Contrast effects on sequence assessments

Loewenstein and his colleagues found divergent preferences for outcomes assessed in isolation versus those embedded in a sequence, i.e. discounting isolated future outcomes versus preferences for increasing and constant sequences. They also found long intervals (i.e. the difference between time delays) rather than long time delays (i.e. the temporal distance from the present) had a detrimental effect on preference for improvement. This thesis proposes a descriptive model of sequence preferences, namely the contrasts model, which acknowledges the difference between interval and delay. The idea is that delay and interval are two different kinds of variables. Delay is non-relational and describes characteristics of individual outcomes, whereas interval is relational and describes characteristics of outcomes in relation to one another. Built on this idea, the contrasts model assumes that the value of a sequence consists of a non-relational part (the endowment value), which is a function of delay and nominal value of the component outcomes and a relational part (the contrast value), which is a function of the signed value difference between the outcomes, their interval and domain relatedness (i.e. whether or not the outcomes share the same domain). Delay and interval influence the endowment and the contrast respectively. Empirical investigations provide evidence for the contrasts model. Decision makers are capable of distinguishing between influences of delay and interval even when the two coincide and exert conflicting influences. Experiments using both money and non-monetary outcomes also show that preferences for improvement can be made more pronounced by shortening intervals and/or enhancing relatedness between the outcomes

Contrast effects : incentive value of N-lengths

E.J. Capaldi has developed a sequential explanation of the partial reinforcement effect. The central assumption of this explanation is that non reinforced trials occasion a specific and distinctive internal stimulus and that this stimulus is progressively modified by successive non reinforcements. In this experiment, forty, male albino Holtzman rats traversed a straight alley runway under different patterns of partial reinforcement. Group One received an N3-length, i.e., three successive non-reinforced trials followed by a reinforced trial. Group Two received an N1-length, i.e., one non-reinforced trial followed by a reinforced trial. Group Three received an N3-length for the first ten days of acquisition training and was then shifted to an N1-length for the last five days of acquisition training. Group Four received an N1-length for the first ten days of acquisition training and an N3-length for the last five days of acquisition training. All groups received five days of extinction training. The results indicate that partial reinforcement patterns not only effect extinction performance but also effect acquisition performance in extended training

Effects of talker variability on spectral contrast effects.

Spectral contrast effects are context-dependent effects that influence the way we perceive certain sounds. Evidence of these effects can be seen in experiments where a precursor sound (e.g. a sentence) is followed by a target vowel sound (like /ɪ/ as in bit or /ɛ/ as in bet ). If the precursor\u27s frequency was emphasized in areas more consistent with the frequency of /ɛ/, listeners tend to perceive the target sound to be the opposite i.e. /ɪ/. A recent study shows using sentence precursors from 200 different talkers diminishes these effects questioning previous claims that talker variability has no influence on spectral contrast effects (Assgari & Stilp, 2015; Lain, Liu, Lotto, & Holt 2012). This study investigated the influence of one, four, eight, and sixteen talkers using conversational speech. Sentences were filtered with +5 dB filter gain to emphasize frequency regions consistent with either /ɛ/ or /ɪ/. One-talker, four-talker, and eighttalker conditions all produced contrast effects while the sixteen-talker condition failed to produce an effect. Results suggest talker variability has a greater influence on spectral contrast effects than previously thought

The phantom illusion

It is well known that visible luminance gradients may generate contrast effects. In this work we present a new paradoxical illusion in which the luminance range of gradual transitions has been reduced to make them invisible. By adopting the phenomenological method proposed by Kanizsa, we have found that unnoticeable luminance gradients still generate contrast effects. But, most interestingly, we have found that when their width is narrowed, rather than generating contrast effects on the surrounded surfaces, they generate an assimilation effect. Both high- and low-level interpretations of this “phantom” illusion are critically evaluated

A Multi-Scale Network Model of Brightness Perception

A neural network model of brightness perception is developed to account for a wide variety of difficult data, including the classical phenomenon of Mach bands and nonlinear contrast effects associated with sinusoidal luminance waves. The model builds upon previous work by Grossberg and colleagues on filling-in models that predict brightness perception through the interaction of boundary and feature signals. Model equations are presented and computer simulations illustrate the model's potential.Air Force Office of Scientific Research (F49620-92-J-0334); Northeast Consortium for Engineering Education (NCEE-A303-21-93); Office of Naval Research (N00014-91-J-4100); German BMFT grant (413-5839-01 IN 101 C/1); CNPq and NUTES/UFRJ, Brazi

