Inhibition in the dynamics of selective attention: an integrative model for negative priming

We introduce a computational model of the negative priming (NP) effect that includes perception, memory, attention, decision making, and action. The model is designed to provide a coherent picture across competing theories of NP. The model is formulated in terms of abstract dynamics for the activations of features, their binding into object entities, their semantic categorization as well as related memories and appropriate reactions. The dynamic variables interact in a connectionist network which is shown to be adaptable to a variety of experimental paradigms. We find that selective attention can be modeled by means of inhibitory processes and by a threshold dynamics. From the necessity of quantifying the experimental paradigms, we conclude that the specificity of the experimental paradigm must be taken into account when predicting the nature of the NP effect

Identity Negative Priming: A Phenomenon of Perception, Recognition or Selection?

The present study addresses the problem whether negative priming (NP) is due to information processing in perception, recognition or selection. We argue that most NP studies confound priming and perceptual similarity of prime-probe episodes and implement a color-switch paradigm in order to resolve the issue. In a series of three identity negative priming experiments with verbal naming response, we determined when NP and positive priming (PP) occur during a trial. The first experiment assessed the impact of target color on priming effects. It consisted of two blocks, each with a different fixed target color. With respect to target color no differential priming effects were found. In Experiment 2 the target color was indicated by a cue for each trial. Here we resolved the confounding of perceptual similarity and priming condition. In trials with coinciding colors for prime and probe, we found priming effects similar to Experiment 1. However, trials with a target color switch showed such effects only in trials with role-reversal (distractor-to-target or target-to-distractor), whereas the positive priming (PP) effect in the target-repetition trials disappeared. Finally, Experiment 3 split trial processing into two phases by presenting the trial-wise color cue only after the stimulus objects had been recognized. We found recognition in every priming condition to be faster than in control trials. We were hence led to the conclusion that PP is strongly affected by perception, in contrast to NP which emerges during selection, i.e., the two effects cannot be explained by a single mechanism

A

feature-binding model with localized excitation

A Computational Approach to Negative Priming

Priming is characterized by a sensitivity of reaction times to the sequence of stimuli in psychophysical experiments. The reduction of the reaction time observed in positive priming is well-known and experimentally understood [Scarborough et al., 1977]. Negative priming – the opposite effect – is experimentally less tangible [Fox, 1995]. The dependence on subtle parameter changes (such as response-stimulus interval) usually varies. The sensitivity of the negative priming effect bears great potential for applications in research in fields such as memory, selective attention, and aging effects. We develop and analyze a computational realization, CISAM, of a recent psychological model for action decision making, the ISAM [Kabisch, 2003], which is sensitive to priming conditions. With the dynamical systems approach of the CISAM, we show that a single adaptive threshold mechanism is sufficient to explain both positive and negative priming effects. This is achieved by comparing results obtained by the computational modeling with experimental data from our lab. The implementation provides a rich base from which testable predictions can be derived, e.g. with respect to hitherto untested stimulus-combinations (e.g. single-object trials)

Summary of results of Experiment 1.

a<p>Standard deviation in parentheses.</p>b<p>Difference of CO and priming condition.</p

An example sequence of stimuli of

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032946#s4" target="_blank"><b>Experiment 3</b></a><b>.</b> A trial begins with the display of the stimulus compound which is replaced by the color cue after a button press by the subjects. The fixation cross and the mask are omitted in the shown sequence for clarity.</p