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Gavin Lawrence

Publications and source records attributed to Gavin Lawrence.

2 recordsLinked to original sources

Can the location negative priming process operate in a proactive manner?

The location negative priming (NP) effect refers to the fact that the processing of a current target stimulus (probe trial) is delayed when it appears at a location that has recently contained a distractor event (prime trial), relative to when it occurs at a previously unoccupied position. One view is that the process causing the NP effect involves the inhibition of the internal representation of the prime-distractor event, and that the future processing of target stimuli that involve this event are prolonged because this distractor inhibition is persistent. In this study, we examined the possibility that the NP process (inhibition) could act proactively; specifically asking whether inhibition could be allocated to a location merely predicted to hold a future distractor event. To do this, we cued the probe distractor's location using an otherwise traditional location NP paradigm. No evidence of a proactive NP process was obtained. Probe-trial target latency was the same whether it appeared at the cued distractor location or at a new location, but was delayed when it occupied the prime-distractor location (NP effect). The location NP process is seemingly a reactive one, applying inhibition only when an actual distractor is present, much as past theories have implied.

Attention↗

Online versus offline processing of visual feedback in the control of movement amplitude.

Researchers have suggested that visual feedback not only plays a role in the correction of errors during movement execution but that visual feedback from a completed movement is processed offline to improve programming on upcoming trials. In the present study, we examined the potential contribution of online and offline processing of visual feedback by analysing spatial variability at various kinematic landmarks in the limb trajectory (peak acceleration, peak velocity, peak negative acceleration and movement end). Participants performed a single degree of freedom video aiming task with and without vision of the cursor under four criterion movement times (225, 300, 375 and 450 ms). For movement times of 225 and 300 ms, the full vision condition was less variable than the no vision condition. However, the form of the variability profiles did not differ between visual conditions suggesting that the contribution of visual feedback was due to offline processes. In the 375 and 450 ms conditions, there was evidence for both online and offline control as the form of the variability profiles differed significantly between visual conditions.

Adolescent↗