Modulation of motor area activity during observation of unnatural body movements

We investigated the processes underlying stimulus-response compatibility by using a lateralized auditory stimulus in a simple and choice reaction time (RT) paradigm. Participants were asked to make either a left or right key lift in response to either a control (80 dB) or startling (124 dB) stimulus presented to either the left ear, right ear, or both ears. In the simple RT paradigm, we did not find a compatibility effect for either control or startle trials but did find a right-ear advantage which we attribute to anatomical asymmetry of auditory pathways. In the choice RT paradigm, we found compatibility effects for both startle and control trials as well a high incidence of error for contralateral stimulus-response mapping. We attribute these results to automatic activation of the ipsilateral response, which must then be inhibited prior to initiation of the correct response. The presence of compatibility effects for startle trials also suggest that similar pathways are being used to initiate movements in a choice RT situation, as opposed to involuntary triggering that is thought to occur in a simple RT situation.     

Brain activation during spatial updating and attentive tracking of moving targets

Keeping aware of the locations of objects while one is moving requires the updating of spatial representations. As long as the objects are visible, attentional tracking is sufficient, but knowing where objects out of view went in relation to one's own body involves an updating of spatial working memory. Here, multiple object tracking was employed to study spatial updating and its neural correlates. In a dynamic 3D-scene, targets moved among visually indistinguishable distractors. The targets and distractors either stayed visible during continuous viewpoint changes or they turned invisible. The parametric variation of tracking load revealed load-dependent activations of the intraparietal sulcus, the superior parietal lobule, and the lateral occipital cortex in response to the attentive tracking task. Viewpoint changes with invisible objects that demanded retention and updating produced load-dependent activation only in the precuneus in line with its presumed involvement in updating spatial working memory.     

Independent race of colour and word can predict the Stroop effect

Mainstream theories of the Stroop effect suggest that faster colour classification on congruent trials (say, the word RED printed in red colour) relative to incongruent trials (GREEN in red) is due to channel interaction. Namely, information from the irrelevant word channel perturbs processing of the print colour, causing in turn slower processing of incongruent displays. In this note, I advance a new model in which colour and word are processed in parallel and completely independent channels. The Stroop effect is then the outcome of signal redundancy in congruent displays, where both colour and word contribute to the same response. Numerical computations show that the model can produce the Stroop effect (along with high accuracy rates) for a subset of parameter values. Thus, it provides a proof of existence for a separate channel theory, and a challenge to many existing theories.     

Representing Spatial Structure Through Maps and Language: Lord of the Rings Encodes the Spatial Structure of Middle Earth

Spatial mental representations can be derived from linguistic and non‐linguistic sources of information. This study tested whether these representations could be formed from statistical linguistic frequencies of city names, and to what extent participants differed in their performance when they estimated spatial locations from language or maps. In a computational linguistic study, we demonstrated that co‐occurrences of cities in Tolkien’s Lord of the Rings trilogy and The Hobbit predicted the authentic longitude and latitude of those cities in Middle Earth. In a human study, we showed that human spatial estimates of the location of cities were very similar regardless of whether participants read Tolkien’s texts or memorized a map of Middle Earth. However, text‐based location estimates obtained from statistical linguistic frequencies better predicted the human text‐based estimates than the human map‐based estimates. These findings suggest that language encodes spatial structure of cities, and that human cognitive map representations can come from implicit statistical linguistic patterns, from explicit non‐linguistic perceptual information, or from both.     

A Test of the Testing Effect: Acquiring Problem‐Solving Skills From Worked Examples

The “testing effect” refers to the finding that after an initial study opportunity, testing is more effective for long‐term retention than restudying. The testing effect seems robust and is a finding from the field of cognitive science that has important implications for education. However, it is unclear whether this effect also applies to the acquisition of problem‐solving skills, which is important to establish given the key role problem solving plays in, for instance, math and science education. Worked examples are an effective and efficient way of acquiring problem‐solving skills. Forty students either only studied worked examples (SSSS) or engaged in testing after studying an example by solving an isomorphic problem (STST). Surprisingly, results showed equal performance in both conditions on an immediate retention test after 5 min, but the SSSS condition outperformed the STST condition on a delayed retention test after 1 week. These findings suggest the testing effect might not apply to acquiring problem‐solving skills from worked examples.     

