185 research outputs found
Mask-induced priming and the negative compatibility effect
No full textAbstract. Under certain conditions, masked primes have produced counter-intuitive negative compatibility effects (NCE), such that RT is increased, not decreased, when the target is similar to the prime. This NCE has been interpreted as an index of automatic motor inhibition, triggered to suppress the partial motor activation caused by the prime. An alternative explanation is that perceptual interactions between prime and mask produce positive priming in the opposite direction to the prime, explaining the NCE without postulating inhi-bition. Here the potential role of this “mask-induced priming ” was investigated in two experiments, using masks composed of random lines. Experiment 1 compared masks that included features of the primes and targets with masks that did not. The former should create more mask-induced priming, but the NCE did not differ between masks. Experiment 2 employed masks that contained features of either one target or the other, but not both. These asymmetric masks produced significant mask-induced priming, but it was insufficient in size to account for the prime-related NCE. Thus mask composition can contribute to NCEs, but when random line masks are employed, the major source of the NCE seems to be motor-inhibition
Inhibition versus attentional momentum in cortical and collicular mechanisms of IOR
No full textInhibition of return (IOR)-the automatic bias against returning attention or gaze to recently visited locations-is thought to have both collicular and cortical components and has been associated with the oculomotor system. Recently, distinct IOR mechanisms have been revealed that may have collicular and cortical origins: While standard luminance stimuli cause IOR in both manual and saccadic eye movement responses, "S cone" stimuli, which are invisible to the direct collicular pathway, caused manual IOR but not saccadic IOR. However, it has not been shown that the separate mechanisms are both inhibition of return, rather than facilitation due to attentional momentum or a visual motion transient. Here, we examined this question using four target and cue locations instead of two. Inhibition at the cued location predicts that responses for all noncued locations should be similar, whereas facilitation at the location opposite the cue predicts that the perpendicular locations would be more similar to the cued location than to the opposite location. Our results conform to the former prediction for both saccadic IOR and S cone generated IOR, demonstrating that both mechanisms of IOR are indeed inhibitory
Negative and positive masked-priming - implications for motor inhibition
No full textMasked stimuli can prime responses to subsequent target stimuli, causing response benefits when the prime is similar to the target. However, one masked-prime paradigm has produced counter-intuitive negative compatibility effects (NCE), such that performance costs occur when prime and target are similar. This NCE has been interpreted as an index of an automatic self-inhibition mechanism that suppresses the partial motor activation caused by the prime. However, several alternative explanations for the NCE have been proposed and supported by new evidence. As a framework for discussion, I divide the original theory into five potentially separable issues and briefly examine each with regard to alternative theories and current evidence. These issues are: 1) whether the NCE is caused by motor inhibition or perceptual interactions; 2) whether inhibition is self-triggered or stimulus-triggered; 3) whether prime visibility plays a causal role; 4) whether there is a threshold for triggering inhibition; 5) whether inhibition is automatic. Lastly, I briefly consider why NCEs have not been reported in other priming paradigms, and what the neural substrate for any automatic motor inhibition might be
Causal claims in health news insufficiently discriminate experimental from correlational evidence
No full textWe coded causal claims in news, press releases and abstracts. We see if these differentiate experimental from correlational evidenc
Probabilistic antecedents of voluntary action are essential components of decision processes.
No full textWhen decision outcomes can be predicted above chance from neural activity before participants indicate the decision is made, some claim this must change our concepts of voluntary decision, while others dismiss such data as reflecting small biases from the legacy of previous trials or the participant’s pre-decision thoughts. In an interactive competitive decision framework, the existence of such probabilistic pre-decision biases is not challenging, but taken for granted. But neither are they uninteresting. Their interaction with incoming evidence about response options is what decisions are made of, and thus, studying their nature is an essential component of volition research
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