Correlates and stability of alternate stimuli in a computer-based measure of inspection time

Inspection time tasks assess the ability to make a simple visual discrimination, typically in milliseconds. Typically, IT stimuli consists of a pi-shaped figure, in which subjects select the side with the significantly longer leg. To prevent storage in iconic memory, a backward mask is then introduced. However, some participants have reported that the mask may cause the shorter leg to appear to lengthen, creating a possible strategy that facilitates performance. As a result, alternative stimuli/masks have been developed; however, these alternative stimuli may be processed differently. This study assessed the cognitive correlates and stability of an alternative stimuli/mask. Results indicated that processing of the stimuli was influenced by an interaction between the complexity of the stimuli and the number of times it was presented. Specifically, the alternative stimulus/mask produced slower processing, particularly at the time of a second administration; however, it contributed an important and unique relationship with speeded, general intelligence.     

Advances in the assessment of cognitive skills using computer-based measurement

The impact of technology in the field of intellectual assessment has, for the most part, been limited to computerized administration and scoring. Anderson’s (2001) theory of intelligence suggests that performance on traditional IQ measures is acquired via two main routes, thinking and dedicated processing systems known as modules. Empirical data used to support this relationship between the speed of basic processing and intellectual functioning have been evidenced primarily by correlations between measures of general intelligence and measures of inspection time (IT). These IT measures allow individuals to make a forced choice discrimination task without a motor component. Because only the time used to cognitively solve the problem is recorded, these responses typically occur in milliseconds. Many theorists (e.g., Burns & Nettelbeck, 2002; Deary, 2000; Jensen, 2006) consider IT to be a more “pure” measure of intelligence, because the influences of verbal skills, memory, and socialization are minimized and results are therefore considered to be more culture-fair. Until relatively recently, IT measurement was restricted to complex and expensive specialized laboratory equipment. This article describes the theoretical background and developmental process of a computer-based IT measure that is easily adaptable to accommodate the needs of the researcher.