Visual search in a multi-element asynchronous dynamic (MAD) world

In visual search tasks participants search for a target among distractors in strictly controlled displays. We show that visual search principles observed in these tasks do not necessarily apply in more ecologically valid search conditions, using dynamic and complex displays. A multi-element asynchronous dynamic (MAD) visual search was developed in which the stimuli could either be moving, stationary, and/or changing in luminance. The set sizes were high and participants did not know the specific target template. Experiments 1 through 4 showed that, contrary to previous studies, search for moving items was less efficient than search for static items and targets were missed a high percentage of the time. However, error rates were reduced when participants knew the exact target template (Experiment 5) and the difference in search efficiency for moving and stationary targets disappeared when lower set sizes were used (Experiment 6). In all experiments there was no benefit to finding targets defined by a luminance change. The data show that visual search principles previously shown in the literature do not apply to these more complex and "realistically" driven displays.     

Effects of age on searching for and enumerating targets that cannot be detected efficiently

We investigated the effects of old age on search, subitizing, and counting of difficult-to-find targets. In Experiment 1, young and older adults enumerated targets (Os) with and without distractors (Qs). Without distractors, the usual subitization-counting function occurred in both groups, with the same subitization span of 3.3 items. Subitization disappeared with distractors; older adults were slowed more overall by their presence but enumeration rates were not slowed by ageing either with or without distractors. In contrast, search rates for a single target (O among Qs) were twice as slow for older as for young adults. Experiment 2 tested and ruled out one account of age-equivalent serial enumeration based on the need to subvocalize numbers as items are enumerated. Alternative explanations based on the specific task differences between detecting and enumerating stimuli are discussed.     

Parental Intimate Partner Violence, Parenting Practices, and Adolescent Peer Bullying: A Prospective Study

Intimate partner violence (IPV) has been recognized as a major public health concern, with millions of children exposed to parental violence each year. Childhood exposure to parental violence has been linked to both maladaptive parenting practices and a host of adjustment difficulties in the exposed children. The Children in the Community Study followed a representative sample of youth, their parents, and their own offspring for over 25?years, in seven separate assessments. The current study examined the association between reports of IPV and parenting practices among original study members (Generation 2; N?=?396) and their adolescent offspring’s (Generation 3; N?=?129, M age?=?12.8 (2.4), range?=?10–18) reports of overt and relational bullying and victimization behaviors on average 6–7?years later. Results indicate that parental reports of any IPV predicted higher offspring overt peer victimization, while severe IPV predicted higher offspring relational peer bullying and overt peer victimization. For female offspring, any IPV predicted higher relational peer victimization and for male offspring, severe IPV predicted higher overt peer bullying. Parenting practices did not significantly mediate the association between IPV and peer bullying or victimization. Implications for prevention and directions for future research are discussed.     

Single-word reading in college dyslexics

Recent studies of single-word processing in dyslexic populations have focused on the differential predictions made by ‘delay’ and ‘deviance’ models. Many experiments in this area have sought to determine whether the reading process in dyslexia is idiosyncratic or similar to processing in younger non-dyslexic readers. Most relevant research has, however, failed to take account of recent developments in theoretical models of reading. Furthermore, relatively little research has examined the reading behaviour of ‘highly compensated’ subjects, who achieve high-level academic qualifications despite their developmental dyslexia. The present paper examines such a population, and concludes that its single-word reading is governed by the same spelling-to-sound word characteristics as reading by other groups. The implications of the results for the deviance/delay hypothesis and for models of word naming are discussed.     

Visual Marking of Locations and Feature Maps: Evidence from Within-dimension Defined Conjunctions

Recently, Watson and Humphreys (1997, 1998) proposed that the selection of new visual events can be aided by the top-down inhibition of old information-visual marking (VM) and that the mechanisms of marking differ for static and moving stimuli. Stationary stimuli are marked by location-based inhibition, whereas moving stimuli are marked by inhibition applied at the level of whole-feature maps. Here we provide a test of this 'two-mechanism' account. We show that static items can be marked even when old and new stimuli contain the same features and so cannot be distinguished by activation within a unique feature map. However, moving old items could not be marked unless they possessed a unique feature (colour). Manipulations of grouping strength, both within and between distractor sets, did not affect the basic findings. The results support the existence of two mechanisms for VM and counter an object-based inhibition explanation of performance.