Transient attention does increase perceived contrast of suprathreshold stimuli: a reply to Prinzmetal, Long, and Leonhardt (2008)

Carrasco, Ling, and Read (2004) showed that transient attention increases perceived contrast. However, Prinzmetal, Long, and Leonhardt (2008) suggest that for targets of low visibility, observers may bias their response toward the cued location, and they propose a cue-bias explanation for our previous results. Our response is threefold. First, we outline several key methodological differences between the studies that could account for the different results. We conclude that the cue-bias hypothesis is a plausible explanation for Prinzmetal et al.'s (2008) results, given the characteristics of their stimuli, but not for the studies by Carrasco and colleagues, in which the stimuli were suprathreshold (Carrasco, Ling, & Read, 2004; Fuller, Rodriguez, & Carrasco, 2008; Ling & Carrasco, 2007). Second, we conduct a study to show that the stimuli used in our previous studies are not near-threshold, but suprathreshold (Experiment 1, Phase 1). Furthermore, we found an increase in apparent contrast for a high-contrast stimulus when it was precued, but not when it was postcued, providing more evidence against a cue-bias hypothesis (Experiment 1, Phase 2). We also show that the visibility of the stimuli in Prinzmetal et al. (2008) was much lower than that of Carrasco, Ling, and Read, rendering their stimuli susceptible to their cue-bias explanation (Experiment 2). Third, we present a comprehensive summary of all the control conditions used in different labs that have ruled out a cue bias explanation of the appearance studies. We conclude that a cue-bias explanation may operate with near-threshold and low-visibility stimuli, as was the case in Prinzmetal et al. (2008), but that such an explanation has no bearing on studies with suprathreshold stimuli. Consistent with our previous studies, the present data support the claim that attention does alter the contrast appearance of suprathreshold stimuli.     

Further evidence for systematic reliability differences between explicit and implicit memory tests

Meier and Perrig (2000) as well as Buchner and Wippich (2000) have shown that simple dissociations between explicit and implicit memory measures need not reflect functional dissociations of hypothetical underlying memory systems. Instead, such dissociations may also result from the fact that some widely used implicit memory measures are simply less reliable than the explicit measures with which they have been compared. We extend this argument in two ways. First, we show that illusion-based memory measures such as the priming measures derived from fame andpreference judgement tasks are also subject to the reliability problem. Second, we show that yes-no and two-alternative forced-choice paradigms should, and in fact do, yield virtually identical results as far as the reliability of the memory tests is concerned.     

An Examination of the Actor-Observer Effect in Young Drivers' Attributions for Their Own and Their Friends' Risky Driving

The attributions of 70 young drivers for their own and their friends' risky driving were examined using open-ended questions to determine if there were self-other differences consistent with the actor-observer effect. Six response categories were created, 4 of which were rated as more dispositional than situational by a subsample of the participants and 2 of which were rated as more situational than dispositional. While the largely dispositional category "Showing off, acting cool" was used significantly more for friends than for self, and the largely situational "In a hurry, late" was used significantly more for self than for friends, there was only limited support for the actor-observer effect overall. The participants also rated their friends as taking more risks than themselves. The actor-observer differences are suggested to be influenced primarily by motivational factors and the context in which young people observe their friends' driving. New approaches to traffic safety interventions are suggested.     

Auditory phonemic perception in dyslexia: Categorical identification and discrimination of stop consonants

The possibility that phonological confusions may underlie some difficulties in processing written language was investigated using four speech perception tasks. Twelve dyslexic and four normal-reading children identified and discriminated synthetic speech syllables which varied either in voice-onset time (signaling the feature of voicing) or direction of formant transitions (signaling place of articulation). Results indicate that, like normal-reading children and adults, dyslexic children perceive these sounds categorically. Discrimination of the stimuli was limited by their identifiability. It is suggested that linguistic disturbances at other stages of the grapheme to meaning transformation underlie misreading.     

Suicide and African American teenagers: risk factors and coping mechanisms

In this study we investigated whether locus of control, hopelessness, and depression were primary risk factors for suicide ideation and attempts in African American youth, and whether congruency between locus of control and religious coping style reduced suicide risk. The sample consisted of 176 African American high school students (115 females; 61 males). Multiple and logistic regression were used to determine relationships among study variables. Depression was found to mediate the relationship between hopelessness and suicidal behaviors. External locus of control led to greater risk for hopelessness and depression, with a trend in the predicted direction for suicide attempts. Religious coping style alone was not always associated with reduction of risk of suicidal behaviors, yet some evidence suggests that congruency between locus of control and religious coping style reduces risk. Results provide additional support for suicide interventions to target depressive symptoms. Results also highlight the importance of examining the role of culturally salient variables such as fatalism and religious coping style when developing intervention programs for suicide.     

Goal-directed memory: the role of cognitive control in older adults' emotional memory

The present study revealed that older adults recruit cognitive control processes to strengthen positive and diminish negative information in memory. In Experiment 1, older adults engaged in more elaborative processing when retrieving positive memories than they did when retrieving negative memories. In Experiment 2, older adults who did well on tasks involving cognitive control were more likely than those doing poorly to favor positive pictures in memory. In Experiment 3, older adults who were distracted during memory encoding no longer favored positive over negative pictures in their later recall, revealing that older adults use cognitive resources to implement emotional goals during encoding. In contrast, younger adults showed no signs of using cognitive control to make their memories more positive, indicating that, for them, emotion regulation goals are not chronically activated.     

The interaction of objective and subjective organizations in a localization search task

We investigated how both objective and subjective organizations affect perceptual organization and how this perceptual organization, in turn, influences observers’ performance in a localization search task. Two groups of observers viewing exactly the same stimuli (objective organization) performed in significantly different ways, depending on how they were induced to parse the display (subjective organization). In Experiments 1 and 2, the observers were asked to describe the location of a tilted target among a varying number of vertical or horizontal distractors. Subjective organization was induced by instructing observers to parse the display into either three horizontal regions (rows) or three vertical regions (columns). The position of the target was critical: location performance, as assessed by reaction time and errors, was consistently impaired at the locations adjacent to the boundaries defining the regions, producing what we refer to as thesubjective boundary effect. Furthermore, the extent of this effect depended on whether the stimulus-driven and conceptually driven information concurred or conflicted. This made location information more or less accessible. In Experiment 1, the strength of objective grouping was a function of the proximity of the items (near or far conditions) and their orientation in a 6×6 matrix. In Experiment 2, the strength of objective grouping was a function of similarity of color (items were color coded by rows or by columns) and the orientation of the items in a 9×9 matrix. The subjective boundary effect was more pronounced when the display promoted grouping in the direction orthogonal to that of the task (e.g., when observers parsed by rows but vertical distractors were closer together [Experiment 1] or color coded [Experiment 2] to induce global columns). In contrast, this effect decreased when the direction of both objective and subjective organizations was parallel (e.g., when observers parsed by rows and horizontal distractors were closer together [Experiment 1] or were color coded [Experiment 2] to induce global rows). A localization search task proved to be an ideal forum in which objective and subjective organizations interacted. We discuss how these results indicated that observers’ performance in a localization task was determined by the interaction of objective and subjective organizations, and that the resulting perceptual organization constrained coarse location information.