Acta Psychologica

Published by Elsevier
Print ISSN: 0001-6918
Publications
Adults' processing of unit and decimal fractions was investigated using the numerical comparison task. When unit fractions were compared to integers, the pattern of distance effect found suggests that they were perceived to be on the same mental number line as integers; however, their representation was undifferentiated, as they were perceived to have the same magnitude. This was found both with simultaneous and with sequential presentation. When decimal fractions were compared to integers, the pattern of results suggests that they were also represented on the same mental number line with integers, but their representation was differentiated. Possible explanations for the different patterns found for unit and decimal fractions are discussed. Moreover, compatibility between the magnitude of the whole fraction and that of its components relative to the compared integer affected performance in the case of decimal fractions and unit fractions presented simultaneously, but not in the case of unit fractions presented sequentially. This suggests that sequential processing reduces the components representation of fractions and the whole number bias.
 
Participants compared durations of paired white-noise bursts, with interstimulus interval (ISI) 100, 300, 900, or 2700 ms, presented in the order standard (St)-comparison (Co) or Co-St. St was 50 or 1000 ms, and 75% difference thresholds for "longer" and "shorter" judgments were estimated. In Experiment 1 feedback was given; in Experiment 2, with ISIs 900 and 2700 ms, there was no feedback. For St=1000 ms, the just noticeable difference (JND) in noise duration was generally smaller with the order St-Co than with Co-St; for St=50 ms, the JND relation was the opposite. JNDs increased with shorter ISIs. Time-order errors were positive for St=50 ms and negative for St=1000 ms, and approached zero for longer ISIs. Using Hellström's sensation-weighting (SW) model, the ratio of the stimulus weights for the first and second burst was estimated; this ratio was generally >1 for St=50 ms and <1 for St=1000 ms. JNDs were smaller with feedback than without; the greatest reduction was found for St=1000 ms and an ISI of 2700 ms with the order Co-St, possibly because feedback increased participants' attention to the first stimulus. These results demonstrate the sensitivity of discrimination measures for long as well as brief durations to the factors of ISI, presentation order, and feedback. They also suggest different modes of stimulus processing for short and long durations.
 
Prefrontal cortex provides both inhibitory and excitatory input to distributed neural circuits required to support performance in diverse tasks. Neurological patients with prefrontal damage are impaired in their ability to inhibit task-irrelevant information during behavioral tasks requiring performance over a delay. The observed enhancements of primary auditory and somatosensory cortical responses to task-irrelevant distractors suggest that prefrontal damage disrupts inhibitory modulation of inputs to primary sensory cortex, perhaps through abnormalities in a prefrontal-thalamic sensory gating system. Failure to suppress irrelevant sensory information results in increased neural noise, contributing to the deficits in decision making routinely observed in these patients. In addition to a critical role in inhibitory control of sensory flow to primary cortical regions, and tertiary prefrontal cortex also exerts excitatory input to activity in multiple sub-regions of secondary association cortex. Unilateral prefrontal damage results in multi-modal decreases in neural activity in posterior association cortex in the hemisphere ipsilateral to damage. This excitatory modulation is necessary to sustain neural activity during working memory. Thus, prefrontal cortex is able to sculpt behavior through parallel inhibitory and excitatory regulation of neural activity in distributed neural networks.
 
Executive dysfunctions can be frequently observed in schizophrenia. They are more persistent than psychotic symptoms and are assumed to contribute to a variety of clinical signs of the disease. However, the cognitive mechanisms underlying dysexecutive behaviors are not yet understood. The aim of this article is to demonstrate how saccade tasks can be used to analyze the mechanisms involved in the dysexecutive syndrome of schizophrenic patients. There are numerous reports showing that schizophrenic patients make many unwanted reflexive saccades in the antisaccade task. These errors are usually explained by an impairment of a distinct inhibitory mechanism. However, unwanted reflexive saccades may also be secondary to a more fundamental deficit in activating goal-directed behavior. Recent theoretical and empirical approaches to this issue are reviewed and discussed. An integrative view of deficits in inhibition, goal-directed behavior, and working memory in schizophrenic patients is proposed.
 
In the present study, two experiments were conducted to investigate the interaction between the behavioral inhibition, measured by the stop signal task, and distractor interference, measured by the flanker task and the Stroop task. In the first experiment, the stop signal task was combined with a flanker task. Analysis revealed that participants responded faster when the distractors were congruent to the target. Also, the data suggest that it is more difficult to suppress a reaction when the distractors were incongruent. Whether the incongruent distractor was part of the response set (i.e. the distractor could also be a target) or not, had no influence on stopping reactions. In the second experiment, the stop signal task was combined with a manual version of the Stroop task and the degree of compatibility was varied. Even though in the second experiment of the present study interference control is differently operationalized, similar results as in the first experiment were found, indicating that inhibition of motor responses is influenced by the presentation of distracting information that is not part of the response set.
 
