Fast-same Effect Research Articles

Analyses of response time data in the same–different task.

The Same-Different task presents two stimuli in close succession and participants must indicate whether they are completely identical or if there are any attributes that differ. While the task is simple, its results have proven difficult to explain. Notably, response times are characterized by a fast-same effect whereby Same responses are faster than Different responses even though identical stimuli should be exhaustively processed to be accurate. Herein, we examine a little more than a quarter million response times (N = 255,744) obtained from 327 participants who participated in one of 14 variants of the task involving minor changes in the stimuli or their durations. We performed distribution fitting and analyzed estimated parameters stemming from the ex-Gaussian, lognormal, and Weibull distributions to infer the cognitive processing characteristics underlying this task. The results exclude serial processing of the stimuli and do not support dual-route processing. The fast-same effect appears only through a shift of the entire response time distributions, a feature impossible to detect solely with mean response time analyses. An attention-modulated process driven by entropy may be the most adequate model of the fast-same effect. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Is the fast-same phenomenon that fast? An investigation of identity priming in the same-different task.

The same-different task is a classic paradigm that requires participants to judge whether two successively presented stimuli are the same or different. While this task is simple, with results that have been replicated many times, response times (RTs) and accuracy for both same and different decisions remain difficult to model. The biggest obstacle in modeling the task lies within its effect referred to as the fast-same phenomenon whereby participants are much faster at responding "same" than "different," while most standard cognitive models predict the opposite. In this study, we investigated whether this effect is the result of identity priming activated by the first stimulus. We ran four variants of the same-different task in which identity priming is intended to be attenuated or cancelled in half of the trials. Results for all four variants show that a complete visual match between both stimuli is necessary to observe a fast-same effect and that hampering this relation attenuates same RTs while different RTs remained relatively unchanged. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Sequential sampling models of same-different data and how they explain the fast-same effect.

There have been many empirical endeavors to explain the fact that participants correctly identify same stimuli faster than different stimuli. Despite a large body of literature, a conclusive and unanimous consensus to explain this effect is lacking. The present study offers a new perspective on the same-different task using best-fitting parametric values of 2 sequential sampling models (linear ballistic accumulator [LBA] and drift-diffusion model [DDM]) to evaluate the contribution of 3 theoretical concepts (starting point, accumulation rate, and base time) to the fast-same effect. Eighteen participants were recruited to perform 3 tasks in which they compared letter strings (a) in a normal setting, the control task; (b) with lower contrast, the contrast task; and (c) based on nominal identity, the case task. Both the LBA and the DDM suggests that participants have faster base time in the same condition compared with the different condition. They also suggest that the number of letters and the number of differences influence the accumulation rate. These results suggest that the cognitive processes do not accumulate information as efficiently when the workload is increased. Finally, the limited predictive power of the best-fitting models suggests that better theoretical grounds are needed to identify fundamental cognitive concepts underlying same-different judgments. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

The cognitive architecture of processes responsible to assess similarity and clarity in a comparison task

When asked to compare two stimuli, participants are on average faster to respond Same than Different, an effect coined the fast-same. The dual-process theory argues that information about similarity is processed in priority over any other type of information, causing the fast-same effect. We tested this serial architecture of cognitive processes using a double factorial paradigm, suitable for a Systems Factorial Technology (SFT) analysis. Twenty participants completed a task in which they compared two letters, which were varied on two dimensions: the similarity and the clarity of the letters. Their task was to indicate if the second letter was the Same as the second letter (ranging from identical and clear to similar and slightly blurry) or if it was Different (if the stimuli were either dissimilar or very blurry). The SFT results show that most participants processed the information in serial, but in a mixed order. In other words, for some trials, participants processed similarity first, and for some other trials, they processed clarity first. This implies that participant indeed processed information in serial in the comparison task, but that it does not cause the fast-same effect.

The fast-same effect of an exclusive-OR task.

Participants are faster to decide that two stimuli are identical than to decide that they are different. Opposing theories suggested that this fast-same effect is either due (a) to a response bias toward similarity or (b) to facilitation caused by the repetition of the stimuli attributes. Although both theories predict the fast-same effect in a conventional same-different task, they make distinct predictions for tasks in which response bias is removed. In such tasks, the bias theory predicts that the fast-same would disappear whereas the facilitation theory predicts that the fast-same would remain. We tested those hypotheses using a same-different task in which participants had to indicate if all the attributes of the stimuli were matching or all were mismatching by pressing one response key, or if some attributes were matching and some were mismatching, by pressing another response key. We call this an exclusive-OR same-different task. Results show that participants were much faster in the "all-matching" condition compared with the "all-mismatching" condition, therefore supporting the facilitation theory. A fit of the linear ballistic accumulator model to the observed data provide additional supports that the fast-same effect is not caused by bias, but by a faster accumulation rate of evidence in the "all-matching" condition. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Cognitive architecture and capacity of the cognitive system responsible for Same - Different judgments.

