The number line effect reflects top-down control

Recent evidence indicates that central directional stimuli, such as eyes and arrows, trigger rapid, reflexive shifts of spatial attention. A study by Fischer, Castel, Dodd, and Pratt (2003) suggested that a similar effect might also apply to central numbers, as if a digit's meaning causes attention to be oriented to its relative position on a left-to-right mental number line. However, unlike central eyes and arrows, the orienting effect for central digits emerges slowly, suggesting that top-down endogenous processes may be mediating this effect. Here, we report a series of three experiments that strongly support this hypothesis. Experiment 1 replicated Fischer et al.'s left-to-right number line effect. Experiment 2 showed that this effect could be completely reversed by merely asking participants to imagine a number line running from right to left. Experiment 3 showed that a left-to-right number line effect could be abolished by presenting targets above and below central fixation, as well as to the left and right of center. Experiment 3 also showed that other mental sets, such as imagining a clock, result in attention's being oriented in accordance with where the central digits are represented on a clock face. Together, these data indicate that the spatial representations and attentional orienting related to the perception of digits are both fragile and flexible and depend critically on the top-down spatial mental sets adopted by individuals.     

Effects of survival processing and retention interval on true and false recognition in the DRM and category repetition paradigms

ABSTRACT

Two experiments examined the effects of survival processing and delay on true and related false recognition. Experiment 1 used the Deese-Roediger-McDermott paradigm and found survival processing to increase true and related false recognition. Extending the delay from 5-mins to 1-day reduced true, but not false memory. Measures of the characteristics of true and false memories showed survival processing increased “remember” and “know” responses for related false memory, “know” responses for true memory and gist processing. Experiment 2 made use of the category repetition procedure and found a broadly similar pattern of results for true memory. However, related false memory was decreased by survival processing. Except for one result, no interactions were found between encoding task and delay. Overall, survival processing produced similar or different effects on true/false memory depending on the nature of the list. The mechanisms that might underpin these are evaluated and considered in relation to future work.     

The role of controlled attention on recall in major depression

Information processing biases are hallmark features of major depressive disorder (MDD). Depressed individuals display biased memory and attention for negative material. Given that memory is highly dependent on attention for initial encoding, understanding the interplay of these processes may provide important insight into mechanisms that produce memory biases in depression. In particular, attentional control—the ability to selectively attend to task-relevant information by both inhibiting the processing of irrelevant information and disengaging attention from irrelevant material—may be one area of impairment in MDD. In the current study, clinically depressed (MDD: n = 15) and never depressed (non-MDD: n = 22) participants' line of visual gaze was assessed while participants viewed positive and negative word pairs. For each word pair, participants were instructed to attend to one word (target) and ignore one word (distracter). Free recall of study stimuli was then assessed. Depressed individuals displayed greater recall of negatively valenced target words following the task. Although there were no group differences in attentional control in the context of negative words, attention to negative targets mediated the relationship between depression status and recall of negative words. Results suggest a stronger link between attention and memory for negative material in MDD.     

Using semantic memory to find vs create a mood

Ss produced words from semantic memory which satisfied certain constraints. In Experiment I, a noun category plus a number and a letter were presented (e.g., ANIMAL-I-D, FRUIT-P-3), and S produced an instance of the category which had the given letter in the position designated by the given number. Faster responses occurred when the position cue occurred before the letter rather than after it. In Experiments II and III, Ss saw only a number and a letter (e.g., l-D, P-3) and were required to produce any word that had the given letter in the position designated by the given number. Order of the position and letter cues did not influence response times. The effect of order in one case and not the other strongly suggests that producing a word that satisfies certain semantic constraints involves a different process from producing a word that satisfies only certain orthographic restrictions.     

Sympathetic arousal to a vestibular stressor in high and low hostile men

The aim of the present experiment was to extend the literature on hostility and a cerebral systems based model of sympathetic arousal to a vestibular-based stress. Several authors have concluded that autonomic stress reactivity in high hostile individuals must be interpersonally based, whereas healthy vestibular system functioning does not depend on interpersonal features. Utilizing a vestibular activation paradigm, skin conductance levels of 15 high hostile and 15 low hostile men were recorded after brief passive rotation about the vertical neuroaxis. It was expected that hostile individuals would exhibit higher skin conductance levels after rotation compared with low hostile individuals. The results confirmed expectations of heightened sympathetic tone among high hostiles subsequent to vestibular stress. Overall, the findings are interpreted to support a cerebral model of frontal region capacity limitation for regulation of vestibular stress that is independent of psychosocial mechanisms.     

Grammatical and nongrammatical contributions to closed-class word selection

Closed-class word selection was investigated by focusing on determiner production. Native speakers from three different languages named pictures of objects using determiner plus noun phrases (e.g., in French "la table" [the-sub(feminineA) table], while ignoring distractor determiners printed on the pictures (e.g., "le" [the-sub(masculine)]. The target and distractor expressed either shared or different grammatical and nongrammatical features (gender, number, and definiteness). A gender-facilitation effect was observed and attributed to noun processing. Crucially, across five experiments, distractors that shared a feature with the target determiner never resulted in longer naming latencies than distractors that were more different. These results indicate that activating related candidates is not detrimental for determiner retrieval, suggesting a noncompetitive mechanism of closed-class word selection.     

Time course of selective attention in clinically depressed young adults: an eye tracking study

Depressed individuals display biased attention for emotional information when stimuli are presented for relatively “long” (e.g., 1 s) durations. The current study examined whether attentional biases are sustained over a much longer period. Specifically, clinically depressed and never depressed young adults simultaneously viewed images from four emotion categories (sad, threat, positive, neutral) for 30 s while line of visual gaze was assessed. Depressed individuals spent significantly more time viewing dysphoric images and less time viewing positive images than their never depressed counterparts. Time course analyses indicated that these biases were maintained over the course of the trial. Results suggest that depressed participants' attentional biases for dysphoric information are sustained for relatively long periods even when other emotional stimuli are present. Mood congruent information-processing biases appear to be a robust feature of depression and may have an important role in the maintenance of the disorder.