The effects of spatial frequency and target type on perceived duration

Two experiments are reported that attempt to demonstrate a critical role played by sensory persistence on a standard perceived-duration task employing brief visual stimuli. Experiment 1 examined the effect on perceived duration of varying the spatial frequency of a target. For both 40- and 70-msec flashes, increased spatial frequency resulted in reduced estimates of perceived duration. These results were contrasted with predictions derived from cognitive processing models of duration perception. In Experiment 2, three typical types of target employed in current research (an outlined circle, a “noise”-filled circle, and a completely filled circle) were shown to differ significantly in their perceived duration and in their sensitivity to increases in physical duration. The results were discussed in terms of variable degrees of retinal persistence produced by the three types of targets. The possible implications for specific discrepancies in the literature and across-study comparisons in general were enumerated.     

Task sets under reconstruction: effects of partially incorrect precues.

To perform a task that differs from a previously performed one, it is necessary to prepare for the new task as well as to disable the task set of the preceding task. In a series of three experiments we examined whether preparation for a task shift implies a direct update of the task set that is carried over from the preceding trial. To this end, in Experiments 1 and 2 we factorially varied the relation of the task in trial n, first, to the task in trial n - 1 (intertask relation) and, second, to the task that was precued for trial n (precue-to-task relation). Invalid precues resulted in substantial costs, which increased with longer precueing intervals. However, this increasing effect of the precue-to-task relation was not accompanied by a decreasing effect of the intertask relation. Furthermore, both effects had different qualitative properties. These findings suggest that two tasks can be represented concurrently but on two different levels of representation. In Experiment 3 we observed that the persistence of the effect of the intertask relation depends on the possibility that task repetitions can occur in trials in which a task shift is precued. This suggests that the persistence of the effect of the intertask relation is controlled in a context-sensitive way.     

Target duration effects on iconic memory: the confounding role of changing stimulus dimensions

Observers' accuracy in detecting a narrow spatial gap between two brief, luminous rectangles presented successively was determined within a two-alternative, forced-choice procedure. This successive-field task requires iconic memory, because the information (rectangle position) in the two presentations must be combined for successful gap detection. On this task, the effect of varying the duration of the first rectangle was systematically investigated over several target luminance levels and for several ISI conditions between rectangles. At the long ISI conditions (100 and 300 ms), the effects of increasing stimulus duration was to improve performance. However, at the brief ISI condition (20 ms), increasing stimulus duration initially depressed task performance. It was found that, with practice, this initial performance drop largely disappeared, and the beneficial influence of increasing target duration was again obtained. These results are discussed in terms of (a) a proposed retinal locus for the iconic memory involved and (b), at a more general level, the potentially distracting role of changing stimulus dimensions on a task employing transient stimuli as in the present study.     

The contribution of visual persistence to the perceived duration of brief targets

Two experiments were conducted to examine the role of sensory persistence on tasks of perceived duration employing very brief visual stimuli. Using a standard temporal judgment task, the first experiment replicated both the “size effect” and “empty-filled” illusion reported by previous investigators. However, entirely comparable results were also found with a probematching task, which theoretically assesses the degree of persistence exhibited by a stimulus. The second experiment examined the effect of target luminance on perceived duration. Consistent with a sensory persistence interpretation, judgments of duration increased with increasing luminance. The results from the two experiments were discussed in terms of varying degrees of retinal persistence produced by different stimuli. This view was contrasted with currently dominant interpretations that postulate changes in perceived duration to reflect different information-processing requirements across stimulus conditions.     

A multi-modal investigation of the roles of distress tolerance and emotional reactivity in obsessive-compulsive symptoms

Emerging evidence implicates important roles of poor distress tolerance and heightened emotional reactivity in obsessive-compulsive disorder. To date, investigations have relied mostly on self-report measures, and we sought to extend the literature by examining the relationship between OC symptoms and distress tolerance, as well as emotional reactivity, using three laboratory assessments. Nonclinical participants (N=167) viewed emotional films associated with four different negative emotions and also completed mirror tracing and handgrip persistence tasks. Greater obsessions scores were predictive of poorer emotional tolerance for a sad film and shorter persistence on the mirror tracing task. Among men only, obsessions were negatively correlated with persistence on the handgrip task. Associations between increased emotional reactivity and washing symptoms also emerged. These findings provide further evidence for the role of poor distress tolerance in obsessions and suggest heightened emotional reactivity may play a role in compulsive washing.     

