Fig 1.
Three levels of congruency in the Simon task: a) Congruent b) Incongruent c) Neutral.
Fig 2.
Trial procedure. The presented target represents a congruent condition.
Fig 3.
Experiment 1: Simon and interference effects magnitude as a function of manipulation and session in a) young adults and b) elderly adults.
In the elderly adults group a significant reduction in the Simon effect (incongruent RTs—congruent RTs) and interference (incongruent RTs—neutral RTs) was found only after the positive manipulation and not after negative or neutral manipulation.
Fig 4.
Experiment 1: Mean RTs and standard error (SE) for congruency as a function of manipulation and session for a) young adults and b) elderly adults (detailed data extending Fig. 3).
In the elderly adults group only the Simon effect (incongruent RTs—congruent RTs) differed significantly between positive manipulation and the neutral and negative manipulations. More importantly, the interference effect (incongruent RTs—neutral RTs) differed significantly between the positive manipulation and the neutral and negative manipulations. To insure that the significant decrease after the positive manipulation was not a result of baseline differences, we compared interference effects.
Fig 5.
Experiment 1: Simon effect magnitude as a function of previous congruency between sessions in the positive manipulation for seniors.
Before the manipulation, the Simon effect was significant after both congruent and incongruent trials (maladaptive pattern of sequential analysis). After the manipulation, the Simon effect was significant after congruent, but not after incongruent, trials (appearance of an adaptive pattern).
Fig 6.
Experiment 1: Mean RTs and SE for congruency as a function of previous congruency between sessions in the positive manipulation (detailed data extending Fig. 5).
The maladaptive pattern of sequential analysis was present before the manipulation (Simon effect was significant after both congruent and incongruent trials), while an adaptive pattern of sequential analysis was present after the positive manipulation (Simon effect was significant after congruent, but not after incongruent, trials.
Fig 7.
Experiment 2: Mean RTs and standard error (SE) for congruency as a function of manipulation and session.
The Simon effect (incongruent RTs—congruent RTs) differed significantly between positive manipulation and the neutral manipulation. More importantly, the interference effect (incongruent RTs—neutral RTs) differed significantly between the positive manipulation and the neutral manipulation.
Fig 8.
Experiment 2: Simon and interference effects magnitude as a function of manipulation and session.
A significant reduction in the Simon effect (incongruent RTs—congruent RTs) and interference (incongruent RTs—neutral RTs) was found only after the positive manipulation and not after the neutral manipulation.
Fig 9.
Experiment 2: Mean RTs and SE for congruency as a function of previous congruency between sessions in the positive manipulation.
The maladaptive pattern of sequential analysis was present before the manipulation (Simon effect was significant after both congruent and incongruent trials), while an adaptive pattern of sequential analysis was present after the positive manipulation (Simon effect was significant after congruent, but not after incongruent, trials.