I see into your mind too well: working memory adjusts the probability judgment of others' mental states

Although an increasing number of studies on adults have indicated that working memory (WM) contributes to the ability to understand the mental states of others (i.e., theory of mind), the detailed mechanism by which WM contributes to successful reasoning has not previously been revealed. This study shows that WM modulates the degree of attribution of one's own knowledge to others' mental states. Participants were asked to read a story twice (Experiment 2) or as carefully as possible (Experiment 3) and to estimate the probability percentages of possible choices for a naive protagonist's behavior. The participants were then asked to maintain either a two- or seven-letter alphabet string (i.e., a light or heavy WM load, respectively) during the probability estimation but not during the story comprehension. The results showed that compared to the participants with a light WM load, those with a heavy WM load estimated a significantly higher probability of the choice indicating that the protagonist would behave on the basis of a fact that the participants knew but the protagonist did not. This result indicates that WM moderates the extent to which adults attribute their own knowledge to others' mental states. The role of WM in theory of mind and in heuristic strategy for making probability judgments was then discussed.     

Counteractive control over temptations: Promoting resistance through enhanced perception of conflict and goal value

The present research explored people’s everyday practice of counteractive control. Experience sampling was used to test our prediction that strong temptations would promote self-control. Participants were 237 Japanese citizens with ages ranging from 18 to 69. Results indicated that perceived temptation prompted stronger resistance and restraint of behaviors, compared to those cases where no conflict was perceived. In addition, multilevel path analysis revealed the underlying process such that (a) a strong desire toward temptation intensified perception of conflict; (b) perceived conflict bolstered the value of goals that were in disagreement with the temptation; and (c) highly valued goals promoted self-control (i.e., stronger resistance and hence less yielding to temptation).     

Disruption of visual feature binding in working memory

In a series of five experiments, we studied the effect of a visual suffix on the retention in short-term visual memory of both individual visual features and objects involving the binding of two features. Experiments 1A, 1B, and 2 involved suffixes consisting of features external to the to-be-remembered set and revealed a modest but equivalent disruption on individual and bound feature conditions. Experiments 3A and 3B involved suffixes comprising features that could potentially have formed part of the to-be-remembered set (but did not on that trial). Both experiments showed greater disruption of retention for objects comprising bound features than for their individual features. The results are interpreted as differentiating two components of suffix interference, one affecting memory for features and bindings equally, the other affecting memory for bindings. The general component is tentatively identified with the attentional cost of operating a filter to prevent the suffix from entering visual working memory, whereas the specific component is attributed to the particular fragility of bound representations when the filter fails.     

Does test delay eliminate collaborative inhibition?

Earlier research has demonstrated that collaborative groups recall more than individuals, but less than nominal groups (pooled performance of individuals), thus exhibiting collaborative inhibition. In two experiments, all participants were first asked to recall story material on their own. Some participants were then assigned to pairs and recalled the material collaboratively. On the other hand, the participants in the individual recall condition were asked to recall the material once again on their own. In Experiment 1, the collaborative pairs recalled less than the nominal pairs in accordance with previous studies. In Experiment 2, the timing of the initial individual recall was manipulated by inserting one week between the learning and the recall. The collaborative inhibition was eliminated in this situation. Sources of the collaborative inhibition in immediate recall and its disappearance in delayed recall are discussed in terms of the effect of cross cueing in collaborative remembering.     

The effect of number of kanji radical companions in character activation with a multi-radical-display task

The majority of Japanese complex kanji consist of two subword units (radicals), and each radical is differentiated according to its combinability. Radical-type frequency is defined as the number of radical companions (NC) functioning as the number of characters containing that radical. The current study is intended to address the question of whether the NC plays a role in kanji character activation under a multi-radical-display (MRD) instead of a tachistoscopic display. An MRD task was used in which the NC was manipulated and the frequency of use of the whole characters was matched on average across the experimental conditions. Participants were divided into two groups (good knowledge vs poor knowledge) according to the score of a kanji completion task. The participants' task was to select an appropriate combination of radicals to compose a legitimate character under the MRD condition. The poor-knowledge group yielded relatively more errors than did the good-knowledge group in the low-NC condition, whereas the good-knowledge group yielded more errors in the high-NC condition than in the low-NC condition. These results demonstrate the different influences of NC as metaknowledge (tacit knowledge of radical productivity) in both good and poor readers.     

Humans (Homo sapiens) fail to show an inequity effect in an “up-linkage” analog of the monkey inequity test

Brosnan and de Waal (Nature 425:297–299, 2003) claimed that if a capuchin sees another capuchin receiving a superior food, she tends to reject an inferior, previously acceptable food. They related this phenomenon to human inequity aversion. This phyletic extension is “down linkage,” because nonhuman research is interpreted in terms of human research. The present experiment makes an “up-linkage” test of this claimed connection by attempting to reproduce the capuchin-inequity effect in humans. In Experiment 1’s equity condition, a subject and an adjacent confederate each clicked a computer mouse to mark the number “7” from a random numbers table, earning 0.5 yen per mark. In the inequity condition, the confederate’s pay rate was twice that of the subject. There was no between-condition difference in quitting times or likelihoods. Experiment 2 replicated Experiment 1 except, before beginning, the subject and confederate clicked a mouse over a rapidly switching message that said they would earn either 0.5 or 1 yen per marked seven. For the equity condition in this rigged test, subject and confederate stopped the message at 0.5 yen, while in the inequity condition, these values were 0.5 and 1 yen, respectively. Now, inequity-condition subjects quit sooner than equity-condition subjects. Experiment 1 found no inequity effect, but Experiment 2 did. These results show that: (a) a sense of control/responsibility may be critical to an inequity effect and (b) the inequity effect putatively present in capuchins cannot be reproduced in an up-linkage human analog of that research, thereby calling this linkage into question. This report exemplifies that up- and down-linkage tests are often requisite to establish commonality of psychological process between nonhuman primates and humans.     

