Dogs (Canis lupus familiaris) fail to show understanding of means-end connections in a string-pulling task

Domestic dogs (Canis lupus familiaris) were tested in four experiments for their understanding of means-end connections. In each of the experiments, the dogs attempted to retrieve a food treat that could be seen behind a barrier and which was connected, via string, to a within-reach wooden block. In the experiments, either one or two strings were present, but the treat was attached only to one string. Successful retrieval of the treat required the animals to pull the appropriate string (either by pawing or by grasping the wooden block in their jaws) until the treat emerged from under the barrier. The results showed that the dogs were successful if the treat was in a perpendicular line to the barrier, i.e. straight ahead, but not when the string was at an angle: in the latter condition, the typical response was a proximity error in that the dogs pawed or mouthed at a location closest in line to the treat. When two strings that crossed were present, the dogs tended to pull on the wrong string. The combined results from the experiments show that, although dogs can learn to pull on a string to obtain food, they do not spontaneously understand means-end connections involving strings.     

Application of the means-end theoretic for understanding the cognitive bases of performance appraisal

Applicability of means-end theory to the area of performance appraisal was tested in a sample of 22 nurse supervisors. Individual interviews were conducted which employed triadic sorting and laddering procedures in order to identify cognitive concepts most salient to performance rating. These concepts were classified according to level of abstraction—attribute, consequence, or value. This classification served as the basis for construction of a summary cognitive map of the performance appraisal process for this sample. Cognitive differentiation analysis revealed that, on average, value level concepts accounted for significant variance in performance judgments over and above that which was accounted for by attributes and consequences. Conclusions include an argument for further investigaton of personal values and their effects on the performance appraisal process.     

Preschool children's understanding of causal connections

Preschool-aged children's understanding of causal mechanism was assessed by showing them a simple event sequence in which two objects moved in tandem. The central question was whether children would infer the presence of a mechanism linking the two objects whose movement covaried. This was tested by assessing five responses: actions when asked to move one object, explanations for how the object moved, predictions as to whether both objects would still move without a connection, inferences about the nature and location of the connection, and surprise when the objects moved without any apparent connection. The results from 3-, 4- and 5-year-olds indicated that an understanding of mechanism is firmly established by 5 years but fragile at 3 years and only revealed by some response modes. The implications of the results concerning how to characterize and test for early competence are discussed.     

Development of children's understanding of connections between thinking and feeling

Two studies assessed the development of children's understanding that thoughts and feelings are closely interlinked. These studies showed that, unlike 8-year-olds and adults, 5-year-olds seldom explained a sudden change in emotion that had no apparent external cause by appeal to the occurrence of a thought. They also tended not to recognize that a person who is feeling sad is probably also thinking sad thoughts, or that people may be able to make themselves feel happy just by thinking of something happy. These results are consistent with evidence that young children tend to be unaware of the stream of consciousness and have poor introspective skills. A possible developmental sequence leading to an understanding of these thought-feeling links is proposed.     

The global precedence effect is not affected in inhibition of return

This study assessed whether inhibitory processes occurring in IOR affect perceptual processing of hierarchically organised stimuli. Experiment 1 used a global/local task that presented stimuli to the left or the right side. Results showed a global task advantage and a larger interference in the local than in the global task—the global precedence effect (GPE). These effects were larger than in previous studies using centrally presented stimuli, which suggests a greater involvement of low spatial frequency analysis with peripheral than with central stimuli. Experiment 2 combined the global/local task with IOR. Results replicated those of Experiment 1 but there was no interaction with stimulus location. That is, the GPE was not affected in IOR. Thus, we conclude that the GPE and inhibitory processing occurring in IOR are subserved by different mechanisms.     

Human-directed behaviour in goats is not affected by short-term positive handling

In addition to domestication, interactions with humans or task-specific training during ontogeny have been proposed to play a key role in explaining differences in human–animal communication across species. In livestock, even short-term positive interactions with caretakers or other reference persons can influence human–animal interaction at different levels and over different periods of time. In this study, we investigated human-directed behaviour in the ‘unsolvable task’ paradigm in two groups of domestic goats (Capra aegagrus hircus). One group was positively handled and habituated to a plastic box by the experimenter to retrieve a food reward, while the other group only received standard husbandry care and was habituated to the box without human assistance. In the unsolvable task, the lid was fixed to the box, with the reward inaccessible to the subjects. The goats were confronted with the unsolvable task three times. We observed no difference between the two groups regarding gaze and contact alternations with the experimenter when confronted with the task they cannot solve by themselves. The goats did not differ in their expression rates of both gaze and contact alternations over three repetitions of the unsolvable task; however, they showed earlier gaze and contact alternations in later trials. The results do not support the hypothesis that short-term positive handling or task-specific training by humans facilitates human-directed behaviour in goats. In contrast, standard husbandry care might be sufficient to establish humans as reference persons for farm animals in challenging situations.     

