Final answer:
Schall and Laird's research supports the facial feedback hypothesis, indicating that smiling can make you feel happy and enhance your mood. This aligns with the two-factor theory of emotion, which states that emotions involve physiological arousal and cognitive appraisal. So, the correct answer is option d.
Step-by-step explanation:
The research conducted by Schall and Laird in 2003 supports the facial feedback hypothesis, which suggests that one's facial expression can influence their emotional experience. When individuals practice happy expressions repeatedly, it tends to enhance their happy mood and improve their ability to recall happy memories.
This supports the idea that smiling can make you feel happy. The findings of this research align with the concept of the two-factor theory of emotion, which states that emotions are composed of both physiological arousal and cognitive appraisal. So, the correct answer is option d.