Three experiments investigated individuals’ preferences and affective reactions to negative life experiences. Participants had a more intense negative affective reaction when they were exposed to a highly negative life experience than when they were exposed to two negative events: a highly negative and a mildly negative life event. Participants also chose the situation containing two versus one negative event. Thus, “more negative events were better” when the events had different affective intensities. When participants were exposed to events having similar affective intensities, however, two negative events produced a more intense negative affective reaction. In addition, participants chose the situation having one versus two negative life experiences. Thus, “more negative events were worse” when the events had similar affective intensities. These results are consistent with an averaging/summation (A/S) model and delineate situations when “more” negative life events are “better” and when “more” negative life events are “worse.” Results also ruled out several alternative interpretations including the peak-end rule and mental accounting interpretations.

We evaluated the contributions of somatic and dendritic impulses to the receptive field dimensions of amacrine cells in the amphibian retina. For this analysis, we used the NEURON simulation program with a multicompartmental, multichannel model of an On-Off amacrine cell with a three-dimensional structure obtained through computer tracing techniques. Simulated synaptic inputs were evenly spaced along the dendritic branches and organized into eight annuli of increasing radius. The first set of simulations activated each ring progressively to simulate an area summation experiment, while a second approach activated each annulus individually. Both sets of simulations were done with and without the presence of Na channels in the dendrites and soma. Unexpectedly, the receptive field dimensions observed in the area summation simulations was often smaller than that predicted from the summation of the annular simulations. Collisions of action potentials moving in opposite directions in the dendrites largely accounted for this contraction in receptive field size for the area summation studies. The presence of dendritic Na channels increased the size of the receptive field beyond that achieved in their absence and allowed the physiological size of the receptive field to approximate the physical dimensions of the dendritic tree. This receptive field augmentation was the result of impulse generating ability in the dendrites which enhanced the signal observed at the soma. These simulations provide a plausible mechanistic explanation for physiological recordings from amacrine cells that show similar phenomena.