John Christie

Bio: John Christie is an academic researcher from Dalhousie University. The author has contributed to research in topics: Inhibition of return & Fixation (visual). The author has an hindex of 16, co-authored 26 publications receiving 745 citations. Previous affiliations of John Christie include NSCAD University.

Familiarity and attention: Does what we know affect what we notice?

Abstract: Previous work on the object and word superiority effects has demonstrated that activation from stored representations can facilitate identification of items in a visual display. We predicted that activation of this sort might exogenously attract visual attention toward items that have stored representations. To test this prediction, we presented a familiar (word) and an unfamiliar (nonword) item simultaneously at unpredictable locations, and after varying delays, moved one of the stimuli. In accord with our prediction, at the shortest intervals subjects were more efficient at discriminating motion of the familiar item. Control data demonstrated that this advantage was due to a competitive interaction and not to the familiarity of the items per se.

Of guns and geese: a meta-analytic review of the ‘weapon focus’ literature

Abstract: Weapon focus is frequently cited as a factor in eyewitness testimony, and is broadly defined as a weapon-related decrease in performance on subsequent tests of memory for those elements of an event or visual scene concurrent to the weapon. This effect has been attributed to either (a) physiological or emotional arousal that narrows the attentional beam (arousal/threat hypothesis), or (b) the cognitive demands inherent in processing an unusual object (e.g. weapon) that is incongruent with the schema representing the visual scene (unusual item hypothesis). Meta-analytical techniques were applied to test these theories as well as to evaluate the prospect of weapon focus in real-world criminal investigations. Our findings indicated an effect of weapon presence overall (g= 0.53) that was significantly influenced by retention interval, exposure duration, and threat but unaffected by whether the event occurred in a laboratory, simulation, or real-world environment.

Temporal Order Judgments Activate Temporal Parietal Junction

Abstract: Perceptual temporal order judgments require an individual to determine the relative timing of two spatially separate events. Here we reveal the brain regions involved with this task. We had participants observe perceptually identical visual stimuli while conducting two different tasks: discriminating temporal order or discriminating spatial properties. By contrasting the functional magnetic resonance imaging signals during these tasks, we were able to isolate regions specifically engaged by each task. Participants observed two briefly presented rectangles. In one task, participants were instructed to report which appeared first, and, in the other, they were requested to report which rectangle was squarer. A potential confound of this study is that the temporal order judgment (TOJ) task required processing of brief events (onsets), whereas the shape task did not require temporal selectivity. To address this, we conducted a second study in which both tasks required discriminating brief events concurrent with the object onsets. The stimuli were similar to the first experiment, except a gray line was briefly superimposed on each rectangle at onset. Participants reported either which rectangle appeared first (TOJ) or which rectangle had a slightly wider gray line (shape). The first study found that the TOJ task resulted in greater bilateral activation of the temporal parietal junction (TPJ). The second revealed TOJ activation in the TPJ of the left hemisphere. This suggests that TPJ activation increases when we need to temporally sequence information. This finding supports the notion that the TPJ may be a crucial component of the “when” pathway.

