Differences in Implicit Attitudes in West and East Germans as Measured by the Go/NoGo Association Task and Event-related EEG Potentials.

BACKGROUND AND OBJECTIVE: Implicit social cognition refers to attitudes and stereotypes that may reside outside conscious awareness and control but that still affect human behavior. In particular, the implicit favoritism of an ingroup, to which an individual belongs, as opposed to an outgroup, to which the individual does not belong, characterized as ingroup bias, is of interest and is investigated here. METHOD: We used a Go/NoGo association task (GNAT) and behavioral and electroencephalographic (event-related EEG potential [ERP] analysis) measures to investigate the implicit bias toward cities in East Germany, West Germany, and Europe, in 16 individuals each from West and East Germany (mixed gender, M age = 24). The GNAT assesses an individual's Go and NoGo responses for a given association between a target category and either pole (positive or negative) of an evaluative dimension. RESULTS: Behavioral measures revealed slightly faster reaction times to the combination of European city names and negative, as compared with positive, evaluative words in both groups. ERP analysis showed an increased negativity at 400-800 ms poststimulus in the incongruent conditions of East German city/positive word pairings (in West Germans) and West German city/positive word pairings (in East Germans). CONCLUSION: An implicitly moderately negative evaluation of Europe by both groups was exhibited based on the behavioral data, and an increased level of conflict arising from the "incongruent" pairings (ie, as manifestation of an implicitly negative attitude toward East Germany in West Germans, and toward West Germany in East Germans) was exhibited based on the electrophysiological data.

Studying Implicit Attitudes Towards Smoking: Event-Related Potentials in the Go/NoGo Association Task.

Cigarette smoking and other addictive behaviors are among the main preventable risk factors for several severe and potentially fatal diseases. It has been argued that addictive behavior is controlled by an automatic-implicit cognitive system and by a reflective-explicit cognitive system, that operate in parallel to jointly drive human behavior. The present study addresses the formation of implicit attitudes towards smoking in both smokers and non-smokers, using a Go/NoGo association task (GNAT), and behavioral and electroencephalographic (EEG) measures. The GNAT assesses, via quantifying participants' reaction times, the strength of association between a target category and either pole of an evaluative dimension (positive or negative). EEG analysis is performed to determine the temporal course of the event-related potential (ERP) components underlying Go/NoGo decisions and implicit attitude formation. Both smokers and non-smokers showed prolonged reaction times to smoking-related pictures when the pictures were coupled with positive evaluative words ("incongruent condition"). This indicates negative implicit attitudes towards smoking in both groups alike at the time point of the behavioral response (600-700 ms post-stimulus). However, only the non-smokers, not the smokers, were found to show a delay of the N200 component in the incongruent condition. This is interpreted as reflecting ambivalent or even positive implicit attitudes towards smoking in the smoker group at the time point of the N200 (300-400 ms post-stimulus). Our study thus provides evidence for the hypothesis that implicit attitudes are subject to changes within several hundred milliseconds after stimulus presentation, and can be altered in the course of their formation.

The Electrocortical Signature of Successful and Unsuccessful Deception in a Face-to-Face Social Interaction.

Deceptive behavior, and the evaluation of others' behavior as truthful or deceptive, are crucial aspects of human social interaction. We report a study investigating two participants in a social interaction, performing a deception task. The first participant, the "informant," made true or false autobiographical statements. The second participant, the "detective," then classified these statements as truth or lie. Behavioral data showed that detectives performed slightly above chance and were better at correctly identifying true as compared with deceptive statements. This presumably reflects the "truth bias": the finding that individuals are more likely to classify others' statements as truthful than as deceptive - even when informed that a lie is as likely to be told as the truth. Electroencephalography (EEG) was recorded from the informant. Event-related potential (ERP) analysis revealed a smaller contingent negative variation (CNV) preceding "convincing" statements (statements classified as true by the detective) compared to "unconvincing" statements (statements classified as lie by the detective) - irrespective of whether the statements were actually truthful or deceptive. This finding suggests a distinct electrocortical signature of "successful" compared to "unsuccessful" deceptive statements. One possible explanation is that the pronounced CNV indicates the individuals' higher "cognitive load" when processing unconvincing statements.

The number decision task: Investigation of the representation of multi-digit numbers.

