Mental fatigue is one of the main reasons for the decline of response inhibition. This study aimed to explore the impairing influence of mental fatigue on a driver’s response inhibition. The effects of mental fatigue on response inhibition were assessed by comparing brain activity and behavioral indices when performing a Go/NoGo task before and after a 90-min fatigue manipulation task. Participants in the driving group performed a simulated driving task, while individuals in the control group spent the same time watching movies. We found that participants in the driving group reported higher levels of mental fatigue and had a higher percentage of eye closure and larger lateral deviations from their lane positions, which indicated there was effective manipulation of mental fatigue through a prolonged simulated driving task. After manipulation of mental fatigue, we observed increased reaction time and miss rates, delayed NoGo-N2 latency and Go-P3 latency, and decreased NoGo-P3 amplitude, which indicated that mental fatigue may slow down the speed of the inhibition process, delay the evaluation of visual stimuli and reduce the availability of attentional resources. These findings revealed the underlying neurological mechanisms of how mental fatigue impaired response inhibition.

The gist of natural scenes can be extracted very rapidly and even without focal attention. However, it is unclear whether and to what extent the gist of natural scenes can break through the bottleneck of crowding, a phenomenon in which object recognition will be immensely impaired. In the first two experiments, a target scene, either presented alone or surrounded by four flankers, was categorized at basic (Experiment 1) or global levels (Experiment 2). It was showed that the elimination of high-level semantic information of flankers greatly alleviated the crowding effect, demonstrating that high-level information played an important role in crowding of scene gist. More importantly, participants were able to categorize the scenes in crowding at rather high accuracies, suggesting that the extraction of scene gist might be a prioritized process. To test this hypothesis, in Experiment 3 we compared the crowding effect of three types of stimuli, namely, scenes, facial expressions and letter “E”s. The results showed that scenes could be better categorized than the other two types of stimuli in the crowding condition. This scene gist advantage thus supported our hypothesis. Together, the present studies suggest that scene gist is highly recognizable in crowding, probably due to its prioritization in visual processing.

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Previous research on emotional bias in face perception has shown inconsistent findings, proposing either angry or happy faces to be detected more efficiently. A recent study showed that the anger superiority effect (ASE), which showed in the high attentional demand condition, vanished in the low attentional demand condition. The authors thus proposed an attentional demands modulation hypothesis to interpret the inconsistent findings. The present study tested this hypothesis in a visual crowding task in which participants were instructed to determine whether the target face was happy or angry. Attentional demands were manipulated by changing the strength of crowding, including presenting stimuli in different configurations (Experiment 1), and setting different target-flanker separations and presenting stimuli in different eccentricities (Experiment 2). Experiment 1 showed an ASE when the stimulus configuration incurred a high attentional demand. Intriguingly, the ASE became weaker and then disappeared as the attentional demand became lower. Experiment 2 replicated this finding and showed that the ASE decreased as the target-flanker separation became larger. Together, these results suggest that the emergence and magnitude of ASE is modulated by attentional demands, which supports the attentional demands modulation hypothesis.