Reward Rapidly Enhances Visual Perception

Rewards exert a deep influence on our cognition and behavior. Here, we used a paradigm in which reward information was provided at either encoding or retrieval of a brief, masked stimulus to show that reward can also rapidly modulate perceptual encoding of visual information. Experiment 1 ( n = 30 adults) showed that participants’ response accuracy was enhanced when a to-be-encoded grating signaled high reward relative to low reward, but only when the grating was presented very briefly and participants reported that they were not consciously aware of it. Experiment 2 ( n = 29 adults) showed that there was no difference in participants’ response accuracy when reward information was instead provided at the stage of retrieval, ruling out an explanation of the reward-modulation effect in terms of differences in motivated retrieval. Taken together, our findings provide behavioral evidence consistent with a rapid reward modulation of visual perception, which may not require consciousness.

Spatial and semantic interference on an auditory Stroop test: comparison of young and older adults

Background and Aim: Age related changes in cognitive functioning have been shown to vary depending on the task used. Thus, the study aimed to compare the responses of young and older adults to an auditory Stroop test that asse­ssed spatial (responses to location of the stimuli) and semantic (responses to meaning of the sti­muli) localization. Methods: The “Auditory spatial and semantic localization Stroop test”, developed as a part of the study was administered on 30 young adults aged 18 to 30 years and 30 older adults aged 58 to 70 years having normal hearing. The res­ponse accuracy and reaction time of the parti­cipants were determined for the words “right”, “left”, “front”, and “back.” Results: The older adults had significantly poo­rer response accuracy and reaction time than the young adults for both spatial and semantic loca­lization tasks. Within each participant group, semantic localization had better response accu­racy than spatial localization, while such diffe­rences in reaction time were found only in the older adults. In both groups, a congruency effect was seen for spatial but not for semantic loca­lization when response accuracy was calculated, whereas it was observed only for semantic and not for spatial localization when reaction time was measured. Conclusion: The auditory Stroop test, which measures stimulus interference and cognitive skills, could be used as a simple tool to assess the same for stimuli presented through the audi­tory modality. This would be especially helpful in older adults who may demonstrate cognitive decline with ageing to auditory stimuli. Keywords: Spatial localization; semantic localization; auditory Stroop test; age related changes

Semantic Predictability Facilitates Comprehension of Degraded Speech in a Graded Manner

Previous studies have shown that at moderate levels of spectral degradation, semantic predictability facilitates language comprehension. It is argued that when speech is degraded, listeners have narrowed expectations about the sentence endings; i.e., semantic prediction may be limited to only most highly predictable sentence completions. The main objectives of this study were to (i) examine whether listeners form narrowed expectations or whether they form predictions across a wide range of probable sentence endings, (ii) assess whether the facilitatory effect of semantic predictability is modulated by perceptual adaptation to degraded speech, and (iii) use and establish a sensitive metric for the measurement of language comprehension. For this, we created 360 German Subject-Verb-Object sentences that varied in semantic predictability of a sentence-final target word in a graded manner (high, medium, and low) and levels of spectral degradation (1, 4, 6, and 8 channels noise-vocoding). These sentences were presented auditorily to two groups: One group (n =48) performed a listening task in an unpredictable channel context in which the degraded speech levels were randomized, while the other group (n =50) performed the task in a predictable channel context in which the degraded speech levels were blocked. The results showed that at 4 channels noise-vocoding, response accuracy was higher in high-predictability sentences than in the medium-predictability sentences, which in turn was higher than in the low-predictability sentences. This suggests that, in contrast to the narrowed expectations view, comprehension of moderately degraded speech, ranging from low- to high- including medium-predictability sentences, is facilitated in a graded manner; listeners probabilistically preactivate upcoming words from a wide range of semantic space, not limiting only to highly probable sentence endings. Additionally, in both channel contexts, we did not observe learning effects; i.e., response accuracy did not increase over the course of experiment, and response accuracy was higher in the predictable than in the unpredictable channel context. We speculate from these observations that when there is no trial-by-trial variation of the levels of speech degradation, listeners adapt to speech quality at a long timescale; however, when there is a trial-by-trial variation of the high-level semantic feature (e.g., sentence predictability), listeners do not adapt to low-level perceptual property (e.g., speech quality) at a short timescale.

