Same-different Task Research Articles

Breaking multiple forms of view invariance

Object recognition based solely on spatial characteristics can only hope to provide limited tolerance to variations in appearance. In everyday life natural objects may alter their appearance quite dramatically as a result of changes in viewpoint, distance, orientation and illumination etc. To combat this shortcoming, it has been proposed that the visual system may learn to associate disparate views of objects on the basis of their temporal rather than spatial characteristics. The reasoning behind this suggestion is that views which regularly occur in close temporal proximity are likely to be views of a transforming object. Previous experimental work has confirmed that invariance learning across depth rotations and changes in fixation is affected by the temporal characteristics of stimulus views. In this paper I describe how two other transformation types: fronto-parallel rotation and illumination are also affected by temporal association. Observers viewed sequences of faces undergoing rotation in the image plane or a change in illumination generated by running a light source around the face's vertical mid-line. Unbeknown to the observers, some of the faces changed their identity as the transformation took place. Two experiments were then run to ascertain whether the manipulation had lead to the two endpoint views becoming regarded as valid views of a single face. In the first test participants were required to discriminate true versus mixed identity transformation sequences. In the second, discrimination performance was measured via a two-view, same-different task. Both experiments revealed compelling evidence for the predicted effect of manipulating the temporal characteristics of the face views. The results establish the temporal association mechanism as a general purpose heuristic for coping with a diverse range of invariance learning. They also serve to undermine models of human object recognition which propose the existence of any general purpose view transformation or shape reconstruction system.

Evidence for a pre-match 'mental translation' on a form-matching task

PURPOSE AND APPROACH. The aim was to explore whether there is a pre-match ‘mental translation’, analogous to ‘mental rotation’ and ‘mental scaling’, on a Same-Different simultaneous form-matching task. The basic approach was to vary the environmental separation of the forms, while holding constant everything else that might affect reaction time. METHOD. On a Same-Different task, subjects were presented with two forms flanking a fixation triangle, all shown in the same depth-plane. Distance (simulated) to the forms was varied. Viewing was in stereo. Total visual angle spanned by the centers of the bases of the two forms, in each eye, was held (essentially, effectively) constant as distance to the forms (and so environmental separation) varied. The forms and fixation triangle were shown resting on a bar that spanned a textured enclosure; the top of the bar crossed at eye-level and the bar was anchored to the floor of the enclosure by struts. The top half of the back of the enclosure was open, with the forms silhouetted against a blank field. So: form edge-information and gaze angle were both held constant as distance to the forms (and so environmental separation) varied, and there was no backing surface. In Experiment I, the forms were shown for 400msc; in Experiment II, the forms were shown for 300msc, and the Same-Different discrimination was made slightly easier. RESULTS AND CONCLUSION. In Experiment I, reaction time rose with increases in environmental separation (n = 34, p < .01, R-squared = .9295; Same trials). Results for the 16 subjects run so far in Experiment II also indicate a rise in reaction time with increases in environmental separation (p = .029; Same trials). In both cases, the slopes suggest a fast process. In sum, the results are evidence that comparisons of the forms were preceded by a fast ‘mental translation’, analogous to ‘mental rotation’ and ‘mental scaling’, with the locations of the forms coded in a non-retinal frame of reference.

Similar cerebral networks in language, music and song perception

Two fMRI experiments were conducted using song to investigate the domain specificity of linguistic and musical processing. In Experiment 1, participants listened to pairs of spoken words, “vocalise” (i.e., singing without words), and sung words while performing a same-different task. Results revealed bilateral involvement of middle and superior temporal gyri and inferior and middle frontal gyri while listening to spoken words, sung words and vocalise, although to different degrees. In Experiment 2, participants listened to pairs of sung words that were similar or different in terms of the linguistic and musical dimensions (2×2 factorial event-related design) while performing a same-different task. Results showed widespread interactions between the linguistic and musical dimensions of sung words mainly within the network of brain areas identified in Experiment 1. Consequently, the activity in these brain regions cannot be considered as specific to either language or music processing. Taken together, results of both experiments argue against domain specificity and provide additional evidence for a common cerebral network involved in both lexical/phonological and melodic processing.

