Search

Individuals' reaction time (RT) slopes in tasks of mental rotation have been found to be related to other measures of visual-spatial abilities, and thus are often viewed as a psychometric measure of visual-spatial abilities. The common interpretation of individual RT slopes is as a measure of the speed at which the rotation is carried out. However, electroencephalography studies have found that the process of mental rotation continues after response selection has been carried out, casting doubt on the interpretation of RT slopes as measures of the speed of mental rotation. This study made use of electroencephalography techniques to directly capture individual differences in the speed of mental rotation and assess their association with visual-spatial abilities. We found that individual differences in mental rotation speed are not related to individual differences in RT slopes. Moreover, a computation model supports an alternative explanation by which RT slopes reflect individual differences in differential tolerances for stimulus identification within mental rotation tasks. Public Significance Statement: This research challenges the long-held assumption that reaction time slopes in mental rotation tasks directly reflect individual differences in visual-spatial processing speed. Instead, by employing electroencephalography and behavioral computation models, our findings suggest that these reaction time slopes reflect individual differences in decision thresholds. These findings have significant implications for understanding individual variations in mental rotation performance and spatial reasoning skills. [ABSTRACT FROM AUTHOR]

Representations of the fingers are embodied in our cognition and influence performance in enumeration tasks. Among deaf signers, the fingers also serve as a tool for communication in sign language. Previous studies in normal hearing (NH) participants showed effects of embodiment (i.e., embodied numerosity) on tactile enumeration using the fingers of one hand. In this research, we examined the influence of extensive visuo-manual use on tactile enumeration among the deaf. We carried out four enumeration task experiments, using 1-5 stimuli, on a profoundly deaf group (n = 16) and a matching NH group (n = 15): (a) tactile enumeration using one hand, (b) tactile enumeration using two hands, (c) visual enumeration of finger signs, and (d) visual enumeration of dots. In the tactile tasks, we found salient embodied effects in the deaf group compared to the NH group. In the visual enumeration of finger signs task, we controlled the meanings of the stimuli presentation type (e.g., finger-counting habit, fingerspelled letters, both or neither). Interestingly, when comparing fingerspelled letters to neutrals (i.e., not letters or numerical finger-counting signs), an inhibition pattern was observed among the deaf. The findings uncover the influence of rich visuo-manual experiences and language on embodied representations. In addition, we propose that these influences can partially account for the lag in mathematical competencies in the deaf compared to NH peers. Lastly, we further discuss how our findings support a contemporary model for mental numerical representations and finger-counting habits.

Background: Arithmetic is the domain of academic achievement most consistently related to prenatal alcohol exposure (PAE). Error detection, an important aspect of arithmetic processing, can be examined in a mathematical verification task. Electroencephalographic (EEG) studies using such tasks have shown bursts of synchronized theta‐band activity in response to errors. We assessed this activity for error detection in adolescents with PAE and typically developing (TD) matched controls. We predicted that the PAE group would show smaller theta bursts during error detection and weaker responses depending on the size of the error discrepancy. Methods: Participants' mothers were recruited during pregnancy and interviewed about their alcohol consumption using a timeline follow‐back interview. Participants were followed from infancy and diagnosed for fetal alcohol syndrome (FAS) or partial FAS (PFAS) by expert dysmorphologists. EEGs were recorded for 48 adolescents during a verification task, which required differentiation between correct/incorrect solutions to simple equations; incorrect solutions had small or large deviations from correct solutions. Results: Performance was good–excellent. The PAE group showed lower accuracy than the TD group: Accuracy was inversely related to diagnosis severity. The TD and heavily exposed (HE) nonsyndromal groups showed the expected differentiation in theta‐burst activity between correct/incorrect equations, but the FAS/PFAS groups did not. Degree of impairment in brain response to errors reflected severity of diagnosis: The HE group showed the same differentiation between correct/incorrect solutions as TD but failed to differentiate between levels of discrepancy; PFAS showed theta reactions only in response to large error discrepancies; and FAS did not respond to small or large discrepancies. Conclusions: Arithmetical error–related theta activity is altered by PAE and can be used to distinguish between exposed and nonexposed individuals and within diagnostic groups, supporting the use of numerical and quantitative processing patterns to derive a neurocognitive profile that could facilitate diagnosis and treatment of fetal alcohol spectrum disorders. [ABSTRACT FROM AUTHOR]