Two-alternative Forced-choice Task Research Articles

A novel Android app to evaluate and enhance auditory and tactile temporal thresholds.

With this work, we introduce a novel Android app designed to monitor and enhance auditory and tactile temporal sensitivity. To assess the app's reliability, we tested its technical performance evaluating stimuli production's accuracy (i.e., onset, offset, and duration of stimulation). To validate the app with participants we generated temporal intervals, using either sounds or vibratory stimuli, by implementing two versions of a Two-Alternative Forced-Choice (2AFC) task. Auditory and tactile temporal sensitivity of 12 participants was evaluated using this procedure. To investigate whether temporal abilities could be enhanced using the app, participants were then divided into two groups: one group was trained for four days on the auditory temporal task, while the other was trained for four days on the tactile temporal task. Results suggest that the app can i) effectively measure auditory and tactile temporal thresholds and ii) be used to enhance temporal abilities through perceptual learning. The accessibility of the experimental protocols, combined with our findings, fosters the app's involvement in rehabilitation programs, for example, with a specific focus on sensory disabilities that are associated with temporal deficits (e.g., deafness and Parkinson).Clinical Relevance- The current work introduces a novel app that can be used to monitor and improve temporal abilities, in both the auditory and the tactile modalities.

Unmasking the effects of orthography, semantics, and phonology on 2AFC visual word perceptual identification

ABSTRACT In the two-alternative forced-choice (2AFC) task, the target stimulus is presented very briefly, and participants must choose which of two options was the presented target. Some past research has assumed that the 2AFC task isolates orthographic effects, despite orthographic, semantic, and phonological differences between the options. If so, performance should not differ between word/nonword pairs and British/American word pairs, the latter of which only differ orthographically. In Experiment 1, accuracy and sensitivity were higher during word/nonword trials than British/American trials when participants did not guess, demonstrating that phonological/semantic processing contributes to performance. Experiment 2 showed that target visibility did not interact with pair type on RT, which suggests phonological/semantic processing did not feed back to orthographic encoding in this task. This study demonstrates the influence of phonological/semantic processing on word perceptual identification, and shows that using British/American word pairs provides a method to isolate orthography in the 2AFC task.

Tangled Physics: Knots as a challenge for physical scene understanding

A resurgence of interest in intuitive physics has revealed a remarkable capacity in humans to make common-sense predictions about the unfolding of physical scenes. For example, recent work has shown that observers can correctly judge properties such as stability, weight distribution, gravity and collision physics, especially in rich naturalistic images. These results have suggested that physical scene understanding recruits a general-purpose “physics engine” that reliably simulates how scenes will unfold. Here, we complicate this picture by introducing knots to the study of intuitive physics. Knots are naturalistic stimuli that appear across cultures and time periods, and are widely used in both mundane scenarios (e.g., closing a bag or tying one’s shoes) and more technical applications (e.g., securing a boat or even supporting a rock-climber). Yet, here we show that even basic judgments about knots strain human physical reasoning. Observers viewed photographs of simple “bends” (i.e., knots joining two lengths of string) that share strong visual similarity but greatly differ in structural integrity. For example, observers saw not only “reef” knots (a common knot used for millennia), but also “thief” knots (which differ only in the position of a single strand but are significantly less secure than “reefs”), along with “granny” and “grief” knots (which share a similar relationship). In a two-alternative forced-choice task, observers judged each knot’s stability relative to every other knot. Strikingly, observers reliably ranked weaker knots as strong and stronger knots as weak, both across knot-families (e.g., incorrectly judging granny knots as stronger than reef knots) and within a given family (e.g., failing to judge “thiefs” as weaker than “reefs”). These failures challenge a general-purpose “physics engine” hypothesis, and perhaps suggest that knots and other examples of soft-body physics recruit different cognitive processes than rigid-body physics.

Disentangling the Role of Deviant Letter Position on Cognate Word Processing.

