The locus of semantic priming effects in person recognition

Semantic priming in person recognition has been studied extensively. In a typical experiment, participants are asked to make a familiarity decision to target items that have been immediately preceded by related or unrelated primes. Facilitation is usually observed from related primes, and this priming is equivalent across stimulus domains (i.e., faces and names prime one another equally). Structural models of face recognition (e.g., IAC: Burton, Bruce, & Johnston, 1990) accommodate these effects by proposing a level of person identity nodes (PINs) at which recognition routes converge, and which allow access to a common pool of semantics. We present three experiments that examine semantic priming for different decisions. Priming for a semantic decision (e.g., British/American?) shows exactly the same pattern that is normally observed for a familiarity decision. The pattern is equivalent for name and face recognition. However, no semantic priming is observed when participants are asked to make a sex decision. These results constrain future models of face processing and are discussed with reference to current theories of semantic priming.     

Adjustments to recent and frequent conflict reflect two distinguishable mechanisms

In conflict paradigms such as the Eriksen flanker task, interference has been found to be reduced under conditions of recent and/or frequent cognitive conflict. Using a modified flanker task, we investigated the interplay of conflict recency and conflict frequency by comparing the interference reductions following conflict trials under conditions in which conflict was either frequent or infrequent overall, while controlling for stimulus and response feature repetitions to rule out nonattentional accounts. The reduction of flanker interference after a conflict trial was attenuated when overall conflict was frequent. This result is consistent with models assuming that processing adjustments occur gradually in response to conflict strength, such as the connectionist model of Botvinick, Braver, Barch, Carter, and Cohen (2001), in which both recency and frequency modulations are brought about by the same mechanism. By decomposing response times into initiation times and movement times, we revealed that frequent conflict delayed response initiation but sped up movement. Moreover, whereas frequent conflict reduced interference in both components, interference reduction after individual conflict trials was confined to movement times. Taken together, these results suggest that different mechanisms underlie the two kinds of modulation.     

The Nature and Predictors of Undercontrolled and Internalizing Problem Trajectories Across Early Childhood

Using growth curve modeling, trajectories of undercontrolled (oppositional, irritable, inattentive and overactive behaviors) and internalizing (worried, sad and fearful) problems from 18 months to 4.5 years were studied in a population based sample of 921 Norwegian children. At the population level, undercontrolled problems decreased and internalizing problems increased with increasing age. Child temperament and family factors present at 18 months predicted 43% of the stability and 20% of the linear changes in undercontrolled problems and 30% of the stability and 7% of the linear changes in internalizing problems. Persisting effects of child and family factors from 18 month were found on the two problem dimensions over and above the impact of changes in the same risk factors. Lower initial level of partner support and higher initial level of child emotionality predicted higher slope of undercontrolled problems and higher initial level of family stress predicted higher slope for internalizing problems. As expected, time to time change (t1 to t2 and t2 to t3) in risk factors predicted time to time change in problem scores as well. The study shows the significance of early emerging internalizing and undercontrolled problems, the need to consider their pathways separately from very young ages, lasting effects of early experiences, and the importance of a dynamic approach to the analysis of risk.     

Hiding and finding: The relationship between visual concealment and visual search

As an initial step toward developing a theory of visual concealment, we assessed whether people would use factors known to influence visual search difficulty when the degree of concealment of objects among distractors was varied. In Experiment 1, participants arranged search objects (shapes, emotional faces, and graphemes) to create displays in which the targets were in plain sight but were either easy or hard to find. Analyses of easy and hard displays created during Experiment 1 revealed that the participants reliably used factors known to influence search difficulty (e.g., eccentricity, target—distractor similarity, presence/absence of a feature) to vary the difficulty of search across displays. In Experiment 2, a new participant group searched for the targets in the displays created by the participants in Experiment 1. Results indicated that search was more difficult in the hard than in the easy condition. In Experiments 3 and 4, participants used presence versus absence of a feature to vary search difficulty with several novel stimulus sets. Taken together, the results reveal a close link between the factors that govern concealment and the factors known to influence search difficulty, suggesting that a visual search theory can be extended to form the basis of a theory of visual concealment.     

Spider fearful individuals attend to threat, then quickly avoid it: evidence from eye movements

According to cognitive models of anxiety, anxiety patients exhibit an early reflexive attentional bias toward threat stimuli, which may be followed by intentional avoidance of these stimuli. To determine the time course of attentional vigilance and avoidance, the authors conducted an eye-tracking study in which 22 highly spider fearful participants (SFs) and 23 nonanxious control participants (NACs) studied groups of 4 pictures (spider, butterfly, dog, and cat). The authors found that the very first fixation was on a spider picture more often in SFs than in NACs. However, SFs quickly moved their eyes away from the spider they had fixated first, yielding shorter gaze durations than NACs. Afterward, SFs exhibited shorter gaze durations on spiders than NACs for the rest of the 1-min presentation time. This early reflexive attentional bias toward threat followed by avoidance of threat may explain earlier failures to find attentional biases in anxiety.     

Recognising faces seen alone or with others: when two heads are worse than one

There is a large body of work investigating face identification, but most of this addresses recognition of a single person. Here, we examine how recognition is affected by the presence of a second face. In Experiments 1 and 2, we demonstrate that memory for an unfamiliar face is severely reduced if it is seen alongside a second person. Sequential presentation of two target faces further reduces accuracy. In Experiments 3 and 4, we demonstrate the same disadvantage for two‐face targets in a matching task, where subjects have no time limits or memory requirement. In matching, the damaging effect of a second face is greatest when the targets are placed close together. Furthermore, there is a general advantage for faces presented to the left. We suggest that it may not be possible to extrapolate results from single‐face studies to experiments (or realistic situations) involving more than one person. Copyright © 2006 John Wiley & Sons, Ltd.     

Development of motion processing in children with autism

Recent findings suggest that children with autism may be impaired in the perception of biological motion from moving point-light displays. Some children with autism also have abnormally high motion coherence thresholds. In the current study we tested a group of children with autism and a group of typically developing children aged 5 to 12 years of age on several motion perception tasks, in order to establish the specificity of the biological motion deficit in relation to other visual discrimination skills. The first task required the recognition of biological from scrambled motion. Three quasi-psychophysical tasks then established individual thresholds for the detection of biological motion in dynamic noise, of motion coherence and of form-from-motion. Lastly, individual thresholds for a task of static perception--contour integration (Gabor displays)--were also obtained. Compared to controls, children with autism were particularly impaired in processing biological motion in relation to any developmental measure (chronological or mental age). In contrast, there was some developmental overlap in ability to process other types of visual motion between typically developing children and the children with autism, and evidence of developmental change in both groups. Finally, Gabor display thresholds appeared to develop typically in children with autism.