David De Vito

Suppressing memories of words and familiar objects results in their affective devaluation: Evidence from Think/No-think tasks

Potentially distracting or otherwise-inappropriate stimuli, thoughts, or actions often must be inhibited to prevent interference with goal-directed behaviour. Growing evidence suggests that the impact of inhibition is not limited to reduced neurocognitive processing, but also includes negative affective consequences for any associated stimuli. The link between inhibition and aversive response has primarily been studied using tasks involving attentional- or response-related inhibition of external sensory stimuli. Here we show that affective devaluation also occurs when inhibition is applied to fully-encoded stimulus representations in memory. We first replicated prior findings of increased forgetting of words whose memories were suppressed in a Think/No-think procedure (Experiment 1). Incorporating a stimulus-evaluation task within this procedure revealed that suppressing memories of words (Experiment 2) and visual objects (Experiment 3) also results in their affective devaluation. Given the critical role of memory for guiding thoughts and actions, these results suggest that the affective consequences of inhibition may occur across a far broader range of situations than previously understood.

Neural evidence that inhibition is linked to the affective devaluation of distractors that match the contents of working memory

ABSTRACT Stimuli appearing as visual distractors subsequently receive more negative affective evaluations than novel items or prior targets of attention. Leading accounts question whether this distractor devaluation effect occurs through evaluative codes that become associated with distractors as a mere artefact of attention‐task instructions, or through affective consequences of attentional inhibition when applied to prevent distractor interference. Here we test opposing predictions arising from the evaluative‐coding and devaluation‐by‐inhibition hypotheses using an electrophysiological marker of attentional inhibition in a task that requires participants to avoid interference from abstract‐shape distractors presented while maintaining a uniquely‐colored stimulus in memory. Consistent with prior research, distractors that matched the colour of the stimulus being held in memory elicited a Pd component of the event‐related potential waveform, indicating that their processing was being actively suppressed. Subsequent affective evaluations revealed that memory‐matching distractors also received more negative ratings than non‐matching distractors or previously‐unseen shapes. Moreover, Pd magnitude was greater on trials in which the memory‐matching distractors were later rated negatively than on trials preceding positive ratings. These results support the devaluation‐by‐inhibition hypothesis and strongly suggest that fluctuations in stimulus inhibition are closely associated with subsequent affective evaluations. In contrast, none of the evaluative‐coding based predictions were confirmed. HIGHLIGHTSTest competing hypotheses about how visual distractors become affectively devalued.Recorded event‐related potentials to distractors during visual‐memory maintenance.ERP index of distractor suppression (Pd component) linked to later stimulus ratings.Results confirm predictions from devaluation‐by‐inhibition hypothesis.Findings fail to confirm predictions from evaluative‐coding hypothesis.

Cognitive-behavioral and electrophysiological evidence of the affective consequences of ignoring stimulus representations in working memory

Ignoring visual stimuli in the external environment leads to decreased liking of those items, a phenomenon attributed to the affective consequences of attentional inhibition. Here we investigated the generality of this “distractor devaluation” phenomenon by asking whether ignoring stimuli represented internally within visual working memory has the same affective consequences. In two experiments we presented participants with two or three visual stimuli and then, after the stimuli were no longer visible, provided an attentional cue indicating which item in memory was the target they would have to later recall, and which were task-irrelevant distractors. Participants subsequently judged how much they liked these stimuli. Previously-ignored distractors were consistently rated less favorably than targets, replicating prior findings of distractor devaluation. To gain converging evidence, in Experiment 2, we also examined the electrophysiological processes associated with devaluation by measuring individual differences in attention (N2pc) and working memory (CDA) event-related potentials following the attention cue. Larger amplitude of an N2pc-like component was associated with greater devaluation, suggesting that individuals displaying more effective selection of memory targets—an act aided by distractor inhibition—displayed greater levels of distractor devaluation. Individuals showing a larger post-cue CDA amplitude (but not pre-cue CDA amplitude) also showed greater distractor devaluation, supporting prior evidence that visual working-memory resources have a functional role in effecting devaluation. Together, these findings demonstrate that ignoring working-memory representations has affective consequences, and adds to the growing evidence that the contribution of selective-attention mechanisms to a wide range of human thoughts and behaviors leads to devaluation.

Affective evidence that inhibition is involved in separating accessory representations from active representations in visual working memory

ABSTRACT The multiple state theory of working memory suggests that representations are divided into two states: focused-on active representations and accessory memories held for later use. Here we tested two competing hypotheses regarding the neurocognitive mechanisms responsible for this separation: (1) that accessory memories undergo inhibition or (2) that accessory memories are amplified less than active representations. We explored whether accessory memories undergo affective devaluation, a known index of the involvement of inhibition in a visual task. On each trial participants memorized four items, were cued to focus on one, and then completed a visual search or an affective evaluation task. While search distractors matching the colour of an active item slowed search, those matching an accessory memory did not, replicating previous findings that only active items guide search. Also, accessory items were affectively devalued compared to baseline and active items, supporting the hypothesis that accessory memories undergo inhibition.