Motivational synchronicity: Priming motivational orientations with observations of others’ behaviors

Two experiments tested the motivational synchronicity hypothesis, according to which observation of a target person’s behavior implying an intrinsic or an extrinsic motivational orientation primes the observers’ corresponding motivational orientation. Experiment 1 revealed that participants exposed to a target person intrinsically motivated to perform a task, relative to those exposed to an extrinsically motivated target person, showed greater intrinsic motivation (free-choice persistence) for the same task. Experiment 2 extended this in two important ways: (1) different tasks were used for the target and participant in order to rule out an expectation-based interpretation of the results, and (2) performance on an activity known to be facilitated by intrinsic motivation was used as the dependent measure. It appears that simply observing others’ motivational orientations influences the accessibility of the observers’ corresponding motivational orientation.     

Collective student characteristics alter the effects of teaching practices on academic outcomes

The goal of this study was to examine the influence of collective student characteristics (academic skills and task persistence at the beginning of first grade) and different teaching practices (child-centered, teacher-directed, and child-dominated) on the development of academic skills and task persistence during the first two years in school. We hypothesized that teaching practices would differentially impact the development of academic skills and task persistence depending on the collective needs of the classroom. Participants were 523 students (273 boys) from 32 classrooms across Estonia. By using multilevel modeling, we found several interactions indicating that both contextual influences are important in determining subsequent academic functioning and task persistence but that some teaching practices are more beneficial depending on the collective starting point of students. These findings highlight the importance of studying different contextual influences hand in hand when trying to understand what enhances young children's academic development.     

Automatic activation of task-related representations in task shifting

Stimulus displays consisting of a target and a distractor can produce task conflicts when target and distractor are associated with different tasks. The present study examined whether these stimulus-induced task conflicts are affected by priming the irrelevant task or by increasing the salience of the distractor. In a series of three experiments, we employed a task-shifting paradigm in which subjects had to apply one of two judgments to either the global or the local level of a hierarchical stimulus. In each block, the target level and the judgment were either constant or mixed. Stimulus-induced judgment conflicts were measured by comparing performance for stimuli associated with two judgments and stimuli associated with only one. It turned out that only mixing the target level and not mixing the judgment increased the conflicts. These findings indicate that only the salience of the distractor modulates stimulus-induced conflicts.     

The effect of attention modification with explicit vs. minimal instructions on worry

In this experiment we investigated the effect of different instructions on the modification of attentional biases, and subsequently on worry persistence. Participants without excessive worry completed a modified dot-probe task, designed to train attention either to threat or neutral words. Half of each group was given explicit instructions regarding the relationship between word valence and target location, and half were given the more usual minimal instructions. Impact on worry persistence was assessed by categorizing the valence of thought intrusions before and after a period of instructed worry. Response latencies to test items on the dot-probe task showed that attention had been successfully manipulated in the expected direction, and explicit instructions led to more effective attention modification. Moreover, participants in the attend-threat group who received explicit instructions reported significantly more negative thought intrusions following instructed worry, as rated by an assessor, whereas participants in the attend-neutral group did not. These findings suggest that an attentional bias towards threatening information plays a role in worry persistence, and that explicit instructions may be helpful in modifying this bias.     

Mental effort and task interference in auditory attention

Dual-task performance was examined in three experiments. The primary task was to repeat or to add one to four digits presented auditorily at a rate of 1 digit/second. This primary task was combined with three different secondary tasks in which subjects listened to a list of words either for later recognition of some of the words (Experiment 1) or for detection and a later report of a target word (Experiments 2 and 3). Different patterns of task interference were obtained. Recognition performance was sensitive to between-task variations in capacity demands but did not reflect momentary attentional demands within the primary task. Detection performance reflected both between-task and within-task variation in capacity demands of the primary task. The interference between the primary and the secondary task was mutual, with more interference when the selection-cue in the detection task was a category name than when it was the target word itself. These findings are discussed in terms of effort theory of attention and the role of attentional strategies in dual-task performance.     

