Can a self-propelled box have a goal? Psychological reasoning in 5-month-old infants

Some researchers have suggested that infants' ability to reason about goals develops as a result of their experiences with human agents and is then gradually extended to other agents. Other researchers have proposed that goal attribution is rooted in a specialized system of reasoning that is activated whenever infants encounter entities with appropriate features (e.g., self-propulsion). The first view predicts that young infants should attribute goals to human but not other agents; the second view predicts that young infants should attribute goals to both human and nonhuman agents. The present research revealed that 5-month-old infants (the youngest found thus far to attribute goals to human agents) also attribute goals to nonhuman agents. In two experiments, infants interpreted the actions of a self-propelled box as goal-directed. These results provide support for the view that from an early age, infants attribute goals to any entity they identify as an agent.     

Reasoning about a hidden object after a delay: evidence for robust representations in 5-month-old infants

The present research examined two alternative interpretations of violation-of-expectation findings that young infants can represent hidden objects. One interpretation is that, when watching an event in which an object becomes hidden behind another object, infants form a prediction about the event's outcome while both objects are still visible, and then check whether this prediction was accurate. The other interpretation is that infants' initial representations of hidden objects are weak and short-lived and as such sufficient for success in most violation-of-expectation tasks (as objects are typically hidden for only a few seconds at a time), but not more challenging tasks. Five-month-old infants succeeded in reasoning about the interaction of a visible and a hidden object even though (1) the two objects were never simultaneously visible, and (2) a 3- or 4-min delay preceded the test trials. These results provide evidence for robust representations of hidden objects in young infants.     

The development of young infants' intuitions about support

Previous research has shown that 3-month-old infants, like adults, expect a box to be stable when it is in full contact with a platform, and to fall when it loses all contact with the platform. Do young infants also have expectations about what should happen when the box is only in partial contact with the platform? The present research was designed to address this question. In Experiment 1, 6.5-month-old infants saw two test events: a full-contact and a partial-contact test event. In both events, the infants watched the extended finger of a gloved hand push a box along the top of a platform. In the full-contact event, the box was pushed until its leading edge reached the end of the platform. In the partial-contact event, the box was pushed until only 15% or 70% of its bottom surface remained on the platform. The infants looked reliably longer at the partial-than at the full-contact event when 15%, but not 70%, of the box rested on the platform. These results suggested that the infants were able to judge how much contact was needed between the box and the platform for the box to be stable. A control condition provided evidence for this interpretation. In Experiment 2, 5.5- to 6-month-old infants were found to look equally at the full- and the partial-contact events, even when only 15% of the box's bottom surface remained on the platform. This result suggested that prior to 6.5 months of age infants perceive any amount of contact between the box and the platform to be sufficient to ensure the box's stability. Interpretations of this developmental sequence are considered in the Conclusion.     

Reasoning about the height and location of a hidden object in 4.5- and 6.5-month-old infants

The present experiments examined 6.5- and 4.5-month-old infants' ability to represent and to reason about the height and location of a hidden object. In Experiments 1 and 2, the infants were habituated to a screen that rotated back and forth through a 180 degree arc, in the manner of a drawbridge. Following habituation, a box was placed behind the screen, and the infants saw two test events. In one (possible event), the screen rotated until it reached the occluded box; in the other (impossible event), the screen rotated through either the top 80% or the top 50% of the space occupied by the box. The results indicated that (a) the 6.5-month-old infants were surprised when the screen rotated through the top 80%, but not the top 50%, of the box and (b) the 4.5-month-old infants failed to be surprised even when the screen rotated through the top 80% of the box (4.5-month-old infants do show surprise, however, when the screen rotates through the entire (100%) box (Baillargeon, 1987a]. Experiments 3 and 4 tested whether infants would be better at detecting that the screen rotated farther than it should if provided with a second, identical box to the side of the box behind the screen. This second box stood out of the screen's path and so remained visible throughout the test trials. The results indicated that with the second box present (a) the 6.5-month-old infants showed surprise when the screen rotated through the top 50% of the occluded box and (b) the 4.5-month-old infants were surprised when the screen rotated through either the top 80% or the top 50% of the box. The results of Experiment 5 revealed that the improvement in performance brought about by the second box disappeared when this box was no longer in the same fronto-parallel plane as the box behind the screen. Different models are considered to describe the impressive quantitative and qualitative physical reasoning abilities revealed by these findings.     

Are the times changing? An analysis of sex-role prejudice

Sex bias was studied through evaluation of articles, in a technique modeled upon Goldberg's. Goldberg (1968) indicated that college women evaluated an article more positively when it was ascribed to a male rather than to a female author. The primary purpose of the present research was to examine a diverse sample, including subjects of both sexes and varying ages, and to determine whether sex-role attitudes have changed over time. Therefore, 64 students at the University of California, Santa Cruz, 64 students from San Jose State University, and 96 nonstudents from the San Francisco—Monterey Bay areas each evaluated six articles on several dimensions. Packets were counterbalanced for ascribed sex of author and sex of topic (male, female, or neutral). An analysis of variance yielded significant main effects for sex of subject and sex of topic. Further analyses yielded complex interactions which appeared to be primarily due to the responses of young nonstudents. The absence of an overall sex of author effect and the general pattern of data are interpreted in terms of the generalizability of research findings.Some of the results reported in this paper were presented in a symposium on sex-role research methodology at the annual meeting of the Western Psychological Association, Los Angeles, April 1976.     

The Other Accent Effect in Talker Recognition: Now You See It,Now You Don't

The existence of the Language Familiarity Effect (LFE), where talkers of a familiar language are easier to identify than talkers of an unfamiliar language, is well-documented and uncontroversial. However, a closely related phenomenon known as the Other Accent Effect (OAE), where accented talkers are more difficult to recognize, is less well understood. There are several possible explanations for why the OAE exists, but to date, little data exist to adjudicate differences between them. Here, we begin to address this issue by directly comparing listeners’ recognition of talkers who speak in different types of accents, and by examining both the LFE and OAE in the same set of listeners. Specifically, Canadian English listeners were tested on their ability to recognize talkers within four types of voice line-ups: Canadian English talkers, Australian English talkers, Mandarin-accented English talkers, and Mandarin talkers. We predicted that the OAE would be present for talkers of Mandarin-accented English but not for talkers of Australian English—which is precisely what we observed. We also observed a disconnect between listeners’ confidence and performance across different types of accents; that is, listeners performed equally poorly with Mandarin and Mandarin-accented talkers, but they were more confident with their performance with the latter group of talkers. The present findings set the stage for further investigation into the nature of the OAE by exploring a range of potential explanations for the effect, and introducing important implications for forensic scientists’ evaluation of ear witness testimony.     

Cognitive adaptations arising from nonnative experience of sign language in hearing adults

Three experiments examined spatial transformation abilities in hearing people who acquired sign language in early adulthood. The performance of the nonnative hearing signers was compared with that of hearing people with no knowledge of sign language. The two groups were matched for age and gender. Using an adapted Corsi blocks paradigm, the experimental task simulated spatial relations in sign discourse but offered no opportunity for linguistic coding. Experiment 1 showed that the hearing signers performed significantly better than the nonsigners on a task that entailed 180 degree rotation, which is the canonical spatial relationship in sign language discourse. Experiment 2 found that the signers did not show the typical costs associated with processing rotated stimuli, and Experiment 3 ruled out the possibility that their advantage relied on seen hand movements. We conclude that sign language experience, even when acquired in adulthood by hearing people, can give rise to adaptations in cognitive processes associated with the manipulation of visuospatial information.