The way of coding letter position has been extensively assessed during the recognition of native words, leading to the development of a new generation of models that assume more flexible letter position coding schemes compared to classical computational models such as the interactive activation (IA) model. However, determining whether similar letter position encoding mechanisms occur during the bilingual word recognition has been largely less explored despite its implications for the leading model of bilingual word recognition (multilink) as it assumes the input-coding scheme of the IA model. In this study, we aimed to examine this issue through the manipulation of the position of the deviant letter of cognate words (external and internal letters). Two experiments were conducted with Catalan–Spanish bilinguals (a masked priming lexical decision task and a two-alternative forced-choice task) and their respective monolingual controls. The results revealed a differential processing for the first letter in comparison to the other letters as well as modulations as a function of language cue, suggesting amendments to the input-coding scheme of the multilink model.

A passive and objective measure of recognition memory in Alzheimer's disease using Fastball memory assessment.

Earlier diagnosis of Alzheimer's disease requires biomarkers sensitive to associated structural and functional changes. While considerable progress has been made in the development of structural biomarkers, functional biomarkers of early cognitive change, unconfounded by effort, practice and level of education, are still needed. We present Fastball, a new EEG method for the passive and objective measurement of recognition memory, that requires no behavioural memory response or comprehension of the task . Younger adults, older adults and Alzheimer's disease patients (n = 20 per group) completed the Fastball task, lasting just under 3 min. Participants passively viewed rapidly presented images and EEG assessed their automatic ability to differentiate between images based on previous exposure, i.e. old/new. Participants were not instructed to attend to previously seen images and provided no behavioural response. Following the Fastball task, participants completed a two-alternative forced choice (2AFC) task to measure their explicit behavioural recognition of previously seen stimuli. Fastball EEG detected significantly impaired recognition memory in Alzheimer's disease compared to healthy older adults (P < 0.001, Cohen's d = 1.52), whereas behavioural recognition was not significantly different between Alzheimer's disease and healthy older adults. Alzheimer's disease patients could be discriminated with high accuracy from healthy older adult controls using the Fastball measure of recognition memory (AUC = 0.86, P < 0.001), whereas discrimination performance was poor using behavioural 2AFC accuracy (AUC = 0.63, P = 0.148). There were no significant effects of healthy ageing, with older and younger adult controls performing equivalently in both the Fastball task and behavioural 2AFC task. Early diagnosis of Alzheimer's disease offers potential for early treatment when quality of life and independence can be retained through disease modification and cognitive enhancement. Fastball provides an alternative way of testing recognition responses that holds promise as a functional marker of disease pathology in stages where behavioural performance deficits are not yet evident. It is passive, non-invasive, quick to administer and uses cheap, scalable EEG technology. Fastball provides a new powerful method for the assessment of cognition in dementia and opens a new door in the development of early diagnosis tools.

The complex relationship between conscious/unconscious learning and conscious/unconscious knowledge: The mediating effects of salience in form–meaning connections

This study investigates how implicit and explicit learning and knowledge are associated, by focusing on the salience of target form–meaning connections. The participants were engaged in incidental learning of artificial determiner systems that included grammatical rules of [± plural] (a taught rule), [± actor] (a more salient hidden rule), and [± animate] (a less salient hidden rule). They completed immediate and delayed post-tests by means of a two-alternative forced-choice task with subjective judgments of source attributions. Awareness during the learning phase was identified through analysis of thinking aloud protocols. The results did not support a one-to-one relation between either explicit learning and conscious knowledge, or implicit learning and unconscious knowledge; rather, they indicated that implicit and explicit learning are intricately linked to conscious and unconscious knowledge mediated by the salience of form–meaning connections in target items. This result also suggests the possibility of the later emergence of knowledge without any conscious awareness of it.

Preference for Facial Symmetry Depends on Study Design

Facial symmetry is purportedly attractive, though methods for measuring preference for facial symmetry vary between studies. Some studies have used a two-alternative forced choice (2AFC) task, while others have used a ratings task. How researchers manipulate facial symmetry also varies; some studies have used faces manipulated to be more (or perfectly) symmetrical, while others have used faces manipulated to be more asymmetrical. Here, across three studies, we evaluate and compare these different methods. In Studies 1 and 2 (N = 340 and 256, respectively), we compare facial symmetry preferences as measured by the 2AFC and ratings tasks. Across both studies, we consistently found a significant preference for facial symmetry when using the 2AFC task, but not with the ratings task. Additionally, correlations between facial symmetry preferences as measured by the two tasks were weak or showed no association. In Study 3, 159 participants rated the attractiveness of faces manipulated to be either symmetrical or more asymmetrical. The asymmetrical faces were rated as significantly less attractive compared to the original faces, while the difference in attractiveness ratings between the original and symmetrical versions was comparatively much smaller. These studies suggest that preference for facial symmetry depends greatly on the study design.