Negative priming for spatial location

Abstract: The term negative priming has been used to describe the deleterious consequences for performance when the current target shares properties with an ignored distractor from the previous trial. Location-based negative priming was first reported by Tipper, Brehaut, and Driver (1990) who used a prime-probe procedure wherein the task was to localize targets defined by their identity (shape). Design imbalances in this seminal study, and others, are illustrated and it is indicated how these might have contaminated the reported effects. The findings, from three experiments using an unbiased design, suggest that negative priming in the spatial location procedure may be more closely related to inhibition of return (foR), or to the automatic attraction of attention by new objects, than to the concepts of distractor inhibition, episodic retrieval, and feature mismatch, which have traditionally been used to explain negative priming for spatial location. In its most general sense, negative priming is a purely empirically derived concept referring to any negative effect on performance stemming from a previous experience. Since the seminal work of Lowe (1979), Neill (1977), and Tipper (1985), a somewhat narrower construal of this term has dominated the literature. Negative priming in this narrower sense, and as we will use the term here, refers to retarded responding to a target because it shares properties with a distractor from the previous trial (for a review, see Fox, 1995; see Milliken, Joordens, Merikle, & Seiffert, 1998, for a negative priming effect in the more general sense). The proposal that negative priming might reflect cognitive inhibition (Houghton & Tipper, 1994; Klein & Taylor, 1994; Neill, 1977), coupled with the fact that the method for studying its effects involves both memorial and selective processes, has generated numerous studies of negative priming. These studies vary in emphasis from memory to attention and perception, and their participants include children and the aged, as well as individuals suffering from mental disorders like schizophrenia (e.g., Beech, Powell, McWilliam, & Claridge, 1989; Fox, 1994; Hasher, Stoltzfus, Zacks, & Rypma, 1991). In early studies of negative priming, participants made speeded decisions reporting the identity of a target that had been selected, usually in the presence of a distractor, on the basis of its colour or spatial location. Negative priming was observed as delayed responding when the target had the same identity as the immediately preceding distractor. In an influential paper advocating greater ecological validity, Tipper, Brehaut, and Driver (1990) reversed the task: Participants reported the location of a target that was selected on the basis of its identity. On each trial, a target (O) was presented in one of four locations, with or without a distractor (+), and the task was to press a button corresponding to the target's location. Trials were presented in prime/probe pairs, and the critical pairs involved presenting the probe target in the location that had contained a distractor on the prime trial. Tipper et al. reported impaired performance on these critical trials relative to a control condition, for which the probe's items were presented in new locations. This difference was added to a growing list from other procedures thought to reveal negative priming and came to be referred to as "negative priming for spatial location." Partly because of its putative ecological validity, partly because of the simplicity of the task for the participant, and partly because of its ease of implementation (particularly in stripped-down form, see later), the procedure in which participants localize a target on the basis of its identity has become widely used to study negative priming. However, an examination of the literature using this procedure reveals that the typical implementation, which uses a restricted set of the possible prime-probe combinations, introduces biases: Properties of the upcoming probe array are not randomly related to the prime layout which, therefore, might serve as an informative pre-cue. …

Vector averaging of inhibition of return

Abstract: Observers detected targets presented 400 msec after a display containing one cue or two to four cues displayed simultaneously in randomly selected locations on a virtual circle around fixation. The cue arrangement was completely uninformative about the upcoming target’s location, and eye position was monitored to ensure that the participants maintained fixation between the cue and their manual detection response. Reflecting inhibition of return (IOR), there was a gradient of performance following single cues, with reaction time decreasing monotonically as the target’s angular distance from the cued direction increased. An equivalent gradient of IOR was found following multiple cues whose center of gravity fell outside the parafoveal region and, thus, whose net vector would activate an orienting response. Moreover, on these trials, whether or not the targeted location had been stimulated by a cue had little effect on this gradient. Finally, when the array of cues was balanced so that its center of gravity was at fixation, there was no IOR. These findings, which suggest that IOR is an aftermath of orienting elicited by the cue, are compatible with population coding of the entire cue (as a grouped array for multiple cues) as the generator of IOR.

Analyzing linguistic data: a practical introduction to statistics using R

Abstract: The complete title of this book runs ‘Analyzing Linguistic Data: A Practical Introduction to Statistics using R’ and as such it very well reflects the purpose and spirit of the book. The author guides the reader in about 350 pages from descriptive and basic statistical methods over classification and clustering to (generalised) linear and mixed models. Each of the methods is introduced in the context of concrete linguistic problems and demonstrated on exciting datasets from current research in the language sciences. In line with its practical orientation, the book focuses primarily on using the methods and interpreting the results. This implies that the mathematical treatment of the techniques is held at a minimum if not absent from the book. In return, the reader is provided with very detailed explanations on how to conduct the analyses using R [1]. The first chapter sets the tone being a 20-page introduction to R. For this and all subsequent chapters, the R code is intertwined with the chapter text and the datasets and functions used are conveniently packaged in the languageR package that is available on the Comprehensive R Archive Network (CRAN). With this approach, the author has done an excellent job in enabling researchers and students alike to reproduce the analyses and learn by doing. Another quality as a textbook is the fact that every chapter ends with Workbook sections where the user is invited to exercise his or her analysis skills on supplemental datasets. Full solutions including code, results and comments are given in Appendix A (30 pages). Instructors are therefore very well served by this text, although they might want to balance the book with some more mathematical treatment depending on the target audience. After the introductory chapter on R, the book opens on graphical data exploration. Chapter 3 treats probability distributions and common sampling distributions. Under basic statistical methods (Chapter 4), distribution tests and tests on means and variances are covered. Chapter 5 deals with clustering and classification. Strangely enough, the clustering section has material on PCA, factor analysis, correspondence analysis and includes only one subsection on clustering, devoted notably to hierarchical partitioning methods. The classification part deals with decision trees, discriminant analysis and support vector machines. The regression chapter (Chapter 6) treats linear models, generalised linear models, piecewise linear models and a substantial section on models for lexical richness. The final chapter on mixed models is particularly interesting as it is one of the few text book accounts that introduce the reader to using the (innovative) lme4 package of Douglas Bates which implements linear mixed-effects models. Moreover, the case studies included in this

