The effects of task type and task requirements on the dissociation of skin conductance responses and secondary task probe reaction time.

Although task-irrelevant events elicit smaller skin conductance responses (SCRs) than do task-relevant events, secondary task probe reaction time (RT) is often slower during the former. Three experiments (N = 48 in each) examined the effects of task demands, instructions, and stimulus discriminability on this dissociation effect. SCRs were larger to task-relevant stimuli in all experiments regardless of experimental manipulation.

Human blink startle during aversive and nonaversive Pavlovian conditioning.

Potentiation of blink startle during aversive and nonaversive Pavlovian single-cue conditioning was assessed in human Ss. In Experiment 1 (N = 89), the conditioning group received paired presentations of a visual conditioned stimulus (CS) and an unconditioned stimulus (US), whereas the control group was presented with a random sequence. The US was an electric shock for half the Ss and a nonaversive reaction time task for the other half.

The effect of repeated prepulse-blink reflex trials on blink reflex modulation at short lead intervals.

The amplitude of a blink reflex is inhibited if the reflex eliciting stimulus is preceded by a short prestimulus (e.g. < 250 ms).

Effects of stimulus preexposure and intermodality change on electrodermal orienting.

Previous research has indicated that an intermodality change trial presented after a habituation series elicits larger orienting responses than does the first stimulus of that series. Experiment 1 (N = 48) investigated whether this effect was still present if the change stimulus was not novel but was presented once prior to the habituation series. Two groups of subjects were presented with a series of 24 tones or vibrotactile stimuli.

Reaction time task as unconditional stimulus. Comparing aversive and nonaversive unconditional stimuli.

Nonaversive unconditional stimuli (USs) are seldom used in human classic conditioning of autonomic responses. One major objection to their use is that they produce deficits in electrodermal (ED) second- and third-interval response conditioning. However, a nonaversive reaction time (RT) task that includes feedback of success has been shown to be an effective US while avoiding this disadvantage (Lipp and Vaitl 1988).

Reaction time task as unconditional stimulus. On conditioning skin conductance responses and heart rate, using a nonaversive unconditional stimulus.

The present study was conducted to demonstrate classic conditioning in electrodermal (ED) and heart rate (HR) responses by using a nonaversive reaction time (RT) task as unconditional stimulus (US). Three groups of 12 subjects each were studied to test the efficacy of this US procedure by varying the essential components of the RT task-US between groups. Eight seconds differential delay conditioning was applied in each group.