How Does Negative Emotion Cause False Memories? C. J. Brainerd, L. M. Stein, R. A. Silveira, G. Rohenkohl, & V. F. Reyna Cornell University, Pontifical Catholic University of Rio Grande do Sul, & University of Santa Cruz do Sul

Emotion, Memory Distortion, and Memory Evidence in Crimes - The bulk of criminal evidence (investigations & trials) consists of memory reports (e.g., oral interviews, written narratives, telephone conversations, s, eyewitness identifications, interrogations, depositions, trial testimony) - A common feature of such reports is that emotional content is involved: - Criminal events are inherently emotional - Memory reports are often given in circumstances that are fraught with emotion (police interviews, interrogations, sworn testimony) -Hence, whether and how emotional content distorts memory is a fundamental question when it comes to the reliability of evidence

Basic Scientific Distinctions About Emotional Content - The 2-dimensional model of emotional content - It’s valenced (has a definite positive/negative, pleasant/unpleasant quality) - It’s physically arousing rather than calming - Data: Variations in valence and arousal affect memory performance differently (cf. Kensinger, 2004) - Variations in valence and arousal have different brain signatures - Valence = LVLPFC, MPFC, & RVLPFC activation - Arousal = L & R amygdale activation -Recent work has stressed that specific emotions (anger, sadness) may have unique semantic content [but that’s a story for another day]

Classic Ideas About How Emotion Affects Memory for Events - Dr. Johnson effect (“When a man knows he is to be hanged in a fortnight, it concentrates his mind wonderfully.”) - Scientific version: Negative content focuses attention on target events, improving verbatim memory and suppressing false memory - Go with the flow (e.g., Storbeck & Clore, 2005) - Positive content enhances meaning extraction, increasing false memory but leaving true memory unchanged - So, classic ideas add up to - Memory enhancement by negative emotion - Memory distortion by positive emotion - But, notice that these ideas are just about valence – arousal is missing in action

Fuzzy-Trace Theory & Emotion - Dual-trace theory of false memory - Verbatim traces of actual events: They support true memory and suppress false memory. - Gist traces of meaning content: They support false memories of meaning-sharing events and true memories. - FTT’s take on emotion - Valence is mainly a gist dimension, in 2 senses: Positive or negative valence is a concept in itself (“my junior prom was the pits”) but valence may also stimulate memory for other meaning content. [Think of it on analogy to semantic orienting tasks.] - Arousal is mainly a verbatim interference manipulation. (Sorry, Dr. Johnson.) Heating up the amygdale generates off-task noise that impairs verbatim memory for actual events. [Think of it on analogy to dual-task deficits.] - Negative valence stimulates semantic processing, relative to positive or neutral, producing stronger gist memories. - So, memory distortion is maximized by negative valence. - Caveats about the elderly and about children will be needed later.

How is Emotion-Induced Memory Distortion Studied in the Lab? - Separate emotion from study/test materials via mood induction before study; administer neutral study/test materials - Storbeck & Clore (2005); Bauml & Kuhbandner (2007); Corson & Verrier (2007) - Put the emotion in the study and test materials, as it is in crimes (e.g., Budson et al., 2006; Brainerd et al., in press) - Today’s experiments

Today’s Experiments - 2 experiments - 1 in Portuguese (Brazilian undergrads) - 1 in English (American undergrads) - Basic design: - Study several “emotional” DRM lists - Respond to conjoint recognition tests

Today’s Experiments - Emotional DRM lists - First 15 forward associates of a negative word (e.g., hungry, lie, thief), a neutral word (e.g., fruit, teacher, window), or a positive word (e.g., baby, god, hug) - Associates are presented as study words but the generating word is not - Generating words appear on memory tests as false memory probes - Arousal is controlled across the 3 valence types

Today’s Experiments - Conjoint recognition tests - Test probes: true (school), false (teacher), unrelated (lake – measures response bias) - Questions: verbatim = word on the list? gist = related to a word on the list? verbatim + gist = either a word on the list or a related word? - Math model: extracts measures of verbatim and gist memory, for both true and false items, from this 3 x 3 matrix

Combined Data (Signal Detection) of the Brazilian and U.S. Experiments

Combined Data of the Brazilian and U.S. Experiments

What the Data ( d′ ) Show About Valence-Induced Memory Distortion - False memory is elevated by negative valence, relative to neutral valence. - False memory is lowered by positive valence, relative to neutral valence. - Net memory accuracy ( d′ true - d′ false ) is increased by positive, relative to neutral. - Net memory accuracy is decreased by negative, relative to neutral. - When valence is negative, memory is net inaccurate: The sign of d′ true - d′ false is negative.

Valence Effects on Verbatim and Gist Memory

Modeling Data: What Valence Does to Gist and Verbatim Memory - False memory probes: - Gist support for false items increases as we move from positive to neutral to negative. - Verbatim suppression of false items decreases as we move from positive to neutral to negative - True memory probes: - Gist support for true items increases from positive to neutral, but not from neutral to negative. - Verbatim support for true items varies only slightly across the 3 valence conditions

The Story So Far for Negative Valence - It increases false memory hugely and decreases net accuracy (because true memory does not increase nearly enough to compensate). - This is mainly a gist-memory effect. Negative valence is an especially good gist that is preferentially processed. - The distortion effects are valence-specific: Positive valence actually reduces false memory and increases net accuracy.

The Story So Far for Negative Valence - Arousal now needs to be folded into the valence picture - We’re working on it - CEL norming project - It looks like arousal amplifies gist processing (increasing false memory) when valence is positive

Two Caveats About Vulnerable Populations - Older adults, who are frequent victims of certain types of crimes: - Display positive gist-processing preferences, rather than the negative preferences of younger adults (Mikels, Carstensen). - So, it is likely that negative distortion effects will morph into positive ones in late adulthood. - Recent data from our labs and Mikel’s lab confirm this prediction. - Children, who are also frequent victims of certain types of crimes: - Display lower levels of false memory when distortion depends on extracting the gist of experience (Brainerd, Reyna, & Ceci, 2008). - So, it is likely that negative distortion effects will be absent or greatly attenuated in children and emerge with development. - Recent data from our labs confirm this prediction.