This review addresses the effects of the cognitive enhancer D-cycloserine (DCS) on the memory processes that occur in conditioned fear extinction, which is the experimental model for exposure techniques to reduce clinical anxiety. All reported rat studies show an enhanced fear extinction effect when DCS is administered acutely before or shortly after extinction training. DCS also promotes the generalization of this fear extinction effect. In addition, DCS reduces some forms of relapse (reduced reinstatement, reduced spontaneous recovery), but not others (contextual renewal, rapid reacquisition). It is argued that this pattern of results is best explained by assuming that DCS promotes extinction learning to the background context, resulting in enhanced contextual inhibition. Four human studies have produced mixed results, but some methodological issues complicate the reported failures. It is concluded that DCS is a promising tool as an adjunct to extinction techniques in exposure treatment, but that more pre-clinical and clinical research is needed to fully characterize its behavioral consequences.
 
Tasks play an important role in much research on human behavior, and differences in tasks and task characteristics have been shown to mediate differences in individual and social behavior. Thus, it is unfortunate that we know relatively little about the nature of tasks and their behavioral implications. This paper attempts to lay the ground work for furthering our understanding of the differences among tasks and the ways in which tasks influence behavior. Three general ‘problem areas’ are reviewed and evaluated in the paper: (a) problems in defining the concept ‘task’ — i.e., what are the components and characteristics of an adequate task definition; (b) problems relevant to the description of tasks — i.e., what are the most useful and appropriate bases for making task descriptions and comparisons; and (c) problems relevant to understanding task effects — i.e., how do task factors make differences in the ways people think and act.After evaluating several issues relevant to the problems of task definition and description, one working definition of the concept is proposed, and one general approach to task description is suggested as likely to be most useful in understanding the behavioral impact of tasks. Finally, a framework is proposed which outlines the diversity of effects which may be attributable to task factors in a performance situation, and suggests how these effects may be conceptualized and related.
 
According to ideomotor theory, voluntary actions are selected and initiated by means of anticipated action effects. Prior experiments yielded evidence for these effect anticipations with response-effect (R-E) compatibility phenomena using blocked R-E relations. Daily actions, however, typically evoke different effects depending on the situational context. In the present study, we accounted for this natural variability and investigated R-E compatibility effects by a trial-by-trial variation of R-E compatibility relations. In line with recent observations regarding ideomotor learning, R-E compatibility influenced responding only when participants responded in free choice trials assuming that participants then adopted an intention-based action control mode. In contrast, R-E compatibility had no impact when participants responded according to imperative stimuli throughout the experiment, thus when participants adopted a stimulus-based action control mode. Interestingly, once an intention-based mode was established because of free choice trials within an experimental block, we observed response compatibility effects in free as well as forced choice trials. These findings extend and refine theoretical assumptions on different action control modes in goal-directed behavior and the specific contribution of ideomotor processes to intention-based action control.
 
This study examined the relationship between two sources of interference in human information processing: the Stroop effect and the Simon effect. Forty subjects pressed a left- or right-hand key in response to a Stroop color word located on the left or right side of a screen. For one group, ink color was the relevant cue and, for another group, word meaning was the relevant cue. Independent variables were: congruence, i.e., agreement or lack thereof between the ink color and meaning of the Stroop word; spatial correspondence, i.e., agreement or lack thereof between the location of the Stroop word and the location of the key used to make the response; and stimulus duration, i.e., 400 or 100 ms. Each of these variables had a significant effect on RT, and there were no significant interactions. According to Sternberg's additive-factor logic, these findings suggest that the Stroop effect (congruence) and the Simon effect (spatial correspondence) involve separate stages of processing. If one assumes that manipulation of stimulus duration effects the encoding stage, then results also suggest that neither the Stroop effect nor the Simon effect involves the stimulus encoding stage.
 
Velocity sensitivity of areas 17 and 18 of the cat has been evaluated by preparing neuronal velocity-response (VR) curves in paralyzed and anaesthetized cats. VR curves suggest two possible mechanisms for neuronal coding of stimulus velocity as well as criterion for distinguishing between cells involved in analysis of stationary or moving objects. VR curves differ between cortical areas and with retinal eccentricity. Neurones with larger receptive fields (RFs) become, on the average, sensitive to faster velocities. Parallels with human psychophysics are pointed out as support of the suggestion that the present results are relevant for our insights in human motion perception.
 
