The action property of an object appears to function as an intrinsic part of its mental representation. This phenomenon has been demonstrated in cases where although the grasp response evoked by a visual object is irrelevant to a participant’s task it still appears to be encoded. This is an affordance effect. Recent findings have shown that dangerous objects can modulate the motor system by evoking aversive affordances. However, the way the time course of response activation generated by the dangerous object develops remains unclear. To investigate this process, we used a priming paradigm that varied the stimulus-onset asynchrony (SOA) between a prime and a target. Participants were asked to judge a symbol after presentation of a dangerous object. Results showed a significant congruency effect between the affordance of the ignored object and the requisite response when the SOA was 800 and 1,200 ms, (t(29) = 4.13, p < .001; t(29) = 2.56, p < .05, respectively). However, with briefer SOAs (0 and 400 ms), this congruency effect was not observed (ps > .10). Results indicate the time course of response activation with a dangerous object are relatively long-lasting.

Objects observation automatically elicits the activation of a reach-to-grasp response specifically directed to interact with the object, which is termed affordance. Murphy, van Velzen, and de Fockert (2012) found that only when an irrelevant object receives sufficient attention, it can potentiate an action. However, it remains unclear whether the dangerous object would afford an action when it receives insufficient attention. In this study, we manipulated the perceptual load in a letter identification task. Participants were required to identify a target letter with the right or left hand while ignoring a neutral or dangerous graspable object. The target letter was presented either on its own (low perceptual load), alongside five non-target letters (high load), or alongside eight non-target letters (super high load). Under the low perceptual load, for both neutral and dangerous object, responses were faster when the action afforded by the ignored object was congruent (vs. incongruent) with the current target response (t(27) = 4.44, p < .001; t(27) = 7.99, p < .001, respectively). However, during the high perceptual load, for dangerous object, responses were slower when the action afforded by the ignored object was congruent (vs. incongruent) with the current target response (t(27) = 4.97, p < .001). There was not any effect for both neutral object and dangerous object under super high perceptual load. These results suggest the affordance of dangerous object is also sensitive to the perceptual load. An irrelevant dangerous object can’t potentiate an action if it receives insufficient attention.