A group construal account of drop-in-the-bucket thinking in policy preference and moral judgment

Decisions, both moral and mundane, about saving individuals or resources at risk are often influenced not only by numbers saved and lost, but also by proportions of groups saved and lost. Consider choosing between a program that saves 60 of 240 lives at risk and one that saves 50 of 100. The first option maximizes absolute number saved; the second, proportion saved. In two studies, we show that the influence of proportions on such decisions depends on how items at risk are mentally represented. In particular, we show that proportions have greater influence on people's decisions to the extent that the items at risk are construed as forming groups, as opposed to distinct individuals. Construal was manipulated by means of animated displays in which resources at risk moved either independently (promoting individual construal) or jointly (promoting group construal). Results support the hypothesis that (a) decision makers form mental representations which vary in the degree to which resources at risk are construed as groups versus individuals and (b) construal of resources as groups promotes the influence of proportions on decisions and moral judgments.     

Potentiation and overshadowing of shape by wall color in a kite-shaped maze using rats in a foraging task

The interaction between redundant geometric and featural cues in open field search tasks has been examined widely with results that are not always consistent. Cheng (1986) found evidence that when searching for food in rectangular environments, rats used the geometrical characteristics of the environment rather than local featural cues, suggesting that geometry had overshadowed featural cues. More recently, Graham et al. (2006) and Pearce et al. (2006) found that wall color facilitated (potentiated) learning about the shape of the environment by rats in a kite-shaped water maze. The first experiment in the present research replicated the paradigm used by Graham et al. and Pearce et al. using rats in a foraging situation, but with conditions similar, and found the same results, potentiation of shape by color. Experiments 2 and 3 revealed overshadowing instead of potentiation of shape by wall color under the same conditions except that the wall colors of the test environment were not the same as those used during training. The results are consistent with an analysis of the role of associations formed between wall color and geometry in such situations (Rhodes et al., 2009) and extend our understanding of how featural and spatial cues interact.     

Analysis of the US-preexposure effect in flavor acceptance conditioning

In three experiments, rats received exposure to a sucrose solution followed by conditioning with a neutral flavor as the conditioned stimulus (CS) and sucrose as the unconditioned stimulus (US). In Experiments 1 and 2, some rats were given both the preexposure and the conditioning phases in a highly familiar context (the homecage), whereas other animals received both phases in a novel and distinctive context. In both cases the magnitude of the conditioning effect was reduced by preexposure to the US. Experiment 3 directly assessed the possible role of contextual cues by changing the context between the exposure phase and the conditioning phase but found no loss of the US-preexposure effect in these conditions. These results lend no support to the blocking-by-context account of the US-preexposure effect; alternative interpretations are considered.     

Manipulations of start and food locations affect navigation on a foraging task

Rats were able to search multiple food cups in a foraging task and successfully return to a fixed, but not a variable, start location. Reducing the number of food cups to be searched resulted in an improvement in performance in the variable start condition. Performance was better when only one or two food cups had to be visited but was still impaired if the food was not found in the first cup searched. Variable start locations impaired performance when only one food cup had to be searched, if that cup was moved over the table. These findings suggest that there is an interaction between memory processes and the navigational processes that allows an animal to return to its start location after a foraging trip. It appears that a fixed location for the food or the start point of a foraging trip is a necessary precondition for accurate performance.     

Lasting effects of alcohol: Subliminal alcohol cues,impairment expectancies,and math performance

Many people believe that drinking alcohol reduces cognitive performance, and prior research has shown such expectancy‐related impairment even when people merely thought that the (non‐alcoholic) drink they consumed contained alcohol. This study tested whether subliminal priming with alcohol‐related cues would similarly result in expectancy‐consistent cognitive performance decrements. Additionally, the moderating role of alcohol use was examined. After assessing participants' baseline math performance, participants were primed with alcohol‐related or neutral words and then completed a post‐treatment math task. Whereas impairment expectancies had no influence on math performance in control participants, expectancies predicted math performance for participants primed with alcohol‐related words. As hypothesized, expectancy‐consistent impairment in performance was only observed among high alcohol users. The current findings suggest that, in the presence of alcohol‐related cues in the environment, some people may perform less on cognitive tasks even in the absence of actual or assumed alcohol consumption and without being aware of it. Copyright © 2011 John Wiley & Sons, Ltd.