Holistic and analytic processes in the comparison of letters

College students made “same-different” judgments about successively presented pairs of letters whose degree of difference, in terms of the number of line segments out of register, was systematically varied. Reaction time was found to decrease with increases in the degree of difference in “different” responses, as well as to depend on the number of line segments present in the second (probe) letter. “Same” responses were much faster than different responses and were unaffected by the number of segments in the probe letter. This pattern of results suggests analytic (component-by-component) processing of “different” letters and holistic processing of “same” letters. The results have important implications for studies of multi-letter comparisons, in which it is commonly assumed that letter comparisons are holistic in nature.     

Visual search through color displays: Effects of target-background similarity and background uniformity

The effects of target-background similarity and background uniformity were investigated in two experiments in which subjects reported the presence or absence of an achromatic target item in arrays containing irrelevant chromatic items. In Experiment 1, both “present” and “absent” decision times were an increasing function of the similarity of a predefined target item to the background, and were shortened when the interitem similarity of the background set was increased. In Experiment 2, the effects of target-background similarity on the “present” decision were replicated when subjects were not informed on each trial as to which member of the target set might appear in the array, and the “absent” decision was faster when each row of the array comprised background items of a single color than when these items were allocated randomly to array locations. The results are interpreted in terms of the role of pre-attentive grouping operations.     

Search for a matching or mismatching letter pair

The perceptual matching task was modified in order to increase the error rate and thus to reveal more clearly whether internal noise more often changes an objective match into a perceived mismatch than vice versa (noisy-operator theory). In Experiment 1, subjects searched for a “same” pair in a list of “different” pairs or for a “different” pair in a list of “same” pairs. As predicted, the target pair was overlooked or missed more often on “different” lists. False alarms, though, were not higher on “same” lists, owing apparently to rechecking, which also produced slower search through “different” lists. To disable the rechecking mechanism, rapid serial visual presentation (RSVP) was used in Experiments 2 and 3. As predicted, misses exceeded false alarms on “different” lists, whereas the reverse held on “same” lists, both at the physical level (Experiment 2) and at the name level (Experiment 3). Letter set size and repetition were varied in Experiments 1 and 2, and the results indicate that when letter pairs are presented in close temporal and spatial proximity, subjects are influenced by extraneous interpair comparisons in addition to relevant intrapair comparisons in deciding whether or not a target pair is present.     

Dependent spatial channels in visual processing

The present experiments were designed to test whether or not processing in visual information channels defined by spatial position is independent in the visual search paradigm. In Experiment 1 subjects were asked to judge whether or not a red square was present in a display of two colored geometric figures. Their mean reaction time (RT) to respond no to a “divided target” display in which one figure was red and the other was a square was about 100 msec longer than to control displays containing either two red circles or two green squares. This result is inconsistent with a spatially serial independent-channel model and with many spatially parallel independent-channel models. The relatively slow responding to divided target displays was replicated in Experiments 2 and 3, when subjects judged whether or not an “A” was present in a display of two alphanumeric characters, and a divided target display was one which contained two features of “A.” Experiments 4 and 5 demonstrated that the dependence observed in the first three experiments was probably the result of two mechanisms: crosstalk integration, whereby the target features are integrated across the two spatial channels, and repetition facilitation, whereby processing is facilitated (in some cases) when the two figures in the display are physically identical. Experiment 6 suggested that subjects organized the display in terms of spatial channels even when the task allowed subjects to ignore spatial location.     

Parallel perceptual processing and decisional strategies: A reinterpretation of the Shaw and LaBerge effect

A reinterpretation is offered for an effect found by Shaw and LaBerge (1971) in a tachistoscopic detection paradigm. Their Ss were instructed to “scan” the letters of a multiletter stimulus array in a particular sequence. The Ss were more accurate in identifying a target letter if it occurred earlier rather than later in the instructed sequence. Although Shaw and LaBerge interpreted this result as supporting a limited-capacity attentional mechanism, the result is also consistent with a nonattentional parallel processing conception: the payoff incentives used to encourage the correct “scanning sequence” could alter Ss’ postperceptual decisional strategy so as to produce the results obtained. Given the compatibility of a parallel processing conception with the results of Shaw and LaBerge and the results of other detection experiments, the need for postulating a spatial capacity limit or attentional mechanism is questioned.     