The Rorschach EA-ep variable as related to persistence in a task frustration situation under feedback conditions

Eighty nonpatients, subdivided into four levels based on the Rorschach EA-ep variable, were randomized into two groups and subjected to a frustrating pursuit rotor task. Extrinsic feedback was provided by a noticeable sound that would occur whenever the tracker was off target. Results indicate that where ep is significantly greater than EA a greater persistence occurred even though the extrinsic feedback signaled no substantial improvement in performance. Two of the three elements contributing to the ep, inanimate movement (m) plus the grey-black and shading answers (T, Y, V, C,), and one variable unrelated to ep, white space (S), account for much of the variance in persistence. The findings are discussed in terms of an overload state that interferes with appropriate processing and mediation in a complex situation.     

Assessing the role of alternative response rates and reinforcer rates in resistance to extinction of target responding when combining stimuli

Studies of behavioral momentum reveal that reinforcing an alternative response in the presence of a target response reduces the rate of target responding but increases its persistence, relative to training the target response on its own. Because of the parallels between these studies and differential‐reinforcement techniques to reduce problem behavior in clinical settings, alternative techniques to reduce problem behavior without enhancing its persistence are being explored. One potential solution is to train an alternative response in a separate stimulus context from problem behavior before combining the alternative stimulus with the target stimulus. The present study assessed how differences in reinforcement contingencies and rate for alternative responding influenced resistance to extinction of target responding when combining alternative and target stimuli in pigeons. Across three experiments, alternative stimuli signaling a response–reinforcer dependency and greater reinforcer rates more effectively decreased the persistence of target responding when combining alternative and target stimuli within the same extinction tests, but not when compared across separate extinction tests. Overall, these findings reveal that differences in competition between alternative and target responding produced by contingencies of alternative reinforcement could influence the effectiveness of treating problem behavior through combining stimulus contexts.     

The role of item similarity in part-list cueing impairment

The presentation of a subset of studied items as retrieval cues can have detrimental effects on recall of the remaining (target) items. In three experiments we examined whether such part-list cueing impairment depends on the similarity between cue and target items. Item similarity was manipulated by making use of pre-experimental semantic similarities between cue and target items (Experiments 1 and 2), or was episodically induced through a similarity-encoding task, in which participants were asked to interrelate cue and target items in a meaningful way (Experiment 3). In all three experiments reliable part-list cueing impairment arose when the similarity between cues and targets was low, but no impairment was found when the similarity between cues and targets was high. Inhibitory as well as non-inhibitory explanations of the findings are discussed.     

What’s in an object file? Evidence from priming studies

Six experiments were conducted to investigate the nature of the contents of object files, temporary representations that store information about objects. Experiment 1 used a lexical priming paradigm with a lexical decision task, in which the prime and target could appear in either the same or different locations. The results indicated a greater priming effect when the prime and target appeared in the same location than when they appeared in different locations (object- or location-specific priming). Experiment 2 replicated these findings for objects that changed position during the display. Experiment 3 demonstrated that these findings reflected the inclusion of abstract identity information, rather than physical form, in object files. Three additional experiments tested for the presence of three types of semantic information (related concepts, semantic features, and category membership) in object files. No object-specific priming effects were found. Taken together, these experiments suggest that an object file includes identity information, but not semantic information. Implications of the results for object file theory are discussed.     

