Early interference in a priming task with brief masked targets.

Priming effects were examined in 2 experiments with 216 undergraduates in which a pronunciation or lexical decision task was used. Attention was manipulated by varying the probability that prime and target would be strongly associated. Both experiments showed significant interference in the low attention condition and at the 200-msec SOA, presumably before the onset of consciously directed processing. Two subsequent experiments with 160 undergraduates used a short SOA and the low attention condition to determine the conditions under which this interference would occur by varying the interstimulus interval, target duration, and the mask. Interference occurred only when targets were brief and masked. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention and interference in the perception of brief visual displays.

Five experiments, with 61 undergraduates, examined an interference effect that occurs when 2 brief visual displays are presented closely in time. When a single target was displayed 100–200 msec after a 5-item array, Ss were remarkably poor at deciding whether or not the target was in the array; performance was much better when the target either preceded the array or followed it by a longer interval. This effect was independent of a number of visual display parameters, suggesting that it was not due to visual contour interaction. In addition, visual similarity did not interact with the effect, indicating that it probably did not occur during item identification. However, when Ss added one to a digit target before deciding whether it occurred in the array, the effect was substantially reduced. Results suggest a model in which abstract identity information about the target is confused with the array at certain temporal intervals. A quantitative version of this model fit the data quite well. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How visual imagery interferes with vision.

Mental visual imagery interferes with vision: the Perky (1910) effect. Is the effect optical, sensory, perceptual, attentional, or just a response bias? Acuity was measured (in undergraduates and graduates) using target lines, with and without images (of lines). Optics (fixation, pupil size, accommodation), response bias, global attention (effort, diversion of attention to imagery), perceptual assimilation (target incorporation by imagery) and perceptual masking (of target by imagery) all fail to explain the effect. Foveally, local attention plays a limited role, as the Perky effect in divided attention is half that in focused attention, but this interaction vanishes with extrafoveal targets. Images produce primarily sensory interference, mimicking a reduction in target energy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quantitative theories of metacontrast masking.

In metacontrast masking, the effect of a visual mask stimulus on the perceptual strength of a target stimulus varies with the stimulus-onset asynchrony (SOA) between them. As SOA increases, the target percept first becomes weaker, bottoms out at an intermediate SOA, and then increases for still larger SOAs. As a result, a plot of target percept strength against SOA produces a U-shaped masking curve. Theories have proposed special mechanisms to account for this curve, but new mathematical analyses indicate that it is a robust characteristic of a large class of neurally plausible systems. The author describes 3 quantitative methods of accounting for the U-shaped masking effect and analyzes previously published mathematical models of masking. The models produce the masking curve through mask blocking, whereby a strong internal representation of the target blocks the mask's effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of cognitive load on semantic priming in patients with schizophrenia.

Schizophrenic and control participants received 2 blocks of trials in each experiment. In 1 block they were exposed to regular priming trials (doctor–nurse), and in another block a nonlexical probe was presented at prime onset for 40 ms. Regardless of stimulus onset asynchrony (SOA), the schizophrenic patients showed hyperpriming when no distractor was present. Paying attention to the distracting stimulus reduced priming in the patient group irrespective of SOA. Under certain situations, the reduction in priming appeared even when participants were asked to ignore the distracting stimulus. Thus, even a nonsemantic distractor may be detrimental to schizophrenic patients' language processing. That SOA did not modulate the reduction in priming effect is consistent with the suggestion that attentional resources are required even with short prime–target intervals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The generality of the effects of cue structure similarity on cue discrimination and recall.

Investigated the effect of cue similarity on associative learning, recall, and cue discrimination in 5 experiments involving a total of 634 undergraduates as Ss. In all experiments, cues consisted of 3 elements shared with other cues. Position and consistency of these elements varied among different conditions. In each experiment, Ss associated some kind of target information with a meaningless string of consonants or meaningful words. The procedures for acquisition included (1) single vs multiple study presentations, (2) a long mixed list containing various structures, (3) incidental learning involving semantic processing of cues and targets, (4) use of sentences containing both cues and targets, and (5) embedding cues and targets in a story. Results show that shared elements produced interference with all procedures and materials. (French abstract) (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Location confusions in visual information processing.