High calcium intake does not prevent stress-salt hypertension in dogs

Avoidance conditioning sessions and isotonic saline (1.3 L/day) were administered to dogs for 12 days under conditions of a low (0.1%) or high (1.5%) calcium diet. Twenty-four-hour mean arterial pressure increased comparably during the stress-salt conditioning periods on both the low (systolic: +16 ± 5 mm Hg; diastolic: +6 ± 2 mm Hg) and high (systolic: +17 ± 4 mm Hg; diastolic: +11 ± 4 mm Hg) calcium diets. Urine volume, sodium excretion, and serum calcium levels on the high calcium diet were not significantly different from those on the low calcium diet. In a second experiment, calcium was infused continuously for six days into the arterial circulation of normotensive or stress-salt hypertensive dogs at a rate of 0.12–0.23 mEq/min. Although serum calcium levels increased by up to 50% under these conditions, there were no significant effects on 24-hour levels of arterial pressure. In contrast to the protective effect of augmented potassium intake, these findings indicate that calcium intake does not influence the development of stress-salt hypertension in dogs.     

Comparison of active and purely visual performance in a multiple-string means-end task in infants

The aim of the present study was to understand what factors influence infants’ problem-solving behaviours on the multiple-string task. The main question focused on why infants usually solve the single string-pulling task at 12 months at the latest, whereas most 16-month-old infants still cannot solve the task when several strings are presented, only one of which is attached to the desired object. We investigated whether this difficulty is related to infants’ ability to inhibit their spontaneous immediate actions by comparing active and purely visual performance in this task. During the first part of the experiment, we assessed the ability of infants aged 16–20 months to solve the multiple-string task. The infants were then divided into three groups based on performance (a “failure” group, an “intermediate” group, and a “success” group). The results of this action task suggest that there were differences in infants’ performance according to their level of inhibitory control of their preferred hand. In the second part of the experiment, the three groups’ predictive looking strategies were compared when seeing an adult performing the task. We found that only infants who successfully performed the action task also visually anticipated which string the adult had to pull in the visual task. Our results suggests that inhibitory control was not the only factor influencing infants’ performance on the task. Furthermore, the data support the direct matching hypothesis (Rizzolatti and Fadiga, 2005), according to which infants need to be able to perform actions themselves before being able to anticipate similar actions performed by others.     

Amphetamine increases intertrial but not conditional instrumental responding in the cortico-basomedial amygdalar dogs

The effect of partial cortico-basomedial amygdaloid lesions on dogs’ social behavior was investigated. The lesions did not affect the conditional instrumental responding (CRs) reinforced by petting or the dogs’ need for petting (US). The lesions increased the number of intertrial responses (ITRs) in all dogs. Subsequently the effect of low amphetamine doses (0.5 mg/l kg) administered intramuscularly to the amygdalar animals on the same behavioral parameters of the social behavior was examined. Amphetamine did not affect CRs but dramatically increased the ITRs and dogs’ need for petting. These findings suggest that the cortico-basomedial amygdaloid region may be involved in the cortical inhibitory mechanisms that are indispensable for promoting behavioral acts according to their usefulness and the situational context.     

Face recognition in pictures is affected by perspective transformation but not by the centre of projection

Recognition of unfamiliar faces is susceptible to image differences caused by angular sizes subtended from the face to the camera. Research on perception of cubes suggests that apparent distortions of a shape due to large camera angle are correctable by placing the observer at the centre of projection, especially when visibility of the picture surface is low (Yang and Kubovy, 1999 Perception & Psychophysics 61 456-467). To explore the implication of this finding for face perception, observers performed recognition and matching tasks where face images with reduced visibility of picture surface were shown with observers either at the centre of projection or at other viewpoints. The results show that, unlike perception of cubes, the effect of perspective transformation on face recognition is largely unaffected by the centre of projection. Furthermore, the use of perspective cues is not affected by textured surfaces. The limitation of perspective in restoring 3-D information of faces suggests a stronger role for image-based, rather than model-based, processes in recognition of unfamiliar faces.     

