Inspection time: a flash mask to reduce apparent movement effects

How Do People Perform an Inspection Time Task? An Examination of Visual Illusions, Task Experience, and Blinking

In the inspection time (IT) paradigm, participants view two lines of unequal length (called the Pi-figure) for a short exposure time, and then judge which of the two lines was longer. Early research has interpreted IT as a simple index of mental speed, which does not involve motor activity. However, more recent studies have associated IT with higher-level cognitive mechanisms, including focused attention, task experience, and the strategic use of visual illusions. The extent to which these factors affect IT is still a source of debate. We used an eye-tracker to capture participants' (N = 147) visual attention while performing IT trials. Results showed that blinking was time-dependent, with participants blinking less when the Pi-figure was visible as compared to before and after. Blinking during the presentation of the Pi-figure correlated negatively with response accuracy. Also, participants who reported seeing a brightness illusion had a higher response accuracy than those who did not. The first experiment was repeated with new participants (N = 159), enhanced task instructions, and the inclusion of practice trials. Results showed substantially improved response accuracy compared to the first experiment, and no significant difference in response accuracy between those who did and did not report illusions. IT response accuracy correlated modestly (r = 0.18) with performance on a short Raven's advanced progressive matrices task. In conclusion, performance at the IT task is affected by task familiarity and involves motor activity in the form of blinking. Visual illusions may be an epiphenomenon of understanding the IT task.

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.

Genetic covariation among facets of openness to experience and general cognitive ability

Genetic and environmental sources of covariation among cognitive measures of verbal IQ, performance IQ (PIQ), academic achievement, 2-choice reaction time (CRT), inspection time (IT) and the 6 Openness facets of the NEO Personality Inventory-Revised (NEO PI-R) were examined. The number of twin and twin-sibling pairs ranged from 432 (182 MZ, 350 DZ/sibling) to 1023 (273 MZ, 750 DZ/sibling) for cognitive measures, and between 432 (90 MZ, 342 DZ/sibling) - 437 (91 MZ, 346 DZ/sibling) for Openness facets. Structural equation modeling best supported a model with a 3-factor additive genetic structure. A genetic general factor subsumed the 5 cognitive measures and 5 of the 6 Openness facets (Actions did not load significantly). A second additive genetic factor incorporated the 6 Openness facets, and a third additive genetic factor incorporated the 5 cognitive measures. Specific additive and dominance genetic effects were also evident, as were shared common and shared unique environmental influences, and specific unique environmental effects. The Openness facets of Ideas and Values evidenced the strongest phenotypic correlations with cognitive indices, particularly verbal measures. The genetic correlations among Openness facets and cognitive measures ranged from -.06 to .79. Results were interpreted as suggesting that Openness is related to general cognitive ability (g) through a genetic mechanism and that gengenders a minor but discernable disposition towards Openness for the majority of facets.

Endogenous testosterone levels, mental rotation performance, and constituent abilities in middle-to-older aged men

Evidence from both human and animal studies suggests that gonadal steroids, such as testosterone, exert activational effects on adult spatial behavior. Endogenous testosterone levels decline gradually but variably as men age; it remains to be shown whether these decreases are associated with age-related declines in visuo-spatial performance or constituent abilities indicative of generalized age-related cognitive decline. Ninety-six healthy, community dwelling men aged between 38 and 69 years completed the Vandenberg and Kuse Mental Rotation Test (MRT) together with a battery of tests including processing speed, executive function, perceptual discrimination, working memory, and reaction time measures. Significant main effects of tertiles of calculated free testosterone levels (cEFT) were found on composite measures of processing speed, executive function, and perceptual discrimination ability in a subset of men aged over 50 years in age and crystallized intelligence controlled analyses; higher cEFT levels were associated with poorer performance. Hierarchical multiple regression and path analyses on the whole data set showed that cEFT levels negatively moderated processing speed performance, which in turn predicted both working memory and MRT performance with aging. Together these data suggest that age-related declines in endogenous testosterone levels in healthy middle-to-older aged men are not associated with generalized age-related cognitive decline.

Measuring Auditory Inspection Time in Primary School Children

This study investigated the relationship between visual inspection time (VIT) and a new measure of auditory inspection time (AIT: see Parker, Crawford, & Stephen, 1999 ). The purpose was twofold: first, to understand the generality of the mechanism underpinning performance on visual IT tasks (VIT); second, to evaluate the efficacy of this new auditory task. Participants were 80 primary school children aged 10–12 years. They each completed AIT, VIT, and a marker test for each of general speediness (Gs), fluid ability (Gf), and crystallized ability (Gc). AIT and VIT were positively correlated with each other, and they both correlated with the marker of Gs. However, the data suggest that the nature of IT tasks changes as task difficulty increases. Thus, IT appears to be a purer measure of processing speed at longer exposure durations. These findings are discussed in relation to the methodology employed in IT estimation and in light of recent comments concerning the psychological complexity of IT.

