Semantic boost on episodic associations: an empirically-based computational model

Words become associated following repeated co-occurrence episodes. This process might be further determined by the semantic characteristics of the words. The present study focused on how semantic and episodic factors interact in incidental formation of word associations. First, we found that human participants associate semantically related words more easily than unrelated words; this advantage increased linearly with repeated co-occurrence. Second, we developed a computational model, SEMANT, suggesting a possible mechanism for this semantic-episodic interaction. In SEMANT, episodic associations are implemented through lateral connections between nodes in a pre-existent self-organized map of word semantics. These connections are strengthened at each instance of concomitant activation, proportionally with the amount of the overlapping activity waves of activated nodes. In computer simulations SEMANT replicated the dynamics of associative learning in humans and led to testable predictions concerning normal associative learning as well as impaired learning in a diffuse semantic system like that characteristic of schizophrenia.     

Location vs. frequency of pure tones as a basis of fast discrimination

There are ample data suggesting that a spatial difference between two competing auditory messages provides a better basis for selective attention and listening than other differences. The present experiments show that the spatial difference (left vs. right ear) between two auditory inputs leads to their faster discrimination than even large differences in frequency (in the same ear). These results might explain the afore-mentioned privileged status of the spatial dimension as a basis of selective attention: spatial differences lead in faster identification of relevant or attended input than differences in other dimensions.     

Non-aging fore-periods and simple reaction time

This study deals with the relationship between the momentary objective probability of the delivery of a stimulus and the reaction time in a simple reaction-time task. The hypothesis was that the reaction time is closely related to the objective probability via expectancy i.e., the momentary probability of the delivery of the stimulus as experienced by the subject. This problem was experimentally approached from two directions: (1) by varying the objective probability, in which case the reaction times should change inversely with the objective probability, and (2) by keeping the objective probability constant (by using the Bernoulli process), in which case the reaction times should not change. Eight male subjects were used. The first assumption proved to be correct, whereas the second held only when certain mean inter-stimulus intervals were used.     

Event-related brain potentials reflect traces of echoic memory in humans

In sequences of identical auditory stimuli, infrequent deviant stimuli elicit an event-related brain potential component called mismatch negativity (MMN). MMN is presumed to reflect the existence of a memory trace of the frequent stimulus at the moment of presentation of the infrequent stimulus. This hypothesis was tested by applying the recognition-masking paradigm of cognitive psychology. In this paradigm, a masking sound presented shortly before or after a test stimulus diminishes the recognition memory of this stimulus, the more so the shorter the interval between the test and masking stimuli. This interval was varied in the present study. It was found that the MMN amplitude strongly correlated with the subject’s ability to discriminate between frequent and infrequent stimuli. This result strongly suggests that MMN providesa measure for a trace of sensory memory, and further, that with MMN, this memory can be studied without performance-related distortions.     

Associating unseen events: semantically mediated formation of episodic associations

In prior work, we developed a computational model of how episodic associations between words are formed. Simulating associative learning, the model indicated that strongly associated semantically unrelated words facilitate the episodic association of other exemplars included in their semantic neighborhoods. This prediction was supported empirically by the present study. First, the incidental formation of strong associations between unrelated words, such as dog and table, improved cued recall of weak associations formed incidentally between semantic neighbors, like cat and chair. Second, deciding that two words were semantically unrelated was facilitated by forming strong associations between other words in their respective semantic neighborhoods, even if the tested pair was not presented at study. Together with the computational model, the present results demonstrate that forming episodic associations between words can implicitly mediate the association of other exemplars from the same semantic categories and reveal a mechanism by which the semantic system contributes to the formation of new episodic associations.     

Preattentive auditory context effects

The effects of auditory context on the preattentive and perceptual organization of tone sequences were investigated. Two sets of experiments were conducted in which the pitch of contextual tones was varied, bringing about two different contextual manipulations. Preattentive auditory organization was indexed by the mismatch negativity event-related potential, which is elicited by violations of auditory regularities even when participants ignore the sounds (e.g., by reading a book). The perceptual effects of the contextual manipulations on auditory grouping were assessed using target-detection and orderjudgment tasks. The close correspondence found between the effects of auditory context on the perceptual and preattentive measures of auditory grouping suggests that a large part of contextual processing is preattentive.     

Managing the aftermath: Scapegoating as crisis communication strategy

Should firms struggling with a brand crisis use scapegoating, the assignment of blame to another entity? Across three studies, we offer evidence of the value of scapegoating. We show that when firms use scapegoating, they reduce consumers' attributions of a firm's crisis responsibility, controllability, and stability. Compared to other strategies, including no response, denial, apology, and justification, scapegoating is most effective at reducing these attributions. However, attributions of crisis controllability seem more influential in reducing a firm's crisis responsibility. Scapegoating also increases consumers' word‐of‐mouth (WOM) intentions more than the no response strategy, but not more than denial, apology, and justification. The effect of scapegoating, however, depends on the scapegoat type. Whereas using an underdog scapegoat such as a regular company employee or a small partner firm can backfire and result in negative WOM intentions, the use of topdog scapegoats seems to have more positive effects. When firms use topdog scapegoats, such as the top management of a large firm, negative WOM intentions likely decrease. This type of effect seems to occur due to a reduction in the firm's crisis responsibility that scapegoating engenders.