TESTING THE INTERPRETATION OF INSPECTION TIME AS A MEASURE OF SPEED OF SENSORY PROCESSING

Explaining the relationship between inspection time (IT) and IQ depend s on understanding the psychophysics of IT. White's (1996, Personality and Individual Differences, 20, 351-363) argument that IT is a measur e of temporal resolution within the visual system was tested. Two pred ictions were made on the basis of White's argument that IT does not de pend on line-length discriminations but on discriminating target from mask. First,;radically different target-mask configurations would resu lt in the same response outcome. Second, increasing the number of alte rnative targets would not increase IT. Three subjects performed four p attern masking tasks presented on a LED display with stimulus onset as ynchronies (SOAs) ranging from 0-75 msec and using three configuration s of backward mask. Results met the predictions. Psychometric function s for different tasks were near identical and IT estimates did not inc rease as the number of targets was increased. It is therefore possible that the IT-IQ relationship applies generally to pattern backward mas king tasks. Results also confirmed the prediction (Levy, 1992, Persona lity and Individual Differences, 13, 987-1002; White, 1996, Personalit y and Individual Differences, 20, 351-363) that discriminative accurac y does not rise above chance level until after some small, non-zero SO A. (C) 1998 Elsevier Science Ltd. All rights reserved.