Evidence for processing of constituent singleand multiletter codes: Support for multilevel coding in word perception

This investigation assessed whether constituent codes are activated during word processing. In two experiments, a priming procedure was used to test whether printed word primes facilitate skilled readers’ identification of subsequently presented letter and letter bigram targets appearing in the primes (present condition), relative to the same targets not appearing in the primes (absent condition). Experiment 1 demonstrated the priming of single-letter targets and indicated that priming effects are facilitative and not inhibitory. In Experiment 2, high- and low-frequency bigram targets appearing in word primes were shown to have a processing advantage over bigram targets not appearing in word primes. Single-letter constituents in low-frequency bigrams also benefited from priming; however, single letters in high-frequency bigrams showed no such benefit. The results in general suggest that both single- and multiletter constituents are available during word processing, and hence support multicomponent models of word perception.     

The Impact of “Display‐Set” Options on Decision‐Making

The way a choice set is constructed can have a significant influence on how individuals perceive and evaluate their options, and make decisions between them. Here, I examine whether a “display set” of visible but unavailable options can exert these same types of influences on whether or not to choose a single (target) item. Across a series of experiments, purchase intent is increased when the display set and target are drawn from the same category, but decreased when the display and target items are mismatched. This effect is shown to depend on perceived similarity, such that increasing display‐target similarity increases purchase intent towards the target. Furthermore, contrary to the predictions made by previous neural and behavioral research on choice sets, the relative value and/or number of display‐only items have no significant impact on these decisions. These findings reveal a novel choice behavior in commonly encountered settings such as online marketplaces. Copyright © 2016 John Wiley & Sons, Ltd.     

Spatial processing and perceptual sequence learning in SRT tasks

We investigated the influence of processing relevant spatial information on learning a probabilistic sequence of irrelevant locations. Using the SRT design of Remillard (2003), we found that spatial perceptual learning occurs with paired but not with single targets. The pairs of targets consisted of the same stimuli, but in a different order, so that responses could have been based on the left-right location of an element, relative to the other element of the pair. The prerequisite of spatial pairs of targets suggests that spatial processing of relevant information plays a crucial role in perceptual location learning. In addition, spatial perceptual learning only took place when the target pair was presented together with other stimuli, but was absent when the target pair was presented in a blank field. Since in the latter case attention is automatically captured, this suggests that sequence learning requires endogenous attention.     

Stimulus-specific processing consequences of pattern goodness

Two issues concerning the effects of visual pattern goodness on information processing time were investigated: the role of memory vs. encoding and the role of individual stimulus goodness vs. stimulus similarity. A sequential “same-different” task was used to provide differentiation of target item or memory effects from display item or encoding effects. Experiment 1 used four alternative stimuli in each block of trials. The results showed that good patterns were processed faster than poor patterns for both “same” and “different” responses. Furthermore, the goodness of the target item had a greater effect on reaction time than did the goodness of the display item, indicating that memory is more important than encoding in producing faster processing of good stimuli. Effects of interstimulus similarity on processing time were minimal, although isolation of good stimuli in a similarity space could explain many of the results. Experiment 2 replicated the results of Experiment 1, despite the fact that differences in similarity space had been minimized by using only two alternative stimuli in each block. In addition, the speed of processing a “same” pair was essentially independent of the particular alternative stimulus in a block. These results suggest that in this task, there is a processing advantage for good stimuli that is stimulus specific, with the effect operating primarily in memory.     

A conceptual category effect in visual search: O as letter or as digit

Evidence is presented for a processing mechanism in visual recognition that depends upon how the stimulus array is conceptually categorized rather than upon its physical characteristics. Ss had to detect a letter or digit target in a field of letters or digits. When target and field were of the same category, reaction time increased with display size. When target and field category differed, reaction times were independent of display size. This category effect held even for the ambiguous target character 0 that yielded reaction time functions appropriate to how it was specified prior to presentation: as “zero” or as “ō.”     

Some characteristics of selective attention in visual perception determined by vocal reaction time

Previous research had found that the accuracy with which an S could report an indicated letter or target in a briefly exposed multiletter display decreased as the number of irrelevant letters increased, and accuracy increased if the position of the target letter was indicated 150 msec before the display was presented. Iii the present experiment, these variables were reinvestigated using vocal reaction time as the dependent variable. An interpretation of the accuracy measures in terms of differential processing times was supported. The results of the two experiments were discussed in terms of a model of attentional selectivity.     