Verbal representation in task order control: An examination with transition and task cues in random task switching

Recent task-switching studies in which a predictable task sequence has been used have indicated that verbal representation contributes to the control of task order information. The present study focused on the role of verbal representation in sequential task decisions, which are an important part of task order control, and examined the effects of articulatory suppression in a random-task-cuing paradigm with two different types of cues presented just before the presentation of a stimulus: a transition cue and a task cue. The former cue provided information only about switching or repeating the task, whereas the latter was associated directly with the identity of the task (i.e., indicating a parity or a magnitude task). In Experiment 1, in which transition cues guided task sequences, articulatory suppression impaired performance in both repetition and switch trials, thereby increasing the mixing costs. In Experiment 2, in which a task cue, rather than a transition cue, was presented to examine the influence of a cue-decoding process, articulatory suppression had no specific effect on task performance. Experiment 3, in which the transition cue and the task cue were randomly presented in the same block to equalize the memory load and task strategy for the two types of cues, confirmed that articulatory suppression significantly increased the mixing costs only in transition cue trials. The results from the three experiments indicated that the use of verbal representation is effective in sequential task decision—that is, in selecting a task set on the basis of transient task order information in both repetition and switch trials.     

Power imbalance,its legitimacy,and aggression

Sixty Japanese female students were asked to exchange shocks in electric roulette games with female opponents. The subjects were assigned to either the 80%, 50%, or 20% win conditions. Half of them were then led to judge that the power unbalance was legitimate by being informed that the assignment was based on a prior performance contest, with the good performer being assigned to the advantageous position. The other subjects were led to perceive the power imbalance as illegitimate by being informed that the assignment was randomly decided. The opponents always severely attacked them. The retaliation by the subjects was analyzed by a two-way ANOVA with Power Imbalance and Legitimacy. It was found that the subjects both in the 20% and 50% win conditions set more intense shocks to their opponents than those in the 80% win condition. This is not consistent with the fear of retaliation hypothesis which had predicted that the subjects would refrain from intensely aggressing against the opponent who had a greater aggressive capacity. It was also found that in the 80% win condition, the subjects set more intense shocks when the unbalance had been determined by their performance than when determined by luck, whereas in the 20% win condition, they set more intense shocks when the imbalance had been determined by luck than when determined by their performance. These suggest that retaliation depended upon perceived justifiability of aggression which was predicated on the legitimacy of the power imbalance. Finding in the 50% win condition that the shock settings were higher when the power imbalance had been determined by their performance than when determined by luck was interpreted in terms of their heightened competitiveness.     

Habituation of exploratory activity to new stimuli, to the absence of a previously presented stimulus and to new contexts, in rats

Rats trained to run a shuttle-alleyway for food exhibited exploratory behaviour to a novel visual/tactual stimulus presented in a specific place of the alley. Intermittent presentation of the same stimulus in the same place resulted in reduction of the exploratory activity (habituation), both within and between sessions. The animals also directed exploratory activity to the absence of the previously presented stimulus at the place where the stimulus had been presented before; this latter response also habituated. The presentation (1) of the same stimulus to which the animals had already habituated in another place in the alleyway or when the animals were running in an opposite direction to the previous trials of stimulus presentation, or (2) of another stimulus, resulted, again, in the appearance of exploratory activity. These results lead to the conclusion that the animals code external events, store this information, and use it to detect spatial- and directional-contextual changes and to generate predictions about that specific environment.     

DISCRIMINATION OF VARIABLE SCHEDULES IS CONTROLLED BY INTERRESPONSE TIMES PROXIMAL TO REINFORCEMENT

In Experiment 1, food‐deprived rats responded to one of two schedules that were, with equal probability, associated with a sample lever. One schedule was always variable ratio, while the other schedule, depending on the trial within a session, was: (a) a variable‐interval schedule; (b) a tandem variable‐interval, differential‐reinforcement‐of‐low‐rate schedule; or (c) a tandem variable‐interval, differential‐reinforcement‐of‐high‐rate schedule. Completion of a sample‐lever schedule, which took approximately the same time regardless of schedule, presented two comparison levers, one associated with each sample‐lever schedule. Pressing the comparison lever associated with the schedule just presented produced food, while pressing the other produced a blackout. Conditional‐discrimination accuracy was related to the size of the difference in reinforced interresponse times and those that preceded it (predecessor interresponse times) between the variable‐ratio and other comparison schedules. In Experiment 2, control by predecessor interresponse times was accentuated by requiring rats to discriminate between a variable‐ratio schedule and a tandem schedule that required emission of a sequence of a long, then a short interresponse time in the tandem's terminal schedule. These discrimination data are compatible with the copyist model from Tanno and Silberberg (2012) in which response rates are determined by the succession of interresponse times between reinforcers weighted so that each interresponse time's role in rate determination diminishes exponentially as a function of its distance from reinforcement.