Method matters: Systematic effects of testing procedure on visual working memory sensitivity.

Visual working memory (WM) is traditionally considered a robust form of visual representation that survives changes in object motion, observer's position, and other visual transients. This article presents data that are inconsistent with the traditional view. We show that memory sensitivity is dramatically influenced by small variations in the testing procedure, supporting the idea that representations in visual WM are susceptible to interference from testing. In the study, participants were shown an array of colors to remember. After a short retention interval, memory for one of the items was tested with either a same-different task or a 2-alternative-forced-choice (2AFC) task. Memory sensitivity was much lower in the 2AFC task than in the same-different task. This difference was found regardless of encoding similarity or of whether visual WM required a fine or coarse memory resolution. The 2AFC disadvantage was reduced when participants were informed shortly before testing which item would be probed. The 2AFC disadvantage diminished in perceptual tasks and was not found in tasks probing visual long-term memory. These results support memory models that acknowledge the labile nature of visual WM and have implications for the format of visual WM and its assessment.

Priming by numb3r5 does not involve top-down feedback.

Using the same-different task, Perea, Duñabeitia, Pollatsek, and Carreiras (2009) showed that digits resembling letters ("leet digits"; e.g., 1 = I, 4 = A) primed pseudoword strings (e.g., V35Z3D-VESZED), but letters resembling digits ("leet letters") did not prime digit strings (e.g., 9ES7E2-935732), and suggested that this is due to top-down feedback available for letter, but not digit, strings. Here we show that (a) single letters show as much leet priming as 3-letter words (Experiment 1); (b) leet priming is equally robust for digit strings and pseudowords when the string is 4 items long but not when 6 items long (Experiment 2); and (c) with 6-item strings, orthotactically illegal letter strings (e.g., OIAUEQ) behave just like digit strings (Experiment 3). These results indicate that the asymmetry in leet priming is not due to top-down feedback available selectively for letter strings. We offer an alternative explanation based on the Bayesian reader account of masked priming proposed by Norris and Kinoshita (2008), and the role played by the orthotactic knowledge used to extend the functional capacity of visual working memory involved in performing the same-different task.

A model of vPFC neurons performing a same-different task: an alternative model of working memory

Event Abstract Back to Event A model of vPFC neurons performing a same-different task: an alternative model of working memory Jung Lee1* and Yale Cohen2 1 University of Pennsylvania School of Medicine, Department of Otorhinolaryngology, United States 2 University of Pennsylvania School of Medicine, United States Working memory is a fundamental component of cognition. Classically, the neural correlates of working memory is thought to involve persistent or sustained activity that is mediated by strongly recurrently connected groups of neurons. Recently, we recorded from neurons in the ventrolateral prefrontal cortex (vPFC), while monkeys reported whether sequentially presented auditory stimuli were the same or different and found that vPFC neural activity is predictive of the monkeys’ decisions. Since this task required the monkeys to compare sequential stimuli, vPFC neurons should have access to a memory trace of the previous stimulus. However, we could not identify such a trace (i.e., persistent activity) in the firing rates of vPFC neurons between stimulus presentation nor could we identify a memory trace in neurons of the superior temporal gyrus (STG), a cortical region which projects to the vPFC. Instead, we found that memory traces appeared to be stored in the local-field potentials (LFPs) of the vPFC. Here, we present a model of the vPFC that incorporates both LFPs (membrane potentials) and spiking activity. This circuit has three layers: an input, middle, and output layer; the output layer is the read-out layer. The middle layer contains two groups of neurons each of which is tuned to a different stimulus and a third group which is "untuned". The two tuned neural groups are also bilaterally connected with a group of inhibitory inter-neurons. All of the synaptic weights are static except for the synapses between the tuned neurons and the inter-neurons and the untuned neurons and the output (read-out neurons). These dynamic synapses are updated by a simple rule that captures only qualitative properties of realistic dynamic synapses as proposed by Tsodyks et al.: action potentials potentiate the synapse; otherwise, it is depressed. As a consequence of this architecture, a negative feedback loop is established between the tuned neurons and the inter-neurons. When the same stimulus is presented sequentially, this feedback loop suppresses activity in those neurons that are tuned to this stimulus, but it does not affect the activity levels in the other tuned group. Consequently, when a different stimulus is presented, the responses of these neurons are robust. As a result, this circuit can discriminate between sequential stimuli. Furthermore, due to the connectivity of the untuned neural group, the spiking activity of the output neurons (1) does not habituate when the same stimulus is presented sequentially and (2) is enhanced when a different stimulus is presented. Whereas the spiking activity does not habituate, an analysis of the network’s membrane potential indicates that the average membrane potential does habituate. This overall pattern of spiking activity and membrane-potential changes mimics that seen in our vPFC data. It is possible to build a circuit-level model of working memory based on dynamic synapses that does not produce persistent activity. This model raises the possibility of alternative mechanisms underlying working memory. Conference: Computational and Systems Neuroscience 2010, Salt Lake City, UT, United States, 25 Feb - 2 Mar, 2010. Presentation Type: Poster Presentation Topic: Poster session III Citation: Lee J and Cohen Y (2010). A model of vPFC neurons performing a same-different task: an alternative model of working memory. Front. Neurosci. Conference Abstract: Computational and Systems Neuroscience 2010. doi: 10.3389/conf.fnins.2010.03.00232 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: 04 Mar 2010; Published Online: 04 Mar 2010. * Correspondence: Jung Lee, University of Pennsylvania School of Medicine, Department of Otorhinolaryngology, Philadelphia, United States, jleeh@mail.med.upenn.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Jung Lee Yale Cohen Google Jung Lee Yale Cohen Google Scholar Jung Lee Yale Cohen PubMed Jung Lee Yale Cohen 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.