Tested in 2 experiments, using 21 undergraduates, the location-confusion model proposed by P. Dixon (see record 1986-21077-001) to account for interference that occurs when deciding whether a briefly presented target item appeared in a briefly presented array. The model assumed that information about the location of items decayed quickly and that Ss sometimes had difficulty deciding whether a particular identity code corresponded to the target or the array. Exp 1 confirmed the assumption that the interference only occurred with visual targets. Exp 2 tested for interference at the level of identity codes for well-learned vs arbitrary visual patterns (AVPs). No interference from AVPs on accuracy was observed. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A fair test of the spreading activation hypothesis: a study of affective congruency effects in the Stroop test

It is argued that the Stroop color-naming task is especially suited to investigate affective priming effects in the sense of an automatic spreading of activation to other concepts of the same valence, because (a) the Stroop task is not prone to an explanation of affective congruency effects on the basis of reaction priming or reaction interference, and (b) it is possible to detect specific (fast and efficient stimulus processing due to heightened accessibility) as well as nonspecific (cognitive interference, triggering of global action tendencies) effects of an activation of valenced concepts in the Stroop task. Two experiments were conducted to investigate associative and affective priming effects with the Stroop task. In a first experiment (N = 36, SOA = 300 ms) a standard priming procedure was chosen; the primes were presented without any processing instructions. In a second experiment (N = 48, SOA = 500ms) the primes had to be reproduced after naming the color of the target. In both experiments significant association effects were found for the associative material. For the valenced material no affective congruency effects were found in either experiment. The present results are not compatible with the hypothesis of an automatic affective spreading of activation that was given as an explanation of affective congruency effects in previous studies using different tasks.     

Better to take one long or two quick looks? Independent processing of evidence from discrete visual presentations.

Should we prefer one long look to two quick looks of equal overall duration? The authors systematically compared conditions in which a circular letter array was available either for a single look of 2d ms duration (onset asynchrony [SOA] from target to mask) or for two separate looks of d ms each. On the basis of the geometry of the underlying psychometric function relating the SOA to the probability of target identification, separate activation models with peaked hazard functions predict that for short SOAs single long looks would lead to better identification performance and that this advantage decreases (and may turn into a disadvantage) with increasing SOA. These predictions were tested, confirmed, and extended in 5 letter-identification experiments that focused on the mechanism by which information extracted from single arrays is integrated across different looks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dilution: A theoretical burden or just load? A reply to Tsal and Benoni (2010).

Load theory of attention proposes that distractor processing is reduced in tasks with high perceptual load that exhaust attentional capacity within task-relevant processing. In contrast, tasks of low perceptual load leave spare capacity that spills over, resulting in the perception of task-irrelevant, potentially distracting stimuli. Tsal and Benoni (2010) find that distractor response competition effects can be reduced under conditions with a high search set size but low perceptual load (due to a singleton color target). They claim that the usual effect of search set size on distractor processing is not due to attentional load but instead attribute this to lower level visual interference. Here, we propose an account for their findings within load theory. We argue that in tasks of low perceptual load but high set size, an irrelevant distractor competes with the search nontargets for remaining capacity. Thus, distractor processing is reduced under conditions in which the search nontargets receive the spillover of capacity instead of the irrelevant distractor. We report a new experiment testing this prediction. Our new results demonstrate that, when peripheral distractor processing is reduced, it is the search nontargets nearest to the target that are perceived instead. Our findings provide new evidence for the spare capacity spillover hypothesis made by load theory and rule out accounts in terms of lower level visual interference (or mere “dilution”) for cases of reduced distractor processing under low load in displays of high set size. We also discuss additional evidence that discounts the viability of Tsal and Benoni's dilution account as an alternative to perceptual load. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Concurrent response-selection processes in dual-task performance: Evidence for adaptive executive control of task scheduling.

This article reports 4 experiments that used the psychological refractory period procedure to characterize how people perform multiple tasks concurrently. For each experiment, a primary choice-reaction task was paired with a secondary choice-reaction task that had two levels of response-selection difficulty. Experiments 1 and 2 varied secondary-task response-selection difficulty by manipulating the number of stimulus-response (S-R) pairs. The effect of this factor on secondary-task reaction times (M) decreased reliably as the stimulus onset asynchrony (SOA) decreased. Experiments 3 and 4 varied secondary-task response-selection difficulty by manipulating S-R compatibility. Again, the effect of this factor on secondary-task M decreased reliably as SOA decreased. These results raise doubts about the existence of an immutable structural response-selection bottleneck and suggest that response selection for 2 concurrent tasks may overlap temporally. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Within- and between-modality associations in probed recall: A test of the separate-streams hypothesis.

