Braking reaching movements: a test of the constant tau-dot strategy under different viewing conditions

Following F. Zaal and R. J. Bootsma (1995), the authors studied whether the decelerative phase of a reaching movement could be modeled as a constant tau-dot strategy resulting in a soft collision with the object. Specifically, they investigated whether that strategy is sustained over different viewing conditions. Participants (N = 11) were required to reach for 15- and 50-mm objects at 2 different distances under 3 conditions in which visual availability of the immediate environment and of the reaching hand were varied. Tau-dot estimates and goodness-of-fit were highly similar across the 3 conditions. Only within-participant variability of tau-dot estimates was increased when environmental cues were removed. That finding suggests that the motor system uses a tau-dot strategy involving the intermodal (i.e., visual, proprioceptive, or both) specification of information to regulate the decelerative phase of reaching under restricted viewing conditions. The authors provide recommendations for improving the derivation of tau;(x) estimates and stress the need for further research on how time-to-contact information is used in the regulation of the dynamics of actions such as reaching.     

Non-specific encoding of threat in social phobia and panic disorder

This study employs a release of proactive interference technique to explore encoding-related processes in social phobia. Twenty-six individuals with social phobia and 24 individuals with panic disorder participated in the memory task. Significant release of proactive interference was found when neutral and threat dimensions were encoded, but not when social and physical threat dimensions, or when positive and threat dimensions were presented. Threat was therefore differently encoded depending on the active encoding context in which semantic processing occurred. Individuals with social phobia or panic disorder did not differ in the release of proactive interference. The present experiment consequently yields little support for the specificity hypothesis in memory of anxious individuals. Instead, the findings generally demonstrate that threat encoding is similar for people with social phobia and those with panic disorder.     

Preference-consistent evaluation of information in the hidden profile paradigm: beyond group-level explanations for the dominance of shared information in group decisions

Common explanations for the failure of groups to solve so-called hidden profiles focus on group processes, namely insufficient discussion of unshared information and premature consensus on a suboptimal alternative. As 2 experiments show, even in the absence of such group processes, hidden profiles are hardly ever solved. In Experiment 1, participants first received individual information about a personnel selection task and then read a group discussion protocol containing full information exchange. If the individual information was misleading (hidden profile), most participants failed to detect the correct alternative. In Experiment 2, it was determined that this effect is due to preference-consistent evaluation of information that constitutes an individual-level process mediating the failure of group members to solve hidden profiles.     

Distributed cortical networks for syntax processing: Broca's area as the common denominator

Different types of syntactic information (word category, grammatical gender) are processed at different times during word recognition. However, it is an open issue which brain systems support these processes. In the present event-related fMRI study, subjects performed either a syntactic gender decision task on German nouns (GEN), a word category decision task (WC, nouns vs. prepositions), or a physical baseline task (BASE). Reaction times in WC were faster than in GEN, supporting earlier electrophysiological results. Relative to BASE, both syntactic tasks activated the inferior tip of BA 44. In addition, BA 45 showed activation in GEN, whereas BA 47 was activated in WC. The imaging data indicate that the inferior portion of BA 44 together with type-specific prefrontal areas supports both initial word category related and later syntactic processes.     

Illusory illusions: the significance of fixation on the perception of geometrical illusions

Some well-known geometrical illusions disappear when the eyes are fixating and saccades are suppressed for a period of time. This disappearance is not accompanied by fading due to stabilisation of the retinal image. Any saccade made on purpose restores the illusion immediately. The fixation time after which some illusions disappeared was measured for four illusions and four subjects each. Effects of practice have been observed after measurements were repeated on successive days. Present theories of vision cannot readily explain the effect.     

N200, N250r, and N400 event-related brain potentials reveal three loci of repetition priming for familiar names

The authors assessed immediate repetition effects on event-related potentials (ERPs) while participants performed familiarity decisions for written personal names. For immediately repeated familiar names, the authors observed 3 distinct ERP modulations. At 180-220 ms, a posterior N200 effect occurred for names preceded by same-font primes only. In addition, an increased left temporal negativity (N250r, 220-300 ms) and a reduced central-parietal negativity (N400, 300-400 ms) were seen both for same-font and different-font repetitions. In a 2nd experiment, when names were preceded by either their corresponding face or the face of a different celebrity, only the N400 effect was preserved. These findings suggest that the N200, N250r, and N400 effects reflect facilitated processing at font-specific featural, lexical, and semantic levels of processing, respectively.     

Strength of hindsight bias as a consequence of meta-cognitions

Hindsight bias is the tendency of people to falsely believe that they would have correctly predicted the outcome of an event once it is known. The present paper addresses the ongoing debate as to whether the hindsight bias is due to memory impairment or biased reconstruction. The memory impairment approach maintains that outcome information alters the memory trace of the initial judgement, whereas the biased reconstruction approach assumes that people who have forgotten their initial judgements are forced to guess and, in the presence of outcome information, are likely to use this information as an anchor. Whereas the latter approach emphasises the role of meta-cognitive considerations, meta-cognitions are not included in the memory impairment explanation. Two experiments show that the biased reconstruction approach provides a better explanation for empirical findings in hindsight bias research than does the memory impairment explanation.