Toby J. Lloyd-Jones

Eliciting person descriptions from eyewitnesses: A survey of police perceptions of eyewitness performance and reported use of interview techniques

Techniques such as the cognitive interview (CI) have the potential to improve witness recall. Nevertheless, there is also laboratory evidence of “verbal overshadowing”; the phenomenon whereby verbally describing aspects of an event (such as the face of a perpetrator) can have negative consequences for eyewitness memory. Seventy-two UK police officers were surveyed regarding their perceptions of eyewitness performance and the methods they use to elicit person descriptions from witnesses. Factors commonly believed to influence description quality were the viewing conditions of the event, the characteristics of the witness, and their mental distress. When eliciting person descriptions there was a consensus that some components of the CI were more frequently used and believed to be more useful than others. Witnesses were generally believed to provide accurate, but incomplete person descriptions. Nevertheless, there were instances where officers reported requesting elaborative face descriptions. We propose that verbal overshadowing is unlikely to be a major concern for most police officers; however, under some circumstances its potential impact should be considered. It is also clear that it would be of benefit for future research on verbal overshadowing to examine a number of variables relevant to the forensic setting.

Sources of error in picture naming under time pressure

We used a deadline procedure to investigate how time pressure may influence the processes involved in picture naming. The deadline exaggerated errors found under naming without deadline. There were also category differences in performance between living and nonliving things and, in particular, for animals versus fruit and vegetables. The majority of errors were visually and semantically related to the target (e.g., celery—asparagus), and there was a greater proportion of these errors made to living things. Importantly, there were also more visual-semantic errors to animals than to fruit and vegetables. In addition, there were a smaller number of pure semantic errors (e.g., nut—bolt), which were made predominantly to nonliving things. The different kinds of error were correlated with different variables. Overall, visual-semantic errors were associated with visual complexity and visual similarity, whereas pure semantic errors were associated with imageability and age of acquisition. However, for animals, visual-semantic errors were associated with visual complexity, whereas for fruit and vegetables they were associated with visual similarity. We discuss these findings in terms of theories of category-specific semantic impairment and models of picture naming.

Independent influences of verbalization and race on the configural and featural processing of faces: a behavioral and eye movement study

Describing a face in words can either hinder or help subsequent face recognition. Here, the authors examined the relationship between the benefit from verbally describing a series of faces and the same-race advantage (SRA) whereby people are better at recognizing unfamiliar faces from their own race as compared with those from other races. Verbalization and the SRA influenced face recognition independently, as evident on both behavioral (Experiment 1) and eye movement measures (Experiment 2). The findings indicate that verbalization and the SRA each recruit different types of configural processing, with verbalization modulating face learning and the SRA modulating both face learning and recognition. Eye movement patterns demonstrated greater feature sampling for describing as compared with not describing faces and for other-race as compared with same-race faces. In both cases, sampling of the eyes, nose, and mouth played a major role in performance. The findings support a single process account whereby verbalization can influence perceptual processing in a flexible and yet fundamental way through shifting ones processing orientation.

Dissociating positive and negative influences of verbal processing on the recognition of pictures of faces and objects.

Four experiments investigated the role of verbal processing in the recognition of pictures of faces and objects. We used (a) a stimulus-encoding task where participants learned sequentially presented pictures in control, articulatory suppression, and describe conditions and then engaged in an old-new picture recognition test and (b) a poststimulus-encoding task where participants learned the stimuli without any secondary task and then either described or not a single item from memory before the recognition test. The main findings were as follows: First, verbalization influenced picture recognition. Second, there were contrasting influences of verbalization on the recognition of faces, compared with objects, that were driven by (a) the stage of processing during which verbalization took place (as assessed by the stimulus-encoding and poststimulus-encoding tasks), (b) whether verbalization was subvocal (whereby one goes through the motions of speaking but without making any sound) or overt, and (c) stimulus familiarity. During stimulus encoding there was a double dissociation whereby subvocal verbalization interfered with the recognition of faces but not objects, while overt verbalization benefited the recognition of objects but not faces. In addition, stimulus familiarity provided an independent and beneficial influence on performance. Post stimulus encoding, overt verbalization interfered with the recognition of both faces and objects, and this interference was apparent for unfamiliar but not familiar stimuli. Together these findings extend work on verbalization to picture recognition and place important parameters on stimulus and task constraints that contribute to contrasting beneficial and detrimental effects of verbalization on recognition memory.