Directional biosonar beams allow echolocating harbour porpoises to actively discriminate and intercept closely spaced targets

Echolocating toothed whales face the problem that high sound speeds in water mean that echoes from closely-spaced targets will arrive at time delays within their reported auditory integration time of some 264 µsec. Here we test the hypothesis that echolocating harbour porpoises cannot resolve and discriminate targets within a clutter interference zone given by their integration time. To do this, we trained two harbour porpoises (Phocoena phocoena) to actively approach and choose between two spherical targets at four varying inter-target distances (13.5, 27, 56 and 108 cm) in a two-alternative forced-choice task. The free-swimming, blindfolded porpoises were tagged with a sound and movement tag (DTAG4) to record their echoic scene and acoustic outputs. The known ranges between targets and the porpoise, combined with the sound levels received on target-mounted hydrophones revealed how they controlled their acoustic gaze. When targets were close together and the discrimination task was more difficult due to smaller echo time delays and lower echo level ratios between the targets, buzzes were longer and started from farther away, source levels were reduced at short ranges, and the porpoises clicked faster, scanned across the targets more, and delayed making their discrimination decision until closer to the target. We conclude that harbour porpoises can resolve and discriminate closely-spaced targets, suggesting a clutter rejection zone much shorter than their auditory integration time, and that such clutter rejection is greatly aided by spatial filtering with their directional biosonar beam.

Interaural time difference tuning in the rat inferior colliculus is predictive of behavioral sensitivity

While a large body of literature has examined the encoding of binaural spatial cues in the auditory midbrain, studies that ask how quantitative measures of spatial tuning in midbrain neurons compare with an animal's psychoacoustic performance remain rare. Researchers have tried to explain deficits in spatial hearing in certain patient groups, such as binaural cochlear implant users, in terms of declines in apparent reductions in spatial tuning of midbrain neurons of animal models. However, the quality of spatial tuning can be quantified in many different ways, and in the absence of evidence that a given neural tuning measure correlates with psychoacoustic performance, the interpretation of such finding remains very tentative. Here, we characterize ITD tuning in the rat inferior colliculus (IC) to acoustic pulse train stimuli with varying envelopes and at varying rates, and explore whether quality of tuning correlates behavioral performance. We quantified both mutual information (MI) and neural d' as measures of ITD sensitivity. Neural d' values paralleled behavioral ones, declining with increasing click rates or when envelopes changed from rectangular to Hanning windows, and they correlated much better with behavioral performance than MI. Meanwhile, MI values were larger in an older, more experienced cohort of animals than in naive animals, but neural d' did not differ between cohorts. However, the results obtained with neural d' and MI were highly correlated when ITD values were coded simply as left or right ear leading, rather than specific ITD values. Thus, neural measures of lateralization ability (e.g. d' or left/right MI) appear to be highly predictive of psychoacoustic performance in a two-alternative forced choice task.

Shape familiarity modulates preference for curvature in drawings of common-use objects.

Drawing is a way to represent common-use objects. The contour of an object is a salient feature that defines its identity. Preference for a contour (curved or angular) may depend on how familiar the resulting shape looks for that given object. In this research, we examined the influence of shape familiarity on preference for curved or sharp-angled drawings of common-use objects. We also examined the possibility that some individual differences modulated this preference. Preference for curvature was assessed with a liking rating task (Experiment 1) and with a two-alternative forced-choice task simulating approach/avoidance responses (Experiment 2). Shape familiarity was assessed with a familiarity selection task where participants selected the most familiar shape between the curved and the angular version for each object, or whether both shapes were equally familiar for the object. We found a consistent preference for curvature in both experiments. This preference increased when the objects with a curved shape were selected as the most familiar ones. We also found preference for curvature when participants selected the shape of objects as equally familiar. However, there was no preference for curvature or preference for angularity when participants selected the sharp-angled shapes as the most familiar ones. In Experiment 2, holistic and affective types of intuition predicted higher preference for curvature. Conversely, participants with higher scores in the unconventionality facet showed less preference for the curved drawings. We conclude that shape familiarity and individual characteristics modulate preference for curvature.