The comparison and fitting of given classification schemes

A permutation procedure is described for statistically comparing a given classification scheme, characterized as a hierarchically organized collection of subsets, to either a proximity matrix or a second classification scheme defined on the same basic set of objects. To prevent a bias that may result when an optimization method is used to construct the classification structures being considered, it is assumed that the desired comparisons involve classifications and/or proximities that have been derived from separate sources. In addition to an extensive number of examples used to clarify the major points in the presentation of the inference strategy, several heuristic optimization techniques are also introduced and illustrated. These latter procedures attempt to “fit” the form of a target classification structure by relabeling the rows and simultaneously the columns of a given proximity matrix to maximize the correspondence between the fixed target and the relabeled proximity matrix.     

Stroop interference with response,comparison, and encoding stages in a sentence-picture comparison task

The paper discusses a Stroop variant of the word-picture comparison task analyzed by Chase and Clark (1971). The locatives above or below were printed at the center of a reference square, and Ss reported “Yes” if there was a word or an array of Xs in the location specified and “No” if there was not. Under the control (Xs) conditions, above displays were classified faster than below displays and true displays faster than false displays. These effects were unaltered when the words “yes” or “no” or “right” or “wrong” were printed in place of the Xs, although there was a small overall increase in response latency under these Stroop conditions that was independent of agreement or disagreement between the distractor and the response to be made. When the locatives up and down were printed on the display, a substantial Stroop effect was observed, and the above-below and true-false effects were eliminated. These results are discussed in relation to theories about the nature of Stroop interference and processes involved in sentence-picture comparisons.     

Category effects in visual search: A failure to replicate the “oh-zero” phenomenon

In the experiment of Jonides and Gleitman (1972), subjects searched displays of digits or letters for single, specified digit or letter targets. The slope of the function relating reaction time to display size was positive (mean=25 msec/item) if target and nontargets belonged to the same alphanumeric category (within-category search), but zero if target and nontargets belonged to different categories (between-category search). This held even for the target O, whose categorical relationship to nontargets was determined entirely by the name it was given. In the present paper, two attempted replications are reported, one as close as practically possible. For the unambiguous targets A, Z, 2, and 4, slopes were greater in within-category search than in between-category search, but positive and very variable in both cases. For the ambiguous target O, slopes were identical in within-category and between-category search, and again positive. The results suggest that with single, specified targets, differences between within-category and between-category search may be due entirely to variation in the average physical resemblance between target and nontargets. In line with previous findings, they show that one cannot characterize within-category search as generally “serial” and between-category search as generally “parallel.”     

Hybrid search in the temporal domain: Evidence for rapid,serial logarithmic search through memory

In hybrid search, observers memorize a number of possible targets and then search for any of these in visual arrays of items. Wolfe (2012) has previously shown that the response times in hybrid search increase with the log of the memory set size. What enables this logarithmic search of memory? One possibility is a series of steps in which subsets of the memory set are compared to all items in the visual set simultaneously. In the present experiments, we presented single visual items sequentially in a rapid serial visual presentation (RSVP) display, eliminating the possibility of simultaneous testing of all items. We used a staircasing procedure to estimate the time necessary to effectively detect the target in the RSVP stream. Processing time increased in a log–linear fashion with the number of potential targets. This finding eliminates the class of models that require simultaneous comparison of some memory items to all (or many) items in the visual display. Experiment 3 showed that, similar to visual search, memory search efficiency in this paradigm is influenced by the similarity between the target set and the distractors. These results indicate that observers perform separate memory searches on each eligible item in the visual display. Moreover, it appears that memory search for one item can proceed while other items are being categorized as “eligible” or “not eligible.”     

“None of the above” as a correct and incorrect alternative on a multiple-choice test: Implications for the testing effect

Both positive and negative testing effects have been demonstrated with a variety of materials and paradigms (Roediger & Karpicke, 2006b). The present series of experiments replicate and extend the research of Roediger and Marsh (2005) with the addition of a “none-of-the-above” response option. Participants (n=32 in both experiments) read a set of passages, took an initial multiple-choice test, completed a filler task, and then completed a final cued-recall test (Experiment 1) or multiple-choice test (Experiment 2). Questions were manipulated on the initial multiple-choice test by adding a “none-of-the-above” response alternative (choice “E”) that was incorrect (“E” Incorrect) or correct (“E” Correct). The results from both experiments demonstrated that the positive testing effect was negated when the “none-of-the-above” alternative was the correct response on the initial multiple-choice test, but was still present when the “none-of-the-above” alternative was an incorrect response.     