Gender Differences in Mental Rotation Across Adulthood

Although gender differences in mental rotation in younger adults are prominent in paper-pencil tests as well as in chronometric tests with polygons as stimuli, less is known about this topic in the older age ranges. Therefore, performance was assessed with the Mental Rotation Test (MRT) paper-pencil test as well as with a computer-based two-stimulus same-different task with polygons in a sample of 150 adults divided into three age groups, 20–30, 40–50, and 60–70 years. Performance decreased with age, and men outperformed women in all age groups. The gender effect decreased with age in the MRT, possibly due to a floor effect. Gender differences remained constant across age, however, in the error rates of the computer-based task.

The role of neighbourhood density in transposed-letter priming

We investigated how transposed-letter (TL) priming effects are modulated by neighbourhood density in lexical decision task and cross-case same-different task. Robust identity priming and TL priming effects were observed in both tasks. Neighbourhood density facilitated ‘word’ decisions and reduced the size of identity priming effect in the lexical decision task. It had no effect on the same-different task, and did not modulate identity or TL priming. We take these results as indicating that neighbourhood density modulates priming during lexical access. In the lexical decision task, the difference between identity priming and TL priming was reduced for words from high-density neighbourhood. The last finding is at odds with the ‘lexical tuning’ hypothesis which has been used to explain modulatory effects of neighbourhood density on masked form priming effects. We also discuss implication of the results for various letter position coding schemes.

Behavioral and electrophysiological evidence for the impact of regional variation on phoneme perception

This event-related potential (ERP) study examined the impact of phonological variation resulting from a vowel merger on phoneme perception. The perception of the /e/–/ε/ contrast which does not exist in Southern French-speaking regions, and which is in the process of merging in Northern French-speaking regions, was compared to the /ø/–/y/ contrast, which is stable in all French-speaking regions. French-speaking participants from Switzerland for whom the /e/–/ε/ contrast is preserved, but who are exposed to different regional variants, had to perform a same-different task. They first heard four phonemically identical but acoustically different syllables (e.g., /be/–/be/–/be/–/be/), and then heard the test syllable which was either phonemically identical to (/be/) or phonemically different from (/bε/) the preceding context stimuli. The results showed that the unstable /e/–/ε/ contrast only induced a mismatch negativity (MMN), whereas the /ø/–/y/ contrast elicited both a MMN and electrophysiological differences on the P200. These findings were in line with the behavioral results in which responses were slower and more error-prone in the /e/–/ε/ deviant condition than in the /ø/–/y/ deviant condition. Together these findings suggest that the regional variability in the speech input to which listeners are exposed affects the perception of speech sounds in their own accent.