Women's Preferences for Strong Men Under Perceived Harsh Versus Safe Ecological Conditions.

Ecological conditions provide information about available resources for one's environment. In humans, this has been shown to influence reproductive behavior, as individuals may engage in trade-offs between partner quality and investment. For instance, many women may trade-off preferences for men with physical features indicative of social dominance and health over physical features indicative of commitment and investment. The current study explored women's preferences for formidable men under safe vs. harsh ecological conditions. Across three studies, U.S. university women (N = 1,098) were randomly assigned to a perceived harsh or safe ecological condition. They were asked to rate the attractiveness of men's body types (i.e., muscular vs. less muscular). Findings revealed that in general, women rated stronger men as more attractive than weaker men irrespective of the ecological condition. Evidence for preference as a function of ecology appeared only when a two-alternative forced-choice task was used (Study 3), but not in rating tasks (Studies 1 and 2). Study 3 showed that women had a relatively stronger preference for stronger men for short-term relationships in a resource scarce ecological condition. This research provides some evidence that perceived ecological conditions can drive women's preferences for men with enhanced secondary sex characteristics as a function of mating context. These findings are consistent with previous research indicating the importance of physical characteristics in men's attractiveness, and it adds to the existing literature on ecological factors and mating preferences.

Do congruent lip movements facilitate speech processing in a dynamic audiovisual multi-talker scenario? An ERP study with older and younger adults

In natural conversations, visible mouth and lip movements play an important role in speech comprehension. There is evidence that visual speech information improves speech comprehension, especially for older adults and under difficult listening conditions. However, the neurocognitive basis is still poorly understood. The present EEG experiment investigated the benefits of audiovisual speech in a dynamic cocktail-party scenario with 22 (aged 20–34 years) younger and 20 (aged 55–74 years) older participants. We presented three simultaneously talking faces with a varying amount of visual speech input (still faces, visually unspecific and audiovisually congruent). In a two-alternative forced-choice task, participants had to discriminate target words (“yes” or “no”) among two distractors (one-digit number words). In half of the experimental blocks, the target was always presented from a central position, in the other half, occasional switches to a lateral position could occur. We investigated behavioral and electrophysiological modulations due to age, location switches and the content of visual information, analyzing response times and accuracy as well as the P1, N1, P2, N2 event-related potentials (ERPs) and the contingent negative variation (CNV) in the EEG. We found that audiovisually congruent speech information improved performance and modulated ERP amplitudes in both age groups, suggesting enhanced preparation and integration of the subsequent auditory input. In the older group, larger amplitude measures were found in early phases of processing (P1-N1). Here, amplitude measures were reduced in response to audiovisually congruent stimuli. In later processing phases (P2-N2) we found decreased amplitude measures in the older group, while an amplitude reduction for audiovisually congruent compared to visually unspecific stimuli was still observable. However, these benefits were only observed as long as no location switches occurred, leading to enhanced amplitude measures in later processing phases (P2-N2). To conclude, meaningful visual information in a multi-talker setting, when presented from the expected location, is shown to be beneficial for both younger and older adults.

Acetylcholine from the nucleus basalis magnocellularis facilitates the retrieval of well-established memory