Independent effects of colour on object identification and memory

We examined the effects of colour on object identification and memory using a study–test priming procedure with a coloured-object decision task at test (i.e., deciding whether an object is correctly coloured). Objects were selected to have a single associated colour and were either correctly or incorrectly coloured. In addition, object shape and colour were either spatially integrated (i.e., colour fell on the object surface) or spatially separated (i.e., colour formed the background to the object). Transforming the colour of an object from study to test (e.g., from a yellow banana to a purple banana) reduced priming of response times, as compared to when the object was untransformed. This utilization of colour information in object memory was not contingent upon colour falling on the object surface or whether the resulting configuration was of a correctly or incorrectly coloured object. In addition, we observed independent effects of colour on response times, whereby coloured-object decisions were more efficient for correctly than for incorrectly coloured objects but only when colour fell on the object surface. These findings provide evidence for two distinct mechanisms of shape–colour binding in object processing.

Verbal overshadowing of multiple face recognition: Effects on remembering and knowing over time

“Verbal overshadowing”, the phenomenon whereby the verbal reporting of a visual memory of a face interferes with subsequent recognition of that face, arises for the presentation of multiple faces following a single face description. We examined the time course of verbal overshadowing in the multiple face paradigm, and its influence on recollection and familiarity-based recognition judgements. Participants were presented with a series of faces and then described a further face (or not, in the control condition). Study faces were subsequently discriminated from distractors at either a short or long lag after initial presentation, in a yes/no recognition task using the remember/know procedure. Verbal overshadowing was most apparent at the short lag, for discrimination and false “know” judgements. We discuss these findings in terms of the nature of verbal interference in this paradigm.

Verbalising visual memories

In this paper, we introduce a special issue on the role of verbalisation in visual memory. In particular, we provide an overview of research on: (a) verbal interference and facilitation in face and person recognition; (b) similarities and differences between effects of verbalisation and processing in the Navon task (i.e., global or local letter identification; Navon, 1977); and (c) effects of verbalisation in visual imagery and object memory. We argue that verbal processes influence the encoding, storage, and retrieval of visual information. Moreover, different forms of verbal interference and facilitation are likely to be due to different mechanisms in different contexts. The state of the art is that we are just beginning to understand the rich complexity of the problem.

The time course of activation of object shape and shape+colour representations during memory retrieval.

Little is known about the timing of activating memory for objects and their associated perceptual properties, such as colour, and yet this is important for theories of human cognition. We investigated the time course associated with early cognitive processes related to the activation of object shape and object shape+colour representations respectively, during memory retrieval as assessed by repetition priming in an event-related potential (ERP) study. The main findings were as follows: (1) we identified a unique early modulation of mean ERP amplitude during the N1 that was associated with the activation of object shape independently of colour; (2) we also found a subsequent early P2 modulation of mean amplitude over the same electrode clusters associated with the activation of object shape+colour representations; (3) these findings were apparent across both familiar (i.e., correctly coloured – yellow banana) and novel (i.e., incorrectly coloured - blue strawberry) objects; and (4) neither of the modulations of mean ERP amplitude were evident during the P3. Together the findings delineate the timing of object shape and colour memory systems and support the notion that perceptual representations of object shape mediate the retrieval of temporary shape+colour representations for familiar and novel objects.

Animal recognition and eye movements: the contribution of outline contour and local feature information

We assessed the importance of outline contour and individual features in mediating the recognition of animals by examining response times and eye movements in an animal-object decision task (i.e., deciding whether or not an object was an animal that may be encountered in real life). There were shorter latencies for animals as compared with nonanimals and performance was similar for shaded line drawings and silhouettes, suggesting that important information for recognition lies in the outline contour. The most salient information in the outline contour was around the head, followed by the lower torso and leg regions. We also observed effects of object orientation and argue that the usefulness of the head and lower torso/leg regions is consistent with a role for the object axis in recognition.

Long-term repetition priming and semantic interference in a lexical-semantic matching task: tapping the links between object names and colors

Using a novel paradigm to engage the long-term mappings between object names and the prototypical colors for objects, we investigated the retrieval of object-color knowledge as indexed by long-term priming (the benefit in performance from a prior encounter with the same or a similar stimulus); a process about which little is known. We examined priming from object naming on a lexical-semantic matching task. In the matching task participants encountered a visually presented object name (Experiment 1) or object shape (Experiment 2) paired with either a color patch or color name. The pairings could either match whereby both were consistent with a familiar object (e.g., strawberry and red) or mismatch (strawberry and blue). We used the matching task to probe knowledge about familiar objects and their colors pre-activated during object naming. In particular, we examined whether the retrieval of object-color information was modality-specific and whether this influenced priming. Priming varied with the nature of the retrieval process: object-color priming arose for object names but not object shapes and beneficial effects of priming were observed for color patches whereas inhibitory priming arose with color names. These findings have implications for understanding how object knowledge is retrieved from memory and modified by learning.