Glyconutrients and Perception, Cognition, and Memory

Neuropsychological tests were administered to 62 college students to assess the influence of glyconutrients on perception, cognition and memory in two randomized, double-blind, placebo-controlled, counterbalanced studies. Participants were given both a glyconutritional supplement and a control substance prior to testing. In Exp. 1. a Same-Different visual discrimination task, Raven's Standard Progressive Matrices, and the Stroop test were administered. In Exp. 2, simple and complex working-memory capacity were measured. Participants receiving the supplement performed significantly more accurately on the visual discrimination task and the first session of the simple working-memory test.

Transposed-letter priming of prelexical orthographic representations.

A prime generated by transposing two internal letters (e.g., jugde) produces strong priming of the original word (judge). In lexical decision, this transposed-letter (TL) priming effect is generally weak or absent for nonword targets; thus, it is unclear whether the origin of this effect is lexical or prelexical. The authors describe the Bayesian Reader theory of masked priming (D. Norris & S. Kinoshita, 2008), which explains why nonwords do not show priming in lexical decision but why they do in the cross-case same-different task. This analysis is followed by 3 experiments that show that priming in this task is not based on low-level perceptual similarity between the prime and target, or on phonology, to make the case that priming is based on prelexical orthographic representation. The authors then use this task to demonstrate equivalent TL priming effects for nonwords and words. The results are interpreted as the first reliable evidence based on the masked priming procedure that letter position is not coded absolutely within the prelexical, orthographic representation. The implications of the results for current letter position coding schemes are discussed.

The Dissociation of Egocentric and Allocentric Mental Rotation through an In-Rotation Effect

Mental rotation involves the spatial transformation of the mental image of a physical stimulus.The following two mental rotation tasks have been employed in the literature:(1) left-right or normal-mirror judgment task and(2) the same-different judgment task.The time taken in making these judgments as well as the errors made often increase with the angular difference in orientation between the stimuli,or the difference between imagined and normalized orientation. Further,mental rotation can be classified into two categories based on the reference frame adopted: egocentric and allocentric.The stimuli representing bodies or body parts such as hands are often considered as a special class of stimuli;this is because when they are used as stimuli in mental rotation tasks,they tend to induce egocentric mental rotation.However,there is no conclusive evidence demonstrating that material of body parts in fact draws forth egocentric mental rotation;more importantly,there has been no evidence demonstrating that the images of body parts can also elicit allocentric mental rotation. In the current study,using two experimental paradigms(left-right judgment task and same-different judgment task),we explored the possibility of the dissociation of these two processing mechanisms using a special stimulus(hand),which may induce a mental transformation of either the viewer's own body(hand) or the visual display.The stimuli comprised images of the back of the human hands created by a 3D graphics software.Each picture of the hand was presented at an orientation rotated in the medial(in-rotation) or lateral(out-rotation) direction from the upright orientation. In experiment 1,each participant completed a left or right hand judgment task(LR task) when the picture of either a left or right hand was presented.Three factors were manipulated: hands(left hand vs.right hand),the direction of rotation(in-rotation vs.out-rotation),and the magnitude of rotation(45,90, and 135).All possible combinations of the different levels of the hands,direction of rotation,and degree of rotation were tested in a within-subject 2×2×3 completely randomized factorial design.In experiment 2,each participant completed a same or different judgment task(SD task) when the pictures of two hands were presented.In addition to the 3 factors used in experiment 1,there was an additional factor: the match(match vs.no-match).For both experiments,the dependent variables were the reaction time and the errors in the judgment. For both experiments,the results indicated that the degree of rotation did have an effect,i.e.,the performance decreased as the degree of rotation increased.In addition,for the LR task,for the same magnitude of rotation,the hand when rotated medially(in-rotation) was recognized more quickly and accurately than when rotated laterally(out-rotation).Such an effect of the direction of rotation(we termed it the "in-rotation effect") was not seen for the SD task.This suggests that the processing of mental rotation in the LR task was limited by the biomechanical constraints of the corresponding physical rotation.Thus,the subjects might have used the egocentric frame of reference in mental rotation for the LR task but the allocentric frame of reference in the SD task.Therefore,the hand stimuli can elicit either egocentric or allocentric mental rotation depending on the experimental task. These results suggest that participants use different spatial transformation mechanisms in LR(egocentric) and SD(object-centric) tasks.It appears that both the material of the body parts and the paradigms of mental rotation determine the reference frame that the participants adopt;further,we can state that the in-rotation effect might serve as an indicator of the dissociation of egocentric and allocentric mental rotation.Further,the result provided a good method for clarifying the disputation of unitary and multiple-systems models in egocentric and allocentric mental rotation.