Perceptual Learning on Inspection Time and Motion Perception

Perceptual learning on simple perceptual tasks is interpreted as plasticity of neuronal populations in the sensory cortex (M. Fahle & T. Poggio, 2002). The authors examined individual differences on perceptual learning for 2 tasks-inspection time (IT) and a motion direction discrimination task that was instantiated as random dot kinematograms. The authors' main questions were whether individual differences in perceptual learning were consistent across the 2 tasks and whether perceptual learning correlated with cognitive abilities test scores. In all, 56 young adults completed 16 threshold estimations on 1 of 2 orthogonal versions of each task. Then, the authors made 2 further threshold estimations for the untrained, orthogonal version. Participants also completed a battery of 6 cognitive abilities tests that measured fluid ability (Gf) and perceptual speed (Gs). Perceptual learning was demonstrated for both tasks, but the degree of learning across tasks was not characteristic of the individual. Learning on IT correlated with Gs (r = .35), but learning on the motion direction discrimination task was unrelated to cognitive ability. Correlations of IT with cognitive measures were stable over the training period. IT was correlated with both the motion direction discrimination task (r = -.39) and an unmasked line length judgment task (r = -.31). The authors concluded that perceptual learning on IT correlates with cognitive abilities test scores, that correlations of IT with cognitive abilities test scores are stable as task performance improves with practice, and that the IT task is psychologically complex.

The string measure of the ERP: what does it measure?

The event-related brain potential (ERP) has been investigated extensively inan effort to understand the neurophysiological bases of intelligence. Measures derived from the ERP have been used as indices of intelligence, particularly the string measure of the complexity of the ERP. However, the string measure has been criticised for being non-specific and for being dependent on ERP amplitude. These criticisms were tested by investigating relationships between ERP string measure, ERP amplitude measures, and the ERP power spectrum. It was found that the string measure was non-specific in that it indexes both low and high frequency event-related activity; the string measure is also dependent on ERP amplitude. The string measure is therefore not a valid measure of the ERP. It was concluded that the string measure should be abandoned; human intelligence cannot map in a simple way onto gross measures of scalp-recorded electrocortical activity.

Reductionism and intelligence: the case of inspection time

Successes in science tend to be successful attempts at reduction and causal interaction. The reduction of the interaction of bodies to the laws of motion and the reduction of chemical phenomena to elements and their interactions are good examples. In these cases reductionism leads to observed phenomena being explained by a relatively small number of basic concepts and the laws which govern the interaction of the concepts. The spectrum of inquiry that stretches from common sense to scientific psychology is infused with a tendency toward reductionism. Hippocrates and Galen originated and developed, respectively, the notion that temperamental differences might be reducible to the amounts of four bodily fluids, or humours (black bile, yellow bile, blood and phlegm), that a person produced. Astrologers reduced stable personality differences to the positions of the stars and planets at the time of birth. And differential psychologists have reduced the personality trait adjectives contained in the lexicon to about five major dimensions.

The abilities of a musical savant and his family

The ability of a male autistic savant (TR) to play two unfamiliar piano pieces after listening to a tape-recording was tested, closely following the procedures of Sloboda, Hermelin, and O'Connor (1985). Other components of TR's musical ability--pitch recognition, improvisation, and ability to provide harmonic accompaniment--were also examined. TR's musical precocity was examined in relation to his general level of intellectual functioning as indexed by a battery of standardized psychological tests of intelligence, memory, reading, visual organization, and creativity. His parents and two male siblings also completed tests of intelligence. Results from psychometric testing indicated that TR has idiosyncratic levels of cognitive functioning with difficulties in verbal reasoning but high levels of concentration and memory. His speed of information processing, as indicated by Inspection Time, and was better than average. TR demonstrated perfect pitch recognition and other family members also demonstrated excellent relative pitch. TR's ability to recall and perform structured music within both the diatonic and whole-tone systems was exceptional but dependent upon his familiarity with musical structure and was therefore organized and rule-driven. Furthermore, TR demonstrated competence in improvisation and composition, albeit restricted by his adherence to structural representations of familiar musical rules.