Ejs. Sonugabarke et al., THE ROLE OF INTERVAL UNDERESTIMATION IN HYPERACTIVE CHILDRENS FAILURETO SUPPRESS RESPONSES OVER TIME, Behavioural brain research, 94(1), 1998, pp. 45-50
The relationship between response inhibition and time estimation abili
ties was investigated in a group of hyperactive and non-hyperactive ch
ildren. Children performed a discrete trials intertemporal response ta
sk under two conditions. Under both conditions children had to respond
within a 2 s window, which was delayed for a set period (either 5 or
15 s). In condition one (signalled condition), these response requirem
ents were signalled by changes in the expression of a face drawn on a
computer screen. In condition two (unsignalled condition), always pres
ented on the trial following the signalled condition, these changes in
expression were obscured by a hand drawn over the mouth of the face s
o that effective performance depended on the childs ability to estimat
e the point at which the facial expression changed on the preceding tr
ial. Both groups of children had little difficulty inhibiting response
s when the response requirements were signalled. All children made far
more errors under the unsignalled condition. Hyperactive children dis
played a systematic tendency to respond before the response window occ
urred. Taken together, these data give no support to the idea that hyp
eractivity is essentially a problem of disinhibition and raise interes
ting questions about the role of time mis-estimation in the disorder.
(C) 1998 Elsevier Science B.V. All rights reserved.