Participants tend to match identical pairs of stimuli faster than different pairs. Despite many endeavours to explain this fast-same effect, there is still no theoretical consensus. A potential reason for the lack of consensus is that the cognitive architecture and capacity underlying such phenomenon is assumed and not formally tested. For example, the dual-process approach suggests that Same responses arise from a parallel treatment, whereas Different responses arise from a serial treatment. It also suggests that in both conditions, the capacity of the process is unaffected by workload (unlimited capacity). Alternative approaches argue that the fast-same effect can be explained by parallel or coactive architectures with channels working in either limited or super capacity. In this study, we formally assess the architecture (three possibilities: serial, parallel and coactive) and the capacity (three possibilities: unlimited, limited and super-capacity) of the cognitive system in a Same-Different task using Systems Factorial Technology (SFT). We recruited twenty participants to perform a double-factorial task lasting four sessions. Because of the lack of effectiveness of the blurring manipulation, we cannot draw a strong conclusion about the cognitive architecture. As for the capacity, the results show that it is mostly limited for the majority of participants. However, between 300 and 500 ms, participants tend to have a much stronger processing capacity in the Same condition compared to the Different condition. This short but strong burst of activity for identical stimuli might explain the fast-same effect.

Into the Mind’s Eye: Exploring the Fast-Same Effect in the Same-Different Task

Abstract The fast-same effect is the observation that “same” responses are much faster than “different” responses in the same-different task. Moreover, identical stimuli are responded to faster than stimuli that are the same in name only (e.g., B and b). We examine Bamber’s (1969) identity reporter model (a two-stage model predicting load effects), Proctor’s (1981) facilitation framework, and Krueger and Shapiro’s (1981) priming framework, proposed to account for these effects. Facilitation and priming are strong for identical and repeated stimuli, for phonological associates, and, in principle, for any form of association. We thus manipulated two types of associations: nominal (changing the letter case, preserving phonology) and learned (matching arbitrary symbols to letters) associations and used extended training to see variations in load effects. We found that overall performance benefits from phonological information and from training, although training did not change load effects. Additionally, the results from a transfer phase show capacity limitation for learned associates, which severely constrains facilitation. This finding is inconsistent with a priming framework. The results are discussed using an expanded version of Bamber’s identity reporter model, which is also compatible with Proctor’s facilitation framework.

Optimal inference of sameness and difference

Event Abstract Back to Event Optimal inference of sameness and difference Christopher Summerfield1*, Vincent De Gardelle2, Sophie Avery1 and Steven Buckingham1 1 University of Oxford, Department of Experimental Psychology, United Kingdom 2 Laboratoire Psychologie de la Perception (CNRS UMR 8158) Université Paris Descartes, France Cognitive scientists have long debated the mechanisms by which observers judge perceptual similarity and difference. One classic finding is that human observers are faster to judge two successively-occurring visual stimuli (reference and probe) to be the same than different, but slower to detect difference on only one dimension (e.g. colour) than two or more dimensions (e.g. colour and shape). This fast-same effect is counterintuitive, because visual similarity can only be verified by an exhaustive search over all relevant features or dimensions, predicting slower decision latencies for same than different responses. A further puzzle is that the effect is sensitive to whether the sameness is defined by a conjunctive or a disjunctive rule – the criterion effect. Researchers have struggled to provide a unified account of perceptual comparison that can accommodate these two phenomena. Here, we show that an ideal observer model in which stimulus features are processed simultaneously can account for both effects. The model predicts decision latencies for humans making both conjunctive and disjunctive perceptual comparison judgments about visual stimuli with both discrete and continuously-varying feature information. The model has a single free parameter, encoding an observer’s prior belief that recently occurring perceptual events will be repeated in the near future. These findings contribute to a growing literature arguing that the human visual system performs perceptual inference in a statistically optimal fashion. Keywords: Bayesian decision theory, ideal observer models, Visual psychophysics Conference: Neural Coding, Decision-Making & Integration in Time, Rauischholzhausen, Germany, 26 Apr - 29 Apr, 2012. Presentation Type: Poster Presentation Topic: Neural Coding, Decision-Making & Integration in Time Citation: Summerfield C, De Gardelle V, Avery S and Buckingham S (2012). Optimal inference of sameness and difference. Front. Neurosci. Conference Abstract: Neural Coding, Decision-Making & Integration in Time. doi: 10.3389/conf.fnins.2012.86.00017 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 12 Jan 2012; Published Online: 16 Jan 2012. * Correspondence: Dr. Christopher Summerfield, University of Oxford, Department of Experimental Psychology, Oxford, United Kingdom, christopher.summerfield@psy.ox.ac.uk Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract Supplemental Data The Authors in Frontiers Christopher Summerfield Vincent De Gardelle Sophie Avery Steven Buckingham Google Christopher Summerfield Vincent De Gardelle Sophie Avery Steven Buckingham Google Scholar Christopher Summerfield Vincent De Gardelle Sophie Avery Steven Buckingham PubMed Christopher Summerfield Vincent De Gardelle Sophie Avery Steven Buckingham Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Impact of Stimulus Integrity on Age Differences in Letter Matching