Do threatening stimuli draw or hold visual attention in subclinical anxiety

Abstract: Biases in information processing undoubtedly play an important role in the maintenance of emotion and emotional disorders In an attentional cueing paradigm, threat words and angry faces had no advantage over positive or neutral words (or faces) in attracting attention to their own location, even for people who were highly state-anxious In contrast, the presence of threatening cues (words and faces) had a strong impact on the disengagement of attention When a threat cue was presented and a target subsequently presented in another location, high state-anxious individuals took longer to detect the target relative to when either a positive or a neutral cue was presented It is concluded that threat-related stimuli affect attentional dwell time and the disengage component of attention, leaving the question of whether threat stimuli affect the shift component of attention open to debate

Dual-Process Models in Social and Cognitive Psychology: Conceptual Integration and Links to Underlying Memory Systems

Abstract: Models postulating 2 distinct processing modes have been proposed in several topic areas within social and cognitive psychology. We advance a new conceptual model of the 2 processing modes. The structural basis of the new model is the idea, supported by psychological and neuropsychological evidence, that humans possess 2 memory systems. One system slowly learns general regularities, whereas the other can quickly form representations of unique or novel events. Associative retrieval or pattern completion in the slow-learning system elicited by a salient cue constitutes the effortless processing mode. The second processing mode is more conscious and effortful; it involves the intentional retrieval of explicit, symbolically represented rulesfrom either memory system and their use to guide processing. After presenting our model, we review existing dual-process models in several areas, emphasizing their similar assumptions of a quick, effortless processing mode that rests on well-learned prior associations and ...

The Self and Autobiographical Memory: Correspondence and Coherence

Abstract: A modified version of Conway and Pleydell-Pearce's Self Memory System (SMS) account of autobiographical memory and the self is introduced. Modifications include discussion of a fundamental tension between adaptive correspondence (experience-near sensory-perceptual records of goal activity) and self-coherence (a more abstracted and conceptually-rich long-term store of conceptual and remembered knowledge). This tension is examined in relation to each SMS component—the episodic memory system, long-term self, and the working self. The long-term self, a new aspect of the model, consists of the interaction of the autobiographical knowledge base and the conceptual self. The working self, depending on goal activity status, mediates between episodic memory and the long-term self. Applications of the SMS to personality and clinical psychology are provided through analysis of self-defining memories and adult attachment categories, as well as case histories of traumatic memory. The SMS's role in imagination ...

Are there bilingual advantages on nonlinguistic interference tasks? Implications for the plasticity of executive control processes

Abstract: It has been proposed that the unique need for early bilinguals to manage multiple languages while their executive control mechanisms are developing might result in long-term cognitive advantages on inhibitory control processes that generalize beyond the language domain. We review the empirical data from the literature on nonlinguistic interference tasks to assess the validity of this proposed bilingual inhibitory control advantage. Our review of these findings reveals that the bilingual advantage on conflict resolution, which by hypothesis is mediated by inhibitory control, is sporadic at best, and in some cases conspicuously absent. A robust finding from this review is that bilinguals typically outperform monolinguals on both compatible and incompatible trials, often by similar magnitudes. Together, these findings suggest that bilinguals do enjoy a more widespread cognitive advantage (a bilingual executive processing advantage) that is likely observable on a variety of cognitive assessment tools but that, somewhat ironically, is most often not apparent on traditional assays of nonlinguistic inhibitory control processes.