Linking impulsivity and inhibitory control using manual and oculomotor response inhibition tasks

Separate cognitive processes govern the inhibitory control of manual and oculomotor movements. Despite this fundamental distinction, little is known about how these inhibitory control processes relate to more complex domains of behavioral functioning. This study sought to determine how these inhibitory control mechanisms relate to broadly defined domains of impulsive behavior. Thirty adults with attention-deficit/hyperactivity disorder (ADHD) and 28 comparison adults performed behavioral measures of inhibitory control and completed impulsivity inventories. Results suggest that oculomotor inhibitory control, but not manual inhibitory control, is related to specific domains of self-reported impulsivity. This finding was limited to the ADHD group; no significant relations between inhibitory control and impulsivity were found in comparison adults. These results highlight the heterogeneity of inhibitory control processes and their differential relations to different facets of impulsivity.     

Depressed people are not less motivated by personal goals but are more pessimistic about attaining them

Despite its theoretical importance, personal goal motivation has rarely been examined in clinical depression. Here we investigate whether clinically depressed persons (n = 23) differ from never-depressed persons (n = 26) on number of freely generated approach and avoidance goals, appraisals of these goals, and reasons why these goals would and would not be achieved. Participants listed approach and avoidance goals separately and generated explanations for why they would (pro) and would not (con) achieve their most important approach and avoidance goals, before rating the importance, likelihood, and perceived control of goal outcomes. Counter to hypothesis, depressed persons did not differ from never-depressed controls on number of approach or avoidance goals, or on the perceived importance of these goals. However, compared to never-depressed controls, depressed individuals gave lower likelihood judgments for desirable approach goal outcomes, tended to give higher likelihood judgments for undesirable to-be-avoided goal outcomes, and gave lower ratings of their control over goal outcomes. Furthermore, although controls generated significantly more pro than con reasons for goal achievement, depressed participants did not. These results suggest that depressed persons do not lack valued goals but are more pessimistic about their likelihood, controllability, and reasons for successful goal attainment.     

The relationship between n-back performance and matrix reasoning — implications for training and transfer

We have previously demonstrated that training on a dual n-back task results in improvements in fluid intelligence (Gf) as measured by matrix reasoning tasks. Here, we explored the underlying mechanisms of this transfer effect in two studies, and we evaluated the transfer potential of a single n-back task. In the first study, we demonstrated that dual and single n-back task performances are approximately equally correlated with performance on two different tasks measuring Gf, whereas the correlation with a task assessing working memory capacity was smaller. Based on these results, the second study was aimed on testing the hypothesis that training on a single n-back task yields the same improvement in Gf as training on a dual n-back task, but that there should be less transfer to working memory capacity. We trained two groups of students for four weeks with either a single or a dual n-back intervention. We investigated transfer effects on working memory capacity and Gf comparing the two training groups' performance to controls who received no training of any kind. Our results showed that both training groups improved more on Gf than controls, thereby replicating and extending our prior results.     

Semantic interference in a delayed naming task: evidence for the response exclusion hypothesis

In 2 experiments participants named pictures of common objects with superimposed distractor words. In one naming condition, the pictures and words were presented simultaneously on every trial, and participants produced the target response immediately. In the other naming condition, the presentation of the picture preceded the presentation of the distractor by 1,000 ms, and participants delayed production of their naming response until distractor word presentation. Within each naming condition, the distractor words were either semantic category coordinates of the target pictures or unrelated. Orthogonal to this manipulation of semantic relatedness, the frequency of the pictures' names was manipulated. The authors observed semantic interference effects in both the immediate and delayed naming conditions but a frequency effect only in the immediate naming condition. These data indicate that semantic interference can be observed when target picture naming latencies do not reflect the bottleneck at the level of lexical selection. In the context of other findings from the picture-word interference paradigm, the authors interpret these data as supporting the view that the semantic interference effect arises at a postlexical level of processing.     