The reports by Fitts and Peterson [J. Exp. Psychol. 67(2) (1964) 103-113] and Klapp [J. Exp. Psychol. Hum. Percept. Perform. 104(2) (1975) 147-153] concerning the effects of movement amplitude and target diameter on reaction time present conflicting results. Fitts and Peterson reported that reaction time increased when movement amplitude was lengthened. Klapp reported an interaction in which target diameter effect on reaction time was moderated by movement length: for small targets, reaction time decreased with increasing movement length but reaction time remained unchanged (or increased modestly) when target diameter was large. Two experiments were conducted to replicate and examine the inconsistency in the reaction time results. For both experiments movement time results were in agreement with the predictions of Fitts' law. However, the results for reaction time were mixed: support was obtained for Klapp (1975) but not for Fitts and Peterson (1964). Further analysis identified several potential variables that could have influenced reaction time and explained the different effects on reaction time reported by Fitts and Peterson (1964) and Klapp (1975). The potential variables could include: limb posture at the start of a response; number of limb segments required to perform the task; and the effect of pooling reaction time data from targets located right and left of the start point, and from near and far targets.
 
The experimental study of Gerbino and Salmaso (1987) focused on the process of amodal completion, i.e. the process that leads to the impression of a total pattern in the absence of information about all parts of the pattern. One of the questions that they have attempted to answer with respect to this process is whether or not it depends on the categorization of the modal part (i.e. the part about which visual information is present) as a modification of a complete prototype. The major conclusion of their experiments is that amodal completion does not depend upon categorization. Furthermore, they interpret their results as indicating that neither the truncated form of the occluded part nor the unification/segregation of contour segments are phenomenally real. We designed some variants of the tunnel effect to demonstrate (1) that the explicit categorization of some parts of the input can have an influence on amodal completion and (2) that the truncated form of a pattern can be phenomenally real. Our results corroborate these hypotheses and can, therefore, interpreted as refuting two rather central claims of Gerbino and Salmaso (1987). The conclusion of our experiment must be that amodal completion is not as primary as they have supposed but can be influenced by kinetic occlusion and categorization stored in visual memory.
 
Using neutral stimuli (mushrooms and flowers) and phobia-relevant stimuli (snakes and spiders), the present investigation examined the effect of gaze shifts on subjective evaluation of stimuli in female subjects (N = 29). One group of subjects had to orient to the right, whereas the other group had to orient to the left in order to see the stimuli. When left-handed subjects were excluded from the analysis, the results showed that subjects in the 'orient right' group gave a significantly more positive evaluation than subjects in the 'orient left' group. The results provide a replication of the phenomenon described by Drake (1987).
 
It is often argued that picture-plane face inversion impairs discrimination of the spacing among face features to a greater extent than the identity of the facial features. However, several recent studies have reported similar inversion effects for both types of face manipulations. In a recent review, Rossion (2008) claimed that similar inversion effects for spacing and features are due to methodological and conceptual shortcomings and that data still support the idea that inversion impairs the discrimination of features less than that of the spacing among them. Here I will claim that when facial features differ primarily in shape, the effect of inversion on features is not smaller than the one on spacing. It is when color/contrast information is added to facial features that the inversion effect on features decreases. This obvious observation accounts for the discrepancy in the literature and suggests that the large inversion effect that was found for features that differ in shape is not a methodological artifact. These findings together with other data that are discussed are consistent with the idea that the shape of facial features and the spacing among them are integrated rather than dissociated in the holistic representation of faces.
 
Hommel (2011-this issue) has reviewed the major lines of research and ongoing controversies on and around the Simon effect. Van der Lubbe and Abrahamse (2010) take issue with Hommel's assessment of the role of attention shifting in the Simon effect. This rejoinder argues that van der Lubbe and Abrahamse's criticism is off target because it (a) fails to distinguish between the attention-shifting account of (spatial stimulus coding in) the Simon effect-which Hommel discusses and criticizes-and the premotor theory of attention-which Hommel does not discuss; (b) confuses the relationship between the attention-shifting account and the referential-coding account of spatial stimulus coding in the Simon effect-the actual topic of Hommel's discussion-with the relationship between the premotor theory and the theory of event coding-which the criticism focuses on; and (c) confuses the uncontroversial role of attention in stimulus selection with the controversial role of attention in the generation of location codes.
 
