early-acquired words than for late-acquired words. The authors conclude that the age of acquisition is an important variable in the activation of the meaning of visually presented words. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Long-term potentiation and spatial learning are associated with increased phosphorylation of TrkB and extracellular signal-regulated kinase (ERK) in the dentate gyrus: Evidence for a role for brain-derived neurotrophic factor.

In this study, the authors investigate changes in the presynaptic terminal of the dentate gyrus that accompany 2 types of hippocampal-dependent plasticity: spatial leanting and long-term potentiation (LTP). Parallel changes occurred in the dentate gyrus of rats that had undergone training in the Morris water maze and had sustained LTP. In both cases, KCl-induced brain-derived neurotrophic factor release was increased, and this was accompanied by increased phosphorylation of TrkB and the mitogen-activated protein kinase, ERK. Glutamate release was also enhanced, and the data suggest thak this may be a consequence of increased activation of TrkB and ERK. Because the data indicate that similar cellular modifications are shared by these 2 forms of plasticity, they provide circumstantial evidence that LTP satisfies some of the requirements of a memory-inducing cellular substrate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Animals' representation of enclosed spaces: Evidence for use of a similar frame of reference following different disorientation procedures in the domestic chick (gallus gallus).

A wide range of vertebrate species has been proved to be capable, following passive disorientation, to reorient into enclosures of different shapes using the metrical distribution of surfaces as surfaces and the geometric sense of left and right. Two procedures can be used to get a subject to loose its orientation: The subject itself can be rotated with the eyes closed or in the dark (viewer-movement procedure) or the external enclosure can be rotated while the subject stays still in a fixed position with the eyes closed or in the dark (i.e., without the possibility to notice any change outside; space-movement procedure). Although the 2 procedures are equivalent in that both cause a change in the spatial relationships between the viewer and the external layout, it has been suggested on the basis of research in human infants that they may involve the use of different frames of reference to reestablish one's bearing and relocate the target. However, no comparison between viewer- and space-movement procedures has been carried out in nonhuman species. Here, the authors show that newborn domestic chicks (Gallus gallus) can reorient effectively irrespective of the specific disorienting procedure applied. The results are discussed in comparative and developmental perspectives. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dynamic illusion effects in a reaching task: Evidence for separate visual representations in the planning and control of reaching.

The effects of an orientation illusion on perception and 2 different actions were investigated. An 8-cm?×?2-cm cylindrical bar was placed in front of participants at various orientations. A background grating was used to induce an orientation illusion. In a perception task, the illusion affected participants' ability to align the bar with their sagittal planes. In one reaching task, a similar effect of the illusion was found on the choice between 2 possible grasping postures. In a second reaching task involving a single grasping posture, the orientation illusion affected the orientation of the hand at the beginning of the reach but not near its end. The authors argue that reaching trajectories are planned and initiated through a context-dependent representation but are corrected on-line through a context-independent representation. The relation of this model to a more general dichotomy between perception and action is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Daily Depression and Cognitions About Stress: Evidence for a Traitlike Depressogenic Cognitive Style and the Prediction of Depressive Symptoms in a Prospective Daily Diary Study.

The authors examined the stability and dynamic structure of negative cognitions made to naturalistic stressors and the prediction of depressive symptoms in a daily diary study. Young adults reported on dispositional depression vulnerabilities at baseline, including a depressogenic cognitive style, dysfunctional attitudes, rumination, neuroticism, and initial depression, and then completed short diaries recording the inferences they made to the most negative event of the day along with their experience of depressive symptoms every day for 35 consecutive days. Daily cognitions about stressors exhibited moderate stability across time. A traitlike model, rather than a contextual one, explained this pattern of stability best. Hierarchical linear modeling analyses showed that individuals' dispositional depressogenic cognitive style, neuroticism, and their daily negative cognitions about stressors predicted fluctuations in daily depressive symptoms. Dispositional neuroticism and negative cognitive style interacted with daily negative cognitions in different ways to predict daily depressive symptoms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)