Abstract: The motivational dimensional model of affect, proposed by Gable and Harmon-Jones (2010), posits that approach motivational intensity of positive affect modulates the influence of positive affect on cognition. In line with this model, accumulating evidences have supported this hypothesis. Studies have found that low approach-motivated positive affect (e.g., serenity) broadens, whereas high approach-motivated positive affect (e.g., desire) narrows cognitive breadth, such as the breadth of attention, memory, and cognitive categorization. However, little is known about whether the influence of positive affect on cognitive control, which partly reflects the temporality of cognitive processes, is modulated by the approach motivational intensity of positive affect. Therefore, two experiments in this study were conducted to investigate this issue. In experiment 1, a modified stop-signal task was used to explore the influence of approach motivational intensity of positive affect on inhibition control. The stop signal task involved two concurrent tasks, a primary go task and a secondary stop task. The go task was a two-choice reaction time task that required participants to discriminate the location of black squares (2.4 cm × 2.4 cm) positing on the center of the left or right part of the screen. The stop task, which occurred pseudo-randomly and infrequently (25% of the total trials), involved presentation of a red circle (stop signal) that countermanded the go signal by instructing participants to inhibit their planned response to the go task on that trial. Ninety-one undergraduates were randomly assigned to the three conditions: low approach-motivated positive affect (31, 17 females), high approach-motivated positive affect (30, 16 females), and neutral (30, 16 females) conditions. One-way ANOVAs demonstrated that the effects of emotional pictures on response execution and inhibition were significant. Scheffe tests revealed that, relative to the neutral condition, response inhibition was faster in low approach-motivated positive affect condition, while response execution was faster in high approach-motivated positive affect condition. In experiment 2, we used typical numerical classification tasks to examine the influence of approach motivational intensity of positive affect on task switching. Eighty-four new undergraduates (48 females) were randomly assigned to three experimental conditions. Participants had to judge whether a digit (1~9, excluding 5) was smaller or larger than five (smaller–larger task) or whether it was odd or even (odd–even task). We used either a square or diamond frame with sides that were 4.8 cm in length as task cues to indicate the smaller–larger task or odd–even task, respectively. Repeated measures ANOVAs on reaction time and error rate showed that low approach-motivated positive affect facilitated switched task, while high approach-motivated positive affect facilitated repeated task. Results also indicated that low approach-motivated positive affect reduced reaction time and error switch costs, whereas high approach-motivated positive affect increased reaction time switch costs. In summary, this research suggests that low approach-motivated positive affect enhances cognitive flexibility, whereas high approach-motivated positive affect enhances cognitive stability. The current research extends previous work on cognitive breadth to cognitive control which partly reflects the temporality of cognitive processes. Taken together, this line of research suggests that the effects of positive affect on cognitive processes are modulated by its approach motivational intensity.

Key words: positive affect, approach motivation, cognitive control, stop signal task, task switching