Durgin et al. (2010) argued that the apparent accuracy of the palmboard measure of geographical slant is accidental and reflects limitations in wrist flexion that reduce palmboard adjustments by just the right amount given the perceptual overestimations upon which they are based. This account is inconsistent with findings that verbal reports and palmboard adjustments are dissociable. In addition to previous evidence found for such dissociation, Durgin et al. also found verbal/palmboard dissociations in Experiment 2. Experiments 1 and 3 of Durgin et al. lacked verbal reports and instead compared palmboard adjustments to free-hand estimates in the context of small wooden surfaces. These experiments are not relevant to the issue of verbal/palmboard dissociability. Across studies, the accuracy of Durgin et al.'s palmboard implementation is far less than that found by others (Feresin & Agostini, 2007). The design of Durgin et al.'s Experiment 5 misrepresented the experimental conditions of Creem and Proffitt (1998), and consequently, the findings of this study have no bearing on the issue at hand.
 
We recently showed that palm board measures are systematically inaccurate for full-cue surfaces within reach of one's hand, whereas free-hand gestures and reaching actions are quite accurate for such surfaces (Durgin, Hajnal, Li, Tonge, & Stigliani, 2010). Proffitt and Zadra (2010) claim that our demonstration that palm boards are highly inaccurate is irrelevant to interpreting past and present findings concerning dissociations between verbal reports and palm board estimates. In their paper they offer a theoretical representation of the findings of Bhalla and Proffitt (1999) and argue that our analysis is incompatible with their account. We offer here an alternative account of the findings of Bhalla and Proffitt, based on their actual data (which are fully compatible with our original analysis). We further show how our account generalizes to more recent studies that continue (1) to mistakenly describe null statistical effects on (insensitive) palm boards as evidence of a "dissociation" from (more sensitive) verbal measures that show a similar relative magnitude of change and (2) to introduce uncontrolled demand characteristics.
 
In this reply, we respond to methodological points raised by Boot and Simons (2012) to a paper on video game experience and optimization of executive control processes (Strobach, Frensch, & Schubert, 2012). In sum, we assume that differences in strategies to recruit expert game players and novices cannot explain performance differences in cognitive tasks between both groups of participants as a sole account. Further, in contrast to Tetris training, exclusive effects after training with an action game on complex task situations including two different tasks certainly do not result from differences in the levels of motivation between both training types during the transfer tests. Finally, a lack of retest effects from pre- to post-test during transfer may result from relatively short durations of these tests. We discuss these points in conjunction with a perspective for balancing false positive and false negative errors in training research.
 
Strobach, Frensch, and Schubert (2012) presented evidence that action video game experience improves task-switching and reduces dual-task costs. Their design commendably adhered to many of the guidelines proposed by Boot, Blakely and Simons (2011) to overcome common method and interpretation problems in this literature. Adherence to these method guidelines is necessary in order to reduce the influence of demand characteristics, placebo effects, and underreporting that might otherwise produce false positive findings. In their paper, Strobach et al. (2012) appear to have misinterpreted some of these proposed guidelines, meaning that their methods did not eliminate possible sources of demand characteristics and differential placebo effects. At this important, early stage of video game research, reducing the likelihood of false positive findings is essential. In this commentary we clarify our methodological critiques and guidelines, identify ways in which this new study did and did not meet these guidelines, and discuss how these methodological issues should constrain the interpretation of the reported evidence.
 
