Table 2.

Factors to consider when designing a study to assess emotional memory.

Factor	Why consider this factor?	When is it most prevalent?	How to manipulate?	Possible to control for in data analyses?
semantic coherence/relatedness	Stronger semantic clustering of emotional (vs. neutral) stimuli can contribute to emotional enhancement of memory by making stimuli easier to organize. It also can boost false memories because lures are more closely related to studied items.	if not using categorized neutral items if selecting emotional stimuli from a small number of categories (e.g., vicious animals, injured people)	use a design that fully crosses emotional content and semantic relatedness	if standardized database available, use calculated coherence of emotional and neutral stimuli as a covariate in analyses
attention allocation	Emotional stimuli often attract attention. This can enhance memory for the emotional stimuli but can reduce memory for neutral (or low-priority; see Mather & Sutherland, 2011) stimuli competing for processing resources.	if processing demands of task are high (e.g., limited time to process stimuli; multiple stimuli competing for resources)	manipulate task demands (e.g., divided attention and full attention) alter salience of neutral stimuli by manipulating the stimuli or the task	measure eye gaze and use looking time as a covariate (Note: this will only co-vary overt, not covert, attention)
distinctiveness	Many effects of emotion may be due to the incongruent or unexpected nature of the stimulus or event, rather than to an emotional response to that stimulus or event.	if frequency (both within the study session and within an everyday context) is not matched between emotional and neutral stimuli if familiarity and frequency are not matched between emotional and neutral events if mixed lists are used rather than pure lists (this may also affect induced arousal of person; see below)	compare performance in mixed lists to performance in pure lists compare surprising events that elicit different magnitudes of emotional reactions (e.g., garden-path sentences ending in emotional vs. semantic non sequitur)	include ratings of frequency, familiarity, and surprise as covariates
arousal	Arousal can influence memory in a number of ways, depending on whether the arousal refers to the ratings given to a single stimulus within a stream of stimuli, to the state of an individual induced by the presented stimuli or event, or to the natural state of an individual that is unrelated to the stimuli or event.	Stimulus characteristic: if stimuli are not matched for arousal; if an event is surprising; likely to be correlated with the intensity of the emotional response Induced state of person: when emotional stimuli are presented in a block (rather than intermixed with neutral stimuli), or when an event is of relatively long duration (more than a few seconds) Natural state of person: individual variations are always present but may be exaggerated when comparing different patient groups or age groups	Stimulus characteristic: select stimuli to include multiple levels of arousal (e.g., low- and high-arousal negative stimuli) Induced state of person: compare pure to mixed lists of emotional stimuli (although this may also affect stimulus distinctiveness; see above) include intentional mood induction as part of experimental design Natural state of person: direct manipulation likely impossible, but can compare groups selected a priori to differ in baseline state (e.g., high- vs. low-anxiety group)	Stimulus characteristic: include ratings of arousal as a covariate Induced state of person: include change in cortisol or alpha amylase as an estimate of arousal response Natural state of person: include baseline cortisol or alpha-amylase level as an estimate of natural arousal state

Note: This table does not present an exhaustive list. Depending on the goals of the experiment, other factors to consider may include: valence of the stimuli (how positive or negative), discrete emotions elicited by the stimuli, mood of the participant, stimulus complexity, event rehearsal