Dogs demonstrate perspective taking based on geometrical gaze following in a Guesser–Knower task

Currently, there is still no consensus about whether animals can ascribe mental states (Theory of Mind) to themselves and others. Showing animals can respond to cues that indicate whether another has visual access to a target or not, and that they are able to use this information as a basis for whom to rely on as an informant, is an important step forward in this direction. Domestic dogs (Canis familiaris) with human informants are an ideal model, because they show high sensitivity towards human eye contact, they have proven able to assess the attentional state of humans in food-stealing or food-begging contexts, and they follow human gaze behind a barrier when searching for food. With 16 dogs, we not only replicated the main results of Maginnity and Grace (Anim Cogn 17(6):1375–1392, 2014) who recently found that dogs preferred to follow the pointing of a human who witnessed a food hiding event over a human who did not (the Guesser–Knower task), but also extended this finding with a further, critical control for behaviour-reading: two informants showed identical looking behaviour, but due to their different position in the room, only one had the opportunity to see where the food was hidden by a third person. Preference for the Knower in this critical test provides solid evidence for geometrical gaze following and perspective taking in dogs.     

Estimating the growth of internal evidence guiding perceptual decisions

Perceptual decision-making is thought to involve a gradual accrual of noisy evidence. Temporal integration of the evidence reduces the relative contribution of dynamic internal noise to the decision variable, thereby boosting its signal-to-noise ratio. We aimed to estimate the internal evidence guiding perceptual decisions over time, using a novel combination of external noise and the response signal methods. Observers performed orientation discrimination of patterns presented in external noise. We varied the contrast of the patterns and the delay at which observers were forced to signal their decision. Each test stimulus (patterns and noise sample) was presented twice. Across two experiments we varied the availability of the visual stimulus for processing. Observer model analyses of discrimination accuracy and response consistency to two passes of the same stimulus, suggested that there was very little growth in the internal evidence. The improvement in accuracy over time characterised by the speed-accuracy trade-off function predominantly reflected a decreasing proportion of non-visual decisions, or pure guesses. There was no advantage to having the visual patterns visible for longer than 80 ms, indicating that only the visual information in a short window after display onset was used to drive the decisions. The remarkable constancy of the internal evidence over time suggests that temporal integration of the sensory information was very limited. Alternatively, more extended integration of the evidence from memory could have taken place, provided that the dominant source of internal noise limiting performance occurs between-trials, which cannot be reduced by prolonged evidence integration.     

How the growth of science ends theory change

This paper outlines a defense of scientific realism against the pessimistic meta-induction which appeals to the phenomenon of the exponential growth of science. Here, scientific realism is defined as the view that our current successful scientific theories are mostly approximately true, and pessimistic meta-induction is the argument that projects the occurrence of past refutations of successful theories to the present concluding that many or most current successful scientific theories are false. The defense starts with the observation that at least 80% of all scientific work ever done has been done since 1950, proceeds with the claim that practically all of our most successful theories were entirely stable during that period of time, and concludes that the projection of refutations of successful theories to the present is unsound. In addition to this defense, the paper offers a framework through which scientific realism can be compared with two types of anti-realism. The framework is also of help to examine the relationships between these three positions and the three main arguments offered respectively in their support (No-miracle argument, pessimistic meta-induction, underdetermination).     

Uniforms affect the accuracy of children's eyewitness identification decisions

A substantial proportion of line‐up identifications involving child eyewitnesses in the UK are conducted by police officers wearing uniform. This study examined the possibility that wearing a uniform constitutes an authority cue that adversely affects a child's ability to make accurate eyewitness identifications. Sixty participants aged 9–10 years old witnessed a staged crime and were later asked to identify a ‘burglar’ from a simultaneous line‐up using a 2 (uniform: present vs. absent) × 2 (target: present vs. absent) design. Children in the uniform present conditions made significantly more choices than children in the uniform absent conditions. More importantly, in the presence of a uniform, children made significantly more false identifications in target‐absent line‐ups. Analysis of supplementary, identification‐related variables (identification time and confidence, state anxiety) suggested that (1) the children experienced uncertainty if the target was absent from the line‐up, but (2) this uncertainty was not expressed when the line‐up administrator wore a uniform, leading to an increase in false identifications. Implications for line‐up administration procedures for children are discussed. Copyright © 2009 John Wiley & Sons, Ltd.     