Verbal estimates for hill slants (4-34°) grossly overestimate their slant (Proffitt et al., 1995), but verbal estimates indicate that the perceptual exaggeration for the slants of near wooden surfaces (6-36°; Durgin, Hajnal, et al., 2010, Experiment 1) is much less pronounced. Predictions of the model of hill perception developed by Li and Durgin (2010; Durgin & Li, 2012) in a study parametrically manipulating of slant and viewing distance are also shown.
Predicted palm board settings for hills (solid line) vs near surfaces (black circles) based on combining (1) a model of the perceived (reported) slants of hill surfaces that takes viewing distance into account (Durgin & Li, 2012; Li & Durgin, 2010), (2) verbal report data for near surfaces (Durgin, Li, et al., 2010), and (3) palm board matches to near surfaces (Durgin, Hajnal, et al., 2010). The perceived hill slant model (Durgin & Li, 2012) is h′ = 1.5*h + 5*ln(D), where h′ is perceived slant (°), h is actual hill slant (°) and D is horizontal viewing distance (m) to the hill surface from the base of the hill, assuming an eye-height of 1.6 m. The polynomial model of the verbal report data (Durgin, Li, et al., 2010, Experiment 1) for near surfaces is s = 0.000142 * s′ 3 − 0.015 * s′ 2 + 1.185 * s′ + 0.525, where s′ is perceived slant (°) and s is the presented surface orientation (°). We deduce the s equivalent to a given h (the slant of a near surface that is perceptually equivalent to a given hill based on verbal report; Li & Durgin, 2011) by setting s′ equal to h′ for the given h. The palm board setting prediction for hill h is then 0.61 * s (Durgin, Hajnal, et al., 2010, Experiment 3).
Coefficients of variation (CoV) for haptic (palm board) and verbal estimates of hill slope computed from the data of Proffitt et al. (1995) as reported in Bhalla and Proffitt (1999). In the range of hills from 5 to 34°, verbal estimates were proportionally less variable between participants than were haptic matches with a palm board, t(6) = 2.83, p b .05.
Two palm boards used by Durgin, Hajnal, et al. (2010). At left is shown the simple palm board (PB1) used in the demonstration Experiments 1 and 2 of Durgin, Hajnal, et al. (2010; it was also used by Durgin, Ruff, et al. (2012), Experiment 2). The head of the tripod served as the axis of rotation; the tripod head must be somewhat frictional to hold its position when set. At right is shown the low-friction palm board (PB2) used in Experiment 3 of Durgin, Hajnal, et al. (2010; it was also used by Durgin, Ruff, et al. (2012), Experiment 1, and by Li & Durgin, 2011). The axis is through the center of the palm board and the surface can be rotated effortlessly. Hand orientation can be read to 0.5° from the protractor, or to 0.1° by attaching a lightweight inclinometer or lightweight motion-capture equipment (Vicon) as used by Durgin, Hajnal, et al. (2010). 
Apparatuses used in the present experiment. Left: A low-friction palm board with an added “ roof ” to block the view of the hand; a removable wooden stop marking 0° is clamped into place. Center: The adjustable slant presentation device (with a sample surface mounted on it). The same device was used in Experiment 3 of Durgin, Hajnal, et al. (2010); (see also Durgin & Li, 2011, 2012; Durgin, Ruff, et al., 2012; Li & Durgin, 2009, 2012b). It can be used to vary slant in small steps between horizontal and vertical. Right: The visual surface used here was gravel-covered. The surface is from the set used by Durgin & Li (2011) in studies of perceived near-surface orientation. Durgin, Hajnal, et al. (2010) used wooden surfaces of irregular shape. During the present experiment, the tripod holding the surface was covered by black felt. 
Hills appear much steeper than they are. Although near surface slant is also exaggerated, near surfaces appear much shallower than equivalently slanted hills. Taylor-Covill and Eves (2013) propose a new type of palm orientation measuring device that provides outputs that accurately reflect the physical slants of stairs and hills from 19 to 30° and also seems to accurately reflect the slants of near surfaces (25-30°). They question the validity of the observations of Durgin, Hajnal, Li, Tonge & Stigliani (2010), who observed that palm boards grossly underestimated near surfaces. Here I review our recent work on the visual and haptic perception of near surface orientation in order to place Taylor-Covill and Eves' arguments in context. I note in particular that free hand measures of real surfaces in near space show excellent calibration, but free hand measures show gross exaggeration for hills. This leads to the question of the grounds for preferring a mechanical device to a freely wielded hand. In addition I report an investigative replication of the crucial observations that led to our concerns about the value of palm boards as measures of perception and note the specific methodological details that we have accounted for in our procedures. Finally, I propose some testable hypotheses regarding how better-than-expected haptic matches to hills may arise.
 
In a recent paper, we provided independent evidence on the accuracy of 'haptically' measured geographical slant perception (Taylor-Covill & Eves, 2013). Durgin (2013) argues that the devices used in our work, namely the palm-board, and palm-controlled inclinometer (PCI), are not measures of perception. In response, we outline four failures of replication in the laboratory work of Durgin and colleagues on which they base their model of slant perception. We also highlight fundamental differences between the perceptual tasks Durgin and colleagues ask of participants relative to those of Proffitt and colleagues' traditional measures. These subtle differences might help explain how the two groups have arrived at discrepant conclusions.
 
How does the cognitive system encode the location of objects in a visual scene? In the past decade, this question has attracted much attention in the field of visual-word recognition (e.g., "jugde" is perceptually very close to "judge"). Letter transposition effects have been explained in terms of perceptual uncertainty or shared "open bigrams". In the present study, we focus on note position coding in music reading (i.e., a 2D scenario). The usual way to display music is the staff (i.e., a set of 5 horizontal lines and their resultant 4 spaces). When reading musical notation, it is critical to identify not only each note (temporal duration), but also its pitch (y-axis) and its temporal sequence (x-axis). To examine note position coding, we employed a same-different task in which two briefly and consecutively presented staves contained four notes. The experiment was conducted with experts (musicians) and non-experts (non-musicians). For the "different" trials, the critical conditions involved staves in which two internal notes that were switched vertically, horizontally, or fully transposed - as well as the appropriate control conditions. Results revealed that note position coding was only approximate at the early stages of processing and that this encoding process was modulated by expertise. We examine the implications of these findings for models of object position encoding.
 