Retrieval deficit of long-term memory is a cardinal symptom of dementia and has been proposed to associate with abnormalities in the central cholinergic system. Difficulty in the retrieval of memory is experienced by healthy individuals and not limited to patients with neurological disorders that result in forgetfulness. The difficulty of retrieving memories is associated with various factors, such as how often the event was experienced or remembered, but it is unclear how the cholinergic system plays a role in the retrieval of memory formed by a daily routine (accumulated experience). To investigate this point, we trained rats moderately (for a week) or extensively (for a month) to detect a visual cue in a two-alternative forced-choice task. First, we confirmed the well-established memory in the extensively trained group was more resistant to the retrieval problem than recently acquired memory in the moderately trained group. Next, we tested the effect of a cholinesterase inhibitor, donepezil, on the retrieval of memory after a long no-task period in extensively trained rats. Pre-administration of donepezil improved performance and reduced the latency of task initiation compared to the saline-treated group. Finally, we lesioned cholinergic neurons of the nucleus basalis magnocellularis (NBM), which project to the entire neocortex, by injecting the cholinergic toxin 192 IgG-saporin. NBM-lesioned rats showed severely impaired task initiation and performance. These abilities recovered as the trials progressed, though they never reached the level observed in rats with intact NBM. These results suggest that acetylcholine released from the NBM contributes to the retrieval of well-established memory developed by a daily routine.

The Impact of Hearing Experience on Children's Use of Phonological and Semantic Information During Lexical Access.

Purpose The purpose of this study was to examine the extent to which phonological competition and semantic priming influence lexical access in school-aged children with cochlear implants (CIs) and children with normal acoustic hearing. Method Participants included children who were 5-10 years of age with either normal hearing (n = 41) or bilateral severe to profound sensorineural hearing loss and used CIs (n = 13). All participants completed a two-alternative forced-choice task while eye gaze to visual images was recorded and quantified during a word recognition task. In this task, the target image was juxtaposed with a competitor image that was either a phonological onset competitor (i.e., shared the same initial consonant-vowel-consonant syllable as the target) or an unrelated distractor. Half of the trials were preceded by an image prime that was semantically related to the target image. Results Children with CIs showed evidence of phonological competition during real-time processing of speech. This effect, however, was less and occurred later in the time course of speech processing than what was observed in children with normal hearing. The presence of a semantically related visual prime reduced the effects of phonological competition in both groups of children but to a greater degree in children with CIs. Conclusions Children with CIs were able to process single words similarly to their counterparts with normal hearing. However, children with CIs appeared to have increased reliance on surrounding semantic information compared to their normal-hearing counterparts.

Learning to distinguish: shared perceptual features and discrimination practice tune behavioural pattern separation

ABSTRACT Pattern separation is a computational mechanism performed by the hippocampus allowing the reduction of overlap between sensory inputs with similar perceptual features. Our first aim was to develop a new paradigm sensitive to the behavioural consequences of pattern separation (mnemonic discrimination). For this purpose, we constructed morphed face stimuli with parametrically changing levels of similarity. After encoding participants saw studied items and similar lure faces. Perceptual similarity affected false recognition and there was a gradual reduction in discrimination accuracy with the increment of similarity between the stimuli. However, confidence ratings were sensitive to smaller changes (Experiment 1) than the other test type with “old”/“similar”/“new” response options (Experiment 2). Mnemonic discrimination relies strongly on retrieving details of the original stimulus. Therefore, we investigated whether pattern separation can be tuned by retrieval in the form of a discrimination task (Experiment 3). Our findings suggest that repeatedly encountering the stimuli within a two-alternative forced-choice task (in comparison with the repeated presentation of the material) increased both the correct identification and the false recognition of similar stimuli two days after encoding. We conclude that basic computational mechanisms of the hippocampus can be tuned by a task that requires discrimination between studied and new stimuli.

Chinese Aesthetic Mask: Three Forehead and Five Eyes-Holistic Processing and Facial Attractiveness.

Human face processing has been attributed to holistic processing. Here, we ask whether humans are sensitive to configural information when perceiving facial attractiveness. By referring to a traditional Chinese aesthetic theory-Three Forehead and Five Eyes-we generated a series of faces that differed in spacing between facial features. We adopted a two-alternative forced-choice task in Experiment 1 and a rating task in Experiment 2 to assess attractiveness. Both tasks showed a consistent result: The faces which fit the Chinese aesthetic theory were chosen or rated as most attractive. This effect of configural information on facial attractiveness was larger for faces with highly attractive features than for faces with low attractive features. These findings provide experimental evidence for the traditional Chinese aesthetic theory. This issue can be further explored from the perspective of culture in the future.

Hunger or thirst state uncertainty is resolved by outcome evaluation in medial prefrontal cortex to guide decision-making.

