Event rate and reaction time performance in ADHD: Testing predictions from the state regulation deficit hypothesis using an ex-Gaussian model

According to the state regulation deficit (SRD) account, ADHD is associated with a problem using effort to maintain an optimal activation state under demanding task settings such as very fast or very slow event rates. This leads to a prediction of disrupted performance at event rate extremes reflected in higher Gaussian response variability that is a putative marker of activation during motor preparation. In the current study, we tested this hypothesis using ex-Gaussian modeling, which distinguishes Gaussian from non-Gaussian variability. Twenty-five children with ADHD and 29 typically developing controls performed a simple Go/No-Go task under four different event-rate conditions. There was an accentuated quadratic relationship between event rate and Gaussian variability in the ADHD group compared to the controls. The children with ADHD had greater Gaussian variability at very fast and very slow event rates but not at moderate event rates. The results provide evidence for the SRD account of ADHD. However, given that this effect did not explain all group differences (some of which were independent of event rate) other cognitive and/or motivational processes are also likely implicated in ADHD performance deficits.     

Conceptual coherence affects phonological activation of context objects during object naming

In 4 picture-word interference experiments, speakers named a target object that was presented with a context object. Using auditory distractors that were phonologically related or unrelated either to the target object or the context object, the authors assessed whether phonological processing was confined to the target object or not. Phonological activation of the context objects was reliably observed if the target and context objects were embedded in a conceptually coherent scene (e.g., if the picture showed a mouse eating some cheese), regardless of whether the target was cued by its thematic role (agent vs. patient) or by color. However, this activation dissipated if the two objects were presented in an arbitrary object array (e.g., if the cheese was presented along with a finger). These findings suggest that conceptual coherence among multiple objects affects the information flow in the conceptual-lexical system during speech planning.     

Relationship between sexual activity and intraspecific fighting in male mice

Significantly more male mice having cohabited and mated with intact females subsequently displayed intraspecific fighting behavior after castration than males having cohabited with noncycling (ovariectomized) females. Also, intact males that failed to achieve a criterion for aggression during three screening tests subsequently showed a marked increase in fighting after having had copulatory experience relative to males that lived with ovariectomized females. Lastly, spontaneously aggressive males copulated more frequently than nonfighters.     

The effect of varying danger controllability on attention to threat messages

The objective of this study is to determine whether attention toward fear messages is affected by variation in the controllability of the associated danger. There is no consensus regarding the effectiveness of fear appeals in driving adaptive behaviour, and it may be the case that threat messages fail to capture attention if the associated danger is not explicitly controllable. One hundred and sixty undergraduate university students completed a computer task that involved exposure to threat cues signalling a danger (money loss). In high control blocks, attending to threat cues provided a high chance of avoiding the danger, whereas in low control blocks, attending to threat cues provided little chance of avoiding the danger. Attentional capture by threat was measured. A mixed-design analysis of variance showed there was greater attentional capture by threat cues in high control blocks compared with low control blocks. This effect was observed with a short stimulus exposure duration and was magnified with a long exposure duration. Fear appeals could capture attention to a greater degree if the danger related to the threat message was communicated as being controllable. This has significant practical implications for the implementation of fear appeals.     

Postintentional neglect

F. Mechsner (2004) seems to deny a functional importance of postintentional processes, except that their characteristics can be taken into account at the perceptual-cognitive level of control. In that perspective, processes that are critical for the understanding of motor control and its limitations are neglected. On the other hand, the functional importance of task conceptions or task sets, which can vary and affect performance even for tasks that appear identical to an observer, is emphasized.     

Demands on attention and the role of response priming in visual discrimination of feature conjunctions

This study examined how response mapping of features within single- and multiple-feature targets affects decision-based processing and attentional capacity demands. Observers judged the presence or absence of 1 or 2 target features within an object either presented alone or with distractors. Judging the presence of 2 features relative to the less discriminable of these features alone was faster (conjunction benefits) when the task-relevant features differed in discriminability and were consistently mapped to responses. Conjunction benefits were attributed to asynchronous decision priming across attended, task-relevant dimensions. A failure to find conjunction benefits for disjunctive conjunctions was attributed to increased memory demands and variable feature-response mapping for 2- versus single-feature targets. Further, attentional demands were similar between single- and 2-feature targets when response mapping, memory demands, and discriminability of the task-relevant features were equated between targets. Implications of the findings for recent attention models are discussed.     

The role of reference points in ordinal numerical comparisons by rhesus macaques (Macaca mulatta)

Two experiments examined ordinal numerical knowledge in rhesus macaques (Macaca mulatta). Experiment 1 replicated the finding (E. M. Brannon & H. S. Terrace, 2000) that monkeys trained to respond in descending numerical order (4-->3-->2-->1) did not generalize the descending rule to the novel values 5-9 in contrast to monkeys trained to respond in ascending order. Experiment 2 examined whether the failure to generalize a descending rule was due to the direction of the training sequence or to the specific values used in the training sequence. Results implicated 3 factors that characterize a monkey's numerical comparison process: Weber's law, knowledge of ordinal direction, and a comparison of each value in a test pair with the reference point established by the first value of the training sequence.     

STIVID: A VBSCRIPT-based program for adding visual and auditory stimuli on videotapes

Some psychological experiments require placement of visual and auditory stimuli on predefined frames in a videotape. We introduce STIVID (STImuli on VIDeo) as a method of performing this task. STIVID can add images, words, simple shapes, and audio tones to specific frames of existing video files created in AVI format. STIVID is written in Visual Basic and uses VBScripts to modify the AVI files. Three applications of this program are discussed: adding stimuli for reaction time experiments with couples watching a relational conflict, use of distractors in ADHD experiments, and placing eye masks on actors in existing videotapes to manipulate perceptibility of the target’s facial expression during the mind-reading process.