Word processing studies increasingly make use of regression analyses based on large numbers of stimuli (the so-called megastudy approach) rather than experimental designs based on small factorial designs. This requires the availability of word features for many words. Following similar studies in English, we present and validate ratings of age of acquisition and concreteness for 30,000 Dutch words. These include nearly all lemmas language researchers are likely to be interested in. The ratings are freely available for research purposes.
 
Human behavioral space is three-dimensional (3D), and when moving through 3D space individuals selectively allocate their attention to acquire necessary information. This study aimed to examine the characteristics of attention in real 3D space when observers were moving forward. In static and self-motion situations, relative and absolute cues were used. Results indicated that internal representation for allocation of attention in 3D space is in depth-aware mode whether in static or moving condition. Moreover, near superior asymmetrical switching of attention is more strongly manifested under moving than under static conditions. Our findings indicate that focusing of attention by relative and absolute cues is maintained in self-motion, and that allocation of attention during movement is more viewer-centered than when observers are static.
 
Computer simulations aimed at assessing functional characteristics of the graphic workspace are presented. The simulations involve a 10-df kinematic model of the distal part of the writing arm, and yield the effective workspace of the pen tip under two types of kinematic constraints. The first constraint involves fixing the forearm under various pronation angles, the second governs the protrusion of the pen tip from the finger tips. The effective workspace is analyzed in terms of the effort required to reach the various locations in it, where effort is defined in terms of the joint angles adopted by the wrist and fingers to reach each location. The simulation results show agreements between the distribution of required effort over the workspace and known stroke-direction preferences in drawing. Furthermore, they predict shifts in the biases that are thought to lead to these preferences as a function of both hand pronation and pen protrusion.
 
The present study focuses on geometric features of workspace and joint-space paths of three-dimensional reaching movements. Twelve subjects repeatedly performed a three-segment, triangular-shaped movement pattern in an approximately 60 degrees tilted horizontal plane. Task variables elicited movement patterns that varied in position, rotational direction and speed. Trunk, arm, hand and finger-tip movements were recorded by means of a 3D motion-tracking system. Angular excursions of the shoulder and elbow joints were extracted from position data. Analyses of the shape of 3D workspace and joint-space paths focused on the extent to which the submovements were produced in a plane, and on the curvature of the central parts of the submovements. A systematic tendency to produce movements in a plane was found in addition to an increase of finger-tip path curvature with increasing speed. The findings are discussed in relation to the role of optimization principles in trajectory-formation models.
 
A single experiment investigated how younger (aged 18-32 years) and older (aged 62-82 years) observers perceive 3D object shape from deforming and static boundary contours. On any given trial, observers were shown two smoothly-curved objects, similar to water-smoothed granite rocks, and were required to judge whether they possessed the "same" or "different" shape. The objects presented during the "different" trials produced differently-shaped boundary contours. The objects presented during the "same" trials also produced different boundary contours, because one of the objects was always rotated in depth relative to the other by 5, 25, or 45 degrees. Each observer participated in 12 experimental conditions formed by the combination of 2 motion types (deforming vs. static boundary contours), 2 surface types (objects depicted as silhouettes or with texture and Lambertian shading), and 3 angular offsets (5, 25, and 45 degrees). When there was no motion (static silhouettes or stationary objects presented with shading and texture), the older observers performed as well as the younger observers. In the moving object conditions with shading and texture, the older observers' performance was facilitated by the motion, but the amount of this facilitation was reduced relative to that exhibited by the younger observers. In contrast, the older observers obtained no benefit in performance at all from the deforming (i.e., moving) silhouettes. The reduced ability of older observers to perceive 3D shape from motion is probably due to a low-level deterioration in the ability to detect and discriminate motion itself.
 
In this study, we examined 4.5-month-old infants' visual completion of self-occluding three-dimensional objects. A previous study on this topic reported that 6-month-old, but not 4-month-old infants extrapolate a convex, symmetric prism from a limited view of its surfaces (Soska & Johnson, 2008). As of yet, studies on the development of amodal completion of three-dimensional, self-occluding objects are scarce. Given 4-month-old infants' abilities to derive three-dimensional shape from a variety of visual cues, three-dimensional amodal completion may well depend on the perceptual strength of three-dimensionality in the stimulus displays. The first experiments (1A and 1B) tested this hypothesis by means of a habituation paradigm and showed that 4.5-month-old infants are indeed able to amodally complete the back of a self-occluding object when sufficient three-dimensional cues are available. Further support for volume completion in 4.5-month-old infants was found in a second experiment, again using a habituation paradigm, that measured perceived connectedness between two visually separated, self-occluding, three-dimensional objects.
 