Self-consciousness, outcome expectancy, and persistence

A study investigated persistence as a function of two variables: the disposition to be self-attentive (called private self-consciousness) and outcome feedback on a prior task that was described as closely related to the target task. More specifically, subjects first completed a concealed-figures test and were told that their performances were either very good or very poor. The second test, which ostensibly measured the same abilities, was an insolvable design problem that is commonly used to measure persistence. Feedback concerning prior outcomes had a direct influence on expectancies for the second task, but persistence on that task was a joint function of feedback and self-consciousness. That is, favorable feedback led to greater persistence than did unfavorable feedback, but only among subjects high in self-consciousness. This finding replicates and extends the results of several previous studies. Discussion centers on the relationship between the present research and an earlier experiment which yielded apparently different results.     

Semantic activation and letter search: Blocking or suppression?

Two experiments investigated associative priming with a letter-search prime task where either the prime and letter probe were presented simultaneously, or the letter probe appeared 200 ms (Experiment 1) or 300 ms (Experiment 2) after the prime. Weak associative priming was observed in both experiments, but unlike Stolz and Besner (1996) we found no evidence that priming was increased when the probe was delayed. However, strong associative priming was observed when a semantic decision had to be made on the prime (Experiment 3). Our results are consistent with an account where semantic activation of the prime occurs but its action on the target is suppressed by the prime task. The persistence of weak priming effects with the letter search task is explained in terms of the low-frequency items used.     

Unconscious processing of dichoptically masked words

In three experiments, the subjects' task was to decide whether each of a series of words connoted something good (e.g., fame, comedy, rescue) or bad (stress, detest, malaria). One-half second before the presentation of each such target word, an evaluatively polarized priming word was presented briefly to the nondominant eye and was masked dichoptically by either the rapidly following (Experiment 1) or simultaneous (Experiments 2 and 3) presentation of a random letter-fragment pattern to the dominant eye. (The effectiveness of the masking procedure was demonstrated by the subjects' inability to discriminate the left vs. right position of a test series of words.) In all experiments, significant masked priming effects were obtained; evaluative decisions to congruent masked prime-target combinations (such as a positive masked prime followed by a positive target) were significantly faster than those to incongruent (e.g., negative prime/positive target) or noncongruent (e.g., neutral prime/positive target) combinations. Also, in two of the three experiments, when subjects were at chance accuracy in discriminating word position, their position judgments were nevertheless significantly influenced by the irrelevant semantic content (LEFT vs. RIGHT) of the masked position-varying words. The series of experiments demonstrated that two very different tasks--speeded judgment of evaluative meaning and nonspeeded judgment of word position--yielded statistically significant and replicable influences of the semantic content of apparently undetectable words. Coupled with previous research by others using the lexical decision task, these findings converge in establishing the reliability of the empirical phenomenon of semantic processing of words that are rendered undetectable by dichoptic pattern masking.     

Event-based prospective memory for poorly attended events

In the most frequently used paradigm for studying event-based prospective memory (PM, Einstein & McDaniel, 1990), participants perform an ongoing task and are asked to perform an additional task when a particular stimulus (the PM cue) is presented. In this study three experiments examined how PM performance depends on stimulus selection, which is a major process involved in executive task control according to current theorizing. Participants made semantic judgments about a target word accompanied by two nontargets (distracters). The target was indicated by its spatial position (Experiment 1) or color (Experiment 2). The findings indicated that PM performance was much poorer when the PM cue was irrelevant to the ongoing task, in spite of the fact that nontargets were processed semantically as shown in Experiment 3.     

Analogical transfer in the THOG task

The influences of surface and structural similarity on analogical transfer were examined with 318 undergraduate participants in four experiments using Needham and Amado's (1995) Pythagoras THOG problem as the source problem and Wason's standard abstract THOG task as the target problem. In Experiments 1-3, systematic changes in surface similarity between the source and target problems were introduced by changing the named exemplar, the dimensional values, and the dimensions, respectively, in the target problem. Significant transfer was obtained in all three experiments. In Experiment 4, we explored the basis of this transfer by examining three versions of the Pythagoras THOG problem, factorially combining its facilitating features as source problems. Results indicated that the inclusion of a hypothesis generation request was necessary for significant transfer. The implications of our findings for using transfer versus facilitation as the performance criterion for deductive reasoning are considered.