Biomedical subjects

Wim Fias

Publications and source records attributed to Wim Fias.

21 records · Page 2Linked to original sources

PubMed2002

The quantitative nature of a visual task differentiates between ventral and dorsal stream.

The aim of the present positron emission tomography (PET) study was to investigate how visual processing in dorsal and ventral streams depends on the quantitative nature of the task. In the same-different task, participants identified the presence of an orientation difference between two gratings, presented centrally in succession. In the quantification task, participants estimated the magnitude of the difference and compared it to a fixed standard. Detection of dimming of the fixation point was used as a control task. Visual input, motor responses, and performance were equated across tasks. Subtracting same-different from quantification yielded significant activation in the left superior parietal lobule and left ventral premotor cortex, consistent with results obtained in number-processing tasks. The reverse subtraction yielded activation in the right inferior temporal gyrus, in agreement with earlier results. These results demonstrate that a single attribute can be processed either in the ventral or dorsal stream, depending on the cognitive operations required by the tasks.

Adult↗

PubMed2002

Semantic priming in number naming.

The issue of semantic and non-semantic conversion routes for numerals is still debated in numerical cognition. We report two number-naming experiments in which the target numerals were preceded by another numeral (prime). The primes and targets could be presented either in arabic (digit) notation or in verbal (alphabetical) notation. The results reveal a semantically related distance effect: Latencies are fastest when the prime has the same value as the target and increase when the distance between prime and target increases. We argue that the present results are congruent with the idea that the numerals make access to an ordered semantic number line common to all notations, as the results are the same for within-notation priming (arabic-arabic or verbal-verbal) and between-notations priming (arabic-verbal or verbal-arabic). The present results also point to a rapid involvement of semantics in the naming of numerals, also when the numerals are words. As such, they are in line with recent claims of rapid semantic mediation in word naming.

Female↗

PubMed2000

Heuristic and analytic processes in propositional reasoning with negatives.

The authors report 4 studies on heuristic and analytic processes in conditional reasoning with negations and show that a heuristic negative conclusion bias cannot account for the effects observed on problem-solving latencies derived from eye-movement measures (Experiment 1) and a novel mouse-tracking methodology (Experiment 2). A double negation elimination process can account for both the latency and response-frequency effects of a negation in the clause about which an inference is made. It is further shown that other negation effects cannot be explained by an affirmative premise bias proposed in the literature. Experiments 3 and 4 demonstrate that a novel availability hypothesis provides a viable alternative. It is argued that extant analytic theories need to be extended to incorporate a validating search for counter examples and need to specify how pragmatic and comprehension processes influence such a search.

Adult↗