An exploration of lexical selection in adults who stutter

BACKGROUND AND OBJECTIVE: People who stutter (PWS) are able to anticipate a moment of stuttering. We wished to explore whether this anticipation might be reflected by either unusual word choice and/or delayed word production during a single-word confrontation naming task. METHOD: Nine PWS and nine age- and sex-matched fluent controls completed the single-word confrontation-naming task. Groups were compared on numbers of word-finding and fluency errors, response latency, and naming accuracy, measured against a novel ‘usuality’ criterion. Regression modelling of response accuracy and latency was conducted. RESULTS: The groups did not differ on naming task performance, except for a greater frequency of response latency errors in the PWS group. For both groups, responses containing word-finding or fluency errors were more likely to be non-usual names, and these were associated with longer latencies than accurate responses. For PWS, latency was positively related to participant age, and accuracy inversely related to stuttering severity. CONCLUSIONS: The findings provide insights into word substitution as a generalized behaviour, its function, and associated time-cost. Group-specific relationships imply greater sensitivity in PWS to changing demands and capacities, and highlight the complexity of interactions between physical stuttering behaviour and verbal avoidance.

How Does Task Presentation Impact Motor Inhibition Performance in Young Children?

Peg tapping tasks are commonly used as a measure of inhibitory skill in young children. However, differences in the way the task is presented may influence children’s performance. For example, if a peg tapping task is presented at regular intervals, children can entrain to the presentation pulse, which may in turn support their performance. This study assessed how speed and regularity of presentation may support or impair children’s responses. An experimenter was filmed delivering the tapping task at two different speeds (120 bpm/3,000 ms per trial and 150 bpm/2,400 ms per trial). Additionally, they were filmed delivering the task at regular intervals (i.e., the onset of each trial was predictable), or at irregular intervals (the onset of each trial was unpredictable). N = 103 children aged between 5 and 6 years old were tested on the task. They completed one block with 20 regular interval trials and another block with 20 irregular interval trials. Block presentation order was randomized. Children who achieved over 90% accuracy on the task were then presented with two more blocks at 150 bpm. Children’s response accuracy was measured. Our results show a difference in children’s accuracy across all conditions with trials presented in an irregular manner producing poorer performance on the task. The study demonstrates how speed and regularity of presentation can affect children’s scores on a tapping task used to measure inhibition. Demands on working memory, motor ability, and speed of processing are all affected by adjustments in presentation. Entrainment to a pulse is also a potential mechanism employed by children to support their performance on this task.

Not all smokers are alike: The hidden cost of sustained attention during nicotine abstinence

Background: Nicotine Withdrawal Syndrome (NWS)-associated cognitive deficits are heterogeneous, suggesting underlying endophenotypic subgroups. We identified smoker subgroups based on response accuracy during a cognitively demanding Parametric Flanker Task (PFT) and characterized their distinct neuroimaging endophenotypes using a nicotine state manipulation (sated, abstinent). Methods: Forty-five smokers completed the 25-min PFT in two fMRI sessions (nicotine sated, abstinent). Task-evoked NWS-associated errors of omission (EOm), brain activity, underlying functional connectivity (FC), and brain-behavior correlations between subgroups were assessed. Results: Based on their response accuracy in the high demand PFT condition, smokers split into high (HTP, n=21) and low task performer (LTP, n=24) subgroups. Behaviorally, HTPs showed greater response accuracy independent of nicotine state and greater vulnerability to abstinence-induced EOm. HTPs showed greater BOLD responses in attentional control brain regions for the [correct responses minus errors of commission] PFT contrast across states. A whole-brain FC analysis with these subgroup-derived regions as seeds revealed two circuits: L Precentral : R Insula and L Insula : R Occipital, with abstinence-induced FC strength increases only in HTPs. Finally, abstinence-induced brain (FC) and behavior (EOm) differences were positively correlated for HTPs in a L Precentral : R Orbitofrontal cortical circuit. Conclusion: We used a cognitive stressor (PFT) to fractionate smokers into two subgroups (HTP/LTP). Only the HTPs demonstrated sustained attention deficits during nicotine abstinence, a stressor in dependent smokers. Unpacking underlying smoker heterogeneity with this dual stressor approach revealed distinct smoker subgroups with differential attention deficit responses to withdrawal that could be novel targets for therapeutic interventions to improve cessation outcomes.