The ability to process multi-digit numbers is an essential skill which we investigated using a number decision task. Subjects were asked to decide whether a target number (e.g., 649) is too small or too large to be the mean between two delimiter numbers that constituted the interval (e.g., 567 and 715). Three-digit numbers were presented vertically with (1) growing interval sizes (i.e., distance between the two delimiters; e.g., interval size between 567 and 715 is 148) and target gap to the mean (e.g., the gap between the 'real' mean 641 and the target 649 is 8) and (2) growing interval sizes with constant gap to the mean (i.e., for each interval size the gap between target and mean was held constant). The results showed that target gap to the mean "masked" the influence of interval sizes, i.e., subjects' performance improved with increasing interval sizes (distance effect). This effect was reversed when constant target gaps to the mean and growing interval sizes were presented. These results were replicated presenting the numbers horizontally and with two-digit numbers. Additionally, a significant influence of decade but no effect of unit compatibility on reaction times and error rates, on number magnitude (size effect) and response format was found. Overall, we showed that the number decision task is an efficient tool to investigate multidigit number representation and the results from the experiments revealed evidence for a hybrid model of multi-digit number representation in which numbers are represented as a whole but also on separate mental number lines that interact with each other.

Brain potentials show rapid activation of implicit attitudes towards young and old people.

While previous behavioural research suggests that attitudes, for example towards elderly people, may be activated automatically, this type of research does not provide information about the detailed time-course of such processing in the brain. We investigated the impact of age related attitude information in a Go/NoGo association task that paired photographs of elderly or young faces with positive or negative words. Event related brain potentials showed an N200 (NoGo) component, which appeared earlier in runs which required similar responses for congruent stimulus pairings (e.g. respond to pictures of elderly faces or negative words) than for incongruent pairings (e.g. respond to elderly faces or positive words). As information processing leading to a certain attitude must precede differential brain activity according to the congruence of the paired words and faces, we show that this type of information is activated almost immediately following the structural encoding of the face, between 170 and 230 ms after onset of the face.

Combined expectancies: electrophysiological evidence for the adjustment of expectancy effects.

BACKGROUND: When subjects use cues to prepare for a likely stimulus or a likely response, reaction times are facilitated by valid cues but prolonged by invalid cues. In studies on combined expectancy effects, two cues can independently give information regarding two dimensions of the forthcoming task. In certain situations, cueing effects on one dimension are reduced when the cue on the other dimension is invalid. According to the Adjusted Expectancy Model, cues affect different processing levels and a mechanism is presumed which is sensitive to the validity of early level cues and leads to online adjustment of expectancy effects at later levels. To examine the predictions of this model cueing of stimulus modality was combined with response cueing. RESULTS: Behavioral measures showed the interaction of cueing effects. Electrophysiological measures of the lateralized readiness potential (LRP) and the N200 amplitude confirmed the predictions of the model. The LRP showed larger effects of response cues on response activation when modality cues were valid rather than invalid. N200 amplitude was largest with valid modality cues and invalid response cues, medium with invalid modality cues, and smallest with two valid cues. CONCLUSION: Findings support the view that the validity of early level expectancies modulates the effects of late level expectancies, which included response activation and response conflict in the present study.

Juicy fruit and creepy crawlies: an electrophysiological study of the implicit Go/NoGo association task.

The Go/NoGo association task (GNAT) has been used in behavioral studies to measure the strength of association between different category groups and two poles of an evaluative dimension. However, reaction time data do not provide information about the neural time course of such associative information. We investigated event-related brain potentials (ERPs) elicited when participants were required to respond (Go) or withhold a response (NoGo) according to task instructions. Task instructions paired words from one of two taxonomic categories (fruit/bugs) with either pole of an evaluative dimension (good/bad). Within a given run, Go responses were assigned to one of the categories and one evaluative dimension. ERPs showed an increased negativity over frontal sites to NoGo as compared to Go responses. Moreover, NoGo minus Go difference waves showed that the N200 effect was delayed in trials within incongruent blocks (e.g., "Press if a bug word or a good word") as compared to trials within congruent blocks (e.g., "Press if a bug word or a bad word"). These results suggest that such associative attitude information is available at a very early stage of processing, less than 250 ms after seeing a fruit or a bug word. This finding is further discussed with respect to alternative explanations of the behavioral effect.

Second language interferes with word production in fluent bilinguals: brain potential and functional imaging evidence.

Bilingual individuals need effective mechanisms to prevent interference between their languages. Using event-related brain potentials (ERPs) and functional magnetic resonance imaging (fMRI), we present evidence for interference of phonological information from the nontarget language in German-Spanish bilinguals. A tacit picture-naming task was used in which bilinguals and monolinguals had to make speeded responses based on the first letter of the picture's name in the target language. In one condition, subjects were required to respond when the name began with a vowel and to withhold a response if it started with a consonant. Stimuli had been selected such that in half of the trials, the names in both languages necessitated the same response, whereas in the other half, responses were different for the two languages. For the bilinguals, the language in which the stimuli had to be named was changed after each block. Bilinguals showed phonological interference compared with monolingual performance, which was evident in their performance, ERPs, and fMRI patterns. Nonlanguagespecific brain areas such as the left middle prefrontal cortex were found to be crucial for the control of interference.