Physiological need states direct decision-making towards re-establishing homeostasis. Using a two-alternative-forced-choice task for mice that models elements of human decisions, we found that varying hunger and thirst states caused need-inappropriate choices, such as food-seeking when thirsty. These results show limits on interoceptive knowledge of hunger and thirst states to guide decision-making. Instead, need states were identified after food and water consumption by outcome evaluation, which depended on medial prefrontal cortex.

Salience of spatiochromatic patterns.

We investigated the dependence of perceived contrast on cone-opponent stimulus content and its spatial distribution. Participants matched a comparison patch to a light gray standard of fixed contrast. The first experiment determined the point of iso-salience for gratings, Gabors and Gaussians along cardinal directions in cone-opponent color space for two-alternative forced choice (2AFC) and adjustment tasks. No difference was found between adjustment and 2AFC tasks, meaning that adjustment tasks provide a quick and robust way to measure perceived contrast, at least for relatively large suprathreshold stimuli. In line with the differences in contrast energy between Gaussians, Gabors, and gratings, Gaussians required less contrast to achieve equal perceived salience with a standard irrespective of color. More surprisingly, bluish Gaussians were found to have higher salience than yellowish Gaussians at equal levels of contrast. Although perceived contrast of grating and Gabor patterns likely depends on spatial frequency channels that at 1 cycle-per-degree are not too dissimilarly tuned for color and luminance, for Gaussians the contribution of single-opponent neurons would be greater for color than for luminance. In a follow-up experiment, we found that the bluish/yellowish asymmetry decreased as we reduced the proportion of the lowpass non-flat contrast distribution in the stimulus, with minimal asymmetry for the stimulus with a flat contrast distribution (i.e., uniform patch). Combined, this means that differential engagement of spatial frequency channels, single-opponent and double-opponent neurons impacts on perceived contrast of chromatic suprathreshold stimuli. Perceived contrast thus provides a window into neural computations enacted by low-level cone-opponent mechanisms.

Tablet assessment of word comprehension reveals coarse word representations in 18-⁠20-month-old toddlers.

The present study explores the viability of using tablets in assessing early word comprehension by means of a two-alternative forced-choice task. Forty-nine 18-20-month-old Norwegian toddlers performed a touch-based word recognition task, in which they were prompted to identify the labeled target out of two displayed items on a touchscreen tablet. In each trial, the distractor item was either semantically related (e.g., dog-cat) or unrelated (e.g., dog-airplane) to the target. Our results show that toddlers as young as 18months can engage meaningfully with a tablet-based assessment, with minimal verbal instruction and child-administrator interaction. Toddlers performed better in the semantically unrelated condition than in the related condition, suggesting that their word representations are still semantically coarse at this age. Furthermore, parental reports of comprehension, using the Norwegian version of the MacArthur-Bates Communicative Development Inventories, predicted toddlers' performance, with parent-child agreement stronger in the semantically unrelated condition, indicating that parents declare a word to be known by their child if it is understood at a coarse representational level. This study provides among the earliest evidence that remote data collection in 18-20 month-old toddlers is viable, as comparable results were observed from both in-laboratory and online administration of the touchscreen recognition task.

Tracking statistical learning online: Word segmentation in a target detection task

Despite the essential role of statistical learning in shaping human behavior, there are still controversies concerning its measurement. In this paper, we present a novel online target-detection task in an acoustic word segmentation paradigm, which is able to track the process of learning and does not build on deliberation and decision making. Beside testing the novel online task, we also examined its relationship with two offline measures: the traditional two-alternative forced choice (2AFC) task, and the statistically-induced chunking recall (SICR) task (Isbilen et al., 2017). Participants showed a significant learning effect on the online task, reflected in the decrease of reaction times during training and in the differences between reaction times to predictable versus unpredictable targets. Online learning scores correlated with the 2AFC scores, but this association was only present when participants did not have explicit knowledge about stimuli. SICR scores were not associated with any of the other measures. The internal consistency was higher for online learning measures than for the other two tasks. These findings show that the online target detection task is a good tool for assessing statistical learning, and invite further research on its psychometric properties.