Emotional arousal's opposing effects
Imagine you hear a gunshot go off outside your office door. Years of research show that the surge of arousal you experience at that moment will influence your perception and memory. But some studies find that arousal enhances processing whereas others find that it impairs it. How can one predict what impact arousal will have? The arousal-biased competition model posits that arousal does not have fixed rules about what mental processing to enhance or suppress. Instead, arousal amplifies the stakes of on-going selection processes, leading to "winner-take-more" and "loser-take-less" effects in perception and memory.
How can a surge of arousal simultaneously enhance processing high priority information and impair processing low priority information? In the GANE model, we propose that local interactions of norepinephrine and glutamate can explain emotional arousal's selective effects.
Decision making under stress
Stress hormones affect prefrontal brain regions and dopaminergic pathways involved in decision making (for a review see Mather & Lighthall, 2012). Stress increases the impact of rewarding outcomes on learning (Lighthall et al., 2013). We have found age differences in how stress affects decision making in a driving game (Mather, Gorlick, & Lighthall, 2009) and also sex differences in how stress affects decision making (Lighthall, Mather, & Gorlick, 2009; Lighthall et al., 2012). If you are interested in trying out the driving game, it is available here.
The role of executive resources in older adults' positivity effect
Older adults often show a positivity effect in attention and memory. We have been investigating whether older adults' positivity effects are the result of strategic, self-initiated processes rather than age-related decline in brain areas associated with processing negative stimuli (for a review see Nashiro et al., 2012). In several studies, we found that cognitive resources seem to play a key role in older adults' positivity effects. For instance, during full attention, older adults focus more on positive pictures than younger adults do--but when distracted, older adults focus more on negative pictures (Knight et al., 2007). In addition, prefrontal functional connectivity with the amygdala predicts older adults' positivity effect (Sakaki et al., 2013).