Evolutionary psychology is not the only productive evolutionary approach to understanding consumer behavior

I respond to Vladas Griskevicius and Douglas T. Kendrick (G&;K) and Gad Saad's (S) defenses of the view that Consumer Studies would benefit from the appeal to evolution in all work aimed at understanding consumer behavior. I argue that G&;K and S's reliance on one theoretical perspective, that of evolutionary psychology, limits their options. Further, I point out some specific problems with the theoretical perspective of evolutionary psychology. Finally, I introduce some alternative evolutionary approaches to studying human behavior that could profitably be adopted in consumer research.     

Rich interpretation vs. deflationary accounts in cognitive development: the case of means-end skills in 7-month-old infants

Seven-month-old infants appear to learn means-end skills, such as pushing a button to retrieve a distant toy (Psychological Review 104 (1997) 686). The present studies tested whether such apparent means-end behaviors are genuine, or simply the repetition of trained behaviors under conditions of greatest arousal, as suggested by a dynamic systems reinterpretation. When infants were trained to repeat behaviors that did not serve as means to retrieving toys (pushing a button to light a set of distant lights), their button-pushing differed significantly from infants for whom button-pushing served as a means for retrieving toys. Further, infants demonstrated means-end skills with behaviors that they had not been trained to repeat. Implications for early means-end abilities and for debates surrounding the interpretation of infant behavior are discussed.     

Performance bias: Why judgments of learning are not affected by learning

Past research has shown a performance bias: People expect their future performance level on a task to match their current performance level, even when there are good reasons to expect future performance to differ from current performance. One explanation of this bias is that judgments are controlled by what learners can observe, and while current performance is usually observable, changes in performance (i.e., learning or forgetting) are not. This explanation makes a prediction that we tested here: If learning becomes observable, it should begin to affect judgments. In three experiments, after practicing a skill, participants estimated how they performed in the past and how they expected to perform in the future. In Experiments 1 and 2, participants knew they had been improving, as shown by their responses, yet they did not predict that they would improve in the future. This finding was particularly striking because (a) they did improve in the future and (b) as Experiment 3 showed, they did hold the conscious belief that past improvement predicted future improvement. In short, when learning and performance are both observable, judgments of learning seem to be guided by performance and not learning.     

Brief owner absence does not induce negative judgement bias in pet dogs

Humans in a negative emotional state are more likely to judge ambiguous stimuli as negative. In recent years, similar judgement biases have been found in some non-human animals that were exposed to long-term or short-term treatments aimed at influencing their affective states. Here we tested pet dogs in the presence and absence of their owners in a judgement bias test with an established go/no-go procedure. Even though owner absence is thought to induce a state of anxiety in dogs that have formed an attachment bond with their primary caretakers, we found no difference between the dogs' responses to ambiguous stimuli in the presence or absence of their owners. This result may be explained by the absence of anxiety in dogs that are accustomed to brief periods of separation from their owners, or by a sensitivity limit of the customary judgement bias tests in non-human animals when only a moderate, short-term state of anxiety is induced. In addition, we found significant differences between individuals and populations in the responses to ambiguous stimuli, which give impetus for further research.     

Winds of time and place: How context has affected a 50–year marriage

To examine the effects of contexts on a relationship, we consider the case of our own 50–year marriage and its preliminaries. We employ a three–level conception of a couple's environment. The macrocontext refers to the prevailing cultural winds in a society that affect all its residents during any given historical era. The mesocontext pertains to the settings in which a particular relationship operates, such as its family and other social networks, physical habitats, work settings, or institutional associations, often chosen by the partners themselves. The microcontext is the pair's own intimate environment, constructed over time by the partners’ unique interactions. Each of these contexts has affected us. We describe and analyze instances of luck, choice, and dyadic interaction in our 52–year relationship.     

Recall of morphologically complex forms is affected by memory task but not dyslexia

The authors studied the effect of morphological complexity on working memory in list recall tasks with base words (boy), inflected words (boy + 's) and derived words (boy + hood) in a morphologically rich language: Finnish. Simple serial recall was compared to complex working memory tasks, combining word recall with sentence verification in 8-year-old normally reading participants, dyslexic children, and adults. The normally reading children performed better than dyslexic children on both memory tasks and a test of morphology. Base words were better recalled than morphologically complex words. Memory was better for derived than inflected words in simple but not complex span tasks. There was no interaction between word type and reading group and thus no suggestion of dyslexia being associated with specific problems to represent complex morphology in working memory. Morphological processing in working memory appeared to depend on the task.