Tested the separate-streams hypothesis that short-term processing of verbal information is functionally separated according to presentation modality. Lists of 10 digits were presented to 32 university students such that presentation modality (auditory or visual) changed after every 2nd digit. One digit was repeated at the end of each list as a recall probe. In 1 condition (next-item), Ss were instructed to recall the item that had immediately followed the probe in the original list regardless of presentation modality. In the 2nd condition (next item in the same modality), Ss were instructed to recall the item after the probe and in the same modality. The combination of instructions and positions of the probe and target within the list created 3 main conditions: (1) The probe immediately preceded the target item and was in the same presentation modality (same-mode probe). (2) The probe immediately preceded the target but was in a different presentation modality (different-mode probe). (3) The probe was in the same modality as the target but was separated from it by 2 items in the other modality (temporally distant probe). For both auditory and visual targets, highest recall was obtained with same-mode probes, next highest with temporally distant probes, and lowest with different-mode probes. The results support the hypothesis that auditory and visual information is processed separately in short-term verbal memory. (French abstract) (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interference between phonemes during monitoring: Evidence for an interactive activation model of speech perception.

Explored the finding by J. E. Newman and G. S. Dell (see record 1981-00233-001) that the time needed to detect a target phoneme in a phoneme monitoring task increased when the preceding word contained a phoneme similar to the target. In 3 experiments, 58 undergraduates who were native speakers of English monitored auditorily presented sentences and responded as quickly as possible whenever they detected a specified phoneme. Preceding word-initial phonemes, despite being processed more quickly, increased the response latency to the following target phoneme more than did preceding word-medial phonemes. There was also an increase in response latency even when the S could be highly certain that the similar preceding phoneme was not an instance of the target phoneme. It is argued that the interference effects are due to fundamental characteristics of perceptual processing and that more time is needed to categorize the target phoneme. A computer simulation using an interactive activation model of speech perception is presented to demonstrate the plausibility of this explanation. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The extension of the interference effect to multiplication.

Investigated the interference effect in the number matching task using multiplication facts. 40 Ss verified the presence of a target number (e.g., 8) in a previously presented cue (e.g., 5 x 8) that was masked after 60 msec. The stimulus onset asynchrony (SOA) between cue and target was 100, 120, 220, and 350 msec. Ss were slower to reject targets that were the product of the cue (e.g., 40) than unrelated targets (e.g., 42) at the 100- and 120-msec SOAs. Findings indicate interference effects at these SOAs and support the hypothesis that the cues activated associated numbers resulting in slower latencies for product than unrelated trials. This pattern is consistent with the interference effect found by J. LeFevre et al (see records 76-00346, 79-04985, and 81-43827) using addition facts. The authors conclude that the interference effect previously found with addition facts was due to obligatory activation and not to automatic counting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Information-processing demands of transitive inference.

Investigated the information-processing demands of transitive inference problems with a probe reaction-time (RT) secondary task. Two versions of a primary task were used: the standard 3-term inference problem and a matched verification task that did not require premise integration. In the 1st 2 experiments, with a total of 40 undergraduates, the premise and target-matching components of the primary task were presented sequentially. Results indicate that for the transitive inference task, probe RT was especially slow when the probe occurred during the 2nd premise phase, but no such effect was found with the matched verification task. This implies that premise integration imposed an increased load on processing resources. A 3rd experiment with 10 undergraduates showed that the processing demand associated with premise integration also occurred with simultaneous presentation. Other variations in problem form (e.g., premise markedness, negation, and pivot search) did not influence probe RT, although they are known to affect solution time. It is concluded that solution time and measures of processing load may be independent. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Loci of signal probability effects and of the attentional blink bottleneck.

To investigate the locus of signal probability effects and the influence of stimulus quality on this locus, the authors manipulated probability in Task 2 of a psychological refractory period (PRP) paradigm. The effect was additive with stimulus onset asynchrony (SOA) when the target was not masked but underadditive with decreasing SOA when the target was masked. Even with masking, however, a range of probabilities had effects additive with SOA. The results suggest loci of stimulus probability before the PRP bottleneck as well as at or after the bottleneck. A second issue addressed was the locus of interference in the attentional blink (AB). The AB was larger when the probability of the first of 2 targets was lower. The results lead to the conclusion that one cause of the AB effect is a locus at least as late as the PRP bottleneck. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Increased perceptual and conceptual processing difficulty makes the immeasurable measurable: Negative priming in the absence of probe distractors.