Young and older adults were tested in both a letter-identification and a letter-matching task in which the integrity of the letter stimuli was manipulated through contrast reduction and low-pass spatial frequency filtering. The use of the contrast and filtering manipulations was an attempt to increase encoding difficulty in an effort to examine whether stimulus integrity impacts more than just the initial encoding of the letter pairs in a letter-matching task, namely the comparison process as indexed by fast-same and false-different effects. Of interest in terms of aging is whether a decline in information-processing performance often reported in the aging literature is related to the known encoding deficits of older adults. In the letter-identification task, both contrast reduction and filtering slowed letter-identification speed for both groups, with the effect being larger for the older adults. In the letter-matching task, decreased processing efficiency produced by the contrast-reduction and low-pass-filtering manipulations led to an overall increase in reaction time and errors, but it did not interact with the magnitude of the fast-same effect or false-different effects for either subject group. These findings suggest that the stimulus integrity manipulations only impact the encoding of the letter pairs in the matching task and not the comparison process. The results of the present study support a dual-process model of the matching task consisting of separate encoding and comparison processes. The finding of a larger fast-same effect for older adults suggests that the age effect is occurring at the comparison stage, but it is not impacted by the stimulus integrity manipulations. The findings are described within a generalized slowing framework.

Nominal and physical decision criteria in same-different judgments.

We propose a model in which the physical and nominal dimensions of letter pairs are compared independently of whether subjects use physical (shape task) or nominal (name task) identity as the decision criterion. We attempt to explain the fast-same effect, the preponderance of false-different errors, and the nominal-physical disparity as results of congruent and incongruent outputs of physical and nominal comparison devices that function in both tasks. Subjects performed both tasks with and without response deadlines. The stimuli were presented foveally or unilaterally to one or the other hemisphere. With foveal presentations, the nominal-physical disparity disappeared when congruent and incongruent cells were compared, the fast-same effect occurred only in the shape task, and there was a preponderance of false-different errors only in the name task. Response times and error patterns from centrally presented trials conformed to the predictions of the model. Performance patterns from the lateralized trials conformed only partially. The implications of the data are discussed in the context of several theoretical models of same/different judgments.

Comparison requirements and attention in identical-nonidentical stimulus discriminations.

Perceptual matching data show several puzzling effects. Particularly problematic are the disparities between the processing rates for same and different stimuli--the fast-same effect--and between the processing rates for two same-different judgment tasks that are related as mirror images--the task effect. Current models have difficulty accounting simultaneously for both effects. Central to these models is a stimulus comparison process that derives relative judgments of sameness and difference from tests of the congruence of stimulus representations. A contrasting view holds that same-different judgments can be modeled as absolute, rather than relative, judgments. This latter view is shown to be supported by experimental data. Reaction times for judgments of identical letter strings increase with string length at the same rate whether judgments are based on all the information in the strings or just the information in a single pair of component letters. The data show that stimulus comparisons of the sort described by previous models are not involved in these judgments. An attentional model accounts for the data and for the fast-same and task effects as well.

Same-different judgments of foveal and parafoveal letter pairs by older adults.

