| Description |
The Neural Efficiency Hypothesis (NEH) states that individuals with higher measured intelligence exhibit less neural activation on relatively simple tasks compared to those with lower intelligence (Haier et al., 1988). Furthermore, this phenomenon may interact with repetition suppression, or the reduction of neural activity following repeat stimulus exposure (Grill-Spector et al., 2006). The current study examined the relationship between intelligence and event-related EEG amplitudes and latencies during the third of three task conditions, a visual repetition paradigm. Full Scale IQ (FSIQ) scores from the Wechsler Adult Intelligence Scale III (WAIS-III; Wechsler, 1997) were collected on 30 participants, 18 of whom had sufficient numbers of EEG trials for further analysis (FSIQ: M = 111.56, SD = 13.28, range = 91 to 131). During EEG recording, participants were asked to respond to randomized line drawings representing one of three stimulus conditions from the previous two tasks: Repeated stimuli, Once-viewed, and Novel stimuli. Time-frequency analyses were conducted to identify peak phase-locked activity in the theta (4-7 Hz) and alpha (8-12 Hz) bands between 0 and 500 milliseconds poststimulus. Results demonstrated no significant effects of IQ or stimulus condition on peak theta and alpha amplitudes. However, difference scores between Novel and Once-viewed conditions in peak theta latency showed a strong positive correlation with IQ (r[16] = .712, p < .01). These findings appear consistent with the NEH in suggesting that higher IQ individuals may process previously-seen stimuli more efficiently than lower IQ individuals, as evidenced by shorter peak latencies relative to stimulus onset. |
