Underestimation of length by subjects in motion.

To check a prior observation, in the present experiment, subjects made estimates of the lengths of both the guidelines and the spaces between guidelines on automotive highways so the magnitude of the illusion could be more accurately determined. Ten males and ten females were individually tested at 0 and 60 mph. At 60 mph, spaces were estimated with an error of 85%; lines were estimated with an error of 72%. Combining data for both stimuli, an error of 78% results, which corresponds to underestimation by a factor of 4.67. This illusory effect is considerably greater than that of the moon illusion, considered by many the most powerful of the classical illusions.     

Effect of hemispherectomy in infantile hemiplegics

Four patients with infantile hemiplegia who had undergone hemispherectomy were examined. both left (LH) and right (RH) hemidecorticates obtained borderline defective scores on IQ tests. Patients with isolated right hemispheres were found not to be aphasic or apraxic. Visuospatial and constructional capacities were compromised in all patients. Individuals with an isolated right hemisphere smiled and gestured more than did those with an isolated right hemisphere. EEG and CT scan data showed that the remaining hemisphere was not normal in these patients. Therefore, inferences regarding the functional plasticity of the remaining hemisphere must be made with caution.     

The effect of striatal dopamine depletion and the adenosine A2A antagonist KW-6002 on reversal learning in rats

This study assessed whether dopamine in the dorsomedial striatum is necessary for flexible adaptation to changes in stimulus-response contingencies. As KW-6002 (Istradefylline), an adenosine A(2A) antagonist, improves motor deficits resulting from striatal dopamine depletion, we also tested for potential ameliorative effects of KW-6002 on dopamine depletion-induced cognitive deficits. Male Lister hooded rats were presented with two bowls, discriminable by either a textured covering on the outer surface, their scent or the bowl contents (digging media) in which bait was buried. Once they had learned in which bowl food was buried, the stimulus-response contingencies were reversed. In both phases (acquisition and reversal), the criterion for learning was defined a priori as six consecutive correct trials. Following depletion of dopamine in the dorsomedial striatum, acquisition of the discriminations was intact but there was an increase in the number of trials to attain criterion performance in the reversal phases, indicating an impairment in reversal learning. KW-6002 (1mg/kg bidaily for 10 days) non-specifically increased the number of trials to criterion at all stages of the test and in both controls (sham-operated) and dopamine-depleted rats. Chronic KW-6002 treatment did not improve the reversal deficits in dopamine-depleted rats. These findings suggest that dopamine transmission in the dorsomedial striatum is critical for the flexible shifting of response patterns and the ameliorative effects of KW-6002 following depletion of dopamine in the striatum may be restricted to motor functions without relieving deficits in response-shifting flexibility.     

The influence of surface and edge-based visual similarity on object recognition

The role of 'visual similarity' has been emphasised in object recognition and in particular, for category-specific agnosias. [Laws and Gale, 2002] recently described a measure of pixel-level visual overlap for line drawings (Euclidean Overlap: EO[line]) that distinguished living and nonliving things and predicted normal naming errors and latencies ( [Laws et al., 2002]). Nevertheless, it is important to extend such analyses to stimuli other than line drawings. We therefore developed the same measure for greyscale versions of the same stimuli (EO[grey]), i.e., that contain shading and texture information. EO[grey], however, failed to differentiate living from nonliving things and failed to correlate with naming latencies to the greyscale images. By contrast, EO[line] did correlate with the naming latencies. This suggests that similarity of edge information is more influential than similarity of surface characteristics for naming and for categorically separating living and nonliving things (be they line drawings or greyscale images).     

Not Only Whites: Racial Priming Effect for Black Faces in Black People

Black people are widely negatively stereotyped. The presence of unconscious stereotypes can be effectively assessed with the administration of “racial priming tasks.” An ethnically diverse group was subjected to a priming paradigm to test whether racial cues could bias the identification of target objects. Participants were asked to categorize objects (either as dangerous or nondangerous) after the presentation of Black/White faces as primes. Results show that both Black and White participants were faster in categorizing dangerous objects when primed with Black faces compared to the control condition (i.e., scrambled faces). One possible explanation for this effect is that Black faces are generally associated with a feeling of danger, which ultimately leads to faster responses.     

Modelling and describing human judgement processes: The multiattribute evaluation case

In this article we describe research methods that are used for the study of individual multiattribute evaluation processes. First we explain that a multiattribute evaluation problem involves the evaluation of a set of alternatives, described by their values on a number of alternatives. We discuss a number of evaluation strategies that may be applied to arrive at a conclusion about the attractiveness or suitability of the alternatives, and next introduce two main research paradigms in this area, structural modelling and process tracing. We argue that the techniques developed within these paradigms all have their advantages and disadvantages, and conclude that the most promising technique to detect the true nature of the evaluation strategy used by a judge seems to be the analysis of verbal protocols. At the same time we think it is wise not to rely on just one technique, but to use a multimethod approach to the study of multiattribute evaluation processes whenever that is possible.     

What Does “Mind-Wandering” Mean to the Folk? An Empirical Investigation

Although mind-wandering research is rapidly progressing, stark disagreements are emerging about what the term “mind-wandering” means. Four prominent views define mind-wandering as (a) task-unrelated thought, (b) stimulus-independent thought, (c) unintentional thought, or (d) dynamically unguided thought. Although theorists claim to capture the ordinary understanding of mind-wandering, no systematic studies have assessed these claims. Two large factorial studies present participants (N = 545) with vignettes that describe someone's thoughts and ask whether her mind was wandering, while systematically manipulating features relevant to the four major accounts of mind-wandering. Dynamics explains between four and 40 times more variance in participants' mind-wandering judgments than other features. Our third study (N = 153) tests and supports a unique prediction of the dynamic framework—obsessive rumination contrasts with mind-wandering. Our final study (N = 277) used vignettes that resemble mind-wandering experiments. Dynamics had significant and large effects, while task-unrelatedness was nonsignificant. These results strongly suggest that the central feature of mind-wandering is its dynamics.     

Exploring a Training IRAP as a single participant context for analyzing reversed derived relations and persistent rule-following

Rule-governed behavior and derived stimulus relations have always shared strong conceptual links within behavior analysis. However, experimental analysis linking the two domains remains limited. The current study consisted of three experiments that aimed to continue to bridge this experimental gap. The first experiment sought to establish the extent to which a training version of the implicit relational assessment procedure (IRAP) could be used to establish and successfully reverse experimentally established derived relations. The results suggested that the Training IRAP could successfully produce derived reversals. Experiments 2 and 3 explored the extent to which reversed derived relations would control rule-governed behavior when the contingencies for rule-following competed with the rule. In Experiment 2, the task contingencies were immediately in opposition to the (reversed) derived rule, and participants generally responded in accordance with the task contingencies, rather than the rule. In Experiment 3, the task contingencies were initially rule-consistent before a contingency reversal that later made them rule-inconsistent. Here evidence of rule-persistence emerged. The results of the research are considered within the context of a recent framework that has emerged out of RFT for analyzing the dynamics involved in derived relational responding.