The effect of illustrations in arithmetic problem-solving: Effects of increased cognitive load

Arithmetic word problems are often presented accompanied by illustrations. The present study examined how different types of illustrations influence the speed and accuracy of performance of both good (n = 67) and poor arithmeticians (n = 63). Twenty-four arithmetic word problems were presented with four types of illustrations with increasing information value. The results show that illustrations can have a detrimental effect on performance on arithmetic word problems, produced by irrelevant, redundant or interacting sources of information. Principles from cognitive load theory are used to explain the results, in particular in relation to (poor) working memory ability.     

Modulation of an activity response with associative and nonassociative fear in the rat: A lighting differential influences the form of defensive behavior evoked after fear conditioning

Rats confronted with the onset of a light gradient display a transient increase in locomotion called theactivity response (AR) and a dark preference (Godsil & Fanselow, 2004). These experiments demonstrate that the magnitude of the AR can be blunted with Pavlovian fear-conditioning procedures via associative and nonassociative fear. Although manifested in decreased locomotion, the blunted AR effect was not due to increased freezing or immobility behaviors. Instead, rats displayed reduced rearing and an increase in a class of behaviors calledstationary activity. These results suggest that the lighting differential supplied by the cue influences the topography of defensive behavior and reduces the expression of freezing. This procedure provides a means by which to examine learned and unlearned defensive responses to the same stimulus.     

Stability of pedalling mechanics during a prolonged cycling exercise performed at different cadences

The aim of this study was to analyse the effect of pedalling rate on the pattern of mechanical torque application and on neuromuscular fatigue during prolonged cycling exercise. Eleven well-trained individuals performed three 1-h pedalling sessions, at 50 rev.min-1, 110 rev.min-1 and a freely chosen cadence, at an intensity corresponding to 65% of their maximal aerobic power. The mechanical torque applied on the right pedal was recorded for 30 s every 5 min while pedalling. Contractile and neural properties of the quadriceps and hamstring muscles were analysed before and immediately after each of the three pedalling sessions. The post-exercise reduction in knee extensors maximal voluntary contraction was significant (P<0.01) irrespective of the cadence, but no difference was found between cadences. The use of a particular cadence did not lead to preferentially central or peripheral fatigue. An increase in cadence resulted in greater positive and negative work generated during pedalling. The mechanical pattern was not altered during the exercise, whatever the selected cadence. The present study demonstrates that despite the occurrence of neuromuscular fatigue, trained individuals maintained a stable pedalling pattern throughout an endurance cycling exercise for cadences ranging from 50 to 110 rev.min-1.