Can older adults resist the positivity effect in neural responding? The impact of verbal framing on event-related brain potentials elicited by emotional images

The Last Word: A Comparison of Younger and Older Adults' Brain Responses to Reminders of Death

Objectives

Terror management theory (TMT) suggests increased death awareness motivates various human behaviors and defenses. Recent research reveals age differences in response to increased awareness of death, and older adults' proximity to death may contribute to these differences. In the first known investigation of attention's role in these age differences, we examined brain response associated with attention allocation for death-related stimuli.

Method

Younger (ages 18-28) and older (ages 61-78) adults viewed emotionally neutral, death-related negative, general negative, and positive words while recording event-related potentials (ERPs).

Results

Younger adults exhibited greater amplitudes in the late positive potential component of the ERP in response to death-related than negative words, whereas older adults showed the opposite pattern.

Discussion

Findings provide neurophysiological support for the shift in older adults' responses to death-related stimuli found in other TMT research as well as studies reporting reduced explicit death anxiety in older adults. Results also highlight the importance of considering stimuli content in studies of attention and emotion.

Emotional Modulation of the Late Positive Potential during Picture Free Viewing in Older and Young Adults

Hedonic bias during free viewing of novel emotional and neutral scenes was investigated in older adults and college students. A neurophysiological index of emotional picture processing–the amplitude of the centroparietal late positive potential (LPP)–was recorded from the scalp using a dense sensor array while participants (29 older adults; 21 college students) viewed emotionally engaging or mundane natural scenes that varied in specific content. Both students and older adults showed LPP enhancement when viewing affective, compared to neutral, scenes, and there was no difference in LPP amplitude between older individuals and college students when viewing neutral everyday scenes. However, compared to the college students, older individuals showed attenuated LPP amplitude when viewing emotional scenes, regardless of hedonic valence or specific content. Age related differences could be mediated by a reduction in reactive emotional arousal with age, possible mediated by repeated life exposure to emotional stimuli.

Disgust exposure and explicit emotional appraisal enhance the LPP in response to disgusted facial expressions

The influence of prior exposure to disgusting imagery and the conscious appraisal of facial expressions were examined in an event-related potential (ERP) experiment. Participants were exposed to either a disgust or a control manipulation and then presented with emotional and neutral expressions. An assessment of the gender of the face was required during half the blocks and an affective assessment of the emotion in the other half. The emotion-related early posterior negativity (EPN) and late positive potential (LPP) ERP components were examined for disgust and neutral stimuli. Results indicated that the EPN was enhanced for disgusted over neutral expressions. Prior disgust exposure modulated the middle phase of the LPP in response to disgusted but not neutral expressions, but only when the emotion of the face was explicitly evaluated. The late LPP was enhanced independently of stimuli when an emotional decision was made. Results demonstrated that exposure to disgusting imagery can affect the subsequent processing of disgusted facial expressions when the emotion is under conscious appraisal.