Executive Functions in Preschool Children with Aggressive Behavior: Impairments in Inhibitory Control

The question whether executive function (EF) deficits in children are associated with conduct problems remains controversial. Although the origins of aggressive behavior are to be found in early childhood, findings from EF studies in preschool children with aggressive behavior are inconsistent. The current study aimed to investigate whether preschool children with aggressive behavior show impairments in EF. From a population-based sample, 82 preschool children who were showing aggressive behavior as indicated by scores at or above the 93rd percentile on the Aggressive Behavior Scale of the CBCL 1 1/2-5 were selected. These children with aggressive behavior were matched on IQ to a group of typically developing control children (N = 99). Six neuropsychological tasks were administered to assess set shifting, inhibition, working memory and verbal fluency. A factor analysis was conducted which yielded one clear factor: inhibition. Aggressive preschool children showed poorer performance on this inhibition factor than control children and boys performed worse on this factor than girls. This association between aggressive behavior and inhibition deficits was maintained after controlling for attention problems. In addition, gender differences in all EFs measured were found with boys exhibiting more impairment in EF than girls. These findings demonstrate that preschool children with aggressive behavior show impairments in inhibition, irrespective of attention problems.     

The role of animacy in the real time comprehension of Mandarin Chinese: Evidence from auditory event-related brain potentials

Two auditory ERP studies examined the role of animacy in sentence comprehension in Mandarin Chinese by comparing active and passive sentences in simple verb-final (Experiment 1) and relative clause constructions (Experiment 2). In addition to the voice manipulation (which modulated the assignment of actor and undergoer roles to the arguments), both arguments were either animate or inanimate. This allowed us to examine the interplay of animacy with thematic interpretation. In Experiment 1, we observed no effect of animacy at NP1, but N400 effects for inanimate actor arguments in second position. This result mirrors previous findings in German, thus suggesting that an initial undergoer universally leads to the prediction of an ideal (animate) actor. We also observed an N400 effect for passive sentences with an inanimate initial (undergoer) argument. We attribute this effect to a language-specific property of the passive construction in Chinese, namely that the first argument is negatively affected by the event described (i.e. bears an experiencer role). Experiment 2 showed that both of these effects can also be observed in sentence constructions of another type, in which the critical information sources become available in a different order. These findings provide the first demonstration that the N400 is not only sensitive to general (universal) aspects of thematic processing (i.e. "who is acting on whom") but also to the interaction between thematic interpretation and language-specific pragmatic principles.     

"The" interpretation(s) of conditionals

Recent studies indicate that a vast majority of people judge the probability of a conditional as equivalent to the conditional probability of . This means that in evaluating the applicability of a conditional people do not seem to take into account situations in which the antecedent is false. This has been taken as evidence against the model theory of Johnson-Laird and Byrne (2002). This theory, however, claims that the conditional interpretation in which false-antecedent cases are relevant is only one of many possible interpretations of "if." We present new evidence that confirms this flexibility of the interpretive system. When people are primed by thinking (1) about truth and the difference between the and or (2) are invited to judge which situations are consistent with the conditional, they are more likely to select a probability estimate that takes into account the false-antecedent cases.     

The effects of cortisol increase on long-term memory retrieval during and after acute psychosocial stress

In this study the effects of stress-induced cortisol increases on long-term memory retrieval during and after acute psychosocial stress were examined. Seventy male students were exposed to either a psychosocial stress task or to a non-stressful control task. During and after this task, retrieval was tested for idiosyncratic emotionally negative and neutral word pair associations that were learned 1 day or 5 weeks earlier. Within the stress condition, retrieval of negative words, 5 weeks after learning, was impaired both during and after the stress task compared to the control group. Further, during the stress task, when sympathetic activity was enhanced, impaired retrieval of both neutral and emotional words was significantly related to enhanced cortisol response. In contrast, after the stress task, when cortisol levels were still increased but sympathetic activity was low again, no association was found between cortisol increase and retrieval of either neutral or emotional material. These results are in line with the previous animal research showing that when arousal is high, cortisol increase can impair memory retrieval.