Prefrontal Neurons Predict Choices during an Auditory Same-Different Task

The detection of stimuli is critical for an animal's survival [1]. However, it is not adaptive for an animal to respond automatically to every stimulus that is present in the environment [2-5]. Given that the prefrontal cortex (PFC) plays a key role in executive function [6-8], we hypothesized that PFC activity should be involved in context-dependent responses to uncommon stimuli. As a test of this hypothesis, monkeys participated in a same-different task, a variant of an oddball task [2]. During this task, a monkey heard multiple presentations of a "reference" stimulus that were followed by a "test" stimulus and reported whether these stimuli were the same or different. While they participated in this task, we recorded from neurons in the ventrolateral prefrontal cortex (vPFC; a cortical area involved in aspects of nonspatial auditory processing [9, 10]). We found that vPFC activity was correlated with the monkeys' choices. This finding demonstrates a direct link between single neurons and behavioral choices in the PFC on a nonspatial auditory task.

Multivariate Patterns in Object-Selective Cortex Dissociate Perceptual and Physical Shape Similarity

Prior research has identified the lateral occipital complex (LOC) as a critical cortical region for the representation of object shape in humans. However, little is known about the nature of the representations contained in the LOC and their relationship to the perceptual experience of shape. We used human functional MRI to measure the physical, behavioral, and neural similarity between pairs of novel shapes to ask whether the representations of shape contained in subregions of the LOC more closely reflect the physical stimuli themselves, or the perceptual experience of those stimuli. Perceptual similarity measures for each pair of shapes were obtained from a psychophysical same-different task; physical similarity measures were based on stimulus parameters; and neural similarity measures were obtained from multivoxel pattern analysis methods applied to anterior LOC (pFs) and posterior LOC (LO). We found that the pattern of pairwise shape similarities in LO most closely matched physical shape similarities, whereas shape similarities in pFs most closely matched perceptual shape similarities. Further, shape representations were similar across participants in LO but highly variable across participants in pFs. Together, these findings indicate that activation patterns in subregions of object-selective cortex encode objects according to a hierarchy, with stimulus-based representations in posterior regions and subjective and observer-specific representations in anterior regions.

The comparative psychology of same-different judgments by humans (Homo sapiens) and monkeys (Macaca mulatta).

The authors compared the performance of humans and monkeys in a Same-Different task. They evaluated the hypothesis that for humans the Same-Different concept is qualitative, categorical, and rule-based, so that humans distinguish 0-disparity pairs (i.e., same) from pairs with any discernible disparity (i.e., different); whereas for monkeys the Same-Different concept is quantitative, continuous, and similarity-based, so that monkeys distinguish small-disparity pairs (i.e., similar) from pairs with a large disparity (i.e., dissimilar). The results supported the hypothesis. Monkeys, more than humans, showed a gradual transition from same to different categories and an inclusive criterion for responding Same. The results have implications for comparing Same-Different performances across species--different species may not always construe or perform even identical tasks in the same way. In particular, humans may especially apply qualitative, rule-based frameworks to cognitive tasks like Same-Different.

Analysis of the role of associative inhibition in perceptual learning by means of the same-different task.

