טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentArgaman Elisheva Rotma
SubjectPollyanna Effect vs. Loss Attention: The Role of Event
Mixing in Incidental Memory of Positive and
Negative Events
DepartmentDepartment of Industrial Engineering and Management
Supervisor Professor Eldad Yechiam


Abstract

Greater recall of positive than negative events has been observed in incidental memory studies. Conversely, findings indicate a negativity bias in people’s cognitive performance. This calls into question the established positivity bias in memory, as increased attention ought to improve memory. To account for this apparent inconsistency, we rely on the notion that while negative events increased attention, there is a long decay process for this attentional effect, and hence when positive and negative events are mixed the attentional asymmetry is diminished. Based on a two-process attention-strategy model, we suggest that a negativity bias in incidental memory performance emerges for non-mixed positive and negative events, while a positivity effect emerges given intermixed events. In Studies 1 and 2 participants performed a decision task with mixed positive and negative outcomes, and showed a robust positivity bias in their recollections. In Study 3 participants performed a task with non-mixed positive or negative outcomes, and exhibited a negativity bias in recollections as well as response time. In Study 4 we compared mixed and blocked schedules of positive and negative outcomes, and found that mixing trials eliminated the negativity bias. The findings indicate that humans show both positivity and negativity biases in their incidental recollections depending on the intermixture of events.