You never know where you are going until you know where you have been: Disorganized search after stroke

Disorders in spatial exploration can be expressed in a disorganized fashion of target cancellation. There is debate regarding whether disorganized search is related to stroke in general, to right brain damage or to unilateral spatial neglect (USN) in particular. In this study, 280 stroke patients and 37 healthy control subjects performed a computerized shape cancellation test. We investigated the number of perseverations and several outcome measures regarding disorganized search: Consistency of search direction (best r), distance between consecutive cancelled targets and intersections with paths between previous cancelled targets. We compared performance between patients with left and right brain damage (L, R) and with and without USN (USN+, USN?), resulting in four subgroups: LUSN?, RUSN?, LUSN+, and RUSN+. Higher numbers of intersections were found for the left brain‐ and right brain‐damaged patients with USN and for the right brain‐damaged patients without USN, compared to healthy control subjects. Furthermore, right brain‐damaged patients with USN showed a higher number of intersections compared to right brain‐damaged patients without USN and compared to left brain‐damaged patients with USN. To conclude, disorganized search was most strongly related to the neglect syndrome, and patients with more severe USN were even more impaired.     

Conflict adaptation: It is not what you expect

In two studies, a vocal Stroop task with eight different colours was employed in order to put two core assumptions of the original interpretation of the Gratton effect to the test. We verified whether top-down control processes can elicit conflict adaptation when episodic memory effects are controlled for and to what extent proactive adjustments driven by the subjects' expectancy for congruency level repetition contribute to this effect. Therefore, we presented Stroop stimuli without feature repetitions and investigated whether the induced expectancy manipulation of raising the amount of either congruency level repetitions or alternations in a training phase transferred to an unmanipulated test phase. Over the two experiments, a sequential modulation of the Stroop effect was found in the absence of stimulus feature repetitions, strongly confirming a share for top-down control processes in bringing about the Gratton effect. In the condition where congruency level repetitions were raised, a strong Gratton effect was found. When congruency level alternations outnumbered repetitions, the Gratton effect disappeared completely. However, this difference seemed mainly due to cumulative effects of local, dynamic, trial-to-trial control adjustments rather than expectancy-induced attentional shifting. Once the transition probability changed back to 50% in the test phase of each experiment, a similar Gratton effect was found in both conditions. Taken together, these results are best explained in terms of dynamic reactive control.     

Following logical realism where it leads

Philosophical Studies - Logical realism is the view that there is logical structure in the world. I argue that, if logical realism is true, then we are deeply ignorant of that logical structure:...     

Putting color back where it belongs

I disagree with Ross about the location of colors: They are in the brain, not in the external world. It is difficult to deny that there are colors in our conscious visual experience, and if we take the causal theory of perception seriously, we cannot identify these colors with the beginning of the causal chain in perception (external objects in the distal stimulus field), but we must search for them at the end of the causal chain (in the brain). Several lines of compelling evidence from cognitive neuroscience (e.g., synesthesia, dreaming, and achromatopsia) demonstrate unambiguously that color is in the brain. Furthermore, it seems that Ross has failed to consider one substantial version of subjectivism in his article. This monistic approach to color and consciousness appears to be the least implausible alternative when we try to understand what colors are and where they reside.     

Following the argument where it leads

Throughout the history of western philosophy, the Socratic injunction to ‘follow the argument where it leads’ has exerted a powerful attraction. But what is it, exactly, to follow the argument where it leads? I explore this intellectual ideal and offer a modest proposal as to how we should understand it. On my proposal, following the argument where it leaves involves a kind of modalized reasonableness. I then consider the relationship between the ideal and common sense or ‘Moorean’ responses to revisionary philosophical theorizing.     

How trunk turns affect locomotion when you are not looking where you go

How well do we maintain heading direction during walking while we look at objects beside our path by rotating our eyes, head, or trunk? Common experience indicates that it may be fairly hazardous not to look where you are going. In the present study, 12 young adults walked on a treadmill while they followed a moving dot along a horizontal line with their gaze by rotating primarily either their eyes, head, or trunk for amplitudes of up to 25 degrees . During walking the movement of the center of pressure (COP) was monitored using force transducers under a treadmill. Under normal light conditions, the participants showed little lateral deviation of the COP from the heading direction when they performed the eye or head movement task during walking, even when optic flow information was limited. In contrast, trunk rotations led to a doubling of the COP deviation in the mediolateral direction. Some of this deviation was attributed to foot rotation. Participants tended to point their feet in the gaze direction when making trunk turns. The tendency of the feet to be aligned with the trunk is likely to be due to a preference to have feet and body in the same orientation. Such alignment is weaker for the feet with respect to head position and it is absent with respect to eye position. It is argued that feet and trunk orientation are normally tightly coupled during gait and that it requires special abilities to move both segments independently when walking.     

