Contextual influences on interactive processing: Effects of discriminability,quantity, and uncertainty

Three contextual factors—(1) the discriminability of stimuli in pitch, (2) the number of stimuli differing in pitch, and (3)the uncertainty regarding which stimuli or tasks would appear—were manipulated as subjects performed speeded loudness classifications in each of six experiments. The magnitude of Garner interference and effects of congruity were used to gauge the degree of interactive processing. Enhancing pitch discriminability caused monotonic increases in interference and congruity. Stimulus-task uncertainty mediated the changes in Garner interference wrought by increased discriminability. Uncertainty also caused a surprising shift in congruity from strongly positive to strongly negative as uncertainty grew. Increasing stimulus quantity lowered interference, but had inconsistent effects on congruity. Regression analyses suggested that, collectively, these three contextual variables underlie most failures of selective attention in speeded classification.     

Attentional selection: A salience-based competition for representation

The role of salience in localized attentional interference (LAI) was examined. In two experiments, target discrimination performance was measured as a function of the spatial separation between the target and a salient distractor item. In Experiment 1, both the salience of the distractor and that of a target were manipulated. Distractor salience was manipulated via size changes to the distractor, and target salience was manipulated by using unmasked or onset targets. When the target was of low salience, the magnitude of interference from the distractor increased with distractor salience. However, when the target had an abrupt onset, the distractor had no impact on target performance. In Experiment 2, the attentional salience of the distractor was manipulated using a probability manipulation. Displays contained both a target and a color singleton distractor. The color singleton produced LAI when it was predictive of the target location but not when it was unpredictive of the target location. The results of both experiments are consistent with models of competition-based attentional selection.     

Age-related differences in localized attentional interference

Attentional selection of an object in the visual field degrades processing of neighboring stimuli in young adults. A pair of experiments examined the effects of aging on such localized attentional interference. In Experiment 1, younger and older observers made speeded same-different judgments of target shapes that varied in spatial separation. Performance declined for both age groups as the distance between targets decreased, but an Age x Distance interaction indicated that the magnitude of this effect was larger for older adults. Experiment 2 ruled out sensory masking as an explanation for these findings. Results indicate that older observers experience losses in the ability to attend to multiple spatially proximal stimuli within the visual field.     

Searching for the self: an identity control theory approach to triggers of occupational exploration

Identity control theory researchers have found evidence for two processes of identity development (identity defense and identity change) and have theorized a third process (identity exploration). College students (N = 123) self-rated as high or low in occupational identity certainty and importance received self-discrepant feedback to induce identity disturbance, and dependent measures of identity defense, identity change, and identity exploration were obtained. As predicted, high certainty about identity standards led to identity defense, while low certainty led to identity change. Although an interaction between certainty and importance was hypothesized to predict identity exploration, results showed that the two operated independently. Low certainty predicted exploration of additional occupational areas, whereas high importance predicted exploration of self, environment, and additional occupational areas.     

Spatial interference between attended items engenders serial visual processing

A pair of experiments investigated the architecture of visual processing, parallel versus serial, across high and low levels of spatial interference in a divided attention task. Subjects made speeded judgments that required them to attend to a pair of color-cued objects among gray filler items, with the spatial proximity between the attended items varied to manipulate the strength of interference between attended items. Systems factorial analysis (Townsend & Nozawa, Journal of Mathematical Psychology 39:321-359, 1995) was used to identify processing architecture. Experiment 1, using moderately dense displays, found evidence of parallel processing whether attended objects were in low or high proximity to one another. Experiment 2, using higher-density displays, found evidence of parallel selection when attended stimuli were widely separated but serial processing when they were in high proximity. Divided visual attention can operate in parallel under conditions of low or moderate spatial interference between selected items, but strong interference engenders serial processing.     

Evidence for suppressive mechanisms in attentional selection: feature singletons produce inhibitory surrounds

Four experiments explored inhibitory mechanisms related to attentional selection. Observers viewed multielement displays and performed a form discrimination task involving a probe element. Also present in the stimulus display was a singleton element (possessing a unique color or orientation). In Experiments 1-3, probe discrimination performance was measured as a function of the distance between the probe and the singleton. Experiment 1 revealed that probe discriminations suffered when the probe was adjacent to the singleton, but improved as the spatial separation between the probe and attentionally salient singleton increased. Experiment 2 added a control condition, revealing that probe discriminations were inhibited near the singleton, but returned to control level performance with increased separation. Further, the amount of inhibition increased with larger stimulus onset asynchronies between the singleton and probe. Experiment 3 demonstrated that the extent of the inhibitory region is spatially mediated. In Experiment 4, the task was modified to one of probe detection. No inhibition was observed in the detection task, indicating that the decrease in probe discrimination performance observed in Experiments 1-3 was not due to observers' inability to detect the probe element.     

Attentional selection of objects or features: evidence from a modified search task

Three experiments examined the domain of visual selective attention (i.e., feature-based selection vs. object-based selection). Experiment 1 extended the requirements of the visual search task by requiring a feature discrimination response to target elements presented for short durations (30-105 msec). Targets were embedded in 47 distractor elements and were defined by either a distinct color or a distinct orientation. Observers made a discrimination response to either the target's color or its orientation. When the target-defining feature and the feature to be discriminated were the same (matched conditions), accuracy was enhanced relative to when these features belonged to separate dimensions (mismatched conditions). In Experiment 2, similar results were found in a task in which the target-defining dimension varied from trial to trial and observers performed both color and orientation discriminations on every trial. The results from these two experiments are consistent with feature-based attentional selection, but not with object-based selection. Experiment 3 extended these findings by showing that the effect is rooted in the overlap between target and distractor values in the stimulus set. The results are discussed in the context of recent models of visual selective attention.     

Violent video game play impacts facial emotion recognition

This study assessed the speed of recognition of facial emotional expressions (happy and angry) as a function of violent video game play. Color photos of calm facial expressions morphed to either an angry or a happy facial expression. Participants were asked to make a speeded identification of the emotion (happiness or anger) during the morph. Typically, happy faces are identified faster than angry faces (the happy-face advantage). Results indicated that playing a violent video game led to a reduction in the happy face advantage. Implications of these findings are discussed with respect to the current models of aggressive behavior.     

Attentional templates regulate competitive interactions among attended visual objects

In two experiments, we examined the mechanisms responsible for creating a zone of interference surrounding an attended visual object (see, e.g., Mounts & Gavett, 2004). In Experiment 1, the similarity between attended stimuli and noise items was manipulated in order to contrast an account based on competitive interactions between attended items with an account based on inefficient filtering of unattended stimuli. Consistent with the competitive interaction account, the data revealed that similarity between attended items increased the strength of localized interference, whereas similarity of noise items to the attended stimuli did not. Experiment 2 showed that the interference observed between attended items was determined by their match to attentional templates.