In Experiment 1a, participants were exposed, over a series of trials, to separate presentations of 2 similar checkerboard stimuli, AX and BX (where X represents a common background). In one group, AX and BX were presented on alternating trials (intermixed), in another, they were presented in separate blocks of trials (blocked). The intermixed group performed to a higher standard than the blocked group on a same-different test. A superiority of intermixed over blocked exposure was also evident in a within-subject design (Experiment 1b) and when the test required discrimination between a preexposed stimulus and the background (e.g., AX vs. X), even if the background changed between preexposure and test (AY vs. Y) (Experiment 2). In Experiment 3, the intermixed/blocked effect was observed when, in preexposure, stimulus presentations were alternated with the background alone (e.g., AX/X). This suggests that the perceptual learning effect is not the consequence of inhibitory associations between unique features but to increased salience of those features. Experiment 4 confirmed this finding and also ruled out an account of the effect in terms of trial spacing.

Paradoxical Enhancement of Letter Recognition in Developmental Dyslexia

In a number of studies, children diagnosed with developmental dyslexia reached normal scores in standard visual processing tasks, and some researchers concluded that visual processing deficits are not involved in the syndrome. The tasks used, however, may be insensitive to anomalous visual information processing strategies used to compensate for an underlying deficit. To determine whether children with dyslexia use anomalous visual processing strategies, a same-different task was applied, in which 2 items identical under rotation and reflection were judged as same. Pairs of letters or dot patterns were used, which were either symmetric or asymmetric in shape. Children with dyslexia performed faster than normal-reading children--in particular, remarkably, with letters. Symmetry of dot patterns facilitated performance in both children with dyslexia and normal-reading children; symmetry of letters facilitated performance in children with dyslexia but not in normal-reading children. Children with dyslexia, therefore, fail to adequately differentiate visual processing of linguistic and non-linguistic materials; they process symmetry in letters similarly to that in shapes, which leads in this particular task to the paradoxical observation of children with dyslexia outperforming normal readers with letters.

The spread of the phonological neighborhood influences spoken word recognition

In three experiments, the processing of words that had the same overall number of neighbors but varied in the spread of the neighborhood (i.e., the number of individual phonemes that could be changed to form real words) was examined. In an auditory lexical decision task, a naming task, and a same-different task, words in which changes at only two phoneme positions formed neighbors were responded to more quickly than words in which changes at all three phoneme positions formed neighbors. Additional analyses ruled out an account based on the computationally derived uniqueness points of the words. Although previous studies (e.g., Luce & Pisoni, 1998) have shown that the number of phonological neighbors influences spoken word recognition, the present results show that the nature of the relationship of the neighbors to the target word--as measured by the spread of the neighborhood--also influences spoken word recognition. The implications of this result for models of spoken word recognition are discussed.

Music-to-language transfer effect: may melodic ability improve learning of tonal languages by native nontonal speakers?

In tonal languages, as Mandarin Chinese and Thai, word meaning is partially determined by lexical tones. Previous studies suggest that lexical tones are processed by native listeners as linguistic information and not as pure tonal information. This study aims at verifying if, in nontonal languages speakers, the discrimination of lexical Mandarin tones varies in function of the melodic ability. Forty-six students with no previous experience of Mandarin or any other tonal language were presented with two short lists of spoken monosyllabic Mandarin words and invited to perform a same-different task trying to identify whether the variation were phonological or tonal. Main results show that subjects perform significantly better in identifying phonological variations rather than tonal ones and interestingly, the group with a high melodic ability (assessed by Wing subtest 3) shows a better performance exclusively in detecting tonal variations.

Knowledge of one’s kinematics improves perceptual discrimination

We tested the hypothesis that our ability to detect fine kinematics variations is tuned to reveal more subtle differences when the motion pattern belongs to the observer compared to another individual. To this purpose, we analyzed the responses of 15 subjects in a same-different task on pairs of movements, which could belong to one or two different subjects. Self vs. Other comparisons were obtained by presenting both the observer’s and another participant’s kinematics. Subjects responded faster and more accurately when they observed their own gestures compared to movements of another participant. In the latter case, slight kinematic differences were more likely to remain undetected. These findings are discussed within an ecological framework: in observing others, we are more concerned with detection of goals and intentions, i.e., outstanding variations in motion patterns. Conversely, in self-observation detection of more subtle differences is required to facilitate learning and optimization of motor acts.