Nymph piss and gravy orgies : local and global contrast effects in relational humor

How does the relation between two words create humor? In this paper, we investigated the effect of global and local contrast on the humor of word pairs. We capitalized on the existence of psycholinguistic lexical norms by examining violations of expectations set up by typical patterns of English usage (global contrast) and within the local context of the words within the word pairs (local contrast). Global contrast was operationalized as lexical-semantic norms for single-words and local contrast was operationalized as the orthographic, phonological, and semantic distance between the two words in the pair. Through crowdsourced (Study 1) and best-worst (Study 2) ratings of the humor of a large set of word pairs (i.e., compounds), we find evidence of both global and local contrast on compound-word humor. Specifically, we find that humor arises when there is a violation of expectations at the local level, between the individual words that make up the word pair, even after accounting for violations at the global level relative to the entire language. Semantic variables (arousal, dominance, concreteness) were stronger predictors of word pair humor whereas form-related variables (number of letters, phonemes, letter frequency) were stronger predictors of single-word humor. Moreover, we also find that semantic dissimilarity increases humor, by defusing the impact of low-valence words—making them seem more amusing—and by enhancing the incongruence of highly imageable pairs of concrete words

Scandals and the public's trust in politicians: assimilation and contrast effects

Der Arbeitsbericht geht auf die Auswirkungen des Barschel-Skandals ein. Die Befragten der Studie wurden aufgefordert, sich die Namen von Politikern ins Gedächtnis zu rufen. Anschließend beurteilten sie die Vertrauenswürdigkeit von Politikern im allgemeinen sowie von ausgewählten Beispielen. Dies ergab eine Vertrauensabnahme gegenüber Politikern allgemein, jedoch Vertrauenszuwachs gegenüber bestimmten Politikern. Analysiert werden Assimilierungs- und Widerspruchseffekte innerhalb eines Modells der menschlichen Informationsverarbeitung, demzufolge jede Botschaft zunächst eine grundsätzliche Kategorisierung durchläuft und je nach bereits vorliegender Begriffsbildung bewertet wird. (psz)'Subjects were, or were not, asked to recall the names of politicians who were involved in a scandal and subsequently evaluated the trustworthiness of politicians in general and of three specific exemplars. Answering the scandal question decreased judgements of trustworthiness of politicians in general, but increased perceived trustworthiness of specific exemplars. Thus, an assimilation effect was obtained when the target category 'politicians in general' invited the inclusion of the scandal politicians in the temporary representation formed of the target. In contrast, the primed politicians could not be included in the representations formed of specific individuals. In this case, they were used as a standard of comparison, resulting in contrast effects. These findings are consistent with the inclusion/exclusion model of assimilation and contrast effects that emphasizes the role of categorization processes in the construction of targets and standards. (author's abstract

ADHD: Sibling interaction or dominance: An evaluation of statistical power

Sibling interaction effects are suggested by a difference in phenotypic variance between monozygotic (MZ) twins and dizygotic (DZ) twins, and a pattern of twin correlations that is inconsistent with additive genetic influences. Notably, negative sibling interaction will result in MZ correlations which are more than twice as high as DZ correlations, a pattern also seen in the presence of genetic dominance. Negative sibling interaction effects have been reported in most genetic studies on Attention Deficit Hyperactivity Disorder (ADHD) and related phenotypes, while the presence of genetic dominance is not always considered in these studies. In the present paper the statistical power to detect both negative sibling interaction effects and genetic dominance is explored. Power calculations are presented for univariate models including sources of variation due to additive genetic influences, unique environmental influences, dominant genetic influences and a negative sibling interaction (i.e., contrast effect) between phenotypes of twins. Parameter values for heritability and contrast effects are chosen in accordance with published behavior genetic studies on ADHD and associated phenotypes. Results show that when both genetic dominance and contrast effects are truly present and using a classical twin design, genetic dominance is more likely to go undetected than the contrast effect. Failure to detect the presence of genetic dominance consequently gives rise to slightly biased estimates of additive genetic effects, unique environmental effects, and the contrast effect. Contrast effects are more easily detected in the absence of genetic dominance. If the significance of the contrast effect is evaluated while also including genetic dominance, small contrast effects are likely to go undetected, resulting in a relatively large bias in estimates of the other parameters. Alternative genetic designs, such as adding pairs of unrelated siblings reared together to a classical twin design, or adding non-twin siblings to twin pairs, greatly enhances the statistical power to detect contrast effects as well as the power to distinguish between genetic dominance and contrast effects