Older adults (mean age: 67.9 years) judged whether two adjacent letters, presented either 0.5° (foveal or near condition) or 2.0° (parafoveal or far condition) from fixation, were identical or different. The method was identical to that used previously with young adults (Krueger, 1985). The older (and presumably noisier) adults were slower and less accurate in general, and, consistent with the internal-noise principle, they surpassed the young adults by showing a large, 48-msec fast-same effect and a large, 6% preponderance of false-different responses (i.e., errors onsame trials) over false-same ones. With parafoveal presentation, the fast-same effect, but not the preponderance of false-different responses, increased greatly for the older adults, apparently due to an inability to perceive differing features (Eriksen, O’Hara, & Eriksen s, 1982, missing-feature principle), owing to their more constricted visual fields (Cerella, 1985a). The fast-same effect was larger in the left visual field (right hemisphere) for young adults, but larger in the right visual field (left hemisphere) for older adults.

Effect of backward masking on same-different judgments.

Subjects judged whether two adjacent letters were identical or different. The letter pair was presented briefly, followed by a superimposed patterned mask (Experiments 1 and 2) that was intended to terminate processing early. Previous work using variation in speed stress (Krueger & Chignell, 1985) had indicated that false-same errors (i.e., ondifferent pairs) predominate in early processing (missing-feature principle), whereas false-different errors predominate in late processing (internal-noise principle). The mask did not terminate processing early, however, because it produced a large preponderance of false-different errors (9%). Also, both response time (RT) and the standard deviation of RT increased as the stimulus-onset asynchrony between letter pair and mask decreased. The results indicate that backward masking works by integration (C. W. Eriksen, e.g., 1966) rather than by interruption (Sperling, 1963), and is a graded rather than all-or-none phenomenon. Consistent with the internal-noise principle, a lateral mask (Experiment 2) produced a large preponderance of false-different errors (7%) and a large fast-same effect (50 msec).

Positive effect of heterogeneity of difference on thesame-different disparity in letter matching

Subjects judged whether two adjacent letters were identical or different.Different pairs were similar, for example HM, DO, VY, or dissimilar, for example DY, HV,MO. According to the noisy-operator theory, increasing the heterogeneity of difference (external noise) by intermixing similar and dissimilardifferent pairs ought to produce faster but less accurate responses ondifferent trials. As predicted, the tendency to make more false-different responses (i.e., errors on same pairs) decreased when the similar and dissimilardifferent pairs were intermixed rather than presented in separate blocks. The fast-same effect did not change, however, seemingly due to criterion misadjustment. Proctor and Rao apparently found no effect of heterogeneity of difference on RT and errors because they used a less sensitive procedure (between-subjects design; different set of letters for more and less heterogeneous conditions). Consistent with the internal-noise principle, but not with the response-competition model of Eriksen, O’Hara, and Eriksen, the enhanced fast-same effect on blocks containing only similar (vs. dissimilar)different pairs was accompanied by an increased preponderance of false-different errors.

Effect of intermixed foveal and parafoveal presentation on same-different judgments: evidence for a criterion-inertia model.

Subjects judged whether two adjacent letters, which were presented either 0.5° (foveal or near condition) or 2.0° (parafoveal or far condition) from fixation, were identical or different. The preponderance of false-different responses (i.e., errors onsame trials) over false-same ones increased, whereas the fast-same effect was eliminated, on the far pairs, but only when they were intermixed with near pairs rather than presented in separate (pure) blocks of trials. Intermixing the near and far pairs produced the opposite trends on near trials (i.e., smaller preponderance of false-different errors, larger fast-same effect). Carr et al., who presented trigrams, found a similar criterion misadjustment, which likewise depended on intermixed presentation. They proposed that their easy (familiar or orthographically regular) pairs produced a bias or criterion shift towards “same.” No obvious biasing features were present in the near or far pairs, however, so the criterion misadjustment found here was attributed to the combined effect of internal noise and criterion inertia, not to criterion shifting. Increasing the level of internal noise on far trials produced more spurious perceived mismatches, but on mixed blocks of near and far trials, subjects relied on a common, compromise criterion for responding versus rechecking (recheck moderate perceived differences), instead of the separate, more appropriate criteria for near trials (recheck small differences) and far trials (recheck large differences) used on pure blocks.

Effect of lateral masking and letter reversal on same-different judgments

Subjects judged whether two adjacent letters were identical or different under difficult conditions (brief, parafoveal, laterally masked letter pairs). Consistent with the noisy-operator theory, the increase in internal noise produced more spurious mismatches than matches and thus prompted greater rechecking of different pairs, because a large, nearly 70-msec speed advantage for same pairs was found, along with many false-different responses. Rechecking of spurious mismatches faltered (the fast-same effect remained the same or decreased, whereas false-different errors abounded), when particular letter pairs were presented mirror-reversed (Experiment 1) or had an outer (more peripheral) lateral mask (Experiment 2). Contrary to Wolford’s feature-perturbation model, backward masking greatly exceeded forward masking, especially with an outer mask.