Episodic storage and retrieval in visuo-spatial tasks: evidence of indirect retrieval

Episodic storage contends that the relevant target and irrelevant distractor features of a display are processed and then stored together within the boundaries of an episode, and are linked in this way. Accordingly, the selective and “direct” retrieval of either a stored target or distractor should result in the “indirect” and unintended retrieval of the other stimulus. In the present investigation, interest focused upon spatial tasks and the “indirect” retrieval of prime distractor processing. The novel findings obtained supported the existence of the “indirect” retrieval of prime distractor processing in visuo-spatial tasks and, to a lesser extent, of the stored prime target event, consistent with identity tasks (i.e. bi-directional episodically-based retrieval). Clearly, more is retrieved than is presented (Hintzman, D. L. (1984). MINERVA 2: A simulation model of human memory. Behavior Research Methods, Instruments, & Computers, 16, 96–101. doi:10.3758/BF03202365), as an episodic storage structure would predict.     

Multiletter Word Units in Visual Recognition: Direct Activation by Supraletter Visual Features

Multiletter priming effects have been interpreted as evidence for the representation of separable multiletter units in the visual word recognition system (Whiteley & Walker, 1994). The reported experiments examine whether the activation of such units is pre- or post-lexical. Experiments 2 and 3 employed priming in an alphabetic decision task in which subjects made a discrimination response to test stimuli which could be classed as either targets or foils. Targets were single letters, or consonant bigrams, present or absent in an immediately preceding word, or (Experiment 3 and 4) they were whole words semantically associated or not to a preceding word. Foils were single non-alphanumeric characters, a character plus a letter, or a word with one letter replaced by a character. Experiment 1 was a preliminary to determine the parameters of a sequential presentation manipulation. Experiment 2 compared conditions of simultaneous and sequential presentation where letters of prime words were presented together, or one at a time in rapid succession. With simultaneous presentation, responses to bigram targets were facilitated when these appeared in the prime word, while responses to individual constituent letters of those bigrams were not facilitated. Additionally, responses to primed bigram targets were faster than responses to primed single letter targets. The sequential presentation of prime words resulted in a qualitative change in the response pattern indicative of the disruption of multiletter unit activation. That change was replicated in Experiment 3 where semantic priming confirmed that the prime words were being processed to a level of meaning. The observations challenge a post-lexical account of the multiletter priming effects. Finally, Experiment 4 addressed the question of whether bigram priming reflects the intentional use of prime information to predict following targets. Strategic interpretations are undermined and it is argued that multiletter units are activated automatically as part of normal visual word recognition.     

Collaborative inhibition persists following social processing

In this experiment, participants read target words that were presented in the context of a social sentence “Willow towered over Meadow” or a nonsocial sentence “The willow towered over the meadow.” Subsequently, they received a surprise cued recall test for the target nouns/names and completed the test either alone or in a group of two. Despite the fact that the stimulus materials were held constant across conditions, participants showed a social processing advantage in memory—that is, they remembered the social (name) versions of the target words significantly better than the nonsocial (noun) versions. Further, the social benefit was not strong enough to neutralise the inhibitory effects of collaboration as collaborative groups (two people working together) recalled significantly fewer words than did nominal groups (combined, nonredundant, output of two individuals working separately). The present study also demonstrated robust collaborative inhibition with cued recall, a task previously assumed to eliminate such inhibition.     

Attentional repulsion effect despite a colour-based control set

A salient distractor can have a twofold effect on concurrent visual processes; it can both reduce the processing efficiency of the relevant target (e.g., increasing response time) and distort the spatial representation of the display (e.g., misperception of a target location). Previous work has shown that knowledge of the key feature of visual targets can eliminate the effect of salient distractors on processing efficiency. For instance, knowing that the target of interest is red (i.e., having an attentional control set for red) can eliminate the cost of green distractors on the speed of response to the target. The present study shows that the second mark of irrelevant salient distractors, i.e., distortions in spatial representation, is resistant to such top-down control. Using the attentional repulsion effect, we examined the influence of salient distractors on target localization. Observers had a colour-based control set and the distractors either matched or mismatched with the control set. In the first two experiments, we found systematic mislocalization of targets away from the peripheral distractors (i.e., an attentional repulsion effect). Critically, the effect was caused by distractors that both matched and mismatched the control set. A third experiment, using the same stimuli, found that processing efficiency was perfectly resistant to distractors that did not match the control set, consistent with previous work. Together, the present findings suggest that although top-down control can eliminate the cost of a salient distractor on processing efficiency, it does so without eliminating the distractor's influence on the spatial representation of the display.