Negative priming (NP) refers to the finding that people's responses to probe targets previously presented as prime distractors are usually slower and more error prone than to unrepeated stimuli. In a typical NP experiment, each probe target is accompanied by a distractor. It is an accepted, albeit puzzling, finding that the NP effect depends on the presence of these probe distractors; for, without probe distractors, NP diminishes. This phenomenon causes severe problems for the majority of theoretical accounts of NP. In the present study, we follow a simple argument, namely that without probe distractors, the difficulty of responding to the probe is so low that NP becomes irrelevant. Hence, by increasing perceptual processing difficulty, as well as by increasing conceptual processing difficulty, significant NP effects with constantly absent probe distractors can be reliably observed. In addition, our results also show that NP without probe distractors can be found by exclusively manipulating probe display processing. This finding furthers our understanding of the processes causing NP. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of perception in the mislocalization of the final position of a moving target.

The judged final position of a moving stimulus has been suggested to be shifted in the direction of motion because of mental extrapolation (representational momentum). However, a perceptual explanation is possible: The eyes overshoot the final position of the target, and because of a foveal bias, the judged position is shifted in the direction of motion. To test this hypothesis, the authors replicated previous studies, but instead of having participants indicate where the target vanished, the authors probed participants' perceptual focus by presenting probe stimuli close to the vanishing point. Identification of probes in the direction of target motion was more accurate immediately after target offset than it was with a delay. Another experiment demonstrated that judgments of the final position of a moving target are affected by whether the eyes maintain fixation or follow the target. The results are more consistent with a perceptual explanation than with a memory account. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interhemispheric communication is via direct connections

Two priming experiments, using normal university students as subjects, independently projected low imagery primes and concrete target words to the left or right visual fields (LVF or RVF) to examine the merits of three spreading activation models of interhemispheric communication: (i) callosal relay of a semantically encoded prime; (ii) transfer of products activated as a result of the spread of activation; and (iii) direct connections between the hemispheres. The first experiment temporally separated pairs by a stimulus onset asynchrony (SOA) of 250 ms and obtained strong support for the direct connections model. Priming effects were obtained only when the prime was projected to the RVF and the target to the LVF. The pattern of priming effects suggested that low imagery words projected to the left hemisphere can activate concrete associates in the right hemisphere via direct callosal connections between the two. In the second experiment, the SOA was increased to 450 ms. This time, RVF-RVF priming was obtained along with RVF-LVF priming. The findings are interpreted within a modification of Bleasdale's (1987) framework, where abstract/low imagery words and concrete/high imagery words are represented in separate subsystems in the left hemisphere lexicon. Support was also found for the view that the left hemisphere is comprised of a complex network of abstract and concrete words, while the right hemisphere operates as a subsidiary word processor, subserving linguistic processing with a limited, special purpose lexicon comprised of associative connections between concrete, imageable words (e.g., Zaidel, 1983a; Bradshaw, 1980). Interhemispheric communication in the priming procedure appears to occur at the semantic level, via direct connections between the hemispheres.     

Size matters: Impact of item size and quantity on array choice by chimpanzees (Pan troglodytes).

The authors previously reported that chimpanzees (Pan troglodytes) showed a striking bias to select the larger of 2 candy arrays, despite a reversed reward contingency in which the animals received the smaller, nonselected array as a reward, except when Arabic numerals were used as stimuli. A perceptual or incentive-based interference occurred that was overcome by symbolic stimuli. The authors of the present study examined the impact of element size in choice arrays, using 1 to 5 large and small candies. Five test-sophisticated chimpanzees selected an array from the 2 presented during each trial. Their responses were not optimal, as animals generally selected arrays with larger total mass; thus, they received the smaller remaining array as a reward. When choice stimuli differed in size and quantity, element size was more heavily weighted, although choices reflected total candy mass. These results replicate previous findings showing chimpanzees' difficulties with quantity judgments under reverse reward contingencies and also show that individual item size exerts a more powerful interference effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)