Inspection time and intelligence: further attempts to eliminate the apparent movement strategy

While the inspection time (IT) paradigm has proved itself as one of our best candidates for a reductive measure of general ability, some unsolved problems impede interpretation of the correlation between IQ scores and IT. Foremost among these are concerns that stimulus artifacts may reduce the validity of IT as a measure of processing speed. Attempts to use meta-contrast masks to eliminate apparent movement strategy have proven unsuccessful [Am J Psychol 106 (1993) 191.]. This paper reports on the effectiveness of three backward masks to reduce apparent motion strategies in the IT paradigm as well as assessing putative personality effects on masking and IT. The ability of subjects to use apparent motion was investigated using the traditional IT mask, and two new masks: flash and lines. Apparent motion was most frequently reported by subjects under the traditional masking condition. IQ scores based on a test of figural manipulation (Alice Heim 5 figural) were significantly negatively correlated with reported perception and use of apparent motion cues in the standard IT mask condition, but not in the new mask conditions. Significant negative correlations between IT and IQ were obtained in all masking conditions, suggesting that the use of apparent motion cues does not determine the significant and negative correlation between IT and IQ. Results suggested that future research should employ masks of the type tested here. (C) 2001 Elsevier Science Inc. All rights reserved.