Reactive control in suicide ideators and attempters: An examination of the congruency sequence effect in cognitive and emotional Simon tasks.

Reactive control is the cognitive ability to adjust thoughts and behaviors when encountering conflict. We investigated how this ability to manage conflict and stress distinguishes suicidal from nonsuicidal individuals. The hypothesis was that suicidal individuals would show poorer reactive control when faced with conflict generated by emotional than neutral stimuli. Hence, individuals with a lifetime history of suicide ideation or attempt and nonsuicidal controls were tested in cognitive and emotional Simon tasks. We examined the congruency sequence effect (CSE) in the Simon tasks as an indication of the efficiency of reactive control in resolving conflict. Whereas controls demonstrated significant CSEs in both tasks, suicide attempters showed a significant CSE in the cognitive task but not in the emotional task. Suicide ideators, on the other hand, displayed marginally significant CSEs in both tasks. Comparing groups with pairwise comparison demonstrated that the difference in CSE was significant only in the emotional task between attempters and controls. Our findings of attempters' inefficiency in adjusting reactive control during the emotional task reflect cognitive inflexibility in coping with conflicting situations during which suicidal individuals become vulnerable to suicide attempts in states of negative emotion.

The effect of threatening facial expressions on inhibition-induced forgetting depends on their task-relevance.

Inhibition-induced forgetting refers to impaired memory for the stimuli to which responses were inhibited. The present study aimed to examine if it would be modulated by the processing of threatening facial expressions. Angry and neutral faces were presented in a go/no-go task and subsequent memory for faces was measured in a surprise recognition task. In Experiment 1, task-irrelevant angry and neutral faces appeared randomly, and participants responded to the gender of the faces during the go/no-go task. Results showed that the perception of neutral faces was possibly biased by angry faces. So, in Experiment 2, angry and neutral faces were given in separate blocks while participants still responded to the gender. Inhibition-induced forgetting was not modulated by facial expressions, as it was observed for both angry and neutral faces. Finally, in Experiment 3, where participants were assigned to respond to either angry or neutral faces, so that facial expressions were relevant, inhibition-induced forgetting was negated only in the group in whom responses to angry faces were inhibited. The findings suggest that task-relevance plays a key role in the way the processing of emotional information influences the interaction between cognitive control and memory encoding.

Memory facilitation for emotional faces: Visual working memory trade-offs resulting from attentional preference for emotional facial expressions.

Visual working memory (VWM) for faces is facilitated when they display negative facial expressions. The present study manipulated the emotional heterogeneity of the encoding display in a change detection task to examine whether VWM is enhanced by having a separate memory store or by a bias in the allocation of limited attentional resource. When the encoding display was emotionally heterogeneous, regardless of whether happy or fearful facial expressions were presented, memory for emotional faces increased while memory for neutral faces decreased, indicating a memory trade-off. To investigate whether this occurred as a result of preferential allocation of attentional resource towards emotional expressions over neutral ones, faces were shown sequentially in different quadrants of the display. The memory trade-off between happy and neutral faces disappeared but persisted between fearful and neutral faces at trailing serial positions. When blank intervals were inserted between faces to prevent fearful faces from having prolonged processing that consumes attentional resource that should be shared with neutral faces, the memory trade-off disappeared. Findings support the argument that emotional expressions facilitate VWM due to their bias in obtaining attentional resource but the exact mechanisms through which limited resource is allocated between happy and fearful expressions may differ.

Remembering faces and scenes: The mixed-category advantage in visual working memory.

We examined the mixed-category memory advantage for faces and scenes to determine how domain-specific cortical resources constrain visual working memory. Consistent with previous findings, visual working memory for a display of 2 faces and 2 scenes was better than that for a display of 4 faces or 4 scenes. This pattern was unaffected by manipulations of encoding duration. However, the mixed-category advantage was carried solely by faces: Memory for scenes was not better when scenes were encoded with faces rather than with other scenes. The asymmetry between faces and scenes was found when items were presented simultaneously or sequentially, centrally, or peripherally, and when scenes were drawn from a narrow category. A further experiment showed a mixed-category advantage in memory for faces and bodies, but not in memory for scenes and objects. The results suggest that unique category-specific interactions contribute significantly to the mixed-category advantage in visual working memory. (PsycINFO Database Record

Similarity effects in visual working memory.

Perceptual similarity is an important property of multiple stimuli. Its computation supports a wide range of cognitive functions, including reasoning, categorization, and memory recognition. It is important, therefore, to determine why previous research has found conflicting effects of inter-item similarity on visual working memory. Studies reporting a similarity advantage have used simple stimuli whose similarity varied along a featural continuum. Studies reporting a similarity disadvantage have used complex stimuli from either a single or multiple categories. To elucidate stimulus conditions for similarity effects in visual working memory, we tested memory for complex stimuli (faces) whose similarity varied along a morph continuum. Participants encoded 3 morphs generated from a single face identity in the similar condition, or 3 morphs generated from different face identities in the dissimilar condition. After a brief delay, a test face appeared at one of the encoding locations for participants to make a same/different judgment. Two experiments showed that similarity enhanced memory accuracy without changing the response criterion. These findings support previous computational models that incorporate featural variance as a component of working memory load. They delineate limitations of models that emphasize cortical resources or response decisions.

Statistical learning modulates the direction of the first head movement in a large-scale search task.

Foraging and search tasks in everyday activities are often performed in large, open spaces, necessitating head and body movements. Such activities are rarely studied in the laboratory, leaving important questions unanswered regarding the role of attention in large-scale tasks. Here we examined the guidance of visual attention by statistical learning in a large-scale, outdoor environment. We used the orientation of the first head movement as a proxy for spatial attention and examined its correspondence with reaction time (RT). Participants wore a lightweight camera on a baseball cap while searching for a coin on the concrete floor of a 64-m(2) outdoor space. We coded the direction of the first head movement at the start of a trial. The results showed that the first head movement was highly sensitive to the location probability of the coin and demonstrated more rapid adjustment to changes in environmental statistics than RTs did. Because the first head movement occurred ten times faster than the search RT, these results show that visual statistical learning affected attentional orienting early in large-scale tasks.