The (non-)benefit of choosing: If you get what you want it is not important that you chose it

Self-Determination Theory argues that autonomy plays a major role in intrinsic motivation. Autonomy can be operationalized as choice. Whether positive effects on motivation are caused by the mere act of choosing or by confounding variables is still unclear. In this study (N?=?299, M_age?=?13.1?±?0.6 years), students could work with two polarizing animals. The first group was allowed to choose (choosing & match), two groups were not. In these groups, the teacher allocated the animals to the students resulting in a second group that received the wanted animal (no choosing & match), and a third group that received the unwanted animal (no choosing & no match). Situational motivation and flow experience were assessed. Regarding intrinsic motivation and flow, students in the no choosing & match treatment scored the highest, students of the no choosing & no match group the lowest. In conclusion, matching and not choosing made the difference.     

Visual recognition: as soon as you know it is there, you know what it is

What is the sequence of processing steps involved in visual object recognition? We varied the exposure duration of natural images and measured subjects' performance on three different tasks, each designed to tap a different candidate component process of object recognition. For each exposure duration, accuracy was lower and reaction time longer on a within-category identification task (e.g., distinguishing pigeons from other birds) than on a perceptual categorization task (e.g., birds vs. cars). However, strikingly, at each exposure duration, subjects performed just as quickly and accurately on the categorization task as they did on a task requiring only object detection: By the time subjects knew an image contained an object at all, they already knew its category. These findings place powerful constraints on theories of object recognition.     

Object detection and basic-level categorization: Sometimes you know it is there before you know what it is

A tight temporal coupling between object detection (is an object there?) and object categorization (what kind of object is it?) has recently been reported (Grill-Spector &; Kanwisher, 2005), suggesting that image segmentation into different objects and categorization of those objects at the basic level may be the very same mechanism. In the present work, we decoupled the time course of detection and categorization through two task manipulations. First, inverted objects were categorized significantly less accurately than upright objects across a range of image presentation durations, but no significant effect on object detection was observed. Second, systematically degrading stimuli affected categorization significantly more than object detection. The time course of object detection and object categorization can be selectively manipulated. They are not intrinsically linked. As soon as you know an object is there, you do not necessarily know what it is.     

Looking where you listen: visual cues and auditory attention

In the non-laboratory environment, we are generally able to see the source of the sounds to which we are attending. In a preliminary examination of how and to what degree we might use this visual information, subjects shadowed one of two female voices when able to see the persons speaking (Experiment I) or when able to see, and thus precisely localize, the auditory loudspeakers (Experiment II). Selective performance was improved by being able to see the lip movements of the people whose voices were heard, and by being able to localize visually the sources of the voices.     

The pregnant woman's place and where to find it

A two-part study examined attitudes toward pregnancy. The first part — a department store survey — looked at the location of maternity clothes in different status stores. Clothes were located differently, depending on the social class of the store. High status stores located them in or near lingerie and/or loungewear. Lower status stores located them in or near uniforms and/or half sizes. It is suggested that these differences reflect differential attitudes toward pregnancy in the different social classes. The second part of the study examined pregnant women's attitudes toward themselves. In line with the department store findings, there were differences between upper-class women and working-class women in self-report data. These data suggest that pregnancy is viewed differently, depending on social class.     

Now you see it, now you don't: repetition blindness for nonwords

Repetition blindness (RB) for nonwords has been found in some studies, but not in others. The authors propose that the discrepancy in results is fueled by participant strategy; specifically, when rapid serial visual presentation lists are short and participants are explicitly informed that some trials will contain repetitions, participants are able to use partial orthographic information to correctly guess repetitions on repetition trials while avoiding spurious repetition reports on control trials. The authors first replicated V. Coltheart and R. Langdon's (2003) finding of RB for words but repetition advantage for nonwords (Experiment 1). When all participants were encouraged to utilize partial information in a same/different matching task along with an identification task, a repetition advantage was observed for both words and nonwords (Experiment 2). When guessing of repetitions was made detectable by including non-identical but orthographically similar items in the experiments, the repetition advantage disappeared; instead, RB was found for both words and nonwords (Experiments 3 and 4). Finally, when experiments did not contain any identical items, participants almost never reported repetitions, and reliable RB was found for orthographically similar words and nonwords (Experiments 5 and 6).     

If you can't grab it,it won't grab you: The effect of restricting the dominant hand on target evaluations

This research examines whether and how holding one object influences evaluations of another. Across four studies, we find that occupying the dominant (vs. non-dominant) hand leads to lower evaluations of the target object; further, process data suggests that this effect occurs because dominant hand restriction impairs the ease with which the perceiver simulates holding the target. Boundary conditions that document effect attenuation and reversal are also consistent with this premise. Collectively, the studies offer support for a circular chain of influence between the perception and action systems.