Semantic processing of neglected numbers.
While neglected stimuli can still be processed, few studies have directly addressed the issue of the unconscious access to semantics. In order to clarify this issue, we engaged four patients with unilateral left spatial neglect in a number comparison task. Each target number was preceded by a lateralized number prime, either in the intact or neglected hemifield (HF). Both group analyses and the intensive study of a single patient show that left (neglected) as well as right (consciously perceived) number primes affect performance: primes representing quantities that fall on the same side of the reference as the target lead to faster categorization. This congruency effect is highly suggestive of numerical semantic processing of neglected stimuli. Absence of conscious perception of neglected primes was evaluated using a combination of subjective and objective measures of performance in forced-choice tasks.
Sackur
Jérôme
J
INSERM U562, CEA/DSV, IFR 49, Orsay, France; Department of Philosophy, Université Nanterre-Paris X, Nanterre, France. jerome.sackur@gmail.com
Naccache
Lionel
L
Pradat-Diehl
Pascale
P
Azouvi
Philippe
P
Mazevet
Dominique
D
Katz
Rose
R
Cohen
Laurent
L
Dehaene
Stanislas
S
D000328:Adult; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology*; D001364:Awareness / Q000502:physiology*; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D005108:Extinction, Psychological / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010468:Perceptual Disorders / Q000503:physiopathology* / Q000523:psychology; D011930:Reaction Time / Q000502:physiology; D021641:Recognition, Psychology / Q000502:physiology*; D012016:Reference Values; D012660:Semantics; D014473:Unconscious, Psychology