S-R compatibility and response selection

In serial stage models, perception and action are usually thought to be linked to each other by an S-R translation mechanism. However, phenomena of S-R compatibility suggest a more direct relationship between perceptual and action domains. We discuss behavioral and psychophysiological evidence that irrelevant stimulus information automatically activates response codes, but then decays over time.

In a series of reaction time studies and electrophysiological experiments, we investigated both temporal and functional properties of the assumed automatic response activation process. We found that the amount of interference due to irrelevant spatial information depends upon how long its availability precedes that of the information relevant for response selection. This indicates that response activation decays rather quickly. If response-relevant and irrelevant spatial information are simultaneously available, electrophysiological measurements show that automatic activation of the spatially corresponding response rises soon after stimulus onset, but then dissipates and gets replaced by the activation of the response indicated by the relevant stimulus attribute.

We conclude that these findings do not support a pure translation account, but rather suggest the presence of two parallel and (at least partially) independent routes from perception to action: A direct route, allowing for automatic activation of response codes if stimulus and response features overlap, and an indirect route linking S and R codes in an arbitrary manner. Via the direct route responses may be primed independent of task-specific contingencies, while the correct response is selected via the indirect route. This use suggests that (a) the transmission of stimulus information to response stages does not (fully) depend on task relevance and that (b) different stimulus features can be transmitted asynchronously and independently from one another.     

Children Who Murder: A Review

Despite considerable research on juvenile homicide, pre-adolescent homicide offenders have received less attention. This paper reviews the existing literature on preteen murderers in order to characterize the current state of research knowledge about this population, and draws on some of the work on adolescent homicide as well. The analysis of this literature considers historical context, methodological issues, previous attempts to classify youthful homicide offenders, and predictors of preteen homicidal behavior. While there is a high degree of heterogeneity within this population, several developmental similarities emerged across cases that were associated with the perpetration of homicide by preteens. A high percentage of preteen homicide offenders come from homes characterized by physical abuse, domestic violence, poor or absent parenting, and overall instability. Gun availability may have been a facilitating factor. Support for different etiologies of preteen versus adolescent homicide is weak. Recommendations for future research directions are offered.     

ASSESS: Adjustment Scales for Sociometric Evaluation of Secondary-School Students

The Adjustment Scales for Sociometric Evaluation of Secondary-School Students (ASSESS) was designed to assess peer ratings of the behavior of male and female adolescents. Five scales were developed and crossvalidated: Aggression-Disruptiveness, Withdrawal, Anxiety, Social Competence, and Academic Difficulty. Evidence of adequate internal consistency and testretest reliability was presented. Evaluations by male and female classmates were highly correlated. Sex and age differences accounted for only a small proportion of the total variance.This research was supported by Grant MH-21145 from the National Institute of Mental Health and funds from W. T. Grant Foundation. We wish to acknowledge the assistance of Ronda Brooks, Lina Jandorf, and Jean Sullivan in conducting the data collection, as well as the many school districts that have cooperated.     

What to do and how to do it: sequence learning of action effects and transformation rules

Many goal-oriented actions, for example in tool use, can be characterized by the involvement of two components: The effect that the acting person wants to achieve and the transformation rule that defines the relationship between a bodily movement and the associated action effect. Both in conjunction specify the concrete action that has to be executed. In our experiments, we utilized a sequence learning paradigm to investigate whether these components are represented separately or are bound together to form a more holistic representation of the action. Participants switched between different transformation rules to achieve certain action effects. In one group, there was a fixed sequence of action effects, with randomly varying transformation rules. In the other group, the sequence of transformation rules was fixed, whereas the action effects were randomly varying. Results indicate that both kinds of sequences can be learned and provide evidence for the notion that transformation rules and action effects are represented separately.     

Acting while perceiving: assimilation precedes contrast

To explore the nature of specific interactions between concurrent perception and action, participants were asked to move one of their hands in a certain direction while simultaneously observing an independent stimulus motion of a (dis)similar direction. The kinematics of the hand trajectories revealed a form of contrast effect (CE) in that the produced directions were biased away from the perceived directions ("Experiment 1"). Specifically, the endpoints of horizontal movements were lower when having watched an upward as opposed to a downward motion. However, when participants moved under higher speed constraints and were not presented with the stimulus motion prior to initiating their movements, the CE was preceded by an assimilation effect, i.e., movements were biased toward the stimulus motion directions ("Experiment 2"). These findings extend those of related studies by showing that CEs of this type actually correspond to the second phase of a bi-phasic pattern of specific perception-action interference.     

Is fat perception a thermal effect?

It has been generally assumed that fat is detected by its flavour and by its lubrication of the oral mucosa. A recent study reported a correlation of -.99 between perceived temperature of a product and its fat content. This was significantly higher than correlations of sensory scores for fat flavour, mouthfeel, and afterfeel. This suggested a third detection mechanism; fat may be detected via its effect on the thermal conductivity of the food. In 3 studies, thermal sensitivity in humans was investigated to verify whether oral thermal receptors are sufficiently rapid and accurate to play a role in the perception of fats. The thermal sensitivity of the lips and oral mucosa of the anterior and middle one-third of the tongue were assessed using a Peltier device. Subjects detected 0.5 Hz fluctuations in temperature of 0.08'C on the lower lip, 0.26 degrees C and 1.36 degrees C at the tip and dorsum of the tongue, demonstrating that the lips are sufficiently sensitive to detect small differences in temperature. In two further experiments subjects ingested custards and mayonnaises and then spat out samples after 5, 10, or 20 sec. The temperature of the food and oral mucosa was measured before and after spitting and the rates of heating were calculated. Results suggest assessment of thermal conductivity of food may be used to assess fat content.     

Seeing while moving: measuring the online influence of action on perception

The online influence of movement production on motion perception was investigated. Participants were asked to move one of their hands in a certain direction while monitoring an independent stimulus motion. The stimulus motion unpredictably deviated in a direction that was either compatible or incompatible with the concurrent movement. Participants' task was to make a speeded response as soon as they detected the deviation. A reversed compatibility effect was obtained: Reaction times were slower under compatible conditions—that is, when motion deviations and movements went in the same direction. This reversal of a commonly observed facilitatory effect can be attributed to the concurrent nature of the perception-action task and to the fact that what was produced was functionally unrelated to what was perceived. Moreover, by employing an online measure, it was possible to minimize the contribution of short-term memory processes, which has potentially confounded the interpretation of related effects.     

Transformations in the couplings among intellectual abilities and constituent cognitive processes across the life span

Abstract— Two-component theories of intellectual development over the life span postulate that fluid abilities develop earlier during child development and decline earlier during aging than crystallized abilities do, and that fluid abilities support or constrain the acquisition and expression of crystallized abilities. Thus, maturation and senescence compress the structure of intelligence by imposing age-specific constraints upon its constituent processes. Hence, the couplings among different intellectual abilities and cognitive processes are expected to be strong in childhood and old age. Findings from a population-based study of 291 individuals aged 6 to 89 years support these predictions. Furthermore, processing robustness, a frequently overlooked aspect of processing, predicted fluid intelligence beyond processing speed in old age but not in childhood, suggesting that the causes of more compressed functional organization of intelligence differ between maturation and senescence. Research on developmental changes in functional brain circuitry may profit from explicitly recognizing transformations in the organization of intellectual abilities and their underlying cognitive processes across the life span.