"Same"–"different" judgments: A review of current controversies in perceptual comparisons.

A commonly used experimental paradigm for studying human information processing asks subjects to classify two stimuli with respect to their similarities and differences. The same-different judgment task, in particular, has useful applications in a variety of studies. The interpretation of same-diiferent reaction time data, however, is complicated by the existence of two seemingly anomalous effects, the fast-same effect and the criterion effect. This article examines explanations of these effects and brings evidence from the literature to bear on them. Current models of same-different judgments, two of which are widely accepted, can be rejected on the evidence of data reviewed here. Among the disconfirming data are several results that offer suggestions both for improving current models and for questioning some of their fundamental presuppositions. Sameness and difference are fundamental cognitive relations that enter, at least implicitly, into most forms of adaptive perceptual behavior. Accordingly, experimental tasks requiring subjects to discriminate sameness and difference among stimulus patterns have become standard investigative tools in a number of areas of psychological research, areas ranging from basic psychophysics and stimulus coding to concept learning and language processing. The time taken to make a same-different judgment has been a particularly useful measurement because reaction times (RTs) can often be used to isolate mental processes underlying phenomena of interest (Sternberg, 1969).' Aside from its methodological use as an adaptable and sensitive probe of extrinsic phenomena, the same-different judgment task has itself been the subject of considerable study over the past 15 years. The resulting body of empirical evidence has produced substantial agreement on the functional significance of information-processing operations that subserve perceptual comparisons. However, a debate, contentious at times and still unresolved, has surrounded same-different judgment

Effect of interstimulus interval and heterogeneity of difference on same-different judgments of visual patterns

Subjects judged whether two single lines or matrices of slashes, separated by an interstimulus interval (ISI) ranging from .25 to 3 sec, were identical or different. A long ISI, by increasing internal noise, was expected to produce more spurious mismatches than matches and thus prompt more rechecking of different pairs. However, with a long ISI the fast-same effect was eliminated, whereas false-different errors abounded. The data were fitted by a model that permitted inertia in adjusting the criterion for rechecking. However, intermixing (vs. blocking) trials on ISI in Experiment 2, which ought to have retarded criterion adjustment, did not further reduce the rechecking of spurious mismatches. Consistent with the noisy-operator theory, increasing the heterogeneity of difference (external noise) in Experiments 3 and 4 increased false-same errors.

An examination of response bias in multiletter matching.

When pairs of letters or letter strings are classified as “same” or “different,” correct “same” responses often are faster than correct “different” responses. Researchers have disagreed about the importance of this fast-same phenomenon, with some regarding it as indicative of a critical, basic characteristic of pattern recognition processes and others regarding it as a byproduct of response criteria. The present experiments examined this issue for multiletter matching. Two procedures were used, one in which response bias was manipulated by varying the proportion ofsame pairs and another in which string length effects were examined for a situation designed to minimize premature termination of the comparison process. The procedures provided converging results, indicating that, although the fast-same effect customarily obtained with simultaneous presentation of the pair of letter strings is likely due to response bias, the effect obtained with successive presentation is not. With successive presentation,same strings have a processing advantage overdifferent strings that apparently is due, at least in part, to facilitation in the encoding of the second string.

Further evidence for priming in perceptual matching: temporal, not spatial, separation enhances the fast-same effect.

Sequential (vs. simultaneous) presentation of two letters in a physical-identity matching task enhanced the fast-same effect, but did not reduce the preponderance of false-“different” errors or the effect of visual similarity. Thus, the sequential enhancement of the fast-same effect involves an increased efficiency in encoding (d’) owing to letter repetition, as Proctor claimed, rather than a criterion shift (β), and it involves the visual code rather than the name code. The increased efficiency in detecting sameness with sequential presentation might result from spatial separation (e.g., reduced lateral interference and self-termination), though, rather than temporal separation (e.g., priming), However, such spatial factors as letter size and interletter spacing had no consistent effect on the speed advantage forsame pairs, and it was concluded that temporal, not spatial, separation enhances the fast-same effect on sequential trials, Consistent with the response-competition model (Eriksen, O’Hara, & Eriksen), responses were slower and more errorful to similar than to dissimilardifferent pairs, and were equally fast to dissimilar andsame pairs on simultaneous trials.