The pre-test scores for 95 fourth and fifth grade children were used in factor analysis in which 4 and 6 factors were rotated. The tests were a variety of perception, creativity, and aesthetic preference measures. The 6 factors to emerge from the pool of 14 variables were: a factor of creativity, a perceptual factor of deductive reasoning, a perceptual factor of inductive reasoning, a measure of perceptual field independence, and two aesthetic preference factors. In the four factor analysis the creativity factor, the two perceptual factors, and the aesthetic preference factor remained. The results are discussed with implications for art education.
 
The present study presents timed norms for 590 pictures in Belgian Dutch. We determined name agreement and response latencies. Furthermore, we assessed which factors influenced the naming latencies of the pictures. It appeared that age-of-acquisition, the H-statistic (an index of name agreement), and the number of syllables of the dominant response were significant predictors of the naming latencies. These results are discussed in comparison with previous findings. (c) 2005 Elsevier B.V. All rights reserved.
 
Three matched groups of five subjects, designated sleep deprived with incentive (I), sleep deprived without incentive (NI), no sleep deprivation, no incentive control (C), were run on separate occasions. All underwent h of auditory vigilance performance three times per 24 h, following a baseline non-incentive day. During deprivation, group I were given attractive monetary reward for “hits” and were “fined” for false alarms and misses. These stakes were doubled for each successive deprivation day in an attempt to combat the increasing tiredness effects. At the end of deprivation, groups I and NI were allowed 8 h of recovery sleep, and were tested again, without incentive for I. It was found that incentive was able to maintain performance (hits and d′) at baseline levels for up to 36 h of deprivation. Thereafter, although this performance fell, it remained significantly better than that for NI, for a further day only. Despite substantive rewards on the third day, incentive was ineffective. Following the recovery sleep, performance returned to normal. Although no significant time-of-day effects were found in performance during the normal waking hours, it was apparent that the major decline per 24 h occurred through the night, with a levelling off in the day.
 
Schematic drawing of the events shown during the three familiarization trials in Experiment 1. The infants saw the fish, box, and shoe events in successive trials. 
Mean looking times at the short-and long-frame test events of the infants in Experiments 1, 2, and 3. 
Schematic drawing of the events shown during the six familiarization trials in Experiment 2. The infants saw the six events in six successive trials. 
The present research examined whether 9.5-month-old infants can attribute to an agent a disposition to perform a particular action on objects, and can then use this disposition to predict which of two new objects - one that can be used to perform the action and one that cannot - the agent is likely to reach for next. The infants first received familiarization trials in which they watched an agent slide either three (Experiments 1 and 3) or six (Experiment 2) different objects forward and backward on an apparatus floor. During test, the infants saw two new identical objects placed side by side: one stood inside a short frame that left little room for sliding, and the other stood inside a longer frame that left ample room for sliding. The infants who saw the agent slide six different objects attributed to her a disposition to slide objects: they expected her to select the "slidable" as opposed to the "unslidable" test object, and they looked reliably longer when she did not. In contrast, the infants who saw the agent slide only three different objects looked about equally when she selected either test object. These results add to recent evidence that infants in the first year of life can attribute dispositions to agents, and can use these dispositions to help predict agents' actions in new contexts.
 
Results from recent experiments (e.g., Kovacs, Buchanan, & Shea, 2009a-b, 2010a,b) suggest that when salient visual information is presented using Lissajous plots bimanual coordination patterns typically thought to be very difficult to perform without extensive practice can be performed with remarkably low relative phase error and variability with 5min or less of practice. However, when this feedback is removed, performance deteriorates. The purpose of the present experiment was to determine if reducing the frequency of feedback presentation will decrease the participant's reliance on the feedback and will facilitate the development of an internal representation capable of sustaining performance when the Lissajous feedback is withdrawn. The results demonstrated that reduced frequency Lissajous feedback results in very effective bimanual coordination performance on tests with Lissajous feedback available and when feedback is withdrawn. Taken together the present experiments add to the growing literature that supports the notion that salient perceptual information can override some aspects of the system's intrinsic dynamics typically linked to motor output control. Additionally, the present results suggest that the learning of both externally and internally driven bimanual coordination is facilitated by providing reduced frequency Lissajous feedback.
 