Effects of time pressure on strategy selection and strategy execution in forced choice tests

We examined the effects of cognitive load on the strategy selection in the forced choice test (FCT) when used to detect hidden crime knowledge. Examinees (N = 120) with and without concealed knowledge from a mock crime were subjected to an FCT either under standard circumstances or cognitive load. Cognitive load was implemented through time pressure. The FCT distinguished examinees with concealed knowledge from those without better than chance in both conditions, but the counterstrategies did not differ between conditions. Further investigation revealed that time pressure did affect examinees' ability to follow their intended counterstrategy to produce randomized test patterns, which constitutes an effective counterstrategy in the FCT. Hence, time pressure lowered the success rate of effective counterstrategies, but not their incident rates. Further disambiguation of various cognitive load manipulations and their effects on strategy selection and execution is needed.     

Context‐induced placebo effects—An investigation of contrast effects in response expectations and actual product efficacy

Recent research on the placebo effect of marketing actions has demonstrated that characteristics that are not inherent to a product's physical properties per se, such as its price, brand, or packaging can considerably shape consumers' expectations about and actual efficacy of a marketed product. However, potential contextual effects that other products may have on the construction of consumers' efficacy beliefs and objective consumption outcomes remain unexplored. Across two experimental studies, we show that people's response expectations regarding a focal product are inversely related to the alleged superiority of context options and that such context‐induced expectations can carry over to behavioural performance metrics; a phenomenon we refer to as context‐induced placebo effects.     

Hindsight bias doesn't always come easy: causal models, cognitive effort, and creeping determinism

Creeping determinism, a form of hindsight bias, refers to people's hindsight perceptions of events as being determined or inevitable. This article proposes, on the basis of a causal-model theory of creeping determinism, that the underlying processes are effortful, and hence creeping determinism should disappear when individuals lack the cognitive resources to make sense of an outcome. In Experiments 1 and 2, participants were asked to read a scenario while they were under either low or high processing load. Participants who had the cognitive resources to make sense of the outcome perceived it as more probable and necessary than did participants under high processing load or participants who did not receive outcome information. Experiment 3 was designed to separate 2 postulated subprocesses and showed that the attenuating effect of processing load on hindsight bias is not due to a disruption of the retrieval of potential causal antecedents but to a disruption of their evaluation. Together the 3 experiments show that the processes underlying creeping determinism are effortful, and they highlight the crucial role of causal reasoning in the perception of past events.     

Ingroup bias in the minimal group paradigm shown by three‐person groups with high or low state self‐esteem

From social identity theory a negative relation between self‐esteem and ingroup bias can be deducted. Much research has been done to test this proposition and largely failed to confirm this relation. Unlike many existing studies, we conducted an experiment in which (a) self‐esteem is not conceived as a trait entity but much more situation‐specific, (b) the self‐esteem manipulation is not relative to the outgroup, and (c) the measure of intergroup differentiation is unrelated to the self‐esteem manipulation. We categorised our participants into two arbitrary minimal groups (Klee or Kandinsky fans) and afterwards formed homogeneous three‐person groups (all persons were either Klee or Kandinsky fans). We manipulated the state self‐esteem of these real groups by giving them positive or negative feedback concerning their performance in a problem‐solving task. Afterwards, all groups distributed money to ingroup and outgroup members via Tajfel distribution matrices. Low state self‐esteem groups were found to exhibit stronger ingroup bias than high state self‐esteem groups overall, although the variability of intergroup discrimination was larger in the low state self‐esteem groups, pointing to more heterogeneous reactions to low state self‐esteem. Copyright © 2002 John Wiley & Sons, Ltd.     

Transcranial magnetic stimulation in child psychiatry: disturbed motor system excitability in hypermotoric syndromes

Normal development and dysfunctions of motor system excitability can be investigated in vivo by means of single‐ and paired‐pulse transcranial magnetic stimulation (TMS). While different TMS‐parameters show different developmental time courses between 8 and 16 years of age, distinct dysfunctional patterns of motor system excitability can be demonstrated in child psychiatric disorders with hypermotoric behavior: in tic disorder, a shortened cortical silent period can be stated providing evidence for deficient inhibitory mechanisms within the sensorimotor loop, probably primarily at the level of the basal ganglia. In attention deficit hyperactivity disorder (ADHD), a decreased intracortical inhibition indicates deficient inhibitory mechanisms within the motor cortex (but enhancement of intracortical inhibition after oral intake of 10 mg methylphenidate). In children with comorbid ADHD and tic disorder, the findings of a reduced intracortical inhibition as well as a shortened cortical silent period provide evidence for additive effects at the level of motor system excitability. Thus, TMS allows us to obtain substantial insight into both the normal development and the neurobiological basis of hypermotoric syndromes in child psychiatry.