The Influence Of Motivational Intensity On Positivity Effect In Emotional Memory

Younger adults usually have better memory for negative information than positive information.Whereas older adults increasingly remember positive compared to negative information or decreasingly remember negative compared to positive information with advancing age, and this developmental trend was named "positivity effect" in emotional memory, which is shown as age by valence interations on memory performace. Increasing interesting has been focused on positivity effect by reseachers from social emotion aging and emotional cognition realms in recent years. Socioemotional selectivity theory (SST) assumse that the positivity effect is driven by older people’s goal-directed controlled process for emotional information, for they have chronic goals to pursue wellbeing. Therefore, the positivity effcet will appear when the emotional information can be encoded naturally and controllablly by older people, orelse it will disappear under experimental situation with constraints on goals, attention, and/or cognitive resources, for instance, instructing participants to remember or evaluate the information.However, the results on positivity effect from different experiments are not consistent, and the inconsistence can’t be explained effectively by SST constrained-unconstrained processing condition ideas. Anew sound from researchers exploring the factors modulating the positivity effect suggest that motivational relevance maybe one of the important unconsidered foctors. Almost at the same time, a motivational dimensional model of affect was proposed, which suggests motivation is another emotional dimension different from valence and arousal, which varies in the intensity. So it states that emotions with the same valence can be differentiate as high and low motivational intensity, which influence cognition differently through narrowing or broading cognition. Although the study on positivity effect shares the same topic about motivation with the motivational dimensional model, there is no study on positivity effect from the viewpoint of motivational dimensional model yet.For the inconsistence about positivity effect and the lack of a strong interpretation, as well as the new advance both in positivity effect research and related theory, we tried to examine the conditions for positivity effect appearing or disappearing in emotional memory from the viewpoint of the motivational dimensional model of affect. Three studies including five experiments were conducted.To our knowledge, the motivational dimension has not been tested by subjectively evaluating way. we tested this potential dimension firstly in study 1. We asked younger and older participants to evaluate emotional pictures subjectively on valence, arousal and motivation. The results did not support the motivational dimension is independent of valence and arousal, but both positive and negative emotions vary in motivational intensity from low to high.Then we tested the SST hypotheses that unconstrained process lead to positivity effect and constrained process result in its disappearance in study 2. We examined the age differences through free recall and recognition inspectively under unconstrained (incidental memory test without additional encoding task, Experiment 2) and constrained (intentional memory test, Experiment 3) conditions, as well as the role of motivational intensity for positivity effect. It was found that valence-age interaction for recall under unconstrained condition is marginally significant, but is more evident in constrained condition, which is contrary to the SST assumptions. Positivity effect is modulated by motivational intensity in both experiments, however, which appears in different intensity level. It appears in high motivational emotional pictures in experiment 2, whereas appear in low motivational emotional pictures in experiment 3.For the positivity effect only appears in controlled precess according to SST, we speculate the elderly’s emotion regulation goal is mainly acitivated by strong emotions in a incidental memory situation and can be implemented fully in the unconstrained experimental condition, so the positivity effect in experiment 2 was not so obvious and only appeared in recall for high motivational pictures. However, for a better memory performance, lower motivational pictures relative to high ones need much more effortful and strategic process in the intentional memory task, like self-reference encoding, so lead to the positivity effect.Then we tested our interpretations in sdudy 3. Experiment 4 repeated the experiment 2 by replacing motivational intensity as arousal level (high and low), and experiment 5 repeated experiment 3 by replacing intentional encoding as self-refenrence encoding. Results of experiment 4 were proved to be very similar to experiment 4, and experiment 5 also got similar resulta to experiment 3.For a stable mode of positivity effect was observed, we then proposed a hypothetic model about how motivational intensity induced by emotional sitmulis interact with valence and age in different processing conditions.