Two experiments were conducted to investigate the relation between the attentional blink (AB), a deficit in reporting the second of two targets when it occurs 200-500 ms after the first, and the P3 component of the event-related potential. Consistent with the view that the AB reflects a limited ability to consolidate information in working memory and that the P3 reflects working memory updating, increasing the amplitude of the P3 elicited by a first target (T1) by varying T1 probability (Experiment 1) or T1 cue validity (Experiment 2) led to an increase of the AB. Overall, the P3 elicited by T1 was greater when T2 was not identified than when it was. However, the correlation between P3 and AB magnitude across participants was not significant, leaving open the question of how direct the relationship between the P3 and the AB is.
 
Four experiments tested whether and how initially planned but then abandoned speech can influence the production of a subsequent resumption. Participants named initial pictures, which were sometimes suddenly replaced by target pictures that were related in meaning or word form or were unrelated. They then had to stop and resume with the name of the target picture. Target picture naming latencies were measured separately for trials in which the initial speech was skipped, interrupted, or completed. Semantically related initial pictures helped the production of the target word, although the effect dissipated once the utterance of the initial picture name had been completed. In contrast, phonologically related initial pictures hindered the production of the target word, but only for trials in which the name of the initial picture had at least partly been uttered. This semantic facilitation and phonological interference did not depend on the time interval between the initial and target picture, which was either varied between 200 ms and 400 ms (Experiments 1-2) or was kept constant at 300 ms (Experiments 3-4). We discuss the implications of these results for models of speech self-monitoring and for models of problem-free word production.
 
An active visuo-spatial memory task was used in order to determine the characteristics of mental imagery in subjects with and without visual experience. Subjects were instructed to generate a mental representation of verbally presented 2D patterns that were placed in a grid and to indicate how many pattern elements were in corresponding positions in the two halves of the grid according to a specific grid axis (vertical or horizontal). Unexpectedly, results showed a similar performance in early blind, late blind and sighted subjects. However, subjects' debriefing showed that the three groups used different strategies. The sighted and the late blind subjects took advantage of a visuo-spatial strategy. They generated a mental image of the matrix and they simplified this image to maintain only the relevant information in memory. In contrast, the early blind subjects encoded each pattern element by its location in a (X,Y) coordinate system without visual representation. This indicates that both early and late blind subjects are able to perform an active visuo-spatial imagery task as well as sighted subjects although they use different strategies.
 
Judging what actions are possible and impossible to complete is a skill that is critical for planning and executing movements in both individual and joint actions contexts. The present experiments explored the ability to adapt action possibility judgments to the assumed characteristics of another person. Participants watched alternating pictures of a person's hand moving at different speeds between targets of different indexes of difficulty (according to Fitts' Law) and judged whether or not it was possible for individuals with different characteristics to maintain movement accuracy at the presented speed. Across four studies, the person in the pictures and the background information about the person were manipulated to determine how and under what conditions participants adapted their judgments. Results revealed that participants adjusted their possibility judgments to the assumed motor capabilities of the individual they were judging. However, these adjustments only occurred when participants were instructed to take the other person into consideration suggesting that the adaption process is a voluntary process. Further, it was observed that the slopes of the regression equations relating movement time and index of difficulty did not differ across conditions. All differences between conditions were in the y-intercept of the regression lines. This pattern of findings suggests that participants formed the action possibility judgments by first simulating their own performance, and then adjusted the "possibility" threshold by adding or subtracting a correction factor to determine what is and is not possible for the other person to perform.
 
The current study examined the extent to which task-unrelated thoughts represent both vulnerability to mind-wandering and susceptibility to external distraction from an individual difference perspective. Participants performed multiple measures of attention control, working memory capacity, and fluid intelligence. Task-unrelated thoughts were assessed using thought probes during the attention control tasks. Using latent variable techniques, the results suggested that mind-wandering and external distraction reflect distinct, yet correlated constructs, both of which are related to working memory capacity and fluid intelligence. Furthermore, the results suggest that the common variance shared by mind-wandering, external distraction, and attention control is what primarily accounts for their relation with working memory capacity and fluid intelligence. These results support the notion that lapses of attention are strongly related to cognitive abilities.
 
Possible sex differences in the nature and accuracy of schematic cognitive maps were investigated in two experiments. In experiment 1, 11- and 19-year-olds were asked to examine schematic maps and give directions from memory between various locations on the map. Males at both ages used more Euclidean cues in their directions and were more accurate. In experiment 2, adults were given the Differential Aptitude test of spatial ability in addition to the schematic test. Sex differences were found on both measures. However, personal experience variables were related to sex differences in DAT but not schematic map performance.
 
Top-cited authors
Saul Sternberg
  • University of Pennsylvania
Adam Kendon
  • University of Cambridge
Ola Svenson
  • Stockholm University
Andrew M. Colman
  • University of Leicester
Berndt Brehmer