Biomedical subjects

Bernie Caessens

Publications and source records attributed to Bernie Caessens.

5 recordsLinked to original sources

PubMed2006

Numbers and space: a computational model of the SNARC effect.

The SNARC (spatial numerical associations of response codes) effect reflects the tendency to respond faster with the left hand to relatively small numbers and with the right hand to relatively large numbers (S. Dehaene, S. Bossini, & P. Giraux, 1993). Using computational modeling, the present article aims to provide a framework for conceptualizing the SNARC effect. In line with models of spatial stimulus-response congruency, the authors modeled the SNARC effect as the result of parallel activation of preexisting links between magnitude and spatial representation and short-term links created on the basis of task instructions. This basic dual-route model simulated all characteristics associated with the SNARC effect. In addition, 2 experiments tested and confirmed new predictions derived from the model.

Adult↗

PubMed2005

Unconscious primes activate motor codes through semantics.

Today, it is generally accepted that unconscious stimuli can activate a response code, which leads to a response congruency effect (RCE) on a subsequent target. However, it is not yet clear whether this is due to the semantic processing of the primes or to the formation of direct stimulus-response (S-R) associations bypassing the semantic system. Recently, it was shown that even novel primes, for which no direct S-R links exist, can also evoke an RCE that is in line with the activation of response codes through semantics. In these experiments, the authors examined 3 alternatives for this RCE from novel primes and report a novel effect in unconscious priming. First, the authors show that this effect is not limited to a small set of numerical stimuli but also extends to letter stimuli (Experiments 1-3). Second, the authors show that the RCE is not a side effect of the prime-target distance effect, as has been reported before (Experiments 1-2). Third, the authors found that, for RCE to occur, overlap at the motor level but not at the semantic level was crucial (Experiments 2-3). Finally, in addition, the results showed a category match priming effect independent of RCE. This last result is evidence that novel unconscious primes activate their semantic category prior to the target and might be considered a good marker for semantic processing.

Humans↗

PubMed2004

Backward-compatibility effects with irrelevant stimulus-response overlap: the case of the SNARC effect.

In 3 dual-task experiments, the relationship between primary-task response (R1) and secondary-task response (R2) was varied. In general, R1-left responses were faster when followed by the word one, and right responses were faster when followed by the word two. This backward-compatibility (BWC) effect indicated (a) that activation of R2 was not delayed until R1 selection was completed, and (b) that activation of the vocal responses was accompanied by the automatic activation of magnitude codes, known to be associated with spatial left-right codes (spatial-numerical association of response codes [the SNARC effect]). These findings supported the hypotheses (a) that BWC effects persist even with irrelevant R1-R2 overlap, (b) that the SNARC effect is based on associations between magnitude and spatial representations underlying response processing, and (c) that the production and perception of magnitudes relies on common codes.

Adult↗

PubMed2002

Inhibition and blindness to response-compatible stimuli: a reappraisal.

Recent studies show that the preparation of an action can interfere with the concurrent detection and identification of objects that share features with this action, a phenomenon termed blindness to response-compatible stimuli. In order to account for the blindness effect, an integration mechanism for response features similar to the one suggested for object features has been proposed. In the present article, we propose an alternative explanation, namely an action-effect inhibition mechanism. This mechanism was demonstrated in two versions of a dual-task experiment using a primary stop-signal task. The results showed that when the primary response was withheld (signal-inhibit trials), this resulted in lower identification rates for compatible secondary task stimuli. On the other hand, we did not find any evidence for a blindness effect when the primary response was executed (no-signal trials). Additionally we found that identification rates depended on the time course of the inhibition process as estimated from our data. Consequently, the blindness effect seems to result from the requirement to inhibit the response, perhaps even if only temporary.

Adult↗

PubMed2002

Automatic stimulus-response associations may be semantically mediated.

Three experiments on numerical odd/even judgment are presented. In the first experiment, we show that tachistoscopically presented Arabic primes influence the reaction latencies (RTs) to Arabic targets in two ways: First, RTs to targets are longer when the prime and the target have a different parity status than when they share the same parity status, and second, on compatible trials, RTs are longer when the absolute distance between the prime and the target is larger. Experiments 2 and 3 extend the first finding by showing that the response compatibility effect is also obtained (1) when the primes are not part of the target set and the participants never reacted to them and (2) when the primes are presented in a different modality (verbal numerals) than are the targets (Arabic numerals). On the basis of these results, we conclude that, in masked priming, response codes are automatically activated by stimulus characteristics of the prime and that the activation of response codes is semantically mediated when the primes are meaningful.

Association↗